Science.gov

Sample records for dewatering

  1. Dewatering of fine coal

    SciTech Connect

    Hogg, R.

    1995-10-01

    The factors which control the dewatering of fine coal by gravity/centrifugal drainage and by gas displacement (vacuum/hyperbaric filtration) are evaluated. A generalized model is presented and used to describe dewatering kinetics and to establish dewatering limits. Applications to the design of dewatering systems for fine coal dewatering are discussed.

  2. Flocculation and dewatering

    SciTech Connect

    Scheiner, B.J. ); Ince, D. )

    1990-05-01

    This article deals with flocculation and dewatering and the developments in this field during 1989. Particular attention is paid to fine coal and a discussion of the international viewpoint on this subject is given.

  3. Sludge dewatering technology

    SciTech Connect

    Weismantel, G.E.

    1993-04-01

    Sludge is an environmental dilemma for many industries, from the process and power industries to the paint and paper industries. Sludge problems exist in production pits and tank bottoms, in plating plants and sewage treatment plants. Flue gas desulfurization systems create enormous amounts of sludge. Dewatering sludge is a multi-billion dollar industry. Sludge dewatering is rarely a single-step process. It can involve several steps, ranging from sludge flocculation and thickening to centrifugation or hydrocycling, clarification, settling and filtering. Sludge dewatering requires an understanding of three major components: the feed stock, the dewatering technology, and the ultimate reuse or disposal of the final product. The characteristics of the feed are important because each dewatering technology reacts differently depending on whether the feed stream is dilute or thick, abrasive or corrosive, fibrous or gelatinous. In addition, factors such as the quantity of feed generated, whether the process is batch or continuous, and minimum and maximum production rates are critical to the choice of dewatering technology. Knowing how the final product will be reused or disposed of helps further narrow the options.

  4. Dewatering of fine coal

    SciTech Connect

    Sastry, K.V.S. . Dept. of Materials Science and Mineral Engineering)

    1991-01-01

    Fine coal dewatering is one of the most pressing problem facing the coal cleaning industry. This project was undertaken with the objective of improving the dewatering process with surface chemical activation by primarily understanding the fundamental and process engineering aspects of vacuum filtration. Specific tasks for this project included -- development of an experimental apparatus and procedure to yield highly reproducible results and extensive data from each test, detailed experimental investigation of the dewatering characteristics of coal fines with and without the addition of flocculants and surfactants, and under different operating conditions, and finally identification and establishment of the physical limits of mechanical dewatering. Following are the significant conclusions from the study: Fineness and size distribution of the coal fines have the most significant influence on the coal dewatering process; usage of flocculants and surfactants is almost essential in reducing the cake moisture and in increasing the filter throughputs; based on the experimental data and the literature information, the existence of an asymptotic limit for filter cake moisture correlatable with a capillary number of the filter cake was identified. 66 refs., 23 figs., 7 tabs.

  5. Dewatering blastholes cuts explosives costs

    SciTech Connect

    Pishaw, S.R.

    1987-11-01

    The author discusses ways to use ANFO inexpensively. They say there are several advantages of dewatering and that there are two primary methods of dewatering blastholes or blasting areas. One method is to use pumps and poly sleeving or liners. The other method is presplit dewatering. The author lists some guidelines for presplitting for information, consideration, and discussion. Often larger mining operations require a combination of presplitting and dewatering with blasthole pumps.

  6. Advanced Dewatering Systems Development

    SciTech Connect

    R.H. Yoon; G.H. Luttrell

    2008-07-31

    A new fine coal dewatering technology has been developed and tested in the present work. The work was funded by the Solid Fuels and Feedstocks Grand Challenge PRDA. The objective of this program was to 'develop innovative technical approaches to ensure a continued supply of environmentally sound solid fuels for existing and future combustion systems with minimal incremental fuel cost.' Specifically, this solicitation is aimed at developing technologies that can (i) improve the efficiency or economics of the recovery of carbon when beneficiating fine coal from both current production and existing coal slurry impoundments and (ii) assist in the greater utilization of coal fines by improving the handling characteristics of fine coal via dewatering and/or reconstitution. The results of the test work conducted during Phase I of the current project demonstrated that the new dewatering technologies can substantially reduce the moisture from fine coal, while the test work conducted during Phase II successfully demonstrated the commercial viability of this technology. It is believed that availability of such efficient and affordable dewatering technology is essential to meeting the DOE's objectives.

  7. Thermal dryer dewaters solids

    SciTech Connect

    DiMascio, F.J.; Burrowes, P.A.

    1993-09-01

    Solids incineration is traditionally an energy-intensive solids handling process at wastewater treatment plants. To reduce energy costs, the Buffalo (N.Y.) Sewer Authority has added an indirect thermal dryer to its treatment plant to dewater solids before incineration. In the first 3 months of operation, the authority reduced its solids inventory from 634,400 to 227,300 kg. Solids processed in the plant`s multiple-hearth incinerators varied from 11 to 12.75 wet Mg/hr at feed concentrations averaging 21% total solids. And, the dryer was operated with less than 5% downtime. The cost of this indirect thermal dryer system, including construction and equipment, was $995,000. 1 fig., 2 tabs.

  8. Dewatering Peat With Activated Carbon

    NASA Technical Reports Server (NTRS)

    Rohatgi, N. K.

    1984-01-01

    Proposed process produces enough gas and carbon to sustain itself. In proposed process peat slurry is dewatered to approximately 40 percent moisture content by mixing slurry with activated carbon and filtering with solid/liquid separation techniques.

  9. PILOT INVESTIGATION OF SECONDARY SLUDGE DEWATERING ALTERNATIVES

    EPA Science Inventory

    A pilot investigation of biological sludge thickening and dewatering alternatives, including pressure filtration, precoat vacuum filtration, filter belt pressing, capillary suction, dewatering, gravity filtration, centrifugation, and ultrafiltration has been conducted on waste ac...

  10. Quantification of wastewater sludge dewatering.

    PubMed

    Skinner, Samuel J; Studer, Lindsay J; Dixon, David R; Hillis, Peter; Rees, Catherine A; Wall, Rachael C; Cavalida, Raul G; Usher, Shane P; Stickland, Anthony D; Scales, Peter J

    2015-10-01

    Quantification and comparison of the dewatering characteristics of fifteen sewage sludges from a range of digestion scenarios are described. The method proposed uses laboratory dewatering measurements and integrity analysis of the extracted material properties. These properties were used as inputs into a model of filtration, the output of which provides the dewatering comparison. This method is shown to be necessary for quantification and comparison of dewaterability as the permeability and compressibility of the sludges varies by up to ten orders of magnitude in the range of solids concentration of interest to industry. This causes a high sensitivity of the dewaterability comparison to the starting concentration of laboratory tests, thus simple dewaterability comparison based on parameters such as the specific resistance to filtration is difficult. The new approach is demonstrated to be robust relative to traditional methods such as specific resistance to filtration analysis and has an in-built integrity check. Comparison of the quantified dewaterability of the fifteen sludges to the relative volatile solids content showed a very strong correlation in the volatile solids range from 40 to 80%. The data indicate that the volatile solids parameter is a strong indicator of the dewatering behaviour of sewage sludges. PMID:26003332

  11. Coal filtration process and dewatering aids therefore

    SciTech Connect

    Keys, R.O.

    1990-01-09

    This patent describes an improvement in a method for dewatering an aqueous slurry of solid coal particulates wherein the aqueous slurry contains between about 10 and 60 percent of solid coal particulates and a dewatering aid is added to the slurry followed by vacuum filtration thereof to produce a filter cake of the coal particulates. The improvement for lowering the water content of the filter cake comprises adding to the slurry prior to filtration an effective amount of a dewatering aid selected.

  12. Dewatering of fine coal using hyperbaric filter

    SciTech Connect

    Yang, J.; Wang, X.H.; Parekh, B.K.

    1995-12-31

    Removal of moisture from ultra-fine clean coal (minus 100 mesh) to below 20% level is difficult using conventional dewatering equipment. This paper describes a couple of dewatering approaches which were found to be effective in providing filter cakes containing less than 20% moisture. These approaches involve addition of metal ion-surfactant, and split size dewatering of coal without addition of any reagent.

  13. A review on sludge dewatering indices.

    PubMed

    To, Vu Hien Phuong; Nguyen, Tien Vinh; Vigneswaran, Saravanamuth; Ngo, Huu Hao

    2016-01-01

    Dewatering of sludge from sewage treatment plants is proving to be a significant challenge due to the large amounts of residual sludges generated annually. In recent years, research and development have focused on improving the dewatering process in order to reduce subsequent costs of sludge management and transport. To achieve this goal, it is necessary to establish reliable indices that reflect the efficiency of sludge dewatering. However, the evaluation of sludge dewaterability is not an easy task due to the highly complex nature of sewage sludge and variations in solid-liquid separation methods. Most traditional dewatering indices fail to predict the maximum cake solids content achievable during full-scale dewatering. This paper reviews the difficulties in assessing sludge dewatering performance, and the main techniques used to evaluate dewatering performance are compared and discussed in detail. Finally, the paper suggests a new dewatering index, namely the modified centrifugal index, which is demonstrated to be an appropriate indicator for estimating the final cake solids content as well as simulating the prototype dewatering process. PMID:27386978

  14. Dewatering studies of fine clean coal

    SciTech Connect

    Parekh, B.K.

    1991-01-01

    The main objective of the present research program is to study and understand dewatering characteristics of ultrafine clean coal obtained using the advanced column flotation technique from the Kerr-McGee's Galatia preparation plant fine coal waste stream. It is also the objective of the research program to utilize the basic study results, i.e., surface chemical, particle shape particle size distribution, etc., in developing a cost-effective dewatering method. The ultimate objective is to develop process criteria to obtain a dewatered clean coal product containing less that 20 percent moisture, using the conventional vacuum dewatering equipment. (VC)

  15. Dewatering and incinerating wastewater solids

    SciTech Connect

    Shamat, N.; Hart, J.

    1992-10-01

    The solids processing and incineration-energy recovery system at the Metropolitan Waste Control Commission (MWCC) wastewater treatment plant in St. Paul, Minn., is unique in the wastewater treatment field. The system consists of innovative processes including two types of solids dewatering devices-twin-roll filter presses and plate-and-frame diaphragm filter presses, and two new and four rehabilitated multiple-hearth incinerators. Four of the incinerators are equipped with energy recovery boilers, an economizer, heat wheels, and rotary solids dryers. The plant scum and the odorous gases generated from the thermal solids conditioning process are destroyed by combustion in the incinerators.

  16. Effects of dewatering on chinook salmon redds: tolerance of four developmental phases to daily dewaterings

    SciTech Connect

    Becker, C.D.; Neitzel, D.A.; Fickeisen, D.H.

    1982-09-01

    Four intergravel developmental phases of chinook salmon Oncorhynchus tshawytscha were dewatered experimentally in artificial redds. The redds consisted of aquaria containing a gravel mix and supplied with 4 liters of water per minute at 10 C. Cleavage eggs and embryos (the egg phases), and eleutheroembryos and pre-emergent alevins (the alevin phases) were dewatered 20 consecutive times in 22-day tests. The egg phases were considerably more tolerant than alevins. Some cleavage eggs were killed by 12- and 16-hour daily dewaterings, but embryos survived up to 22-hour daily dewaterings. Embryos also tolerated extended, multiple dewaterings (over 60% survival for four consecutive 118-hour periods) and one-time, continuous dewatering for up to 12 consecutive days (over 80% survival). In contrast, about half the eleutheroembryos were killed by 4-hour daily dewaterings, and nearly all pre-emergent alevins were killed by 1-hour daily dewaterings. Intergravel temperatures were affected by insolation and air temperature. Intergravel temperatures increased to lethal levels during dewatering of cleavage eggs in early fall, and limited their survival. Growth of egg phases from some females was retarded by dewatering, but this phenomenon was not consistent for all egg groups. The size of surviving eleutheroembryos decreased as the length of daily dewatering periods increased.

  17. DESIGN MANUAL: DEWATERING MUNICIPAL WASTEWATER SLUDGES

    EPA Science Inventory

    This manual discusses the many factors involved in selecting and designing dewatering equipment for organic sludges produced during primary and secondary municipal wastewater treatment. ive-step approach is outlined for the selection and design of the dewatering equipment for eit...

  18. Sewage sludge dewatering using flowing liquid metals

    DOEpatents

    Carlson, L.W.

    1985-08-30

    This invention relates generally to the dewatering of sludge, and more particularly to the dewatering of a sewage sludge having a moisture content of about 50 to 80% in the form of small cellular micro-organism bodies having internally confined water.

  19. SURFACE PHENOMENA IN THE DEWATERING OF COAL

    EPA Science Inventory

    The influence of certain surfactants on the dewatering of fine coal has been investigated. The surfactants investigated were found to have a two-fold effect. They were found to effect the pressure differentials required for dewatering in addition to the residual water contents of...

  20. Combined fields dewatering of seaweed (Nereocystis luetkeana)

    SciTech Connect

    Lightfoot, D.G.; Raghavan, G.S.V.

    1994-05-01

    Increasing pressures on our agricultural systems necessitate the investigation of alternative food and feed sources. The ocean coasts of the world provide one potential alternative, as they provide a habitat for millions of tonnes of brown marine algae, or kelp. In this study, a combined fields (mechanical pressure and electro-osmosis) dewatering technique was investigated for dewatering kelp. Electro-osmosis was shown to significantly improve conventional press dewatering of kelp. Dewatering kelp was found to significantly reduce its ash contents and available carbohydrates, and increase its protein, fat, and uronic acid contents. Furthermore, energy costs for producing dried kelp meal were found to be significantly lower if dewatering precedes thermal drying. 35 refs., 9 figs., 3 tabs.

  1. Dewatering of biomaterials by mechanical thermal expression

    SciTech Connect

    Clayton, S.A.; Scholes, O.N.; Hoadley, A.F.A.; Wheeler, R.A.; McIntosh, M.J.; Huynh, D.Q.

    2006-07-01

    Dewatering by mechanical thermal expression (MTE) for a range of materials is explored using a laboratory-scale MTE compression-permeability cell. It is shown that MTE can be used to effectively dewater a range of biomaterials including lignite, biosolids, and bagasse. The underlying dewatering mechanisms relevant to MTE, namely (1) filtration of water expelled due to thermal dewatering, (2) consolidation, and (3) flash evaporation, are discussed. At lower temperatures, the dominating dewatering mechanism is consolidation, but with increasing temperature, thermal dewatering becomes more important. A major focus is an investigation of the effects of processing parameters, including temperature (20 to 200{sup o}C) and pressure (1.5 to 24 MPa), on material permeability, a fundamental dewatering parameter. It is illustrated that permeability is particularly dependent on the processing temperature, owing to changes in both the material structure and the water properties. In addition, a comparison of permeability in the direction of applied force (axial) and perpendicular to the direction of applied force (radial) is presented. It is shown that, due to alignment of particles under the applied force, the permeability and, hence, rate of water removal in the radial direction is greater than in the axial direction. SEM micrographs are presented to illustrate the particle alignment.

  2. Salmonid redd dewatering: What do we know

    SciTech Connect

    Becker, C D; Neitzel, D A

    1983-11-01

    Dewatering of salmonid spawning areas causes abrupt changes in the intergravel environment that may lead to extensive losses of development phases while intergravel in redds. Information on tolerance to dewatering and the extent of physicochemical changes in the gravel during dewatering can be used to assess potential impacts and to design and implement effective mitigation methods. Studies with fall chinook salmon are summarized, and the comparisons are made with results from available literature. Potentially useful methods of mitigation are mentioned. We found that prehatch phases (cleavage eggs and embryos) can be dewatered for several successive days and survive, but posthatch phases (eleutheroembryos and alevins) usually die within 24 hours. Survival of prehatch phases during extended dewatering requires maintenance of favorable intergravel temperature and moisture levels. Elevated temperatures (up to 22/sup 0/C) can be tolerated for up to 8 hours without direct adverse effects, but freezing temperatures (/sup -/1.0/sup 0/C or below) are lethal. Dewatered gravels must remain sufficient moisture to provide near 100% humidity for egg and embryo survival. In field situations, physicochemical conditions that limit survival in dewatered gravels include residual flow, temperature, gravel size and composition, and dissolved oxygen. Biological variables such as alevin behavior and certain species characteristics also influence survival. 29 refs., 6 figs.

  3. Dewatering fine coal slurries by gel extraction

    SciTech Connect

    Gehrke, S.H.; Lyu, Lii-Hurng.

    1990-01-01

    A new technology called gel extraction has been evaluated to determine its economic viability in dewatering the fine and ultrafine coal slurries generated upon separation of sulfur and ash from clean coal during the physical coal cleaning process. Water must be removed from such slurries prior to transportation and combustion but the dewatering costs are substantial, especially for the fine particles below 28 mesh (0.6 mm). Gel extraction is a potential breakthrough in slurry dewatering technology. The goal of this project was to acquire the qualitative and quantitative data needed to estimate the potential of gel extraction for dewatering coal slurries. The specific objectives were to determine the maximum extents of dewatering (minimum surface moisture in the coal product), the clarity of the water removed (minimum solids content), the speed of the dewatering cycles, the service lifetime of the gels, and the factors which influence all of these. With the results obtained, an economic analysis of Ohio coal cleaning plant dewatering technologies was carried out. The polymer gel at the heart of this project, poly (N-isopropylacrylamide) (PNIPA), can swell several times its shrunken weight at 32[degrees]C by absorbing water at 25[degrees]C. In gel extraction, a shrunken NIPA gel is contacted with a slurry at ambient temperature or cooler; the gel swells by absorbing water from the slurry. The gel is then removed from the dewatered slurry and warmed above its critical temperature of 33[degrees]C, which returns it to the shrunken state by releasing the absorbed water. The facts that the gel is reusable and the process is simple and driven by low-grade energy (warm temperatures), and not inherently limited by particle size, made the process an attractive possible alternative to centrifugation, screening, filtration, etc. for slurry dewatering.

  4. Soil vapor extraction with dewatering

    SciTech Connect

    Thomson, N.R.

    1996-08-01

    The physical treatment technology of soil vapor extraction (SVE) is reliable, safe, robust, and able to remove significant amounts of mass at a relatively low cost. SVE combined with a pump-and-treat system to create a dewatered zone has the opportunity to remove more mass with the added cost of treating the extracted groundwater. Various limiting processes result in a significant reduction in the overall mass removal rates from a SVE system in porous media. Only pilot scale, limited duration SVE tests conducted in low permeability media have been reported in the literature. It is expected that the presence of a fracture network in low permeability media will add another complexity to the limiting conditions surrounding the SVE technology. 20 refs., 4 figs.

  5. Developments in coal dewatering in Australia

    SciTech Connect

    Osborne, D.G.; Davis, J.J.

    1995-10-01

    The Australian coal industry is characterized by efficient fines recovery, and the climate does not dictate the use of thermal drying. With the increasing trend to underground mining and hence finer ROM coal, and market pressures for reduced product moistures, dewatering issues are assuming increasing importance in the Australian coal industry. The greatest potential gains in dewatering performance undoubtedly lie in the treatment of finely sized material. This paper examines the dewatering issues which have been recognized by the Australian coal industry, and describes current Australian research in this field.

  6. SLUDGE DEWATERING AND DRYING ON SAND BEDS

    EPA Science Inventory

    Dewatering of water and wastewater treatment sludges was examined through mathematical modeling and experimental work. The various components of the research include: (1) chemical analyses of water treatment sludges, (2) drainage and drying studies of sludges, (3) a mathematical ...

  7. Solution dewatering with concomitant ion removal

    DOEpatents

    Peterson, Eric S.; Marshall, Douglas W.; Stone, Mark L.

    2003-08-05

    One of the biggest needs in the separations and waste handling and reduction area is a method for dewatering ion-containing solutions. Unexpectedly, it has been found that phosphazene polymers can discriminate between water and metal ions, allowing water to pass through the membrane while retaining the ions. This unexpected result, along with the inherent chemical and thermal stability of the phosphazene polymers, yields a powerful tool for separating and dewatering metal-ion-containing solutions.

  8. Dewatering in biological wastewater treatment: A review.

    PubMed

    Christensen, Morten Lykkegaard; Keiding, Kristian; Nielsen, Per Halkjær; Jørgensen, Mads Koustrup

    2015-10-01

    Biological wastewater treatment removes organic materials, nitrogen, and phosphorus from wastewater using microbial biomass (activated sludge, biofilm, granules) which is separated from the liquid in a clarifier or by a membrane. Part of this biomass (excess sludge) is transported to digesters for bioenergy production and then dewatered, it is dewatered directly, often by using belt filters or decanter centrifuges before further handling, or it is dewatered by sludge mineralization beds. Sludge is generally difficult to dewater, but great variations in dewaterability are observed for sludges from different wastewater treatment plants as a consequence of differences in plant design and physical-chemical factors. This review gives an overview of key parameters affecting sludge dewatering, i.e. filtration and consolidation. The best dewaterability is observed for activated sludge that contains strong, compact flocs without single cells and dissolved extracellular polymeric substances. Polyvalent ions such as calcium ions improve floc strength and dewaterability, whereas sodium ions (e.g. from road salt, sea water intrusion, and industry) reduce dewaterability because flocs disintegrate at high conductivity. Dewaterability dramatically decreases at high pH due to floc disintegration. Storage under anaerobic conditions lowers dewaterability. High shear levels destroy the flocs and reduce dewaterability. Thus, pumping and mixing should be gentle and in pipes without sharp bends. PMID:25959073

  9. Dewatering of contaminated river sediments

    NASA Technical Reports Server (NTRS)

    Church, Ronald H.; Smith, Carl W.; Scheiner, Bernard J.

    1994-01-01

    Dewatering of slurries has been successfully accomplished by the proper use of polymers in flocculating the fine particulate matter suspended in mineral processing streams. The U.S. Bureau of Mines (USBM) entered into a cooperative research effort with the U.S. Army Corps of Engineers (Corps) for the purpose of testing and demonstrating the applicability of mining flocculation technology to dredging activities associated with the removal of sediments from navigable waterways. The Corps has the responsibility for maintaining the navigable waterways in the United States. Current technology relies primarily on dredging operations which excavate the material from the bottom of waterways. The Corps is testing new dredging technology which may reduce resuspension of sediments by the dredging operation. Pilot plant dredging equipment was tested by the Corps which generated larger quantities of water when compared to conventional equipment, such as the clam shell. The transportation of this 'excess' water adds to the cost of sediment removal. The process developed by the USBM consists of feed material from the barge being pumped through a 4-in line by a centrifugal pump and exiting through a 4-in PVC delivery system. A 1,000-gal fiberglass tank was used to mix the polymer concentrate. The polymer was pumped through a 1-in line using a variable speed progressive cavity pump and introduced to the 4-in feed line prior to passing through a 6-in by 2-ft static mixer. The polymer/feed slurry travels to the clarifying tank where the flocculated material settled to the bottom and allowed 'clean' water to exit the overflow. A pilot scale flocculation unit was operated on-site at the Corps' 'Confined Disposal Facility' in Buffalo, NY.

  10. An innovative concept for dewatering hydro plants

    SciTech Connect

    Lux, F. III; Bakken, J.R. )

    1992-12-01

    A floating bulkhead that works much like an overhead garage door can be a versatile, reusable, and cost-effective tool for dewatering unit intakes or gated spillway bays at hydroelectric facilities. The floating bulkhead consists of a number of individual floating caissons that can be installed separately by stacking them one on top of another, or pinned together with hinges and installed as a unit. A caisson consists of one or more flotation compartments and a water-filled compartment to sink or float it. Each caisson is lowered into the reservoir from an accessible location, such as a boat launch, and towed into position by a boat. The floating bulkhead is especially suited to structures that have no provisions for dewatering or where the existing dewatering structures are no longer serviceable, or in situations where cranes are not available to install stoplogs.

  11. Behavioral responses of freshwater mussels to experimental dewatering

    USGS Publications Warehouse

    Galbraith, Heather S.; Blakeslee, Carrie J.; Lellis, William A.

    2015-01-01

    Understanding the effects of flow alteration on freshwater ecosystems is critical for predicting species responses and restoring appropriate flow regimes. We experimentally evaluated the effects of 3 dewatering rates on behavior of 6 freshwater mussel species in the context of water-removal rates observed in 21 Atlantic Coast rivers. Horizontal movement differed significantly among species and dewatering rates, but a significant species × dewatering interaction suggested that these factors influence movement in complex ways. Species differences in movement were evident only in controls and under slow dewatering rates, but these differences disappeared at moderate and fast dewatering rates. Burrowing behavior did not differ with respect to species identity or dewatering rate. The proportion of individuals that became stranded did not differ among species, but most individuals became stranded under low and moderate dewatering, and all individuals became stranded under fast dewatering. Mortality after stranding differed strongly among species along a gradient from 25% inPyganodon cataracta to 92% in Alasmidonta marginata. Together, these results suggest that species behavior may differ under gradual dewatering, but all species in our study are poorly adapted for rapid dewatering. Most of the 21 rivers we assessed experienced dewatering events comparable to our moderate rate, and several experienced events comparable to our fast rate. Dewatering events that exceed the movement or survival capability of most mussel species can be expected to result in assemblage-wide impacts. Consequently, the rate of water level change may be important in refining target flow conditions for restoration.

  12. CHEMICAL PRIMARY SLUDGE THICKENING AND DEWATERING

    EPA Science Inventory

    This report presents the results of a ten month study of the thickening and dewatering characteristics of chemical-primary sludges. Alum-primary and ferric-primary sludges were produced in parallel trains of a pilot plant operated using a municipal wastewater. Each chemical treat...

  13. Low Cost Dewatering of Waste Slurries

    NASA Technical Reports Server (NTRS)

    Peterson, J. B.; Sharma, S. K.; Church, R. H.; Scheiner, B. J.

    1993-01-01

    The U.S. Bureau of Mines has developed a technique for dewatering mineral waste slurries which utilizes polymer and a static screen. A variety of waste slurries from placer gold mines and crushed stone operations have been successfully treated using the system. Depending on the waste, a number of polymers have been used successfully with polymer costs ranging from $0.05 to $0.15 per 1,000 gal treated. The dewatering is accomplished using screens made from either ordinary window screen or wedge wire. The screens used are 8 ft wide and 8 ft long. The capacity of the screens varies from 3 to 7 gpm/sq. ft. The water produced is acceptable for recycling to the plant or for discharge to the environment. For example, a fine grain dolomite waste slurry produced from a crushed stone operation was dewatered from a nominal 2.5 pct solids to greater than 50 pct solids using $0.10 to $0.15 worth of polymer per 1,000 gal of slurry. The resulting waste water had a turbidity of less than 50 NTU and could be discharged or recycled. The paper describes field tests conducted using the polymer-screen dewatering system.

  14. Vibration screens for dewatering of minerals -- Theory and practice

    SciTech Connect

    Keller, K.; Stahl, W.

    1995-12-31

    Vibration screens are commonly used not only in classifying bulk material but also in dewatering it. The lack of a comprehensive physical theory of dewatering often leads to difficulties in the design and operation of the vibration screens. Firstly, the dewatering of bulk material will be shown, based on a physical model. Because of the oscillatory motion of the liquid in the bulk, the inertial force of the accelerated liquid and the dripping of water out of the bulk or screen must be taken into special consideration. The physical model put forward shows the effect of the various operations parameters of dewatering screens. The comparison between dewatering theory and practice will be shown by measurements using coal, limestone, etc. Dewatering measurements, which have been conducted on a vibration screen, demonstrate that different vibration frequencies and rates of acceleration lead to different residual moistures. Finally, the possibilities of improving vibration dewatering will be described.

  15. SRB dewatering set. [space shuttle boosters revcovery

    NASA Technical Reports Server (NTRS)

    Wickham, R. E.

    1981-01-01

    The system components and operation of the space shuttle solid rocket booster (SRB) dewatering set are described. The SRB dewatering set consists of a nozzle plug, control console, remote control unit, power distribution unit, umbilical cable, interconnect cables, and various handling and storage items. The nozzle plug (NP) is a remotely controlled, tethered underwater vehicle that is launched from the retrieval vessel (RV) by a crane, descends down the side of the SRB, and is positioned below the SRB nozzle. A TV camera mounted at the top of the NP central core is used by the control console operator to visually guide the NP during descent and docking. The NP is then driven up and locked into the nozzle. Compressed air is passed through the umbilical from the RV, through the NP and into the SRB motor. The water inside the SRB is expelled causing the SRB to rotate to a near horizontal attitude on the surface of the water.

  16. Dewatering studies of fine clean coal

    SciTech Connect

    Parekh, B.K.

    1991-01-01

    Physical cleaning of ultra-fine coal using an advanced froth flotation technique provides a low ash product, however, the amount of water associated with clean coal is high. Economic removal of water from the froth will be important for commercial applicability of advanced froth flotation processes. The main objective of the present research program is to study and understand the dewatering characteristics of ultra-fine clean coal and to develop the process parameters to effectively reduce the moisture to less than 20 percent in the clean coal product. The research approach under investigation utilizes synergistic effects of metal ions and surfactant to lower the moisture of clean coal using a conventional vacuum dewatering technique. During the last year's effort, it was reported that a combination of metal ion and surfactant provided a 22 percent moisture filter cake.

  17. Space Shuttle solid rocket booster dewatering system

    NASA Technical Reports Server (NTRS)

    Fishel, K. R.

    1982-01-01

    After the launch of the Space Shuttle, the two solid rocket boosters (SRB's) are jettisoned into the ocean where they float in a spar (vertical) mode. It is cost effective to recover the SRB's. A remote controlled submersible vehicle has been developed to aid in their recovery. The vehicle is launched from a support ship, maneuvered to the SRB, then taken to depth and guided into the rocket nozzle. It then dewaters the SRB, using compressed air from the ship, and seals the nozzle. When dewatered, the SRB floats in a log (horizontal) mode and can be towed to port for reuse. The design of the remote controlled vehicle and its propulsion system is presented.

  18. Application of amphoteric polyelectrolytes for sludge dewatering

    SciTech Connect

    Watanabe, Y.; Kubo, K.; Sato, S.

    1999-06-08

    Conventional sludge conditioning with polymer flocculants usually involves the addition of either a cationic polymer or a combination of a cationic and an anionic polymer. On the other hand, a combination of a metal coagulant and an amphoteric polymer was found to produce large, mechanically strong flocs. On the basis of this observation and by use of the colloid titration method the efficiency of the sludge charge neutralization with a metal coagulant and the amount of polymer adhered to the sludge particle surfaces were measured to elucidate the mechanism of the amphoteric polymer attachment. This study indicated that amphoteric polymers were roughly divided into two main types by the cation-anion ratio of the polymer according to the efficiency of the charge neutralization. Furthermore, field survey results have demonstrated that a new system gave a two times higher dewatering rate, producing a dewatered sludge cake having a moisture content 2--5% lower than those obtained conventional methods.

  19. Dewatering refuse brings profits to Dorchester Coal

    SciTech Connect

    Morgan, M.; Erickson, L.

    1984-09-01

    A belt filter press is discussed which allowed Dorchester Coal's 150 tph preparation plant to meet certain objectives. The minus 28 mesh refuse had to be dewatered further for trucking and spreading in a landfill because it did not conform to regulatory requirements. The press allowed the plant to operate with a closed water circuit, brought the landfill into compliance, and reduced refuse handling problems. Moreover, the belt press system reduced refuse disposal costs.

  20. Electroacoustic dewatering of food and other suspensions

    SciTech Connect

    Kim, B.C.; Zelinski, M.S.; Criner, C.L.; Senapati, N.; Muralidhara, H.S.; Jirjis, B.; Beard, R.E.; Cummings, C.; Chauhan, S.P.

    1989-05-31

    The food processing industry is a large user of energy for evaporative drying due to limited effectiveness of conventional mechanical dewatering machines. Battelle's Electroacoustic Dewatering (EAD) process improves the performance of mechanical dewatering machines by superimposing electric and ultrasonic fields. A two phase development program to demonstrate the benefits of EAD was carried out in cooperation with the food processing industry, the National Food Processors Association (NFPA) and two equipment vendors. In Phase I, laboratory scale studies were carried out on a variety of food suspensions. The process was scaled up to small commercial scale in Phase II. The technical feasibility of EAD for a variety of food materials, without adversely affecting the food properties, was successfully demonstrated during this phase, which is the subject of this report. Two Process Research Units (PRUs) were designed and built through joint efforts between Battelle and two equipment vendors. A 0.5-meter wide belt press was tested on apple mash, corn fiber, and corn gluten at sites provided by two food processors. A high speed citrus juice finisher (a hybrid form of screw press and centrifuge) was tested on orange pulp. These tests were carried out jointly by Battelle, equipment vendors, NFPA, and food processors. The apple and citrus juice products were analyzed by food processors and NFPA. 26 figs., 30 tabs.

  1. Dredging and dewatering sediment containing hazardous and toxic materials

    SciTech Connect

    Askin, R.C.

    1996-12-31

    Dredging is a common method of remediating ponds containing contaminated wastes. However, dewatering of the dredged solids is usually not well integrated with the dredging phase. As a result, overall project efficiency can be poor. Specifically, since dredges deliver material in a widely varying slurry form and since dewatering presses require the delivered material to be uniform, union of the two systems often results in inconsistent operation of the overall process. In an effort to enhance overall dredging and dewatering process production rates as well as minimize the return of suspended solids in the decant water, a new process was developed to provide a consistent dredged sludge for delivery to the press. This paper discusses modifications made to a conventional dredging and dewatering process to improve production rates and dewatering capabilities. These modifications are applicable to any project where efficient solids dewatering is required and where returning decant water must be visually free of suspended solids. 4 figs.

  2. Improved FGD dewatering process cuts solid wastes

    SciTech Connect

    Moer, C.; Fernandez, J.; Carraro, B.

    2009-08-15

    In 2007, Duke Energy's W.H. Zimmer Station set out to advance the overall performance of its flue gas desulfurization (FGD) dewatering process. The plant implemented a variety of measures, including upgrading water-solids separation, improving polymer program effectiveness and reliability, optimizing treatment costs, reducing solid waste sent to the landfill, decreasing labor requirements, and maintaining septic-free conditions in clarifiers. The changes succeeded in greatly reducing solid waste generation and achieving total annual savings of over half a million dollars per year. 8 figs., 1 tab.

  3. The utilization of forward osmosis for coal tailings dewatering

    EPA Science Inventory

    The feasibility of dewatering coal tailings slurry by forward osmosis (FO) membrane process was investigated in this research. A prototype cell was designed and used for the dewatering tests. A cellulosic FO membrane (Hydration Technology Innovations, LLC, Albany, OR) was used fo...

  4. Ultrafine coal single stage dewatering and briquetting process

    SciTech Connect

    Wilson, J.W.; Honaker, R.Q.

    1995-12-31

    It is well known that a large portion of the pyrite particles in the coal seams of the Illinois Basin are finely disseminated within the coal matrix. In order to liberate these micron size pyrite particles, one must use a fine grinding operation. The ultrafine coal particles are difficult to dewater and create problems in coal transportation, as well as in storage and handling at utility plants. The objective of this research project is to combine the ultrafine coal dewatering and briquetting processes into a single stage operation. This will be accomplished by the use of bitumen based emulsions for dewatering and a compaction device for briquetting. During this reporting period, several types of coal samples with various particle size distributions have been tested for use in the dewatering and briquetting processes. Furthermore, various bitumen emulsions have been tested to determine the optimum dewatering reagent. These dewatering and pelletizing tests were carried out using a lab-scale ram extruder. Discharge from the dewatering and briquetting processes was tested to determine compliance with current federal and state requirements. The influence of bitumen emulsion on the sulfur content of coal pellets made were also examined. In addition, a ram extruder which can be operated continuously to simulate a rotary press operation, has been built and is currently being tested for use in the fine coal dewatering and pelletizing process.

  5. Predicting the moisture content of coals dewatered by vacuum filters

    SciTech Connect

    Arnold, B.J.

    1995-12-31

    Coal cleaning separations, both size- and gravity-based, rely on the use of water to make the process more efficient. Removal of water from the clean coal product reduces transportation costs, handling problems, and coal utilization problems. Coal cleaning refuse is also dewatered prior to disposal. The coal industry uses a wide range of equipment to dewater coal and refuse streams in cleaning plants, including thickeners, screens, filters, centrifuges, and thermal dryers. Aspen Technology Inc. developed the Coal Cleaning Simulator (CCS) running under ASPEN PLUS{trademark}. Simulator models for coal sizing, cleaning, and dewatering devices were developed by ICF Kaiser Engineers and CQ Inc., with assistance from The Pennsylvania State University. CQ Inc. and Penn State collaborated on the dewatering models. The CCS dewatering models predict the remaining free (surface) moisture of the cake, moisture which is potentially removal by mechanical means. By definition, the free moisture is the difference between total and equilibrium moisture. The equilibrium moisture is considered non-removable. One of the simpler dewatering models in the CCS is the vacuum-disk filter model. This paper highlights the calculation for moisture content in the product from this dewatering device.

  6. Dewatering fine coal slurries by gel extraction. Final report

    SciTech Connect

    Gehrke, S.H.; Lyu, Lii-Hurng

    1990-12-31

    A new technology called gel extraction has been evaluated to determine its economic viability in dewatering the fine and ultrafine coal slurries generated upon separation of sulfur and ash from clean coal during the physical coal cleaning process. Water must be removed from such slurries prior to transportation and combustion but the dewatering costs are substantial, especially for the fine particles below 28 mesh (0.6 mm). Gel extraction is a potential breakthrough in slurry dewatering technology. The goal of this project was to acquire the qualitative and quantitative data needed to estimate the potential of gel extraction for dewatering coal slurries. The specific objectives were to determine the maximum extents of dewatering (minimum surface moisture in the coal product), the clarity of the water removed (minimum solids content), the speed of the dewatering cycles, the service lifetime of the gels, and the factors which influence all of these. With the results obtained, an economic analysis of Ohio coal cleaning plant dewatering technologies was carried out. The polymer gel at the heart of this project, poly (N-isopropylacrylamide) (PNIPA), can swell several times its shrunken weight at 32{degrees}C by absorbing water at 25{degrees}C. In gel extraction, a shrunken NIPA gel is contacted with a slurry at ambient temperature or cooler; the gel swells by absorbing water from the slurry. The gel is then removed from the dewatered slurry and warmed above its critical temperature of 33{degrees}C, which returns it to the shrunken state by releasing the absorbed water. The facts that the gel is reusable and the process is simple and driven by low-grade energy (warm temperatures), and not inherently limited by particle size, made the process an attractive possible alternative to centrifugation, screening, filtration, etc. for slurry dewatering.

  7. Disposable sludge dewatering container and method

    DOEpatents

    Cole, Clifford M.

    1993-01-01

    A device and method for preparing sludge for disposal comprising a box with a thin layer of gravel on the bottom and a thin layer of sand on the gravel layer, an array of perforated piping deployed throughout the gravel layer, and a sump in the gravel layer below the perforated piping array. Standpipes connect the array and sump to an external ion exchanger/fine particulate filter and a pump. Sludge is deposited on the sand layer and dewatered using a pump connected to the piping array, topping up with more sludge as the aqueous component of the sludge is extracted. When the box is full and the free standing water content of the sludge is acceptable, the standpipes are cut and sealed and the lid secured to the box.

  8. 29. VIEW NORTHWEST ON SHELTON SIDE OF DAM DURING DEWATERING. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. VIEW NORTHWEST ON SHELTON SIDE OF DAM DURING DEWATERING. SHELTON GATEHOUSE IN LEFT CENTER. - Ousatonic Water Power Company, Dam & Canals, CT Routes 34 & 108, 1 mile North of Derby-Shelton Bridge, Derby, New Haven County, CT

  9. Pressure, centrifugal, and electrically assisted dewatering of coal

    SciTech Connect

    Bainbridge, N.W.; Johnston, B.K.; Lockhart, N.C.

    1995-10-01

    CSIRO and its collaborators have developed a major R and D project on dewatering of coal. This involves sub-projects on (1) the fundamentals of coal-water associations; (2) reducing the variability of product moisture levels from small coal centrifuges; (3) process mechanisms and optimization for fine coal dewatering; (4) pilot scale testing, engineering development and innovation. Results from each of these sub-projects are presented, and the pilot facility incorporating a vacuum filter, belt press, membrane press, hyperbaric filters and centrifuges, is discussed. The vacuum filter and membrane press can be configured for electric-field assisted dewatering, which provides substantial enhancements in the rate and degree of dewatering for fine coal, coal tailings, and other suspensions.

  10. 3. View southwest at dewatered culvert outlet headwall, with part ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. View southwest at dewatered culvert outlet headwall, with part of canal bank removed in back (left) of headwall. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

  11. Ultrafine coal single stage dewatering and briquetting process

    SciTech Connect

    Wilson, J.W.; Ding, Y.; Tobey, M.

    1995-12-31

    The primary goal of the current physical coal cleaning process is to reduce the ash and sulfur content from the coal, that is, to remove the mineral particles from the coal. In order to separate mineral from coal particles efficiently, the finely disseminated mineral matter must be liberated from the coal matrix with the help of an ultrafine grinding operation. The coal becomes very difficult to dewater because of the small particle size produced. Difficulty in coal transportation as well as in its storage and handling at the utility plants are also problems associated with the small coal particles resulting from ultrafine grinding. During this project, several types of coal samples with various particle size distributions have been tested for use in the dewatering and briquetting processes. Furthermore, various bitumen emulsions have been tested to determine the optimum dewatering reagent. These dewatering and pelletizing tests were carried out using a lab-scale hydraulic compacting device. Discharge from the dewatering and briquetting processes was tested to determine compliance with current federal and state requirements. The influence of bitumen emulsion on the sulfur content of coal pellets made were also examined. In addition, a ram extruder which can be operated continuously to simulate a rotary press operation, has been built and is currently being tested for use in the fine coal dewatering and pelletizing process.

  12. Filtration and dewatering: review of literature. [117 references

    SciTech Connect

    Gala, H. B.; Chiang, S. H.

    1980-09-01

    Filtration and dewatering are important aspects of any chemical process involved in producing solid product from a slurry. However, these operations are not studied in as much detail as other industrial operations like distillation, absorption, etc. In the past, the design of filtration equipment was considered more of an art than science. Only in the last few years have attempts been made to understand the fundamental mechanism underlying these operations. In this review, the present status of filtration and dewatering is discussed, particularly concerning the models used for predicting the rate of filtration and dewatering. Effects of various parameters, size of particles in the slurry, their shape and method of cake formation, etc., on the characteristics of these operations are analyzed. A separate chapter on the use of these processes in coal cleaning is included. Dewatering of fine coal and refuse has attracted a great deal of attention in recent years. Special problems associated with dewatering of fine coal are discussed. Enhanced methods of dewatering are reviewed and finally areas requiring further research are highlighted.

  13. Dewatering of fibre suspensions by pressure filtration

    NASA Astrophysics Data System (ADS)

    Hewitt, Duncan R.; Paterson, Daniel T.; Balmforth, Neil J.; Martinez, D. Mark

    2016-06-01

    A theoretical and experimental study of dewatering of fibre suspensions by uniaxial compression is presented. Solutions of a one-dimensional model are discussed and asymptotic limits of fast and slow compression are explored. Particular focus is given to relatively rapid compression and to the corresponding development of spatial variations in the solidity and velocity profiles of the suspension. The results of complementary laboratory experiments are presented for nylon or cellulose fibres suspended in viscous fluid. The constitutive relationships for each suspension were measured independently. Measurements of the load for different fixed compression speeds, together with some direct measurements of the velocity profiles using particle tracking velocimetry, are compared with model predictions. The comparison is reasonable for nylon, but poor for cellulose fibres. An extension to the model, which allows for a strain-rate-dependent component in the network stress, is proposed, and is found to give a dramatic improvement in the model predictions for cellulose fibre suspensions. The reason for this improvement is attributed to the microstructure of cellulose fibres, which, unlike nylon fibres, are themselves porous.

  14. DEVELOPMENT OF DEWATERING AIDS FOR MINERALS AND COAL FINES

    SciTech Connect

    Roe-Hoam Yoon; Ramazan Asmatulu; Ismail Yildirim; William Jansen; Jinmig Zhang; Brad Atkinson; Jeff Havens

    2004-07-01

    MCT has developed a suite of novel dewatering chemicals (or aids) that are designed to cause a decrease in the capillary pressures of the water trapped in a filter cake by (1) decreasing the surface tension of water, (2) increasing the contact angles of the particles to be dewatered, and (3) causing the particles to coagulate, all at the same time. The decrease in capillary pressure in turn causes an increase in the rate filtration, an increase in throughput, and a decrease in pressure drop requirement for filtration. The reagents are used frequently as blends of different chemicals in order to bring about the changes in all of the process variables noted above. The minerals and coal samples tested in the present work included copper sulfide, lead sulfide, zinc sulfide, kaolin clay, talc, and silica. The laboratory-scale test work included studies of reagent types, drying cycle times, cake thickness, slurry temperature, conditioning intensity and time, solid content, and reagent dosages. To better understand the mechanisms involved, fundamental studies were also conducted. These included the measurements of the contact angles of the particles to be dewatered (which are the measures of particle hydrophobicity) and the surface tensions of the filtrates produced from dewatering tests. The results of the laboratory-scale filtration experiments showed that the use of the novel dewatering aids can reduce the moistures of the filter cake by 30 to 50% over what can be achieved using no dewatering aids. In many cases, such high levels of moisture reductions are sufficient to obviate the needs for thermal drying, which is costly and energy intensive. Furthermore, the use of the novel dewatering aids cause a substantial increase in the kinetics of dewatering, which in turn results in increased throughput. As a result of these technological advantages, the novel dewatering aids have been licensed to Nalco, which is one of the largest mining chemicals companies of the world. At

  15. Research and development needs in filtration and dewatering

    SciTech Connect

    Lockhart, N.C.; Kern, R.

    1996-10-01

    The first part of this paper deals with technology issues. These are categorized as (1) fundamental aspects, specifically suspension characteristics and dewatering mechanisms, along with process modelling and control; (2) pre-treatment procedures, both physical and chemical, that optimize the dewatering characteristics; (3) types of dewatering devices based on centrifuges, vacuum and pressure filters with particular reference to various combined field approaches using two or more complementary driving forces to achieve better performance. The second part of the paper (attributed principally to the first-named author) deals with related R and D issues, namely economic assessments and justification for particular R and D strategies, including benchmarking and operational factors that apply in industrial environments. Dewatering operations and R and D needs are also analyzed from the perspective of matching and integration into overall process flowsheets, and in the context of alternative processing or utilization strategies which avoid the dewatering step. The analysis concludes with a discussion on effective identification and utilization of existing knowledge, and the R and D management process. Although the paper draws heavily on experiences relating to the coal industry, much of the material is relevant to fine suspensions in general.

  16. Application of electro acoustics for dewatering pharmaceutical sludge

    SciTech Connect

    Golla, P.S.; Johnson, H.W. ) Senthilnathan, P.R. )

    1992-02-01

    Application of electro acoustic principles for dewatering has been developed by Battelle Institute. The Department of Energy, Battelle Institute, and Ashbrook-Simon-Hartley, have jointly developed an Electro Acoustic Dewatering press (EAD press). The EAD press applies a combination of mechanical pressure, electrical current and ultrasonics. This press is utilized after conventional dewatering devices and can remove up to 50% water from filtered sludge cake at a fraction of the cost incurred in existing thermal drying devices. The dominant mechanism of sludge dewatering by EAD press is electro-osmosis due to the application of a direct current field. Electro-osmosis is caused by an electrical double layer of oppositely charged ions formed at the solid liquid interface, which is characterized by zeta potential. The ultrasonic fields help electro-osmosis by consolidation of the filter cake and by release of inaccessible liquid. The EAD press has been tested successfully on a variety of materials including apple pomace, corn gluten, sewage sludge, and coal fines. A three week long full scale trial was conducted successfully at a pharmaceutical industry to determine the application of this technology for dewatering waste activated sludge.

  17. Heat inactivation of enteric viruses in dewatered wastewater sludge.

    PubMed

    Ward, R L; Ashley, C S

    1978-12-01

    The effect of moisture content on the rates of heat inactivation of enteric viruses in wastewater sludge was determined. The protective effect of raw sludge on poliovirus previously observed (R. L. Ward, C. S. Ashley, and R. H. Moseley, Appl. Environ. Microbiol. 32:339--346, 1976) was found to be greatly enhanced in sludge dewatered by evaporation. Other enteroviruses responded in a similar fashion. This effect did not appear to be due merely to the state of dryness of the sludge samples because in humus-deficient soil, a relatively inert material, the rate of poliovirus inactivation by heat was not significantly altered through dewatering. Instead, this effect appeared to have been caused by protective substances in the sludge, such as detergents, which are concentrated through dewatering. As reported previously (R. L. Ward and C. S. Ashley, Appl. Environ. Microbiol. 34:681-688, 1977; R. L. Ward and C. S. Ashley, Appl. Environ. Microbiol 36:889--897, 1978) raw sludge is not protective of reovirus, but, instead, the ionic detergents in sludge cause the rate of heat inactivation of this virus to be accelerated. Dewatering of sludge, however, was found to partially reverse this virucidal effect. Evidence is presented indicating that this reversal is caused by an unidentified protective substance in sludge also concentrated through dewatering. Finally, it was shown that the effects of raw sludge on heat inactivation of poliovirus and reovirus are greatly reduced by composting, a result that correlated with the degradation of detergents. PMID:216309

  18. Closed-loop operation with alternative dewatering technology

    SciTech Connect

    Halliday, W.S.; Bray, R.P.; Youens, J.W.

    1993-03-01

    The introduction of dewatering devices for closed-loop drilling-fluid circulating systems and reserve pits is derived from technology that has been used in the industrial- and sanitary-waste treatment industries for years. This paper describes an overview of the need for closed-loop systems and provides the optimum design layout, including the fit of a dewatering device, for a drilling location. The introduction of a nonconventional dewatering device, called a screw press/thickener, is reviewed. A case history describing use of this technology in a southern Louisiana inland-marsh-area well is analyzed for the technical and economic viability of operating in a closed-loop mode. Results from this effort include a viable alternative to hauling off waste fluids from drilling sites and the realization that use of this technology can be justified economically.

  19. Dewatering of coalbed methane wells with hydraulic gas pump

    SciTech Connect

    Amani, M.; Juvkam-Wold, H.C.

    1995-12-31

    The coalbed methane industry has become an important source of natural gas production. Proper dewatering of coalbed methane (CBM) wells is the key to efficient gas production from these reservoirs. This paper presents the Hydraulic Gas Pump as a new alternative dewatering system for CBM wells. The Hydraulic Gas Pump (HGP) concept offers several operational advantages for CBM wells. Gas interference does not affect its operation. It resists solids damage by eliminating the lift mechanism and reducing the number of moving parts. The HGP has a flexible production rate and is suitable for all production phases of CBM wells. It can also be designed as a wireline retrievable system. We conclude that the Hydraulic Gas Pump is a suitable dewatering system for coalbed methane wells.

  20. Electrode kinetic and electro-kinetic effects in electroosmotic dewatering of clay suspensions

    SciTech Connect

    Vijh, A.K.

    1997-05-01

    Lockhart`s remarks on the author`s previous interpretation of the electrochemical aspects of the electroosmotic dewatering (EOD) of clay suspensions are analyzed to provide some further clarification. Based on Lockhart`s excellent work, the authors put forward here novel electrochemical interpretations of some features of the following experimental observations: (1) Galvani dewatering; (2) the dewatering efficiency; and (3) high voltage needed for dewatering Al-kaolinite and aluminum electrode effect.

  1. Sludge dewatering: Sewage treatment. (Latest citations from the COMPENDEX database). Published Search

    SciTech Connect

    Not Available

    1993-05-01

    The bibliography contains citations concerning dewatering techniques and equipment for sewage treatment. Sewage sludge dewatering design, development, and evaluation are discussed. Essential types of dewatering equipment such as centrifuges, filters, presses, and drums are considered. (Contains 250 citations and includes a subject term index and title list.)

  2. Sludge dewatering: Sewage treatment. (Latest citations from the EI Compendex*plus database). Published Search

    SciTech Connect

    1996-01-01

    The bibliography contains citations concerning dewatering techniques and equipment for sewage treatment. Sewage sludge dewatering design, development, and evaluation are discussed. Essential types of dewatering equipment such as centrifuges, filters, presses, and drums are considered. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  3. 28. VIEW NORTH TOWARD DERBY DURING DEWATERING. DAM IN CENTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. VIEW NORTH TOWARD DERBY DURING DEWATERING. DAM IN CENTER OF PICTURE WITH SHELTON GATEHOUSE ON LEFT AND DERBY GATEHOUSE ON RIGHT. - Ousatonic Water Power Company, Dam & Canals, CT Routes 34 & 108, 1 mile North of Derby-Shelton Bridge, Derby, New Haven County, CT

  4. 1. VIEW LOOKING NORTH FROM DEWATERED CANAL; HEADGATES AND INTAKE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. VIEW LOOKING NORTH FROM DEWATERED CANAL; HEADGATES AND INTAKE CHANNEL AT LEFT; GUARDLOCK AT CENTER; SHEET PILING THROUGH SITE OF TOWPATH AT RIGHT - Dundee Canal, Headgates, Guardlock & Uppermost Section, 250 feet northeast of Randolph Avenue, opposite & in line with East Clifton Avenue, Clifton, Passaic County, NJ

  5. A parametric study of dewatering of fine coal

    SciTech Connect

    Sung, D.J.; Lee, K.J.; Parekh, B.K.

    1996-12-31

    A statistical design of parametric study of pressure filtration for fine coal dewatering is presented. The effects of five major process parameters of the dewatering, i.e. applied pressure, filtration time, cake thickness, solids concentration and slurry pH, on cake moisture reduction and air consumption were investigated. The study was conducted starting with two level factorial experiments to identify the most significant parameters in the filtration process, and concluding with response surface methodologies to establish an optimum operating condition for the dewatering of fine coal with these significant variables. An operating process condition for the dewatering that provided satisfactory performance was determined to be an applied pressure of 93 psi with a cake thickness of 2.5 cm and a filtration time of 4.8 minutes for this specific laboratory filtration system. At the optimum process condition the filter cake containing about 22 percent moisture by weight was obtained and the air was consumed by 4.1 m{sup 3}/(m{sup 2} min.kg). 6 refs., 4 figs., 2 tabs.

  6. 4. View northwest at the southeast facade of the dewatered ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. View northwest at the southeast facade of the dewatered culvert inlet headwall. Part of canal bank has been removed above the headwall. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

  7. 30. VIEW SOUTHEAST ON SHELTON SIDE OF DAM DURING DEWATERING. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. VIEW SOUTHEAST ON SHELTON SIDE OF DAM DURING DEWATERING. CORNER OF SHELTON LOCKS AND MITRE GATES AT RIGHT. - Ousatonic Water Power Company, Dam & Canals, CT Routes 34 & 108, 1 mile North of Derby-Shelton Bridge, Derby, New Haven County, CT

  8. 1. View southeast at northwest facade of dewatered culvert outlet ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. View southeast at northwest facade of dewatered culvert outlet headwall, above which part of the canal bank has been removed. Buttresses and upper portion of headwall (above arches) are nineteenth-century additions to the lower, original headwall. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

  9. 15. VIEW NORTHNORTHEAST OF TOW TANK No. 2, DEWATERED. ENCLOSED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW NORTH-NORTHEAST OF TOW TANK No. 2, DEWATERED. ENCLOSED AREAS AT BACK OF TUNNEL IS A HOUSING FOR CONDUCTING PERFORMANCE TESTING ON AIRCRAFT MODELS IN A VORTEX. - NASA Langley Research Center, Seaplane Towing Channel, 108 Andrews Street, Hampton, Hampton, VA

  10. Development of an Advanced Fine Coal Suspension Dewatering Process

    SciTech Connect

    B. K. Parekh; D. P. Patil

    2008-04-30

    With the advancement in fine coal cleaning technology, recovery of fine coal (minus 28 mesh) has become an attractive route for the U.S. coal industry. The clean coal recovered using the advanced flotation technology i.e. column flotation, contains on average 20% solids and 80% water, with an average particle size of 35 microns. Fine coal slurry is usually dewatered using a vacuum dewatering technique, providing a material with about 25 to 30 percent moisture. The process developed in this project will improve dewatering of fine (0.6mm) coal slurry to less than 20 percent moisture. Thus, thermal drying of dewatered wet coal will be eliminated. This will provide significant energy savings for the coal industry along with some environmental benefits. A 1% increase in recovery of coal and producing a filter cake material of less than 20 % moisture will amount to energy savings of 1900 trillion Btu/yr/unit. In terms of the amount of coal it will be about 0.8% of the total coal being used in the USA for electric power generation. It is difficult to dewater the fine clean coal slurry to about 20% moisture level using the conventional dewatering techniques. The finer the particle, the larger the surface area and thus, it retains large amounts of moisture on the surface. The coal industry has shown some reluctance in using the advanced coal recovery techniques, because of unavailability of an economical dewatering technique which can provide a product containing less than 20% moisture. The U.S.DOE and Industry has identified the dewatering of coal fines as a high priority problem. The goal of the proposed program is to develop and evaluate a novel two stage dewatering process developed at the University of Kentucky, which involves utilization of two forces, namely, vacuum and pressure for dewatering of fine coal slurries. It has been observed that a fine coal filter cake formed under vacuum has a porous structure with water trapped in the capillaries. When this porous cake

  11. Impact of dewatering technologies on specific methanogenic activity.

    PubMed

    Batstone, Damien J; Lu, Yang; Jensen, Paul D

    2015-10-01

    Dewatering methods for recuperative thickening and final dewatering can potentially impact methanogenic activity and microbial community. This influences both the feasibility of recuperative thickening to increase solids residence time within a digester, and the utilisation of dewatered digestate as inoculum for new digesters. Thickening technology can reduce methanogenic activity through either air contact (rotary drum, DAF, or belt filter press), or by lysing cells through shear (centrifuge). To assess this, two plants with recuperative thickening (rotary drum) in their anaerobic digester, and five without recuperative thickening, had specific methanogenic activity tested in all related streams, including dewatering feed, thickened return, final cake, and centrate. All plants had high speed centrifuges for final dewatering. The digester microbial community was also assessed through 16s pyrotag sequencing and subsequent principal component analysis (PCA). The specific methanogenic activity of all samples was in the expected range of 0.2-0.4 gCOD gVS(-1)d(-1). Plants with recuperative thickening did not have lower digester activity. Centrifuge based dewatering had a significant and variable impact on methanogenic activity in all samples, ranging between 20% and 90% decrease but averaging 54%. Rotary drum based recuperative thickening had a far smaller impact on activity, with a 0% per-pass drop in activity in one plant, and a 20% drop in another. However, the presence of recuperative thickening was a major predictor of overall microbial community (PC1, p = 0.0024). Microbial community PC3 (mainly driven by a shift in methanogens) was a strong predictor for sensitivity in activity to shear (p = 0.0005, p = 0.00001 without outlier). The one outlier was related to a plant producing the wettest cake (17% solids). This indicates that high solids is a potential driver of sensitivity to shear, but that a resilient microbial community can also bestow resilience

  12. Evaluation of Dewatering Performance and Fractal Characteristics of Alum Sludge

    PubMed Central

    Sun, Yongjun; Fan, Wei; Zheng, Huaili; Zhang, Yuxin; Li, Fengting; Chen, Wei

    2015-01-01

    The dewatering performance and fractal characteristics of alum sludge from a drinking-water treatment plant were investigated in this study. Variations in residual turbidity of supernatant, dry solid content (DS), specific resistance to filtration (SRF), floc size, fractal dimension, and zeta potential were analyzed. Sludge dewatering efficiency was evaluated by measuring both DS and SRF. Results showed that the optimum sludge dewatering efficiency was achieved at 16 mg∙L-1 flocculant dosage and pH 7. Under these conditions, the maximum DS was 54.6%, and the minimum SRF was 0.61 × 1010 m∙kg-1. Floc-size measurements demonstrated that high flocculant dosage significantly improved floc size. Correlation analysis further revealed a strong correlation between fractal dimension and floc size after flocculation. A strong correlation also existed between floc size and zeta potential, and flocculants with a higher cationic degree had a larger correlation coefficient between floc size and zeta potential. In the flocculation process, the main flocculation mechanisms involved adsorption bridging under an acidic condition, and a combination between charge neutralization and adsorption-bridging interaction under neutral and alkaline conditions. PMID:26121132

  13. Evaluation of hyperbaric filtration for fine coal dewatering. Final report

    SciTech Connect

    Parekh, B.K.; Hogg, R.; Fonseca, A.

    1996-08-15

    The main objectives of the project were to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20% moisture. The program consisted of three phases, namely Phase 1 -- Model Development, Phase 2 -- Laboratory Studies, Phase 3 -- Pilot Plant Testing. The Pennsylvania State University led efforts in Phase 1, the University of Kentucky in Phase 2, and CONSOL Inc. in Phase 3 of the program. All three organizations were involved in all the three phases of the program. The Pennsylvania State University developed a theoretical model for hyperbaric filtration systems, whereas the University of Kentucky conducted experimental studies to investigate fundamental aspects of particle-liquid interaction and application of high pressure filter in fine coal dewatering. The optimum filtration conditions identified in Phase 1 and 2 were tested in two of the CONSOL Inc. coal preparation plants using an Andritz Ruthner portable hyperbaric filtration unit.

  14. Evaluation of Dewatering Performance and Fractal Characteristics of Alum Sludge.

    PubMed

    Sun, Yongjun; Fan, Wei; Zheng, Huaili; Zhang, Yuxin; Li, Fengting; Chen, Wei

    2015-01-01

    The dewatering performance and fractal characteristics of alum sludge from a drinking-water treatment plant were investigated in this study. Variations in residual turbidity of supernatant, dry solid content (DS), specific resistance to filtration (SRF), floc size, fractal dimension, and zeta potential were analyzed. Sludge dewatering efficiency was evaluated by measuring both DS and SRF. Results showed that the optimum sludge dewatering efficiency was achieved at 16 mg∙L(-1) flocculant dosage and pH 7. Under these conditions, the maximum DS was 54.6%, and the minimum SRF was 0.61 × 10(10) m∙kg(-1). Floc-size measurements demonstrated that high flocculant dosage significantly improved floc size. Correlation analysis further revealed a strong correlation between fractal dimension and floc size after flocculation. A strong correlation also existed between floc size and zeta potential, and flocculants with a higher cationic degree had a larger correlation coefficient between floc size and zeta potential. In the flocculation process, the main flocculation mechanisms involved adsorption bridging under an acidic condition, and a combination between charge neutralization and adsorption-bridging interaction under neutral and alkaline conditions. PMID:26121132

  15. Evaluation of hyperbaric filtration for fine coal dewatering

    SciTech Connect

    Parekh, B.K. ); Hogg, R. ); Fonseca, A. )

    1992-01-01

    Most of the coal presently used by the utility industry is cleaned at preparation plants employing wet processes. Water, while being the mainstay of coal washing, is also one of the least desirable components in the final product. Coarse coal (+3/4 inch) is easily dewatered to a 3--4 percent moisture level using conventional vibrating screens and centrifuges. However, the main problem of excess product moisture occurs in fine (minus 28 mesh) coal and refuse. Even though fines may constitute only about 20 percent of a contemporary cleaning plant feed, they account for two-thirds of the product surface moisture. This high surface moisture offsets many of the benefits of coal cleaning, and can easily undercut the ongoing programs on recovery of fine clean coal from refuse as well as producing an ultra-fine super clean coal fuel. Currently, most of the coal preparation plants utilize vacuum disk type technology for dewatering of the fine coal, providing dewatered product containing about 25 percent moisture. The coal industry would prefer to have a product moisture in the range of 10 to 15 percent, thereby avoiding thermal drying of coal. Hyperbaric filtration. has shown potential in lowering moisture in fine coal to about 20 percent level. This project will develop fundamental information on particle-liquid interaction during hyperbaric filtration and apply the knowledge in developing optimum conditions for the pilot plant testing of the hyperbaric filter system.

  16. Monitoring of sludge dewatering equipment by image classification

    NASA Astrophysics Data System (ADS)

    Maquine de Souza, Sandro; Grandvalet, Yves; Denoeux, Thierry

    2004-11-01

    Belt filter presses represent an economical means to dewater the residual sludge generated in wastewater treatment plants. In order to assure maximal water removal, the raw sludge is mixed with a chemical conditioner prior to being fed into the belt filter press. When the conditioner is properly dosed, the sludge acquires a coarse texture, with space between flocs. This information was exploited for the development of a software sensor, where digital images are the input signal, and the output is a numeric value proportional to the dewatered sludge dry content. Three families of features were used to characterize the textures. Gabor filtering, wavelet decomposition and co-occurrence matrix computation were the techniques used. A database of images, ordered by their corresponding dry contents, was used to calibrate the model that calculates the sensor output. The images were separated in groups that correspond to single experimental sessions. With the calibrated model, all images were correctly ranked within an experiment session. The results were very similar regardless of the family of features used. The output can be fed to a control system, or, in the case of fixed experiment conditions, it can be used to directly estimate the dewatered sludge dry content.

  17. Environmental effects of dredging. Current district dredged material dewatering practices. Technical notes

    SciTech Connect

    1988-04-01

    This technical note summarizes the current US Army Corps of Engineers state of practice in dewatering dredged material. State-of-practice dewatering methods are currently in full-scale use by one or more Corps of Engineers District Offices as contrasted with state-of-the-art methods, which may not have been demonstrated in full-scale applications. The Corps of Engineers conducted research to investigate state-of-the-art dredged material dewatering techniques under the Dredged Material Research Program (DMRP). Based on DMRP research, a number of dewatering methods have been recommended for implementation. The purpose of this note is to describe which of the dewatering practices recommended by DMRP research have been implemented and to determine whether these practices work as well in full-scale applications as was envisioned based on research studies. Also, innovative dewatering techniques developed or applied by the Districts is documented to encourage further investigation and possible use.

  18. Dewatering: Coal and mineral processing. (Latest citations from the COMPENDEX database). Published Search

    SciTech Connect

    Not Available

    1993-05-01

    The bibliography contains citations concerning the technology of dewatering. Included is coverage of techniques, processes, and evaluations applied to coal processing, coal slurry preparation, ash treatments, and processing of other mineral ores. Mechanical devices, heating devices, filtering techniques, air drying, the use of surfactants and flocculants, and design techniques in dewatering systems are discussed. Dewatering of peats, sewage sludges, and industrial sludges are referenced in related bibliographies. (Contains 250 citations and includes a subject term index and title list.)

  19. Application of water-soluble polymer in dewatering of fine coal

    SciTech Connect

    Xingyong, W.

    1999-07-01

    The addition of water-soluble polymer to fine coal slurry to enhance dewatering process of fine coal is considered to be one of the most effective ways of solving the problems of dewatering of fine coal. A series of tests are conducted with a vacuum dewatering apparatus to study the effects of various factors such as the species of polymer, polymer dosage and its ways of addition, and the pH of fine coal slurry on filtrating and dewatering of fine coal.

  20. Dewatering studies of fine clean coal. Annual technical report, September 1, 1990--August 31, 1991

    SciTech Connect

    Parekh, B.K.

    1991-12-31

    The main objective of the present research program is to study and understand dewatering characteristics of ultrafine clean coal obtained using the advanced column flotation technique from the Kerr-McGee`s Galatia preparation plant fine coal waste stream. It is also the objective of the research program to utilize the basic study results, i.e., surface chemical, particle shape particle size distribution, etc., in developing a cost-effective dewatering method. The ultimate objective is to develop process criteria to obtain a dewatered clean coal product containing less that 20 percent moisture, using the conventional vacuum dewatering equipment. (VC)

  1. The effect of coal bed dewatering and partial oxidation on biogenic methane potential

    USGS Publications Warehouse

    Jones, Elizabeth J.P.; Harris, Steve H.; Barnhart, Elliott P.; Orem, William H.; Clark, Arthur C.; Corum, Margo D.; Kirshtein, Julie D.; Varonka, Matthew S.; Voytek, Mary A.

    2013-01-01

    Coal formation dewatering at a site in the Powder River Basin was associated with enhanced potential for secondary biogenic methane determined by using a bioassay. We hypothesized that dewatering can stimulate microbial activity and increase the bioavailability of coal. We analyzed one dewatered and two water-saturated coals to examine possible ways in which dewatering influences coal bed natural gas biogenesis by looking at differences with respect to the native coal microbial community, coal-methane organic intermediates, and residual coal oxidation potential. Microbial biomass did not increase in response to dewatering. Small Subunit rRNA sequences retrieved from all coals sampled represented members from genera known to be aerobic, anaerobic and facultatively anaerobic. A Bray Curtis similarity analysis indicated that the microbial communities in water-saturated coals were more similar to each other than to the dewatered coal, suggesting an effect of dewatering. There was a higher incidence of long chain and volatile fatty acid intermediates in incubations of the dewatered coal compared to the water-saturated coals, and this could either be due to differences in microbial enzymatic activities or to chemical oxidation of the coal associated with O2 exposure. Dilute H2O2 treatment of two fractions of structural coal (kerogen and bitumen + kerogen) was used as a proxy for chemical oxidation by O2. The dewatered coal had a low residual oxidation potential compared to the water-saturated coals. Oxidation with 5% H2O2 did increase the bioavailability of structural coal, and the increase in residual oxidation potential in the water saturated coals was approximately equivalent to the higher methanogenic potential measured in the dewatered coal. Evidence from this study supports the idea that coal bed dewatering could stimulate biogenic methanogenesis through partial oxidation of the structural organics in coal once anaerobic conditions are restored.

  2. Locally produced natural conditioners for dewatering of faecal sludge.

    PubMed

    Gold, Moritz; Dayer, Pauline; Faye, Marie Christine Amie Sene; Clair, Guillaume; Seck, Alsane; Niang, Seydou; Morgenroth, Eberhard; Strande, Linda

    2016-11-01

    In urban areas of low-income countries, treatment of faecal sludge (FS) is insufficient or non-existent. This results in large amounts of FS being dumped into the environment. Existing treatment technologies for FS, such as settling-thickening tanks and drying beds, are land intensive which is limiting in urban areas. Enhanced settling and dewatering by conditioning was evaluated in order to reduce the treatment footprint (or increase treatment capacity). Conventional wastewater conditioners, such as commercially available lime and polymers, are expensive, and commonly rely on complex supply chains for use in low-income countries. Therefore, the treatment performance of five conditioners which could be produced locally was evaluated: Moringa oleifera seeds and press cake, Jatropha curcas seeds, Jatropha Calotropis leaves and chitosan. M. oleifera seeds and press cake, and chitosan improved settling and dewatering and had a similar performance compared to lime and polymers. Optimal dosages were 400-500 kg M. oleifera/t TS, 300-800 kg lime/t TS and 25-50 kg polymer solution/t TS. In comparison, chitosan required 1.5-3.75 kg/t TS. These dosages are comparable to those recommended for wastewater (sludge). The results indicate that conditioning of FS can reduce total suspended solids (TSS) in the effluent of settling-thickening tanks by 22-81% and reduce dewatering time with drying beds by 59-97%. This means that the area of drying beds could be reduced by 59-97% with end-use as soil conditioner, or 9-26% as solid fuel. Least expensive options and availability will depend on the local context. In Dakar, Senegal, chitosan produced from shrimp waste appears to be most promising. PMID:26984372

  3. New coal dewatering technology turns sludge to powder

    SciTech Connect

    2009-03-15

    Virginian Tech's College of Engineering's Roe-Hoan Yoon and his group have developed a hyperbaric centrifuge that can dewater coal as fine as talcum powder. Such coal fines presently must be discarded by even the most advanced coal cleaning plants because of their high moisture content. The new technology can be used with the Microcel technology to remove ash, to re-mine the fine coal discarded to impoundments and to help minimize waste generation. Virginia Tech has received $1 million in funding from the US Department of State to also help the Indian coal industry produce a cleaner product. 1 photo.

  4. OVERVIEW OF REMAINS OF DEWATERING BUILDING, LOOKING SOUTH TOWARD CYANIDE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW OF REMAINS OF DEWATERING BUILDING, LOOKING SOUTH TOWARD CYANIDE PROCESSING AREA. WATER USED IN PROCESSING AT THE STAMP MILL WAS CIRCULATED HERE FOR RECLAMATION. SANDS WERE SETTLED OUT AND DEPOSITED IN ONE OF TWO TAILINGS HOLDING AREAS. CLEARED WATER WAS PUMPED BACK TO THE MILL FOR REUSE. THIS PROCESS WAS ACCOMPLISHED BY THE USE OF SETTLING CONES, EIGHT FEET IN DIAMETER AND SIX FEET HIGH. THE REMAINS OF FOUR CONES ARE AT CENTER, BEHIND THE TANK IN THE FOREGROUND. TO THE LEFT IS THE MAIN ACCESS ROAD BETWEEN THE MILL AND THE PARKING LOT. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  5. Sludge dewatering: Sewage and industrial wastes. (Latest citations from Pollution Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-11-01

    The bibliography contains citations concerning techniques and equipment used in dewatering waste products. Included are techniques for sewage waste as well as industrial, mining, petroleum, and municipal waste sludge. Dewatering processes, device design, and performance evaluations are considered. (Contains 250 citations and includes a subject term index and title list.)

  6. Sludge dewatering: Sewage and industrial wastes. (Latest citations from Pollution Abstracts). Published Search

    SciTech Connect

    Not Available

    1993-07-01

    The bibliography contains citations concerning techniques and equipment used in dewatering waste products. Included are techniques for sewage waste as well as industrial, mining, petroleum, and municipal waste sludge. Dewatering processes, device design, and performance evaluations are considered. (Contains 250 citations and includes a subject term index and title list.)

  7. Redd dewatering effects on hatching and larval survival of the robust redhorse

    USGS Publications Warehouse

    Fisk, J. M., III; Kwak, Thomas J.; Heise, R. J.; Sessions, F. W.

    2013-01-01

    Riverine habitats have been altered and fragmented from hydroelectric dams and change spatially and temporally with hydropower flow releases. Hydropeaking flow regimes for electrical power production inundate areas that create temporary suitable habitat for fish that may be rapidly drained. Robust redhorse Moxostoma robustum, an imperiled, rare fish species, uses such temporary habitats to spawn, but when power generation ceases, these areas are dewatered until the next pulse of water is released. We experimentally simulated the effects of dewatering periods on the survival of robust redhorse eggs and larvae in the laboratory. Robust redhorse eggs were placed in gravel in eyeing-hatching jars (three jars per treatment) and subjected to one of four dewatering periods (6, 12, 24 and 48 h), followed by 12 h of inundation for each treatment, and a control treatment was never dewatered. Egg desiccation was observed in some eggs in the 24- and 48-h treatments after one dewatering period. For all treatments except the control, the subsequent dewatering period after eggs hatched was lethal. Larval emergence for the control treatment was observed on day 5 post-hatching and continued until the end of the experiment (day 21). Larval survival was significantly different between the control and all dewatering treatments for individuals in the gravel. These findings support the need for hydropower facilities to set minimum flows to maintain inundation of spawning areas for robust redhorse and other species to reduce dewatering mortality.

  8. EVALUATION OF FULL-SCALE SUGAR BEET TRANSPORT WATER SOLIDS DEWATERING SYSTEM

    EPA Science Inventory

    The objectives of this study were to evaluate a full-scale vacuum filtration system for dewatering solids removed from the transport water in an operating beet sugar plant in terms of operational reliability and efficiency, economics, and ultimate disposal of the dewatered solids...

  9. Sludge dewatering: Sewage and industrial wastes. (Latest citations from Pollution Abstracts). Published Search

    SciTech Connect

    Not Available

    1992-06-01

    The bibliography contains citations concerning techniques and equipment used in dewatering waste products. Included are techniques for sewage waste as well as industrial, mining, petroleum, and municipal waste sludge. Dewatering processes, device design, and performance evaluations are considered. (Contains 250 citations and includes a subject term index and title list.)

  10. Sludge dewatering: Sewage and industrial wastes. (Latest citations from pollution abstracts). Published Search

    SciTech Connect

    1995-11-01

    The bibliography contains citations concerning sewage sludge dewatering techniques and equipment in industrial and municipal waste treatment systems. Topics include dewatering processes and control, activated sludge systems, fluidized bed systems, biological treatment, heavy metal recovery, and economic aspects. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  11. EVALUATION OF SOLIDS DEWATERING FOR A PILOT-SCALE THIOSORBIC LIME SO2 SCRUBBER

    EPA Science Inventory

    The paper gives results of an evaluation of solids dewatering for a pilot-scale thiosorbic lime SO2 scrubber. Pilot plant data showed that the dissolved magnesium in thiosorbic lime caused deterioration of solids dewatering properties. The slurry settling rate increased when the ...

  12. EVALUATION OF DEWATERING DEVICES FOR PRODUCING HIGH-SOLIDS SLUDGE CAKE

    EPA Science Inventory

    Pilot-plant dewatering tests were made to establish design and operating parameters for dewatering municipal wastewater sludges on recessed plate filter presses (both diaphragm and fixed volume types), continuous belt presses, and retrofit units for a vacuum filter. Results from ...

  13. Development of an Ultra-fine Coal Dewatering Technology and an Integrated Flotation-Dewatering System for Coal Preparation Plants

    SciTech Connect

    Wu Zhang; David Yang; Amar Amarnath; Iftikhar Huq; Scott O'Brien; Jim Williams

    2006-12-22

    The project proposal was approved for only the phase I period. The goal for this Phase I project was to develop an industrial model that can perform continuous and efficient dewatering of fine coal slurries of the previous flotation process to fine coal cake of {approx}15% water content from 50-70%. The feasibility of this model should be demonstrated experimentally using a lab scale setup. The Phase I project was originally for one year, from May 2005 to May 2006. With DOE approval, the project was extended to Dec. 2006 without additional cost from DOE to accomplish the work. Water has been used in mining for a number of purposes such as a carrier, washing liquid, dust-catching media, fire-retardation media, temperature-control media, and solvent. When coal is cleaned in wet-processing circuits, waste streams containing water, fine coal, and noncombustible particles (ash-forming minerals) are produced. In many coal preparation plants, the fine waste stream is fed into a series of selection processes where fine coal particles are recovered from the mixture to form diluted coal fine slurries. A dewatering process is then needed to reduce the water content to about 15%-20% so that the product is marketable. However, in the dewatering process currently used in coal preparation plants, coal fines smaller than 45 micrometers are lost, and in many other plants, coal fines up to 100 micrometers are also wasted. These not-recovered coal fines are mixed with water and mineral particles of the similar particle size range and discharged to impoundment. The wasted water from coal preparation plants containing unrecoverable coal fine and mineral particles are called tailings. With time the amount of wastewater accumulates occupying vast land space while it appears as threat to the environment. This project developed a special extruder and demonstrated its application in solid-liquid separation of coal slurry, tailings containing coal fines mostly less than 50 micron. The

  14. Electro-dewatering of activated sludge: Electrical resistance analysis.

    PubMed

    Conrardy, Jean-Baptiste; Vaxelaire, Jean; Olivier, Jérémy

    2016-09-01

    The significant risk of ohmic heating and the high electric energy consumption at terminal stages of the dewatering are two problems that hamper the development of the electro-dewatering (EDW) technology. In the future prospect of studying these two issues, it is important to provide and analyse quantitative data relative to the behavior of the electric resistance in EDW. It was the main goal of this study. It showed that the electric resistance of the complete system (cake + filter cloth) depended on the cake dryness. It increased sharply when the solids content exceeded around 45%.The solids loading also influenced the apparent resistance at the beginning of the process. The electric resistance of the filter cloth represented about 20% of the total resistance. It remained relatively constant over the process except at the terminal stage where it generally increased sharply. The use of conductive filter, such as metallic cloth, enabled to decrease the electric resistance and reduce the energy consumption of the process. The electric resistance decreased across the cake from the anode to the cathode. This behavior may be explained by several phenomena such as the ions migration and their interaction with the solid, the decrease of dry solids content from the anode to the cathode and the gas presence at the anode (due to electrolysis reaction). PMID:27192354

  15. Comprehensive experimental study on prevention of land subsidence caused by dewatering in deep foundation pit with hanging waterproof curtain

    NASA Astrophysics Data System (ADS)

    Yang, T. L.; Yan, X. X.; Wang, H. M.; Huang, X. L.; Zhan, G. H.

    2015-11-01

    Land subsidence caused by dewatering of deep foundations pit has currently become the focus of prevention and control of land subsidence in Shanghai. Because of the reliance on deep foundation dewatering pit projects, two comprehensive test sites were established to help prevent land subsidence. Through geological environmental monitoring during dewatering of a deep foundation pit, the analysis of the relation between artesian water level and soil subsidence, some basic features of land subsidence caused by dewatering of deep foundation pits are elucidated. The results provide a scientific basis for prevention and control of land subsidence caused by dewatering in deep foundation pits.

  16. POC-scale testing of an advanced fine coal dewatering equipment/technique

    SciTech Connect

    Groppo, J.G.; Parekh, B.K.; Rawls, P.

    1995-11-01

    Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 {mu}m) clean coal. Economical dewatering of an ultra-fine clean coal product to a 20 percent level moisture will be an important step in successful implementation of the advanced cleaning processes. This project is a step in the Department of Energy`s program to show that ultra-clean coal could be effectively dewatered to 20 percent or lower moisture using either conventional or advanced dewatering techniques. As the contract title suggests, the main focus of the program is on proof-of-concept testing of a dewatering technique for a fine clean coal product. The coal industry is reluctant to use the advanced fine coal recovery technology due to the non-availability of an economical dewatering process. in fact, in a recent survey conducted by U.S. DOE and Battelle, dewatering of fine clean coal was identified as the number one priority for the coal industry. This project will attempt to demonstrate an efficient and economic fine clean coal slurry dewatering process.

  17. POC-Scale Testing of an Advanced Fine Coal Dewatering Equipment/Technique

    SciTech Connect

    Karekh, B K; Tao, D; Groppo, J G

    1998-08-28

    Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 mm) clean coal. Economical dewatering of an ultra-fine clean coal product to a 20% level moisture will be an important step in successful implementation of the advanced cleaning processes. This project is a step in the Department of Energy's program to show that ultra-clean coal could be effectively dewatered to 20% or lower moisture using either conventional or advanced dewatering techniques. The cost-sharing contract effort is for 45 months beginning September 30, 1994. This report discusses technical progress made during the quarter from January 1 - March 31, 1998.

  18. Integrated treatment of municipal sewage sludge by deep dewatering and anaerobic fermentation for biohydrogen production.

    PubMed

    Yu, Li; Yu, Yang; Jiang, Wentian; Wei, Huangzhao; Sun, Chenglin

    2015-02-01

    The increasing sludge generated in wastewater treatment plants poses a threat to the environment. Based on the traditional processes, sludge dewatered by usual methods was further dewatered by hydraulic compression and the filtrate released was treated by anaerobic fermentation. The difficulties in sludge dewatering were associated with the existence of sludge flocs or colloidal materials. A suitable CaO dosage of 125 mg/g dry sludge (DS) could further decrease the moisture content of sludge from 82.4 to 50.9 %. The filtrate from the dewatering procedure was a potential substrate for biohydrogen production. Adding zero-valent iron (ZVI) into the anaerobic system improved the biohydrogen yield by 20 %, and the COD removal rate was lifted by 10 % as well. Meanwhile, the sludge morphology and microbial community were altered. The novel method could greatly reduce the sludge volume and successfully treated filtrate along with the conversion of organics into biohydrogen. PMID:25192669

  19. Investigation of operating variables in the fine coal dewatering and briquetting process

    SciTech Connect

    Kan, S.W.; Wilson, J.W.; Dharman, T.

    1998-04-01

    Illinois basin coals contain minerals, including pyrite, which are finely disseminated in micron-size particles. To liberate these mineral matters from the coal matrix, an ultra-fine grinding operation is required, followed by a wet physical cleaning process, such as column flotation. However, the resulting product possesses large surface areas that conventional dewatering techniques cannot perform effectively, and this creates transportation, storage and handling problems at utility plants. To take full advantage of these cleaning technologies, a new dewatering and coal consolidation method must be developed at the downstream end of the deep coal-cleaning process. Following an initial study at the University of Missouri-Rolla (UMR), briquetting was chosen to perform the dual purpose of dewatering and consolidating the fine coal. A bitumen-based emulsion, Orimulsion, proved to be an effective binder and dewatering agent in the briquetting process that assisted in the expulsion of water from the fine coal.

  20. To enhance the dewatering of vacuum filter by adding surfactant reagent

    SciTech Connect

    Cai, Z.; Wu, J.; Liu, H.; Xu, S.

    1997-12-31

    A vacuum filter is the main equipment for fine coal dewatering and usually the moisture content of the cake is high. It has a number of serious handling problems. To reduce the moisture content of the cake, surfactant is added to the slurry which is fed to the filter system to enhance dewatering efficiency. Different kinds of surfactant have been used in the laboratory filter system. A variety of tests have been done and the factors which influence dewatering are investigated. Four of the surfactants have good dewatering efficiency. The moisture contents are decreased 5% or so. Two of them have been used in a commercial process. The method is very simple and will solve an excess moisture problem of coal preparation plants.

  1. Simultaneous dewatering and reconstitution in a high-gravity solid-bowl centrifuge

    SciTech Connect

    Wen, W.W.; Gray, M.L.; Killmeyer, R.P.; Finseth, D.H.

    1994-12-31

    The Pittsburgh Energy Technology Center has developed a dewatering and reconstitution process in which bitumen emulsion is added to a fine clean coal slurry ahead of the dewatering device. The process simultaneously improves dewatering efficiency and reduces dustiness of the fine coal product during subsequent handling. This paper describes the test results from dewatering and reconstitution of fine coal in a 500 lb. per hour continuous bench scale high-gravity solid-bowl centrifuge in PETC`s Coal Preparation Process Research Facility. Test results will be evaluated in terms of type and dosage of emulsion, product moisture and strength, and product handling and dust reduction efficiency. A preliminary cost analysis will also be included.

  2. Effect of brief navigation-related dewaterings on fish eggs and larvae

    USGS Publications Warehouse

    Holland, L.E.

    1987-01-01

    Short-term dewatering of nearshore spawning areas often occurs during passage of commercial tows in the upper Mississippi River as well as in other navigated river systems. This phenomenon was examined experimentally to identify potential effects on survival of fish eggs and larvae. Early life stages of walleyes (Stizostedion vitreum vitreum ) and northern pike (Esox lucius ) were dewatered 2 min in laboratory studies at intervals of either 1, 3, 6, or 12 h from just after fertilization to 10-14 d posthatch. Dewatering did not cause mortality of eggs, but significant mortality of larvae of both species occurred at dewatering frequencies of 1 or 3 h. Therefore, significant mortality first was observed at a frequency equivalent to a mean passage of eight tows per day.

  3. Evaluation of geotextile filtration applying coagulant and flocculant amendments for aquaculture biosolids dewatering and phosphorus removal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wastes contained in the microscreen backwash discharged from intensive recirculating aquaculture systems were removed and dewatered in simple geotextile bag filters. Three chemical coagulation aids, (aluminum sulfate (alum), ferric chloride, and calcium hydroxide (hydrated lime)), were tested in com...

  4. The study and practice of clean coal pressure filter and dewatering process

    SciTech Connect

    Xie, G.; Wu, L.; Ou, Z.

    1999-07-01

    This paper introduces the current status of dewatering of the flotation clean coal and the problems in China. The industrial application of the dewatering process and the newly developed clean coal pressure filter is represented. And the results indicated that this filter press possesses such advantages as fast speed in filter lower moisture in filter cake, convenience in operation, obvious saving on energy, etc. It will have a broad applications.

  5. Combined method for simultaneously dewatering and reconstituting finely divided carbonaceous material

    SciTech Connect

    Wen, W.W.; Deurbrouck, A.W.

    1990-11-13

    A finely-divided carbonaceous material is dewatered and reconstituted in a combined process by adding a binding agent directly into the slurry of finely divided material and dewatering the material to form a cake or consolidated piece which can be hardened by drying at ambient or elevated temperatures. Alternatively, the binder often in the form of a crusting agent is sprayed onto the surface of a moist cake prior to curing. 8 figs.

  6. Combined method for simultaneously dewatering and reconstituting finely divided carbonaceous material

    DOEpatents

    Wen, Wu-Wey; Deurbrouck, Albert W.

    1990-01-01

    A finely-divided carbonaceous material is dewatered and reconstituted in a combined process by adding a binding agent directly into slurry of finely divided material and dewatering the material to form a cake or consolidated piece which can be hardened by drying at ambient or elevated temperatures. Alternatively, the binder often in the form of a crusting agent is sprayed onto the surface of a moist cake prior to curing.

  7. Ultrafine coal single stage dewatering and briquetting process. Technical report, December 1, 1994--February 28, 1995

    SciTech Connect

    Wilson, J.W.

    1996-03-01

    It is well known that a large portion of the pyrite particles in the coal seams of the Illinois Basin, are finely disseminated within the coal matrix. In order to liberate these micron size pyrite particles, one must use a fine grinding operation. The ultrafine coal particles that are produced are difficult to dewater and they create problems in coal transportation as well as in its storage and handling at utility plants. The objective of this research project is to combine ultrafine coal dewatering and briquetting processes into a single stage operation. This will be accomplished by the use of bitumen based emulsions for dewatering and a compaction device for briquetting. During this reporting period, two types of coal samples have been tested for use in the dewatering and briquetting processes. These tests were carried out using Orimulsion as the dewatering reagent. A ram extruder that can be operated continuously is used to fabricate dewatered pellets. The influence of compaction pressure, curing time, binder concentration (2% to 5%), particle size, and compacting time on the performance of coal pellets have been evaluated in terms of their water resistance and wear vulnerability.

  8. Ultrafine coal single stage dewatering and briquetting process. Technical report, September 1--November 30, 1994

    SciTech Connect

    Wilson, J.W.; Honaker, R.Q.

    1994-12-31

    It is well known that a large portion of the pyrite particles in the coal seams of the Illinois Basin, are finely disseminated within the coal matrix. In order to liberate these micron size pyrite particles, one must use a fine grinding operation. The ultrafine coal particles that are produced are difficult to dewater and they create problems in coal transportation as well as in its storage and handling at utility plants. The objective of this research project is to combine ultrafine coal dewatering and briquetting processes into a single stage operation. This will be accomplished by the use of bitumen based emulsions for dewatering and a compaction device for briquetting. During this reporting period, two types of coal samples have been tested for use in the dewatering and briquetting processes. These tests were carried out in conjunction with a selected hydrophobic binder as the dewatering reagent and an uniaxial hydraulic press. The influence of compaction pressure and binder concentration (2 to 5%) on the performance of coal pellets have been evaluated in terms of their water and wear resistance. A laboratory scale ultrafine coal dewatering and briquetting extruder that can be operated continuously for coal pellets fabrication, has been designed and built, and will be available for testing in the next quarter.

  9. Development of a Two-Stage Microalgae Dewatering Process - A Life Cycle Assessment Approach.

    PubMed

    Soomro, Rizwan R; Ndikubwimana, Theoneste; Zeng, Xianhai; Lu, Yinghua; Lin, Lu; Danquah, Michael K

    2016-01-01

    Even though microalgal biomass is leading the third generation biofuel research, significant effort is required to establish an economically viable commercial-scale microalgal biofuel production system. Whilst a significant amount of work has been reported on large-scale cultivation of microalgae using photo-bioreactors and pond systems, research focus on establishing high performance downstream dewatering operations for large-scale processing under optimal economy is limited. The enormous amount of energy and associated cost required for dewatering large-volume microalgal cultures has been the primary hindrance to the development of the needed biomass quantity for industrial-scale microalgal biofuels production. The extremely dilute nature of large-volume microalgal suspension and the small size of microalgae cells in suspension create a significant processing cost during dewatering and this has raised major concerns towards the economic success of commercial-scale microalgal biofuel production as an alternative to conventional petroleum fuels. This article reports an effective framework to assess the performance of different dewatering technologies as the basis to establish an effective two-stage dewatering system. Bioflocculation coupled with tangential flow filtration (TFF) emerged a promising technique with total energy input of 0.041 kWh, 0.05 kg CO2 emissions and a cost of $ 0.0043 for producing 1 kg of microalgae biomass. A streamlined process for operational analysis of two-stage microalgae dewatering technique, encompassing energy input, carbon dioxide emission, and process cost, is presented. PMID:26904075

  10. Development of a Two-Stage Microalgae Dewatering Process – A Life Cycle Assessment Approach

    PubMed Central

    Soomro, Rizwan R.; Zeng, Xianhai; Lu, Yinghua; Lin, Lu; Danquah, Michael K.

    2016-01-01

    Even though microalgal biomass is leading the third generation biofuel research, significant effort is required to establish an economically viable commercial-scale microalgal biofuel production system. Whilst a significant amount of work has been reported on large-scale cultivation of microalgae using photo-bioreactors and pond systems, research focus on establishing high performance downstream dewatering operations for large-scale processing under optimal economy is limited. The enormous amount of energy and associated cost required for dewatering large-volume microalgal cultures has been the primary hindrance to the development of the needed biomass quantity for industrial-scale microalgal biofuels production. The extremely dilute nature of large-volume microalgal suspension and the small size of microalgae cells in suspension create a significant processing cost during dewatering and this has raised major concerns towards the economic success of commercial-scale microalgal biofuel production as an alternative to conventional petroleum fuels. This article reports an effective framework to assess the performance of different dewatering technologies as the basis to establish an effective two-stage dewatering system. Bioflocculation coupled with tangential flow filtration (TFF) emerged a promising technique with total energy input of 0.041 kWh, 0.05 kg CO2 emissions and a cost of $ 0.0043 for producing 1 kg of microalgae biomass. A streamlined process for operational analysis of two-stage microalgae dewatering technique, encompassing energy input, carbon dioxide emission, and process cost, is presented. PMID:26904075

  11. When the Well Runs Dry: Ecological Consequences of Dewatering Rivers

    NASA Astrophysics Data System (ADS)

    Miller, S. W.

    2005-05-01

    Disturbances related to river discharge are thought to define the physical template that structures biological communities and selects for effective life history strategies. Through managing river discharge to support agricultural production in arid and semi-arid landscapes, the timing, frequency, magnitude, and duration of low flow events has been altered. Despite the ubiquitous nature of this management practice, we are currently unable to predict when low flow events impose a disturbance on lotic ecosystems or the spatiotemporal extent of biotic responses. This poster outlines a study that examines gradients in water withdrawal intensity to: 1. Determine if macroinvertebrate communities and environmental variables exhibit threshold or proportional responses to channel dewatering; 2. Characterize spatiotemporal response and recovery patterns of macroinvertebrates to low flow disturbances; 3. Compare life history traits, growth, and developmental rates for invertebrates inhabiting different flow regimes. Preliminary results show macroinvertebrate community structure changing at greater spatial and temporal rates as compared to reference conditions when discharge is reduced by 75 percent or more. The characterization of macroinvertebrate response and recovery patterns to low flow events will help develop innovative strategies that allow agricultural water use, while mitigating structural and functional impacts on lotic systems.

  12. Flotation: A promising microalgae harvesting and dewatering technology for biofuels production.

    PubMed

    Ndikubwimana, Theoneste; Chang, Jingyu; Xiao, Zongyuan; Shao, Wenyao; Zeng, Xianhai; Ng, I-Son; Lu, Yinghua

    2016-03-01

    Microalgal biomass as renewable energy source is believed to be of great potential for reliable and sustainable biofuels production. However, microalgal biomass production is pinned by harvesting and dewatering stage thus hindering the developing and growing microalgae biotechnology industries. Flotation technology applied in mineral industry could be potentially applied in microalgae harvesting and dewatering, however substantial knowledge on different flotation units is essential. This paper presents an overview on different flotation units as promising cost-effective technologies for microalgae harvesting thus bestowing for further research in development and commercialization of microalgae based biofuels. Dispersed air flotation was found to be less energy consuming. Moreover, Jameson cell flotation and dispersed ozone flotation are believed to be energy efficient microalgae flotation approaches. Microalgae harvesting and dewatering by flotation is still at embryonic stage, therefore extended studies with the focus on life cycle assessment, sustainability of the flotation unit, optimization of the operating parameters using different algal species is imperative. Though there are a number of challenges in microalgae harvesting and dewatering, with well designed and developed cultivation, harvesting/dewatering, extraction and conversion technologies, progressively, microalgae technology will be of great potential for biological carbon sequestration, biofuels and biochemicals production. PMID:26928758

  13. Experience dewatering fine coal in solidbowl centrifuges at the York Canyon preparation plant

    SciTech Connect

    Alderman, J.K.

    1995-08-01

    In 1990, a study was undertaken at P&M`s York Canyon preparation plant to evaluate options for dewatering froth flotation product. The existing vacuum disc filter was in need of replacement from wear and neglect, and analysis of the feed to the filter showed that only 7% of the particles were larger than 0.15mm (100 mesh) while nearly 60% of the particles were finer than 0.45mm (325 mesh). Size analysis of the filter cake indicated a mass mean diameter (MMD) of 0.092mm and surface moisture of the filter cake was 33%. Preliminary modeling indicated that a surface moisture of 26% might be attainable for this cake with efficient mechanical dewatering. Based upon the fineness of the feed and the need to replace the filter, in 1991 P&M conducted the field testing with a pilot-scale Sharples high-G solidbowl centrifuge. Data from the pilot scale tests led to the conclusion that the solidbowl centrifuges could recover over 90% of feed solids while providing a surface moisture of about 25% in the product cake. When a decision was made in 1992 to replace the existing plant at York Canyon with a new, larger preparation plant, the commercial scale Sharples high-G solidbowl centrifuges were selected for fine dewatering. The following discussion deals with the plant fine coal dewatering circuitry, start-up problems, remedial actions, and machine dewatering performance.

  14. Study of a solvent/binder combination for viscosity reduction of Orimulsion in fine coal dewatering

    SciTech Connect

    Kan, S.W.; Wilson, J.W.; Dharman, T.; Aksoy, B.S.

    1998-04-01

    To effectively liberate finely disseminated minerals from a coal matrix, a pulverization operation is needed. In this process fine coal particles are formed that possess large surface areas that are difficult to dewater, and create transportation, storage and handling problems at coal cleaning and utility plants. Using both laboratory and pilot scale models, research work conducted at the Department of Mining Engineering at University of Missouri - Rolla (UMR) on a single-stage fine coal dewatering and briquetting technique, has shown the potential of briquetting to enhance the handling, transportation, and storage of fine coal. The operation uses a hydrophobic binder as the dewatering and briquetting agent and requires a compaction device, specifically, a commercial-scale briquetting machine. In the single-stage dewatering/briquetting process, a bitumen-in-water emulsion (Orimulsion), which has high viscosity even at room temperature, was selected as the binder. Due to the tacky nature of the binder, it was felt that by reducing its viscosity using a solvent, the binder could more effectively coat the fine coal surfaces. This study investigated the efficiency of a solvent/binder combination for reducing the viscosity of the Orimulsion for the dewatering of fine coal, and making robust briquettes from predominantly -400 mesh coal particles.

  15. Impact of environmental dewatering of Lower Granite and Little Goose reservoirs on benthic invertebrates and macrophytes

    SciTech Connect

    Cushing, C.E.

    1993-09-01

    An investigation into the effects of dewatering on the benthic fauna in Lower Granite and Little Goose reservoirs was undertaken. Benthos in both the soft bottom regions of the reservoirs as well as those inhabiting the rock rip-rap along the shoreline were studied. These organisms provide an important food resource for both migrating salmonids and resident fish species; thus, impacts of contemplated dewatering schemes require evaluation. The results of these studies indicate that there were no significant, long-term impacts to the soft bottom benthos as a result of dewatering in Little Goose Reservoir. In fact, higher numbers of some taxa indicate that there may have been a washout of these organisms from Lower Granite Reservoir with subsequent deposition in the upper reaches of Little Goose Reservoir. This should be accompanied by a coincident decrease in these organisms in Lower Granite Reservoir. However, we did not have pre-dewatering samples from Lower Granite Reservoir with which we could compare post-filling samples to determine if the dewatering resulted in lower benthic populations.

  16. POC-SCALE TESTING OF AN ADVANCED FINE COAL DEWATERING EQUIPMENT/TECHNIQUE

    SciTech Connect

    X.H. Wang; J. Wiseman; D.J. Sung; D. McLean; William Peters; Jim Mullins; John Hugh; G. Evans; Vince Hamilton; Kenneth Robinette; Tim Krim; Michael Fleet

    1999-08-01

    Dewatering of ultra-fine (minus 150 {micro}m) coal slurry to less than 20% moisture is difficult using the conventional dewatering techniques. The main objective of the project was to evaluate a novel surface modification technique, which utilizes the synergistic effect of metal ions and surfactants in combination for the dewatering of ultra-fine clean-coal slurries using various dewatering techniques on a proof-of-concept (POC) scale of 0.5 to 2 tons per hour. The addition of conventional reagents and the application of coal surface modification technique were evaluated using vacuum filtration, hyperbaric (pressure) filtration, ceramic plate filtration and screen-bowl centrifuge techniques. The laboratory and pilot-scale dewatering studies were conducted using the fine-size, clean-coal slurry produced in the column flotation circuit at the Powell Mountain Coal Company, St. Charles, VA. The pilot-scale studies were conducted at the Mayflower preparation plant in St. Charles, VA. The program consisted of nine tasks, namely, Task 1--Project Work Planning, Task 2--Laboratory Testing, Task 3--Engineering Design, Task 4--Procurement and Fabrication, Task 5--Installation and Shakedown, Task 6--System Operation, Task 7--Process Evaluation, Task 8--Equipment Removal, and Task 9--Reporting.

  17. Plant selection for dewatering and reclamation of tailings

    SciTech Connect

    Silva, M.J.; Naeth, M.A.; Biggar, K.W.; Chanasyk, D.S.; Sego, D.C.

    1998-12-31

    A two-phase greenhouse experiment was conducted to identify the most suitable species for dewatering and reclamation of Composite Tailings (CT) from Alberta oil sands operated by Syncrude Canada Ltd. and Copper Mine Tailings (CMT) from the Kennecott site in Utah. A total of 15 and 9 plant species were selected for testing in CT and CMT, respectively. In Phase 1, distilled water was added weekly to simulate local precipitation. The initial solids content were 80% and 76% and the electrical conductivities were 1.1 dS/m and 3.2 dS/m for CT and CMT, respectively. All plants survived after a ten-week period. In Phase 2 only process water was added weekly to provide a worst case scenario of no precipitation and water recharge due only to process water being released from within the tailings. The initial solids contents were 65% and 76% for CT and CMT, respectively. Surface (0--3 in.) salinity increased dramatically due to the application of process water only; at the end of Phase 2 it had reached toxic levels of approximately 18.9 dS/m and 35.0 dS/m in CT and CMT, respectively. Many plants showed signs of stress due to the high salinity level. The plants which performed the best under both phases in Composite Tailings were creeping foxtail (Alopecurus arundinaceus), reed canarygrass (Phalaris arundinacea), Altai wildrye (Elymus angustus), and red top (Agrostis stolonifera); and in Copper Mine Tailings were Altai wildrye, smooth bromegrass (Bromus inermis) and creeping foxtail.

  18. Improved electroacoustic dewatering (EAD) belt press for food products. Phase 3, Technical progress report

    SciTech Connect

    Not Available

    1994-02-01

    Battelle`s electroacoustic dewatering (EAD) process improves the performance of mechanical dewatering processes for several food products (such as corn fiber) by superimposing electric and ultrasonic fields. EAD has the potential to save 0.027 to 0.035 quad/yr energy by 1995 in the food processing industry, which consumed 0.15 to 0.18 quad in 1986. This report covers Phase III for demonstrating the EAD prototype on corn wet milling products (corn fiber and gluten); only Task 1 (prototype preparation and planning) was completed. EAD performance was examined in the laboratory; availability of a test site was examined. The single-roll, postdewatering EAD belt press prototype can accept material predewatered by a screw press, centrifuge, or any other mechanical dewatering device. The two-belt system, utilizing a copper-polymer cathode belt, performed as well as the three-belt system used in Phase II.

  19. POC-SCALE TESTING OF AN ADVANCED FINE COAL DEWATERING EQUIPMENT/TECHNIQUE

    SciTech Connect

    B.K. PAREKH; D. TAO; J.G. GROPPO

    1998-02-03

    The main objective of the proposed program is to evaluate a novel surface modification technique, which utilizes the synergistic effect of metal ions-surfactant combination, for dewatering of ultra-fine clean coal on a proof-of-concept scale of 1 to 2 tph. The novel surface modification technique developed at the UKCAER will be evaluated using vacuum, centrifuge, and hyperbaric filtration equipment. Dewatering tests will be conducted using the fine clean-coal froth produced by the column flotation units at the Powell Mountain Coal Company, Mayflower Preparation Plant in St. Charles, Virginia. The POC-scale studies will be conducted on two different types of clean coal, namely, high-sulfur and low-sulfur clean coal. The Mayflower Plant processes coals from five different seams, thus the dewatering studies results could be generalized for most of the bituminous coals.

  20. POC-scale testing of an advanced fine coal dewatering equipment/technique

    SciTech Connect

    1998-09-01

    Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 pm) clean coal. Economical dewatering of an ultra-fine clean-coal product to a 20% level moisture will be an important step in successful implementation of the advanced cleaning processes. This project is a step in the Department of Energy`s program to show that ultra-clean coal could be effectively dewatered to 20% or lower moisture using either conventional or advanced dewatering techniques. The cost-sharing contract effort is for 36 months beginning September 30, 1994. This report discusses technical progress made during the quarter from July 1 - September 30, 1997.

  1. A Guide for Developing Standard Operating Job Procedures for the Sludge Conditioning & Dewatering Process Wastewater Treatment Facility. SOJP No. 11.

    ERIC Educational Resources Information Center

    Schwing, Carl M.

    This guide describes standard operating job procedures for the sludge conditioning and dewatering process of wastewater treatment facilities. In this process, sludge is treated with chemicals to make the sludge coagulate and give up its water more easily. The treated sludge is then dewatered using a vacuum filter. The guide gives step-by-step…

  2. Evaluation of hyperbaric filtration for fine coal dewatering. Seventh quarterly technical progress report, April 1, 1994--June 30, 1994

    SciTech Connect

    Parekh, B.K.; Hogg, R.; Fonseca, A.

    1994-10-01

    The main objectives of the project are to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20 percent moisture. This project is oriented into three phases.

  3. Electro-dewatering of wastewater sludge: An investigation of the relationship between filtrate flow rate and electric current.

    PubMed

    Olivier, Jérémy; Conrardy, Jean-Baptiste; Mahmoud, Akrama; Vaxelaire, Jean

    2015-10-01

    Compared to conventional dewatering techniques, electrical assisted mechanical dewatering, also called electro-dewatering (EDW) is an alternative and an effective technology for the dewatering of sewage sludge with low energy consumption. The objectives of this study were to evaluate the dewatering performance and to determine the influence of the process parameters (e.g. applied electric current, applied voltage, and the initial amount of dry solids) on the kinetics of EDW-process for activated urban sludge. Also significant efforts have been devoted herein to provide comprehensive information about the EDW mechanisms and to understand the relationship between these operating conditions with regards to develop a qualitative and quantitative understanding model of the electro-dewatering process and then produce a robust design methodology. The results showed a very strong correlation between the applied electric current and the filtrate flow rate and consequently the electro-dewatering kinetics. A higher applied electric current leads to faster EDW kinetics and a higher final dry solids content. In contrast, the results of this work showed a significant enhancement of the dewatering kinetics by decreasing the mass of the dry solids introduced into the cell (commonly known as the sludge loading). PMID:26304592

  4. Evaluation of hyperbaric filtration for fine coal dewatering. Third quarterly technical progress report, March 1, 1993--May 31, 1993

    SciTech Connect

    Parekh, B.K.; Hogg, R.; Fonseca, A.

    1993-09-01

    The main objectives of the project are to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20 percent moisture. Progress is described.

  5. Dewatering as a non-toxic control of nuisance midge larvae in algal wastewater treatment floways.

    PubMed

    Keller, Troy A; Husted, Emily M

    2015-01-01

    Attached-algae floways have tremendous potential for use in wastewater treatment because natural algal communities show high nutrient removal efficiencies, have low operating costs, and are easy to maintain. Algal wastewater floways may also serve as a sustainable option for producing renewable energy because algae grow rapidly, are easily harvested, and can serve as a source of biomass for biofuel. However, pests such as chironomids (Diptera) colonize open channel periphyton floways and their larvae damage the biofilms. While pesticides can control midge larvae, little information is known about alternative, non-toxic controls. This study examined the effectiveness of periodic, short-term dewatering (4 hours every 9 days) on midge abundance and periphyton growth in 16 recirculating, outdoor floways (3 m long, 0.1 m wide). We compared midge abundance and algal accumulation (chlorophyll a, b, c, and pheophytin) among control (n=8) and dewatered (n=8) floways filled with secondarily treated wastewater (27 days, 10 hours of daylight). Dewatered flumes had 42% fewer midges and 28-49% lower algal productivity (as measured by chlorophyll a, b, c, and pheophytin pigments). Chlorophyll a production rates averaged (±1 SD) 0.5±0.2 μg/cm2/day in control floways compared to 0.3±0.1 μg/cm2/day dewatered floways. Short-term dewatering effectively reduced midges but also damaged periphyton. To maximize the recovery of periphyton biomass, operators should harvest periphyton from floways during dewatering events before periphyton is damaged by desiccation or direct exposure to sunlight. PMID:25607663

  6. Reactive Sandpacks for the Attenuation of Sr-90 in Groundwater for Dewatering Applications

    NASA Astrophysics Data System (ADS)

    Jeen, S.

    2011-12-01

    At many nuclear sites, dewatering is necessary to facilitate building construction, the installation and repair of underground utilities, and the installation of subsurface remedial works in wet ground. When dewatering is required in areas where the groundwater contains contaminants, the proper management of large quantities of contaminated dewatering effluent can be costly and onerous. If the contamination can remain in the ground, the problems and costs of surface storage and treatment would be much reduced. Reactive sandpacks have been proposed as an alternative treatment method for Sr-90 in groundwater. In concept, reactive sandpacks are installed around the screens of dewatering wells, replacing the non-reactive conventional sand pack, such that the contaminant is altered or sorbed in the ground during the dewatering process. While the concept appears to be useful, it has not been determined whether reaction kinetics are fast enough in the fast moving water near the well-screen for satisfactory retention of the contaminant in a dewatering application. This study tested the concept of reactive sandpacks under realistic pumping conditions, by conducting in situ column experiments. Two sets of column experiments were conducted for the period of 49-55 days each, with each set composed of two 10 cm columns placed in a well at the Chalk River site. The well was screened in an actual Sr-90 groundwater plume. Columns were filled with clinoptilolite (i.e., a natural zeolite), and lowered into the well so that groundwater passed through the columns at different velocities in the range expected near the pumping well (33-200 m/day). Measurements of gross beta for the effluent water showed that the columns with higher flow velocities experienced earlier partial breakthrough of Sr-90 than the columns with lower velocities. The extent of the breakthrough of Sr-90 was also proportional to the flow velocity. Distribution coefficients, determined by fitting the normalized

  7. Development of A Continuous Process for Displacement Dewatering

    SciTech Connect

    Dave Beck

    2006-10-30

    The subject of this contract was to investigate the viability of a new process for dewatering paper called displacement pressing. The term “displacement pressing” was coined in the 1980s by researchers to describe a paper dewatering process where air is blown through a sheet of paper while it is being pressed. It was shown at that time that the combination of air and low pressing force could dramatically increase both sheet bulk and sheet solids which in theory would translate into huge savings in energy and fiber consumption. But there was a catch. Although the research results were dramatic, no one could figure out a commercially viable process to carry out displacement pressing. All research work had been done with batch processes, and there was no obvious way to convert these processes into a continuous process. By the end of the early1990’s no one was researching in this area because no continuous process existed. Recently we proposed a new method to carry out displacement pressing. Our process uses special pressing fabrics and a special 4 roll press that we call a “Beck Cluster Press” or BCP. The BCP provides a pressurized atmosphere that acts on a moving web of paper and fabrics. The special fabrics designed for this process use this atmosphere to press the sheet and at the same time, these special fabrics force air through the sheet to carry out displacement pressing. 1 Because of the complexity and cost of building the first functioning BCP, a simple simulator was built to confirm and study the process. Although results from this simulator were extremely favorable, financial times were hard in the paper industry. We are grateful for the DOE contract that allowed us to continue research that showed the tremendous benefits of displacement pressing. Specifically, accomplishments from the DOE contract are as follows: 1. A narrow (5” wide sheet) lab Beck Cluster Press (BCP) was started up, and made operational. This press accepts hand sheets and

  8. 46 CFR 28.815 - Bilge pumps, bilge piping, and dewatering systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... fire pump required by 46 CFR 28.820, a bilge pump may be used for other purposes. (g) Each vessel must comply with the oil pollution prevention requirements of 33 CFR parts 151 and 155. ... 46 Shipping 1 2013-10-01 2013-10-01 false Bilge pumps, bilge piping, and dewatering systems....

  9. 46 CFR 28.815 - Bilge pumps, bilge piping, and dewatering systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... fire pump required by 46 CFR 28.820, a bilge pump may be used for other purposes. (g) Each vessel must comply with the oil pollution prevention requirements of 33 CFR parts 151 and 155. ... 46 Shipping 1 2012-10-01 2012-10-01 false Bilge pumps, bilge piping, and dewatering systems....

  10. 46 CFR 28.815 - Bilge pumps, bilge piping, and dewatering systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... fire pump required by 46 CFR 28.820, a bilge pump may be used for other purposes. (g) Each vessel must comply with the oil pollution prevention requirements of 33 CFR parts 151 and 155. ... 46 Shipping 1 2014-10-01 2014-10-01 false Bilge pumps, bilge piping, and dewatering systems....

  11. Dewatered sewage biosolids provide a productive larval habitat for stable flies and house flies (Diptera: Muscidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species diversity and seasonal abundance of muscoid flies (Diptera: Muscidae) developing in biosolid cake (dewatered biosolids) stored at a wastewater treatment facility in northeastern Kansas was evaluated. Emergence traps were deployed 19 May-20 Oct 2009 (22 wk) and 27 May-18 Nov 2010 (25 wk). A t...

  12. Hydrologic considerations in dewatering and refilling Lake Carlton : Orange and Lake Counties, Florida

    USGS Publications Warehouse

    Anderson, Warren; Hughes, G.H.

    1977-01-01

    Lake Carlton straddles the line between Lake and Orange Counties in central Florida. The 382-acre lake is highly eutrophic and subject to virtually perpetual algal blooms. The Florida Game and Fresh Water Fish Commission has proposed to restore the lake to a less eutrophic state by dewatering the lake long enough to allow the muck on its bottom to dry and compact. Lake Carlton would be permanently sealed off from Lake Carlton. On the assumption that the seasonal rainfall would be normal, and that the dewatering phase would begin on March 1, the predicted time required to dewater the lake at a pumping rate of 50,000 gpm (gallons per minute) is 21 days. The average rate of pumping required to maintain the lake in a dewatered condition is computed to be 2,400 gpm. If pumping is ended May 31, the predicted altitude to which the lake would recover by October 31 as a result of net natural input is 56.2 feet above sea level. Raising the lake level to 63 feet above sea level by October 31 would require that the net natural input be supplemented at an average rate of about 4,860 gpm between May 31 and October 31. (Woodard-USGS)

  13. DEVELOPMENT OF A NEW GRAVITY SEDIMENTATION PROCESS FOR DEWATERING FLUE GAS CLEANING WASTES

    EPA Science Inventory

    The report gives results of a project to develop and test a novel system for dewatering flue gas cleaning (FGC) wastes at the pilot plant level. In this new system, the clarification and thickening functions are conducted in separate, but interconnected, pieces of equipment. The ...

  14. Centrifugal dewatering and reconstitution of fine coal by the GranuFlow Process

    SciTech Connect

    Wen, W.W.; Utz, B.R.; Killmeyer, R.P.

    1997-12-31

    A continuous pilot-scale test of the GranuFlow Process was conducted using a screen-bowl centrifuge for the dewatering and reconstitution of column flotation concentrate at a coal preparation plant in Virginia. In this test, a slipstream of the fine-clean-coal slurry from the column flotation concentrate was treated with a bitumen emulsion before dewatering. The treated products from the screen-bowl centrifuge appeared to be dry and in a free-flowing granular form, while the untreated products were wet, sticky, and difficult to handle. Specifically, test results indicated that the average moisture contents of the dewatered coal were 35.7, 35.5, 32.6, 29.9, and 26.5 wt% with Orimulsion additions of 0, 0.7, 3.2, 4.8, and 6.4 wt%, respectively. The handleability and dust reduction of the dewatered coal product were also vastly improved. A preliminary cost estimate of using Orimulsion in the GranuFlow Process is also included. Because of the simplicity of the process and the low cost of the bitumen emulsion, the commercialization potential of the GranuFlow Process is significant.

  15. DEWATERING WASTEWATER TREATMENT SLUDGE BY CLATHRATE FREEZING: A BENCH-SCALE FEASIBILITY STUDY

    EPA Science Inventory

    Laboratory studies were performed to prove the concept and feasibility for a novel technology to dewater sludges. This involves the formation of solid hydrate crystals of water and specific clathrate-forming agents followed by separation of the hydrate crystal solids from the slu...

  16. Impact of Joule Heating and pH on Biosolids Electro-Dewatering.

    PubMed

    Navab-Daneshmand, Tala; Beton, Raphaël; Hill, Reghan J; Frigon, Dominic

    2015-05-01

    Electro-dewatering (ED) is a novel technology to reduce the overall costs of residual biosolids processing, transport, and disposal. In this study, we investigated Joule heating and pH as parameters controlling the dewaterability limit, dewatering rate, and energy efficiency. Temperature-controlled electrodes revealed that Joule heating enhances water removal by increasing evaporation and electro-osmotic flow. High temperatures increased the dewatering rate, but had little impact on the dewaterability limit and energy efficiency. Analysis of horizontal layers after 15-min ED suggests electro-osmotic flow reversal, as evidenced by a shifting of the point of minimum moisture content from the anode toward the cathode. This flow reversal was also confirmed by the pH at the anode being below the isoelectric point, as ascertained by pH titration. The important role of pH on ED was further studied by adding acid/base solutions to biosolids prior to ED. An acidic pH reduced the biosolids charge while simultaneously increasing the dewatering efficiency. Thus, process optimization depends on trade-offs between speed and efficiency, according to physicochemical properties of the biosolids microstructure. PMID:25494946

  17. Co-conditioning and dewatering of alum sludge and waste activated sludge.

    PubMed

    Lai, J Y; Liu, J C

    2004-01-01

    Co-conditioning and dewatering behaviors of alum sludge and waste activated sludge were investigated. Two different sludges were mixed at various ratios (2:1; 1:1; 1:2; 1:4) for study. Capillary suction time (CST) and specific resistance to filtration (SRF) were utilized to assess sludge dewaterability. Relatively speaking, waste activated sludge, though of higher solid content, was more difficult to be dewatered than alum sludge. It was found that sludge dewaterability and settlability became better with increasing fraction of alum sludge in the mixed sludge. Dosage required of the cationic polyelectrolyte (KP-201C) for dewatering was reduced as well. It is proposed that alum sludge acts as skeleton builder in the mixed sludge, and renders the mixed sludge more incompressible which is beneficial for sludge dewatering. Implications of the results of the study to the sludge management plan for Taipei City that generates both alum sludge and waste activated sludge at significant amount are also discussed. The current sludge treatment and disposal plan in Metropolitan Taipei could be made more cost-effective. PMID:15580993

  18. Comparison of metal lability in air-dried and fresh dewatered drinking water treatment residuals.

    PubMed

    Wang, Changhui; Pei, Yuansheng; Zhao, Yaqian

    2015-01-01

    In this work, the labilities of Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sr, V and Zn in air-dried (for 60 days) and fresh dewatered WTRs were compared using the Toxicity Characteristic Leaching Procedure (TCLP), fractionation, in vitro digestion and a plant enrichment test. The results showed that the air-dried and fresh dewatered WTRs had different properties, e.g., organic matter composition and available nutrients. The air-dried and fresh dewatered WTRs were non-haf zardous according to the TCLP assessment method used in the United States; however, the metals in the two types of WTRs had different lability. Compared with the metals in the fresh dewatered WTRs, those in the air-dried WTRs tended to be in more stable fractions and also exhibited lower bioaccessibility and bioavailability. Therefore, air-drying can decrease the metal lability and thereby reduce the potential metal pollution risk of WTRs. PMID:25560259

  19. Geotextile filtration performance for lagoon sludges and liquid animal manures dewatering

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maintenance and control of liquid levels in anaerobic lagoons and storage ponds require liquid-solid separation as a pretreatment and periodic removal of accumulated sludges. Until local options become available, sludges can be contained, dewatered, and stored using geotextile filtration. We used a ...

  20. Evaluation of thickening and dewatering characteristics of SRC-I wastewater treatment sludges. Final technical report

    SciTech Connect

    Not Available

    1984-05-01

    The SRC-I Demonstration Plant in Newman, Kentucky, will generate several different sludges as a result of providing extensive wastewater treatment. Because construction of this plant has been postponed indefinitely, there has been an opportunity to generate additional data pertinent to waste treatment. Accordingly, this report presents the results of a study on the thickening and dewatering characteristics of several of the wastewater treatment sludges. The study included: evaluation of chemical conditioning agents; aerobic digestion of biological sludges; gravity thickening; and the relative effectiveness of dewatering by centrifuge, vacuum filter, belt filter, and pressure filter. Sludges were tested individually and in combination. The results indicated that the biological sludge could be best dewatered by pressure filtration. The chemical sludges should be combined prior to dewatering, which should be provided by a belt filter. The tar acid sludge will be kept separate, due to its low pH, and ultimate disposal will be by incineration. The tar acid sludge was more concentrated than had been expected. As a result, thickening, rather than centrifuging, is the recommended treatment for this sludge. All sludges were tested for leachate toxicity by the extraction procedure method. The results were negative, indicating the sludges are non-hazardous in heavy metal concentrations, according to RCRA classification. The test results have identified design changes for the proposed wastewater treatment facilities.

  1. Effects of different sludge disintegration methods on sludge moisture distribution and dewatering performance.

    PubMed

    Jin, Lingyun; Zhang, Guangming; Zheng, Xiang

    2015-02-01

    A key step in sludge treatment is sludge dewatering. However, activated sludge is generally very difficult to be dewatered. Sludge dewatering performance is largely affected by the sludge moisture distribution. Sludge disintegration can destroy the sludge structure and cell wall, so as change the sludge floc structure and moisture distribution, thus affecting the dewatering performance of sludge. In this article, the disintegration methods were ultrasound treatment, K2FeO4 oxidation and KMnO4 oxidation. The degree of disintegration (DDCOD), sludge moisture distribution and the final water content of sludge cake after centrifuging were measured. Results showed that three disintegration methods were all effective, and K2FeO4 oxidation was more efficient than KMnO4 oxidation. The content of free water increased obviously with K2FeO4 and KMnO4 oxidations, while it decreased with ultrasound treatment. The changes of free water and interstitial water were in the opposite trend. The content of bounding water decreased with K2FeO4 oxidation, and increased slightly with KMnO4 oxidation, while it increased obviously with ultrasound treatment. The water content of sludge cake after centrifuging decreased with K2FeO4 oxidation, and did not changed with KMnO4 oxidation, but increased obviously with ultrasound treatment. In summary, ultrasound treatment deteriorated the sludge dewaterability, while K2FeO4 and KMnO4 oxidation improved the sludge dewaterability. PMID:25662234

  2. Precision Dual-Aquifer Dewatering at a Low Level Radiological Cleanup in New Jersey

    SciTech Connect

    Gosnell, A. S.; Langman, J. W. Jr.; Zahl, H. A.; Miller, D. M.

    2002-02-27

    Cleanup of low-level radioactive wastes at the Wayne Interim Storage Site (WISS), Wayne, New Jersey during the period October, 2000 through November, 2001 required the design, installation and operation of a dual-aquifer dewatering system to support excavation of contaminated soils. Waste disposal pits from a former rare-earth processing facility at the WISS had been in contact with the water table aquifer, resulting in moderate levels of radionuclides being present in the upper aquifer groundwater. An uncontaminated artesian aquifer underlies the water table aquifer, and is a localized drinking water supply source. The lower aquifer, confined by a silty clay unit, is flowing artesian and exhibits potentiometric heads of up to 4.5 meters above grade. This high potentiometric head presented a strong possibility that unloading due to excavation would result in a ''blowout'', particularly in areas where the confining unit was < 1 meter thick. Excavation of contaminated materials w as required down to the surface of the confining unit, potentially resulting in an artesian aquifer head of greater than 8 meters above the excavation surface. Consequently, it was determined that a dual-aquifer dewatering system would be required to permit excavation of contaminated material, with the water table aquifer dewatered to facilitate excavation, and the deep aquifer depressurized to prevent a ''blowout''. An additional concern was the potential for vertical migration of contamination present in the water table aquifer that could result from a vertical gradient reversal caused by excessive pumping in the confined system. With these considerations in mind, a conceptual dewatering plan was developed with three major goals: (1) dewater the water table aquifer to control radionuclide migration and allow excavation to proceed; (2) depressurize the lower, artesian aquifer to reduce the potential for a ''blowout''; and (3) develop a precise dewatering level control mechanism to insure a

  3. Authigenic Carbonates off Costa Rica Margin: Archives for Dewatering History

    NASA Astrophysics Data System (ADS)

    Han, X.; Suess, E.; Sahling, H.; Garbe-Schönberg, D.; Scholten, J.; Bock, B.

    2003-04-01

    -depleted (18O-enriched) interstitial waters. The 13C-depleted isotope ratios indicate that all of the carbonates result from anaerobic methane oxidation. The large range indicates different C-sources or mixtures forming the different types of carbonates at different locations. Our data demonstrate how authigenic carbonates might be used to reconstruct the dewatering history of the fore-arc off northern and southern Costa Rica, where different styles of plate subduction exist.

  4. Influence of nanoparticles on the polymer-conditioned dewatering of wastewater sludges.

    PubMed

    Boyle, N J; Evans, G M

    2013-01-01

    The effect of using small-scale, high surface area, nanoparticles to supplement polymer-conditioned wastewater sludge dewatering was investigated. Aerobically digested sludge and waste activated sludge sourced from the Hunter Valley, NSW, Australia, were tested with titanium dioxide nanoparticles. The sludge samples were dosed with the nanoparticles in an attempt to adsorb a component of the charged biopolymer surfactants present naturally in sludge. The sludge was conditioned with a cationic polymer. The dewatering characteristics were assessed by measuring the specific resistance to filtration through a modified time-to-filter testing apparatus. The solids content of the dosed samples was determined by a mass balance and compared to the original solids content in the activated sludge. Test results indicated that nanoparticle addition modified the structure of the sludge and provided benefits in terms of the dewatering rate. The samples dosed with nanoparticles exhibited faster water removal, indicating a more permeable filter cake and hence more permeable sludge. A concentration of 2-4% nanoparticles was required to achieve a noticeable benefit. As a comparison, the sludge samples were also tested with a larger particle size, powdered activated carbon (PAC). It was found that the PAC did provide some minor benefits to sludge dewatering but was outperformed by the nanoparticles. The solids content of the final sludge was increased by a maximum of up to 0.6%. The impact of the order sequence of particles and polymer was also investigated. It was found that nanoparticles added before polymer addition provided the best dewatering performance. This outcome was consistent with current theories and previous research through the literature. An economic analysis was undertaken to confirm the viability of the technology for implementation at a full-scale plant. It was found that, currently, this technology is unlikely to be favourable unless the nanoparticles can be

  5. Synthesis, characterization, and secondary sludge dewatering performance of a novel combined silicon-aluminum-iron-starch flocculant.

    PubMed

    Lin, Qintie; Peng, Huanlong; Zhong, Songxiong; Xiang, Jiangxin

    2015-03-21

    Flocculation is one of the most widely used cost-effective pretreatment method for sludge dewatering, and a novel environmentally friendly and efficient flocculant is highly desired in the sludge dewatering field. In this study, a novel combined silicon-aluminum-ferric-starch was synthesized by grafting silicon, aluminum, and iron onto a starch backbone. The synthesized starch flocculant was characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy, X-ray powder diffraction, and thermogravimetric analysis. The dewatering performance of secondary sludge was evaluated according to the capillary suction time, settling volume percentage, and specific resistance to filtration. The results indicated that the copolymer exhibited: (1) a good dewatering efficiency over a wide pH range of 3.0-11.0, (2) superior sludge dewatering performance compared to those of polyaluminum chloride (PACl), polyacrylamide (PAM), ferric chloride, and (3) a discontinuous surface with many channels or voids that helps to mobilize the impermeable thin layer of secondary sludge during filter pressing. Such a novel copolymer is a promising green flocculant for secondary sludge dewatering applications. PMID:25497034

  6. Influence of process operating parameters on dryness level and energy saving during wastewater sludge electro-dewatering.

    PubMed

    Mahmoud, Akrama; Hoadley, Andrew F A; Conrardy, Jean-Baptiste; Olivier, Jérémy; Vaxelaire, Jean

    2016-10-15

    Electrically assisted mechanical dewatering, known as electro-dewatering (EDW), is an alternative emerging technology for energy-efficient liquid/solids separation in the dewatering of wastewater sludge. In this study, the performance of the electro-dewatering (EDW) process for activated wastewater sludge was investigated. The influence of the operating modes; being the timing of voltage (U-EDW) or current (I-EDW) application to either or both the filtration and compression stages, and the influence of the applied pressure (in successive 30 min pressure steps) were studied. The results showed that by delaying the application of the electric field to the filter cake compression stage, there was a potential saving in power consumption of around 10-12% in the case of U-EDW and about 30-46% in the case of I-EDW. The increase of the applied pressure from 0.5 to 12 bar during the filter cake compression stage leads to an increase in electro-dewatering kinetics. The results also reveal that at a low electric field level the increase of the processing pressure has a relatively pronounced effect on the dewatering process. At high levels of the electric field, a minimum processing pressure (4-6 bar) is required to improve the electrical contact between the electrode and the sludge and thus lower the energy consumption. PMID:27448036

  7. Method for simultaneous use of a single additive for coal flotation, dewatering, and reconstitution

    DOEpatents

    Wen, Wu-Wey; Gray, McMahan L.; Champagne, Kenneth J.

    1995-01-01

    A single dose of additive contributes to three consecutive fine coal unit operations, i.e., flotation, dewatering and reconstitution, whereby the fine coal is first combined with water in a predetermined proportion so as to formulate a slurry. The slurry is then mixed with a heavy hydrocarbon-based emulsion in a second predetermined proportion and at a first predetermined mixing speed and for a predetermined period of time. The conditioned slurry is then cleaned by a froth flotation method to form a clean coal froth and then the froth is dewatered by vacuum filtration or a centrifugation process to form reconstituted products that are dried to dust-less clumps prior to combustion.

  8. Review of Design Approaches Applicable to Dewatering Uranium Mill Tailings Disposal Pits

    SciTech Connect

    Gutknecht, P. J.; Gates, T. E.

    1982-03-01

    This report is a review of design approaches in the literature that may be applicable to uranium mill tailings drainage. Tailings dewatering is required in the deep mined-out pits used for wet tailings disposal. Agricultural drainage theory is reviewed because it is seen as the most applicable technology. It is concluded that the standard drain-pipe envelope design criteria should be easily adapted. The differences in dewatering objectives and physical characteristics between agricultural and tailings drainage systems prevent direct technology transfer with respect to drain spacing calculations. Recommendations for further research are based on the drainage features unique to uranium mill tailings. It is recommended that transient solutions be applied to describe liquid movement through saturated and partially saturated tailings. Modeling should be used to evaluate the benefits of drainage design approaches after careful consideration of potential construction problems.

  9. Improved dewatering of CEPT sludge by biogenic flocculant from Acidithiobacillus ferrooxidans.

    PubMed

    Wong, Jonathan W C; Murugesan, Kumarasamy; Yu, Shuk Man; Kurade, Mayur B; Selvam, Ammaiyappan

    2016-01-01

    Bioleaching using an iron-oxidizing bacterium, Acidithiobacillus ferrooxidans, and its biogenic flocculants was evaluated to improve the dewaterability of chemically enhanced primary treatment (CEPT) sewage sludge. CEPT sludge in flasks was inoculated with A. ferrooxidans culture, medium-free cells and the cell-free culture filtrate with and without the energy substance Fe(2+), and periodically the sludge samples were analysed for the dewaterability. This investigation proves that bioleaching effectively improved the sludge dewaterability as evidenced from drastic reduction in capillary suction time (≤20 seconds) and specific resistance to filtration (≥90%); however, it requires an adaptability period of 1-2 days. On the other hand, the biogenic flocculant produced by A. ferrooxidans greatly decreased the time-to-filtration and facilitated the dewaterability within 4 h. Results indicate that rapid dewatering of CEPT sludge by biogenic flocculants provides an opportunity to replace the synthetic organic polymer for dewatering. PMID:26901727

  10. Dewatering studies of fine clean coal. [Quarterly] technical report, December 1, 1991--February 29, 1992

    SciTech Connect

    Parekh, B.K.

    1992-08-01

    Physical cleaning of ultra-fine coal using an advanced froth flotation techniques provides a low ash product, however, due to high surface area of particles the amount of water associated with clean coal is high. Economic removal of water from the froth will be important for commercial applicability of advanced froth flotation processes. The main objective of the present research program is to study and understand the dewatering characteristics of ultra-fine clean coal and to develop process parameters to effectively reduce the moisture to less than 20 percent in the clean coal product. The research approach under investigation utilizes synergistic effects of metal ions and surfactant to lower the moisture of clean coal using a conventional vacuum dewatering technique. The studies have identified a combination of metal ion and surfactant found to be effective in providing a 22 percent moisture filter cake.

  11. Dewatering studies of fine clean coal. Technical report, September 1, 1991--November 30, 1991

    SciTech Connect

    Parekh, B.K.

    1991-12-31

    Physical cleaning of ultra-fine coal using an advanced froth flotation technique provides a low ash product, however, the amount of water associated with clean coal is high. Economic removal of water from the froth will be important for commercial applicability of advanced froth flotation processes. The main objective of the present research program is to study and understand the dewatering characteristics of ultra-fine clean coal and to develop the process parameters to effectively reduce the moisture to less than 20 percent in the clean coal product. The research approach under investigation utilizes synergistic effects of metal ions and surfactant to lower the moisture of clean coal using a conventional vacuum dewatering technique. During the last year`s effort, it was reported that a combination of metal ion and surfactant provided a 22 percent moisture filter cake.

  12. A Case Study on Stratified Settlement and Rebound Characteristics due to Dewatering in Shanghai Subway Station

    PubMed Central

    Wang, Jianxiu; Huang, Tianrong; Sui, Dongchang

    2013-01-01

    Based on the Yishan Metro Station Project of Shanghai Metro Line number 9, a centrifugal model test was conducted to investigate the behavior of stratified settlement and rebound (SSR) of Shanghai soft clay caused by dewatering in deep subway station pit. The soil model was composed of three layers, and the dewatering process was simulated by self-invention of decompressing devise. The results indicate that SSR occurs when the decompression was carried out, and only negative rebound was found in sandy clay, but both positive and negative rebound occurred in the silty clay, and the absolute value of rebound in sandy clay was larger than in silty clay, and the mechanism of SSR was discussed with mechanical sandwich model, and it was found that the load and cohesive force of different soils was the main source of different responses when decompressed. PMID:23878521

  13. A new approach to improve sludge dewatering using a semi-continuous hydraulic press system.

    PubMed

    Kolisch, G; Boehler, M; Arancibia, F C; Pinnow, D; Krauss, W

    2005-01-01

    In future, it will be necessary to incinerate an increasing proportion of the sludge produced by public wastewater treatment. In this context, equipment for more effective dewatering of sewage sludge is required. A hydraulic press system (Bucher HP) which has been used to date in the food industry could represent an alternative to the sludge dewatering systems currently used. The basic suitability of this press system was demonstrated in comprehensive industrial-scale trials at the Glarnerland STP (Switzerland). Dry solids contents of up to 43% were measured in the pressed sludge. Currently, the optimization of individual process parameters is being investigated in a pilot plant at the Schwelm STP operated by Wupperverband (Germany). PMID:16459794

  14. Method for simultaneous use of a single additive for coal flotation, dewatering and reconstitution

    SciTech Connect

    Wen, Wu-Wey; Gray, M.L.; Champagne, K.J.

    1993-11-09

    A single dose of additive contributes to three consecutive fine coal unit operations, i.e., flotation, dewatering and reconstitution, whereby the fine coal is first combined with water in a predetermined proportion so as to formulate a slurry. The slurry is then mixed with a heavy hydrocarbon-based emulsion in a second predetermined proportion and at a first predetermined mixing speed and for a predetermined period of time. The conditioned slurry is then cleaned by a froth flotation method to form a clean coal froth and then the froth is dewatered by vacuum filtration or a centrifugation process to form reconstituted products that are dried to dust-less clumps prior to combustion.

  15. Optimisation of extraction and sludge dewatering efficiencies of bio-flocculants extracted from Abelmoschus esculentus (okra).

    PubMed

    Lee, Chai Siah; Chong, Mei Fong; Robinson, John; Binner, Eleanor

    2015-07-01

    The production of natural biopolymers as flocculants for water treatment is highly desirable due to their inherent low toxicity and low environmental footprint. In this study, bio-flocculants were extracted from Hibiscus/Abelmoschus esculentus (okra) by using a water extraction method, and the extract yield and its performance in sludge dewatering were evaluated. Single factor experimental design was employed to obtain the optimum conditions for extraction temperature (25-90 °C), time (0.25-5 h), solvent loading (0.5-5 w/w) and agitation speed (0-225 rpm). Results showed that extraction yield was affected non-linearly by all experimental variables, whilst the sludge dewatering ability was only influenced by the temperature of the extraction process. The optimum extraction conditions were obtained at 70 °C, 2 h, solvent loading of 2.5 w/w and agitation at 200 rpm. Under the optimal conditions, the extract yield was 2.38%, which is comparable to the extraction of other polysaccharides (0.69-3.66%). The bio-flocculants displayed >98% removal of suspended solids and 68% water recovery during sludge dewatering, and were shown to be comparable with commercial polyacrylamide flocculants. This work shows that bio-flocculants could offer a feasible alternative to synthetic flocculants for water treatment and sludge dewatering applications, and can be extracted using only water as a solvent, minimising the environmental footprint of the extraction process. PMID:25929197

  16. Electrokinetically enhanced flow and dewatering characteristics of concentrated black coal-water suspensions in pipes

    SciTech Connect

    Rozakeas, P.K.; Snow, R.J.

    1997-07-01

    The transportability and dewatering of coal-water mixtures flowing in a pipe may be enhanced by the application of electrokinetic techniques. Previous experimental work by other workers shows a significant reduction in the wall shear stress, and consequently a decrease in pumping energy requirements for the flow of coal-water mixtures in pipes combined with electrodewatering. In this process the pipe wall acts as the cathode and a centrally aligned tube as the anode. The effects of {open_quote}In-pipe electrodewatering{close_quote} on the flow properties and stability of concentrated coal-water mixtures flowing in various alternative anode-cathode arrangements are presented in this paper. The application of an electrical energy flux at the electrode surface (< 6.1 kW/m{sup 2}) in a dewatering section of pipe (L{sub e}=1m) effectively reduces the pumping energy requirements by as much as one order of magnitude. The stability of flow conditions is investigated in a concentric anode-cathode pipe arrangement consisting of a dewatering and a non-dewatering section (L{sub o}). In this system (L{sub o}/L{sub e}) < 4.0. A microscopic study of dilute coal-water suspensions in the presence of a DC electric field revealed the migration of coal particles towards the anode and the structural formation of coal particle chains. The electrorheological behaviour of concentrated coal-water suspensions is examined with the use of a modified coaxial rheometer. The coal fines (d{sub 50}=17.7{mu}m) used in all experiments were produced by milling a low rank bituminous black coal which was followed by a sieving process that eliminated coal particles that were greater than 75{mu}m in size.

  17. An investigation of operating variables in the fine coal dewatering and briquetting process

    SciTech Connect

    Kan, S.W.; Wilson, J.W.; Dharman, T.

    1998-07-01

    Illinois basin coals contain minerals, including pyrite, which are finely disseminated in micron-size particles. To liberate these mineral matters from the coal matrix, an ultra-fine grinding operation is required, followed by a wet physical cleaning process, such as column flotation. However, the resulting product possesses large surface areas that conventional dewatering techniques cannot perform effectively, and this creates transportation, storage and handling problems at utility plants. To take full advantage of these cleaning technologies, a new dewatering and coal consolidation method must be developed at the downstream end of the deep coal-cleaning process. Following an initial study at the University of Missouri-Rolla (UMR), briquetting was chosen to perform the dual purpose of dewatering and consolidating the fine coal. A bitumen-based emulsion, Orimulsion, proved to be an effective binder and dewatering agent in the briquetting process that assisted in the expulsion of water from the fine coal. This paper describes the investigation aimed at examining the relationships between several controllable operating variables. An experimental matrix was designed to examine a range of operating parameters based on earlier work conducted at the Department of Mining Engineering, University of Missouri-Rolla. A total of 13 experiments were performed using Illinois No. 6 coal samples that had a size fraction of 16 mesh x 0 and a moisture content of 31%. Based on results obtained from previous experiments and because of the complexity of the briquetting process, only two variables, roll speed and the briquetting form pressure, were studied for their influence on moisture content, abrasion resistance and friability of briquettes. Concurring with results from previous work, the curing time of the briquettes formed had a significant impact on the moisture content and friability of the compacted fine coal product. Also, the statistical regression models generated from

  18. [Magnetic Fe₃O₄Microparticles Conditioning-Pressure Electro-osmotic Dewatering (MPEOD) of Sewage Sludge].

    PubMed

    Qian, Xu; Wang, Yi-li; Zhao, Li

    2016-05-15

    For magnetic Fe₃O₄ microparticles conditioning--pressure electro-osmotic dewatering (MPEOD) process of activated sludge (AS), the effects of operating parameters (optimal dosage of Fe₃O₄, electric field duration, mechanical pressure and voltage) on the dewatering efficiency and energy consumption were investigated, and the optimal conditions were determined. Moreover, the properties of supernatant and sludge along MPEOD process were studied as well as the interaction force between the sludge biosolids. Taking the energy consumption into consideration, the results showed that the optimal dewatering effect for AS could be achieved with a magnetic Fe₃O₄ microparticles dosage of 0.15 g · g⁻¹, an electric field duration of 2 h, a mechanical pressure of 400-600 kPa and a voltage of 30-50 V. When MPEOD was conducted at 400 kPa and 50 V for 2 h, the sludge reduction rate reached 98.30%, the percentage of water removal was 99.34% and the moisture content of AS decreased from 99.18% to 44.46%. The corresponding consumption of energy was 0.013 3 kW · h · kg⁻¹. The coagulation mechanism played a slight role in the AS conditioning with magnetic Fe₃O₄ micro-particles. In fact, magnetic Fe₃O₄micro-particles could greatly decrease the acid-base interaction (WA) between AS biosolids, cause floc growth and enlarge pores in AS aggregates, which will be beneficial to AS dewatering. Compared to DLVO theory, the extended DLVO theory could accurately describe the aggregation and dispersion behavior of sludge particles. PMID:27506042

  19. Evidence for episodic basin dewatering in salt-dome cap rocks

    SciTech Connect

    Hallager, W.S. ); Ulrich, M.R. ); Kyle, J.R.; Gose, W.A. ); Price, P.E. )

    1990-08-01

    A detailed record of episodic basin-dewatering events is preserved in the anhydrite cap rocks to two Gulf Coast salt domes. Metal rich brines were intermittently expelled geopressured zones deep in the stratigraphic section and were channeled upward along escape structures bounding the salt diapirs. Overhanging anhydrite cap rock helped to focus some escaping fluid into the zone of dissolution between the top of salt and overlying residual anhydrite cap rock. Iron, lead, and zinc sulfide solubilities were exceeded in this zone, possibly in response to dissolution and reduction of cap-rock sulfates. Because the metalliferous brines entered the dissolution zone intermittently, they were recorded as relatively thin horizontal bands of sulfide sandwiched between thicker accumulations of anhydrite. Continued dissolution of salt and underplating of residual anhydrite caused the sulfide bands to be displaced upward relative to the base of the cap, leading to an inverted stratigraphic record of basin-dewatering events. Paleomagnetic data from the Winnfield salt dome suggest the sulfide-producing basin-dewatering events and anhydrite cap-rock accumulation occurred between 157 and 145 Ma.

  20. Emplacement and dewatering of the world's largest exposed sand injectite complex

    NASA Astrophysics Data System (ADS)

    Sherry, Timothy J.; Rowe, Christie D.; Kirkpatrick, James D.; Brodsky, Emily E.

    2012-08-01

    Sandstone injectites form by up or down-section flow of a mobilized sand slurry through fractures in overlying rock. They act as reservoirs and high-permeability conduits through lower permeability rock in hydrocarbon systems. The Yellow Bank Creek Complex, Santa Cruz County, California is the largest known exposure of a sandstone injectite in the world. The complex contains granular textures that record processes of sand slurry flow, multiple pore fluids, and dewatering after emplacement. The injection was initially mobilized from a source containing both water and hydrocarbons. The water-sand slurry reached emplacement depth first, due to lower fluid viscosity. As the sand slurry emplaced, the transition from slurry flow to pore water percolation occurred. This transition resulted in preferred flow channels ˜6 mm wide in which sand grains were weakly aligned (laminae). The hydrocarbon-sand slurry intruded the dewatering sands and locally deformed the laminae. Compaction of the injectite deposit and pore fluid escape caused spaced compaction bands and dewatering pipes which created convolutions of the laminae. The hydrocarbon-rich sand slurry is preserved today as dolomite-cemented sand with oil inclusions. The laminae in this injectite are easily detected due to preferential iron oxide-cementation of the well-aligned sand laminae, and lack of cement in the alternating laminae. Subtle textures like these may develop during sand flow and be present but difficult to detect in other settings. They may explain permeability anisotropy in other sand deposits.

  1. Bioflocculant from pre-treated sludge and its applications in sludge dewatering and swine wastewater pretreatment.

    PubMed

    Guo, Junyuan; Ma, Jing

    2015-11-01

    Potentials of alkaline-thermal (ALT) pre-treated sludge as a bioflocculant were studied in sludge dewatering and swine wastewater pretreatment. When incubated with this ALT pre-treated sludge, dry solids (DS) and specific resistance to filtration (SRF) of typical wastewater activated sludge reached 22.5% and 3.4×10(12)m/kg, respectively, which were much better than that obtained with conventional chemical flocculants. Sludge dewatering was further improved when both the bioflocculant and conventional polyaluminum chloride (PAC) were used simultaneously. Charge neutralization and inter-particle bridging were proposed as the reasons for the enhanced performance in the case of the combined use. With swine wastewater, the bioflocculant could remove COD, ammonium and turbidity by 45.2%, 41.8% and 74.6% when incubated with 20mg/L at pH 8.0. This study suggested that the ALT pre-treated sludge has a great potential as an alternative bioflocculant to conventional flocculants in sludge dewatering and swine wastewater pretreatment. PMID:26259686

  2. Model analysis of effects on water levels at Indiana Dunes National Lakeshore caused by construction dewatering

    USGS Publications Warehouse

    Marie, James R.

    1976-01-01

    The computer models were developed to investigate possible hydrologic effects within the Indiana Dunes National Lakeshore caused by planned dewatering at the adjacent Bailly Nuclear Generator construction site. The model analysis indicated that the planned dewatering would cause a drawdown of about 4 ft under the westernmost pond of the Lakeshore and that this drawdown would cause the pond to go almost dry--less than 0.5 ft of water remaining in about 1 percent of the pond--under average conditions during the 18-month dewatering period. When water levels are below average, as during late July and early August 1974, the pond would go dry in about 5.5 months. However, the pond may not have to go completely dry to damage the ecosystem. If the National Park Service 's independent study determines the minimum pond level at which ecosystem damage would be minimized, the models developed in this study could be used to predict the hydrologic conditions necessary to maintain that level. 

  3. Advanced sludge treatment affects extracellular polymeric substances to improve activated sludge dewatering.

    PubMed

    Neyens, Elisabeth; Baeyens, Jan; Dewil, Raf; De heyder, Bart

    2004-01-30

    The management of wastewater sludge, now often referred to as biosolids, accounts for a major portion of the cost of the wastewater treatment process and represents significant technical challenges. In many wastewater treatment facilities, the bottleneck of the sludge handling system is the dewatering operation. Advanced sludge treatment (AST) processes have been developed in order to improve sludge dewatering and to facilitate handling and ultimate disposal. The authors have extensively reported lab-scale, semi-pilot and pilot investigations on either thermal and thermochemical processes, or chemical oxidation using hydrogen peroxide. To understand the action of these advanced sludge technologies, the essential role played by extracellular polymeric substances (EPS) needs to be understood. EPS form a highly hydrated biofilm matrix, in which the micro-organisms are embedded. Hence they are of considerable importance in the removal of pollutants from wastewater, in bioflocculation, in settling and in dewatering of activated sludge. The present paper reviews the characteristics of EPS and the influence of thermochemical and oxidation mechanisms on degradation and flocculation of EPS. Experimental investigations on waste activated sludge are conducted by the authors to evaluate the various literature findings. From the experiments, it is concluded that AST methods enhance cake dewaterability in two ways: (i) they degrade EPS proteins and polysaccharides reducing the EPS water retention properties; and (ii) they promote flocculation which reduces the amount of fine flocs. PMID:15177096

  4. Adaptation of a briquetting machine for the dewatering and consolidation of fine coal

    SciTech Connect

    Dharman, T.; Wilson, J.W.; Kan, S.W.; Aksoy, B.S.

    1998-12-31

    The Illinois Clean Coal Institute (ICCI) developed a new coal preparation method to recover the high heating value Illinois coal, containing high amounts of sulfur (in the form of pyrite). Unfortunately, the new cleaning method, consisting of fine grinding the coal to liberate mineral matter, such as the pyrite, produced large amounts of high moisture ultra-fine coal. One of the economically viable alternatives to dewater and recover the fine coal was to adapt a commercially available machine. A roll briquetting machine was chosen for the dual purpose of dewatering and consolidating fine coal. Preliminary results indicated that robust briquettes with low moisture content could be produced under the current configuration. However, two areas of concern were realized during the pilot-scale experiments. First, the arching and caking problems resulted in inconsistent feeding of material. Second, back drainage into the feed hopper resulted in varying the feed moisture. Therefore, to effectively utilize the briquetting machine to dewater fine coal, appropriate mechanical modifications were needed. Design changes were conducted on the feed area of the machine, which resulted in the elimination of the problems encountered. Briquettes with consistent low moisture content and adequate strength characteristics could now be produced under the new configuration of the briquetting machine.

  5. Energy recovery from thermal treatment of dewatered sludge in wastewater treatment plants.

    PubMed

    Yang, Qingfeng; Dussan, Karla; Monaghan, Rory F D; Zhan, Xinmin

    2016-01-01

    Sewage sludge is a by-product generated from municipal wastewater treatment (WWT) processes. This study examines the conversion of sludge via energy recovery from gasification/combustion for thermal treatment of dewatered sludge. The present analysis is based on a chemical equilibrium model of thermal conversion of previously dewatered sludge with moisture content of 60-80%. Prior to combustion/gasification, sludge is dried to a moisture content of 25-55% by two processes: (1) heat recovered from syngas/flue gas cooling and (2) heat recovered from syngas combustion. The electricity recovered from the combined heat and power process can be reused in syngas cleaning and in the WWT plant. Gas temperature, total heat and electricity recoverable are evaluated using the model. Results show that generation of electricity from dewatered sludge with low moisture content (≤ 70%) is feasible within a self-sufficient sludge treatment process. Optimal conditions for gasification correspond to an equivalence ratio of 2.3 and dried sludge moisture content of 25%. Net electricity generated from syngas combustion can account for 0.071 kWh/m(3) of wastewater treated, which is up to 25.4-28.4% of the WWT plant's total energy consumption. PMID:27508372

  6. Prediction of full-scale dewatering results of sewage sludges by the physical water distribution.

    PubMed

    Kopp, J; Dichtl, N

    2001-01-01

    The dewaterability of sewage sludge can be described by the total solids concentration of the sludge cake and the polymer-demand for conditioning. The total solids concentration of the sludge cake depends on the physical water distribution. The various types of water in sewage sludge are mainly distinguished by the type and the intensity of their physical bonding to the solids. In a sewage sludge suspension four different types of water can be distinguished. These are the free water, which is not bound to the particles, the interstitial water, which is bound by capillary forces between the sludge flocs, the surface water, which is bound by adhesive forces and intracellular water. Only the share of free water can be separated during mechanical dewatering. It can be shown, that by thermo-gravimeteric measurement of the free water content, an exact prediction of full-scale dewatering results is possible. By separation of all free water during centrifugation the maximum dewatering result is reached. Polymer conditioning increases the velocity of the sludge water release, but the free water content is not influenced by this process. Furthermore it is not possible, to replace the measuring of the water distribution by other individual parameters such as ignition loss. PMID:11443955

  7. Evaluation of hyperbaric filtration for fine coal dewatering. Quarterly technical progress report, 1996

    SciTech Connect

    Parekh, B.K.; Hogg, R.; Fonseca, A.

    1996-12-31

    The main objectives of the project are to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20 percent moisture. The program consist of three phases, namely Phase I, model development, Phase II, laboratory studies, Phase III, field testing. The Pennsylvania State University is leading efforts in Phase I, the University of Kentucky in Phase 11, and Consol Inc. in Phase III of the program. All three organizations are involved in all the three phases of the program. The Pennsylvania State University is developing a theoretical model for hyperbaric filtration systems, whereas the University of Kentucky is conducting experimental studies to investigate fundamental aspects of particle-liquid interaction and application of high pressure filter in fine coal dewatering. The optimum filtration conditions identified in Phase I and II will be tested in a Consol Inc. coal preparation plant using an Andritz Ruthner portable hyperbaric filtration unit. Accomplishments to date are reported for the three phases.

  8. Efficient Calculation of Dewatered and Entrapped Areas Using Hydrodynamic Modeling and GIS

    SciTech Connect

    Richmond, Marshall C.; Perkins, William A.

    2009-12-01

    River waters downstream of a hydroelectric project are often subject to rapidly changing discharge. Abrupt decreases in discharge can quickly dewater and expose some areas and isolate other areas from the main river channel, potentially stranding or entrapping fish, which often results in mortality. A methodology is described to estimate the areas dewatered or entrapped by a specific reduction in upstream discharge. A one-dimensional hydrodynamic model was used to simulate steady flows. Using flow simulation results from the model and a geographic information system (GIS), estimates of dewatered and entrapped areas were made for a wide discharge range. The methodology was applied to the Hanford Reach of the Columbia River in central Washington State. Results showed that a 280 m$^3$/s discharge reduction affected the most area at discharges less than 3400 m$^3$/s. At flows above 3400 m$^3$/s, the affected area by a 280 m$^3$/s discharge reduction (about 25 ha) was relatively constant. A 280 m$^3$/s discharge reduction at lower flows affected about twice as much area. The methodology and resulting area estimates were, at the time of writing, being used to identify discharge regimes, and associated water surface elevations, that might be expected to minimize adverse impacts on juvenile fall chinook salmon (\\emph{Oncorhynchus tshawytscha}) that rear in the shallow near-shore areas in the Hanford Reach.

  9. [Performance and Factors Analysis of Sludge Dewatering in Different Wastewater Treatment Processes].

    PubMed

    Liu, Ji-bao; Li, Ya-ming; Lü, Jian; Wei, Yuan-song; Yang, Min; Yu, Da-wei

    2015-10-01

    Sludge dewatering is one of the keys for sludge disposal and treatment of municipal wastewater treatment plants. In this study, the sludge dewaterability, flocculant consumption and costs of sludge dewatering for different wastewater treatment processes including A2/O and A2/O-MBR processes were analyzed, as well as the factors of sludge dewatering were analyzed by redundancy analysis (RDA) method, based on the data of one municipal wastewater treatment plant of Beijing in 2013. Results showed that both sludge dewaterability and flocculant consumption presented the seasonal variation, which means sludge dewatering was harder and coupled with higher flocculant consumption in the winter. Although the lower moisture content of dewatered sludge was obtained in the A2/O-MBR process (81.92% ± 1.64% ) compared with that in the A2/O process (82.56% ± 1.35%), the consumptions of flocculant [ (8.70 ± 7.25) kg x t(-1) DS] and electric energy (331.82 kW x h x t(-1) DS) in the A2/O-MBR process were higher than those in the A2/O process [(7.42 ± 2.96) kg x t(-1) DS, 121.57 kW x h x t(-1) DS for flocculant consumption and electric energy respectively], resulting in higher operation costs (RMB 204.76 yuan x t(-1) DS of flocculant consumption and RMB 231.61 yuan x t(-1) DS of energy consumption for the A2/O-MBR, RMB 175.00 yuan x t(-1) DS of flocculant consumption and RMB 84.86 yuan x t(-1) DS of energy consumption for the A2/O, respectively). Results of RDA showed that the seasonal variation of sludge dewaterability mainly depended on the content of organic matter in sludge which was related to the seasonal factors such as temperature, and was also impacted by the operating parameters such as SRT in wastewater treatment. PMID:26841614

  10. Dewatering: Coal and mineral processing. January 1970-March 1990 (A Bibliography from the COMPENDEX data base). Report for January 1970-March 1990

    SciTech Connect

    Not Available

    1990-05-01

    This bibliography contains citations concerning the technology of dewatering. Included is coverage of techniques, processes, and evaluations applied to coal processing, coal slurry preparation, ash treatments, and processing of other mineral ores. Mechanical devices, heating devices, filtering techniques, air drying, the use of surfactants and flocculants, and design techniques in dewatering systems are discussed. Dewatering of peats, sewage sludges, and industrial sludges are referenced in related published bibliographies. (Contains 173 citations fully indexed and including a title list.)

  11. Pilot scale single stage fine coal dewatering and briquetting process. Technical report, September 1--November 30, 1995

    SciTech Connect

    Wilson, J.W.; Ding, Y.; Honaker, R.Q.

    1995-12-31

    The primary goal of the current coal preparation research is to reduce the ash and sulfur content from coal, using fine grinding and various coal cleaning processes to separate finely disseminated mineral matter and pyrite from coal. Small coal particles are produced by the grinding operation, thus the ultrafine coal becomes very difficult to dewater. In addition, the ultrafine coal also creates problems during its transportation, storage and handling at utility plants. The current research is seeking to combine ultrafine coal dewatering and briquetting processes into a single stage operation, using hydrophobic binders as coal dewatering and binding reagents with the help of a compaction device. From previous tests, it has been found that coal pellets with a moisture content of less than 15% and good wear and water resistance can be successfully fabricated at pressures of less than 6,000 psi using a lab scale ram extruder. The primary objective of the research described in this quarter has been to extend the lab scale ultrafine coal dewatering and briquetting process into a pilot scale operation, based on the test data obtained from earlier research. A standard roller briquetting machine was used to dewater fine coal-binder mixtures during the briquetting process. The operating parameters, including moisture content of feed, feed rate, and roller speed, were evaluated on the basis of the performance of the briquettes. Briquettes fabricated at rates of up to 108 pellets per minute exhibited satisfactory water and wear resistance, i.e., less than 7.5% cured moisture and less than 8.3% weight loss after 6 min. of tumbling. Also, coal-binder samples with moisture contents of 40 percent have been successfully dewatered and briquetted. Briquetting of fine coal was possible under current feeding conditions, however, a better feeding system must be designed to further improve the quality of dewatered coal briquettes.

  12. Biodegradation and chemical precipitation of dissolved nutrients in anaerobically digested sludge dewatering centrate.

    PubMed

    Galvagno, G; Eskicioglu, C; Abel-Denee, M

    2016-06-01

    The objective of this research was to assess specific side-stream treatment processes for biodegradation and precipitation of dissolved nutrients in dewatering centrate. In this study, characterization was made of a conventional suspended growth deammonification treatment process for transforming dissolved polyphosphate (poly-P), dissolved organic phosphorus (DOP) and dissolved organic nitrogen (DON) in two types of dewatering centrate. The deammonification process was configured as a sequencing batch reactor (SBR), combining partial nitrification and anaerobic ammonia oxidation (anammox) in a single tank. The first centrate feed studied was from the full-scale Annacis Island wastewater treatment plant (AIWWTP) located in Metro Vancouver, Canada. The second centrate feed was from a lab-scale anaerobic digester (AD) fed waste sludge from the existing City of Kelowna Wastewater Treatment Facility (KWTF), located in the Okanagan Valley, Canada. In addition, poly aluminum chloride (PACL) dosing was assessed for final polishing of dissolved nutrients. The deammonification SBR (DeSBR) process showed similar treatment characteristics for both the KWTF and AIWWTP centrates with excellent DON removal and poor non-reactive dissolved phosphorus (NRDP) removal. A statistical comparison of the DOP and poly-P through the DeSBR process suggests that DOP has a higher biodegradation potential. Future research focused on understanding the variables associated with degradation of DOP could lead to better NRDP removal through deammonification processes. Utilization of a post-anammox PACL chemical dosing stage can achieve the objective of precipitating any residual DON and NRDP and producing an effluent that has lower dissolved nutrients than the pre-digestion KWTF dewatering centrate scenario. PMID:27023924

  13. Dewatering studies of fine clean coal. Technical report, March 1, 1992--May 31, 1992

    SciTech Connect

    Parekh, B.K.

    1992-10-01

    Physical cleaning of ultra-fine coal using an advanced froth flotation technique provides a low ash product, however, due to high surface area of particles the amount of water associated with clean coal is high. Economic removal of water to 20 percent or lower moisture level from the clean coal froth will be important for commercial applicability of advanced froth flotation processes. The main objective of the present research program is to study and understand the dewatering characteristics of ultra-fine clean coal and to develop process parameters to effectively reduce the moisture to less than 20 percent in the clean coal product. The research approach under investigation utilizes synergistic effect of metal ions and surfactant to lower the moisture of clean coal using a conventional vacuum dewatering technique. The studies have identified a combination of metal ions and surfactant found to be effective in providing a 22 percent moisture filter cake. During the third quarter, efforts were made to understand reagent adsorption mechanism. Adsorption studies indicated that the presence of metal ions enhanced adsorption of surfactant. It appears that metal ions induced floc formation at pH {approximately}7.0, which are hydrophilic in nature, however addition of surfactant restores the hydrophobicity. Organic polymers along with metal ions were found to be effective in dewatering of fine coal. Continuous filtration tests conducted using a drum filter provided a filter cake containing 24 percent moisture. Additional studies on mechanism of adsorption and continuous filtration using AC Electro-Coagulation will be conducted in the next quarter.

  14. Dewatering studies of fine clean coal. Final technical report, September 1, 1991--August 31, 1992

    SciTech Connect

    Parekh, B.K.

    1992-12-31

    Physical cleaning of ultra-fine coal using advanced froth flotation technique provides a low ash product; however, the amount of water associated with clean coal is high. Economic removal of water from the froth will be important for commercial applicability of the advanced flotation processes. The main objective of the present research program is to study and understand dewatering characteristics of ultra-fine clean coal and to develop process parameters to effectively reduce the moisture to less than 20 percent in the clean coal product. The research approach utilized synergistic effect of metal ions and surfactant addition to lower the moisture of clean coal using the conventional vacuum dewatering technique. The studies have identified a combinations of metal ions and surfactants in providing a 22 percent moisture filter cake. Surface chemical study indicated a direct correlation between the point-of-zero charge (PZC) of metal ion/fine coal system and lowering of moisture in the filter cake. Adsorption of either metal ions or surfactants alone did not provide a significant reduction of moisture in the filter cake. However, a combination of the two provided a filter cake containing about 22 percent moisture. Filtration tests conducted using a laboratory vacuum drum filter indicated that the results obtained in batch filtration could be reproduced on a continuous filtration unit. FT-IR studies indicated that anionic surfactant and metal ions form complex species which adsorbs on the fine coal and results in improved moisture reduction during filtration. Recommendations are offered for testing this novel dewatering process on a pilot scale at a coal preparation plant in Illinois.

  15. Simple systems for treating pumped, turbid water with flocculants and a geotextile dewatering bag.

    PubMed

    Kang, Jihoon; McLaughlin, Richard A

    2016-11-01

    Pumping sediment-laden water from excavations is often necessary on construction sites. This water is often treated by pumping it through geotextile dewatering bags. The bags are not designed to filter the fine sediments that create high turbidity, but dosing with a flocculant prior to the bag could result in greater turbidity control. This study compared two systems for introducing flocculant: passive dosing of commercial solid biopolymer (chitosan) and injection of dissolved polyacrylamide (PAM) in a length of corrugated pipe connected to the bag. The biopolymer system consisted of sequential porous socks containing a "charging agent" followed by chitosan in the corrugated pipe with two levels of dosing. The dissolved PAM was injected into turbid water at a flow-weighted concentration at 1 mg L(-1). For each treatment, sediment-laden turbid water in the range of 2000 to 3500 nephelometric turbidity units (NTU) was pumped into the upstream of corrugated pipe and samples were taken from pipe entrance, pipe exit, and dewatering bag exit. Without flocculant treatment, the dewatering bag reduced turbidity by 70% but the addition of flocculant increased the turbidity reduction up to 97% relative to influent. At the pipe exit, the low-dose biopolymer was less effective in reducing turbidity (37%) but it was equally effective as the high-dose biopolymer or PAM injection after the bag. Our results suggest that a relatively simple treatment with flocculants, either passively or actively, can be very effective in reducing turbidity for pumped water on construction sites. PMID:27479237

  16. Textural evidence for jamming and dewatering of a sub-surface, fluid-saturated granular flow

    NASA Astrophysics Data System (ADS)

    Sherry, T. J.; Rowe, C. D.; Kirkpatrick, J. D.; Brodsky, E. E.

    2011-12-01

    Sand injectites are spectacular examples of large-scale granular flows involving migration of hundreds of cubic meters of sand slurry over hundreds of meters to kilometers in the sub-surface. By studying the macro- and microstructural textures of a kilometer-scale sand injectite, we interpret the fluid flow regimes during emplacement and define the timing of formation of specific textures in the injected material. Fluidized sand sourced from the Santa Margarita Fm., was injected upward into the Santa Cruz Mudstone, Santa Cruz County, California. The sand injectite exposed at Yellow Bank Beach records emplacement of both hydrocarbon and aqueous sand slurries. Elongate, angular mudstone clasts were ripped from the wall rock during sand migration, providing evidence for high velocity, turbid flow. However, clast long axis orientations are consistently sub-horizontal suggesting the slurry transitioned to a laminar flow as the flow velocity decreased in the sill-like intrusion. Millimeter to centimeter scale laminations are ubiquitous throughout the sand body and are locally parallel to the mudstone clast long axes. The laminations are distinct in exposure because alternating layers are preferentially cemented with limonite sourced from later groundwater infiltration. Quantitative microstructural analyses show that the laminations are defined by subtle oscillations in grain alignment between limonite and non-limonite stained layers. Grain packing, size and shape distributions do not vary. The presence of limonite in alternating layers results from differential infiltration of groundwater, indicating permeability changes between the layers despite minimal grain scale differences. Convolute dewatering structures deform the laminations. Dolomite-cemented sand, a signature of hydrocarbon saturation, forms irregular bodies that cross-cut the laminations and dewatering structures. Laminations are not formed in the dolomite-cemented sand. The relative viscosity difference

  17. Evaluation of hyperbaric filtration for fine coal dewatering. Sixth quarterly technical progress report, 1 January--31 March 1994

    SciTech Connect

    Parekh, B.K.; Hogg, R.; Fonseca, A.

    1994-06-01

    The main objectives of the project are to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20% moisture. The program consists of three phases, namely: model development; laboratory studies; and field testing. The Pennsylvania State University is developing a theoretical model for hyperbaric filtration systems, whereas the University of Kentucky is conducting experimental studies to investigate fundamental aspects of particle-liquid interaction and application of high pressure filter in fine coal dewatering. The optimum filtration conditions identified in Phase 1 and 2 will be tested in a Consol Inc. coal preparation plant using an Andritz Ruthner portable hyperbaric filtration unit. Progress to date is described.

  18. How can sludge dewatering devices be assessed? Development of a new DSS and its application to real case studies.

    PubMed

    Bertanza, Giorgio; Papa, Matteo; Canato, Matteo; Collivignarelli, Maria Cristina; Pedrazzani, Roberta

    2014-05-01

    A key issue in biological Waste Water Treatment Plants (WWTPs) operation is represented by the sludge management. Mechanical dewatering is a crucial stage for sludge volume reduction; though, being a costly operation, its optimization is required. We developed an original experimental methodology to evaluate the technical (dewatering efficiency) and financial (total treatment costs) performance of dewatering devices, which might be used as a DSS (Decision Support System) for WWTP managers. This tool was then applied to two real case studies for comparing, respectively, three industrial size centrifuges, and two different operation modes of the same machine (fixed installation vs. outsourcing service). In both the cases, the best option was identified, based jointly on economic and (site-specific) technical evaluations. PMID:24603031

  19. Sludge dewatering: Sewage and industrial wastes. January 1978-December 1989 (A Bibliography from Pollution Abstracts). Report for January 1978-December 1989

    SciTech Connect

    Not Available

    1990-03-01

    This bibliography contains citations concerning techniques and equipment used in sewage, as well as industrial, mining, petroleum, and municipal-waste sludge dewatering. Dewatering processes, device design, and performance evaluations are considered. (This updated bibliography contains 266 citations, 12 of which are new entries to the previous edition.)

  20. Biodiesel from dewatered wastewater sludge: a two-step process for a more advantageous production.

    PubMed

    Pastore, Carlo; Lopez, Antonio; Lotito, Vincenzo; Mascolo, Giuseppe

    2013-07-01

    Alternative approaches for obtaining biodiesel from municipal sludge have been successfully investigated. In order to avoid the expensive conventional preliminary step of sludge drying, dewatered sludge (TSS: 15wt%) was used as starting material. The best performance in terms of yield of fatty acid methyl esters (18wt%) with the lowest energy demand (17MJkgFAME(-1)) was obtained by a new two-step approach based on hexane extraction carried out directly on dewatered acidified (H2SO4) sludge followed by methanolysis of extracted lipids. It was found that sulphuric acid plays a key role in the whole process not only for the transesterification of glycerides but also for the production of new free fatty acids from soaps and their esterification with methanol. In addition to biodiesel production, the investigated process allows valorization of primary sludge as it turns it into a valuable source of chemicals, namely sterols (2.5wt%), aliphatic alcohols (0.8wt%) and waxes (2.3wt%). PMID:23642459

  1. Automation in sludge dewatering by novel on-line characterisation of flocculation.

    PubMed

    Sievers, M; Schroeder, C; Bormann, H; Onyeche, T I; Schlaefer, O; Schaefer, S

    2003-01-01

    A novel on-line method and system for characterisation of sludge flocs in view of improving sludge dewatering has been developed. The characterisation of sludge flocs was carried out after the conditioning or the flocculation process. The system uses a conventional CCD-line scan camera providing an on-line monitoring of the relative floc size distribution by image processing procedures. The image processing procedure has been re-evaluated and adapted to the practical dewatering results, obtained from a chamber filter press of 250 x 250 mm size. A good correlation between the calculated sensor signal and the sludge dewaterability of digested sludge in terms of the up-concentration factor was found. Although different sludge compositions and flocculation systems have been tested within the whole experimental period of six months, a good reproducibility of this correlation was also found. A well balanced floc size distribution is necessary showing that not too many but still some fine flocs and also not too large but compact flocs lead to improved dewaterability. This has been illustrated by an extended range of floc size measurements ranging between 50 microm and 29 mm. The conditioning monitoring system would be suitable for the control of production of good size-balanced flocs to compensate fluctuations in sludge characteristics of the sludge to be conditioned. PMID:12636075

  2. Possibility of sludge conditioning and dewatering with rice husk biochar modified by ferric chloride.

    PubMed

    Wu, Yan; Zhang, Panyue; Zhang, Haibo; Zeng, Guangming; Liu, Jianbo; Ye, Jie; Fang, Wei; Gou, Xiying

    2016-04-01

    Rice husk biochar modified by FeCl3 (MRB-Fe) was used to enhance sludge dewaterability in this study. MRB-Fe preparation conditions and dosage were optimized. Mechanisms of MRB-Fe improving sludge dewaterability were investigated. The optimal modification conditions were: FeCl3 concentration, 3mol/L; ultrasound time, 1h. The optimal MRB-Fe dosage was 60% DS. Compared with raw sludge, the sludge specific resistance to filtration (SRF) decreased by 97.9%, the moisture content of sludge cake decreased from 96.7% to 77.9% for 6min dewatering through vacuum filtration under 0.03MPa, the SV30% decreased from 96% to 60%, and the net sludge solids yield (YN) increased by 28 times. Positive charge from iron species on MRB-Fe surface counteracted negative charge of sludge flocs to promote sludge settleability and dewaterability. Meanwhile, MRB-Fe kept a certain skeleton structure in sludge cake, making the moisture pass through easily. Using MRB-Fe, therefore, for sludge conditioning and dewatering is promising. PMID:26803742

  3. Rapid dewatering of the crust deduced from ages of mesothermal gold deposits

    USGS Publications Warehouse

    Goldfarb, R.J.; Snee, L.W.; Miller, L.D.; Newberry, R.J.

    1991-01-01

    The large-scale migration of fluids through the continental crust has been well documented, but there is no consensus regarding the timing of fluid migration relative to erogenic episodes, or rates of crustal dewatering1. Here we present 40Ar/39Ar dates for muscovites from quartz veins along a major shear zone in southeast Alaska, which show that the veins were emplaced in the early Eocene, during the late stages of orogenic deformation. Hydrothermal activity took place for only about 1 Myr and along a distance of at least 200 km. The fluids were generated by metamorphic reactions in subducted crust along the North American plate margin, and were apparently trapped in the crust by the low permeabilities accompanying a convergent tectonic regime until 56 Myr ago. The rapid dewatering event coincided with a change in plate motion at 56-55 Myr, which caused a shift from convergent to partly transcurrent tectonics. We suggest that this change in tectonic regime led to increased crustal permeabilities and hence the possibility of large-scale fluid migration.

  4. Characterization of a bioflocculant from potato starch wastewater and its application in sludge dewatering.

    PubMed

    Guo, Junyuan; Zhang, Yuzhe; Zhao, Jing; Zhang, Yu; Xiao, Xiao; Wang, Bin; Shu, Bi

    2015-07-01

    A bioflocculant was produced by using potato starch wastewater; its potential in sludge dewatering and potato starch wastewater treatment was investigated. Production of this bioflocculant was positively associated with cell growth, and a highest value of 0.81 g/L was obtained. When incubated with this bioflocculant, dry solids (DS) and specific resistance to filtration (SRF) of typical wastewater activated sludge reached 20.8% and 3.9 × 10(12) m/kg, respectively, which were much better than the ones obtained with conventional chemical flocculants. Sludge dewatering was further improved when both the bioflocculant and conventional polyacrylamide (PAM) were used simultaneously. With potato starch wastewater, chemical oxygen demand (COD) and turbidity removal rates could reach 52.4 and 81.7%, respectively, at pH value of 7.5 when the bioflocculant dose was adjusted to 30 mg/L; from a practical standpoint, the removal of COD and turbidity reached 48.3 and 72.5%, respectively, without pH value adjustment. PMID:25851719

  5. Process for utilizing a pumpable fuel from highly dewatered sewage sludge

    SciTech Connect

    Khan, M.R.

    1993-08-10

    A process is described for disposing of sewage sludge comprising: (1) dewatering an aqueous slurry of sewage sludge having a solids content of at least about 3 wt. % to produce an aqueous slurry of sewage sludge having a solids content in the range of about 5 to 20 wt. %; (2) pressing and/or centrifuging the dewatered slurry of sewage sludge from (1) to produce amorphous sewage sludge having a solids content in the range of about 28 to 50 wt. %; (3) heating the amorphous sewage sludge from (2) in a closed pressure vessel at a temperature in the range of about 150 F to 510 F in the absence of air for a period in the range of about 3 seconds to 60 minutes and shearing the sewage sludge by a rotor/mixer operating at a speed in the range of about 15 to 100 rpm, thereby producing a pumpable slurry of sewage sludge having a viscosity in the range of about 400 to 1,500 centipoise when a measured at 200 F and a higher heating value in the range of about 5,000 to 9,500 Btu/lb, dry basis; and (4) burning said pumpable slurry from (3) in a partial oxidation gasifier, furnace, boiler, or incinerator to produce an effluent gas stream.

  6. Isolation and Characterization of Polyacrylamide-Degrading Bacteria from Dewatered Sludge

    PubMed Central

    Yu, Feng; Fu, Ruimin; Xie, Yun; Chen, Wuling

    2015-01-01

    Polyacrylamide (PAM) is a water-soluble polymer that is widely used as a flocculant in sewage treatment. The accumulation of PAM affects the formation of dewatered sludge and potentially produces hazardous monomers. In the present study, the bacterial strain HI47 was isolated from dewatered sludge. This strain could metabolize PAM as its sole nutrient source and was subsequently identified as Pseudomonas putida. The efficiency of PAM degradation was 31.1% in 7 days and exceeded 45% under optimum culture condition (pH 7.2, 39 °C and 100 rpm). The addition of yeast extract and glucose improved the bacterial growth and PAM degradation. The degraded PAM samples were analyzed by gel-filtration chromatography, Fourier transform infrared and high-performance liquid chromatography. The results showed that high-molecular-weight PAM was partly cleaved to small molecular oligomer derivatives and part of the amide groups of PAM had been converted to carboxyl groups. The biodegradation did not accumulate acrylamide monomers. Based on the SDS-PAGE and N-terminal sequencing results, the PAM amide groups were converted into carboxyl groups by a PAM-induced extracellular enzyme from the aliphatic amidase family. PMID:25893998

  7. Bacterial pathogen indicators regrowth and reduced sulphur compounds' emissions during storage of electro-dewatered biosolids.

    PubMed

    Navab-Daneshmand, Tala; Enayet, Samia; Gehr, Ronald; Frigon, Dominic

    2014-10-01

    Electro-dewatering (ED) increases biosolids dryness from 10-15 to 30-50%, which helps wastewater treatment facilities control disposal costs. Previous work showed that high temperatures due to Joule heating during ED inactivate total coliforms to meet USEPA Class A biosolids requirements. This allows biosolids land application if the requirements are still met after the storage period between production and application. In this study, we examined bacterial regrowth and odour emissions during the storage of ED biosolids. No regrowth of total coliforms was observed in ED biosolids over 7d under aerobic or anaerobic incubations. To mimic on-site contamination during storage or transport, ED samples were seeded with untreated sludge. Total coliform counts decreased to detection limits after 4d in inoculated samples. Olfactometric analysis of ED biosolids odours showed that odour concentrations were lower compared to the untreated and heat-treated control biosolids. Furthermore, under anaerobic conditions, odorous reduced sulphur compounds (methanethiol, dimethyl sulphide and dimethyl disulphide) were produced by untreated and heat-treated biosolids, but were not detected in the headspaces above ED samples. The data demonstrate that ED provides advantages not only as a dewatering technique, but also for producing biosolids with lower microbial counts and odour levels. PMID:25065797

  8. Particulates in hydrometallurgy: Part III. Dewatering behavior of flocculated laterite acid leach residues

    NASA Astrophysics Data System (ADS)

    Briceno, A.; Osseo-Asare, K.

    1995-02-01

    Three polyacrylamide-based polymers of different chemical properties (polymer A, 34 pct anionic, 11×106 mol wt; polymer B, 7 pct anionic, 7.5×106 mol wt; polymer C, nonionic, 13.5×106 mol wt) were used to evaluate the flocculation behavior of laterite acid leach residues. The solid-liquid separation characteristics of the leach residues were investigated with the aid of settling rate, supernatant turbidity, and slurry filtrability measurements. The polymeric flocculants were found to be effective in improving the dewatering properties of the acid leach residues. Polymer effectiveness increased with increasing polymer dosage for all the polymers, but an optimum polymer dose was only found for polymer A (34 pct anionic, 11×106 mol wt) in the studied range of polymer addition. Similarly, the dewatering behavior was improved at higher polymer molecular weight. In addition, it was found that the flocculation performance was adversely affected by an increase in the degree of polymer hydrolysis which, in turn, increases the ratio of carboxylic to amide functional groups in the polymer chain. Polymer C (nonionic ˜0 pct hydrolysis, 13.5×106 mol wt) was found to be the most efficient flocculant in terms of all the performance criteria investigated. The preceding results were rationalized in terms of bridging flocculation, the ionization and molecular configuration of the polymers, hydrogen bonding, and the solid/aqueous interfacial charge.

  9. Bioelectrochemical desalination and electricity generation in microbial desalination cell with dewatered sludge as fuel.

    PubMed

    Meng, Fanyu; Jiang, Junqiu; Zhao, Qingliang; Wang, Kun; Zhang, Guodong; Fan, Qingxin; Wei, Liangliang; Ding, Jing; Zheng, Zhen

    2014-04-01

    Microbial desalination cells (MDCs) with common liquid anodic substrate exhibit a slow startup and destructive pH drop, and abiotic cathodes have high cost and low sustainability. A biocathode MDC with dewatered sludge as fuel was developed for synergistic desalination, electricity generation and sludge stabilization. Experimental results indicated that the startup period was reduced to 3d, anodic pH was maintained between 6.6 and 7.6, and high stability was shown under long-term operation (300d). When initial NaCl concentrations were 5 and 10g/L, the desalinization rates during stable operation were 46.37±1.14% and 40.74±0.89%, respectively. The maximum power output of 3.178W/m(3) with open circuit voltage (OCV) of 1.118V was produced on 130d. After 300d, 25.71±0.15% of organic matter was removed. These results demonstrated that dewatered sludge was an appropriate anodic substrate to enhance MDC stability for desalination and electricity generation. PMID:24534793

  10. Bioelectrochemically-assisted anaerobic composting process enhancing compost maturity of dewatered sludge with synchronous electricity generation.

    PubMed

    Yu, Hang; Jiang, Junqiu; Zhao, Qingliang; Wang, Kun; Zhang, Yunshu; Zheng, Zhen; Hao, Xiaodi

    2015-10-01

    Bioelectrochemically-assisted anaerobic composting process (AnCBE) with dewatered sludge as the anode fuel was constructed to accelerate composting of dewatered sludge, which could increase the quality of the compost and harvest electric energy in comparison with the traditional anaerobic composting (AnC). Results revealed that the AnCBE yielded a voltage of 0.60 ± 0.02 V, and total COD (TCOD) removal reached 19.8 ± 0.2% at the end of 35 d. The maximum power density was 5.6 W/m(3). At the end of composting, organic matter content (OM) reduction rate increased to 19.5 ± 0.2% in AnCBE and to 12.9 ± 0.1% in AnC. The fuzzy comprehensive assessment (FCA) result indicated that the membership degree of class I of AnCBE compost (0.64) was higher than that of AnC compost (0.44). It was demonstrated that electrogenesis in the AnCBE could improve the sludge stabilization degree, accelerate anaerobic composting process and enhance composting maturity with bioelectricity generation. PMID:26115526

  11. Chitosan use in chemical conditioning for dewatering municipal-activated sludge.

    PubMed

    Zemmouri, H; Mameri, N; Lounici, H

    2015-01-01

    This work aims to evaluate the potential use of chitosan as an eco-friendly flocculant in chemical conditioning of municipal-activated sludge. Chitosan effectiveness was compared with synthetic cationic polyelectrolyte Sedipur CF802 (Sed CF802) and ferric chloride (FeCl₃). In this context, raw sludge samples from Beni-Messous wastewater treatment plant (WWTP) were tested. The classic jar test method was used to condition sludge samples. Capillary suction time (CST), specific resistance to filtration (SRF), cakes dry solid content and filtrate turbidity were analyzed to determine filterability, dewatering capacity of conditioned sludge and the optimum dose of each conditioner. Data exhibit that chitosan, FeCl₃and Sed CF802 improve sludge dewatering. Optimum dosages of chitosan, Sed CF802 and FeCl₃allowing CST values of 6, 5 and 9 s, were found, respectively, between 2-3, 1.5-3 and 6 kg/t ds. Both polymers have shown faster water removal with more permeable sludge. SRF values were 0.634 × 10¹², 0.932 × 10¹² and 2 × 10¹² m/kg for Sed CF802, chitosan and FeCl₃respectively. A reduction of 94.68 and 87.85% of the filtrate turbidity was obtained with optimal dosage of chitosan and Sed CF802, respectively. In contrast, 54.18% of turbidity abatement has been obtained using optimal dosage of FeCl₃. PMID:25812088

  12. Isolation and characterization of polyacrylamide-degrading bacteria from dewatered sludge.

    PubMed

    Yu, Feng; Fu, Ruimin; Xie, Yun; Chen, Wuling

    2015-04-01

    Polyacrylamide (PAM) is a water-soluble polymer that is widely used as a flocculant in sewage treatment. The accumulation of PAM affects the formation of dewatered sludge and potentially produces hazardous monomers. In the present study, the bacterial strain HI47 was isolated from dewatered sludge. This strain could metabolize PAM as its sole nutrient source and was subsequently identified as Pseudomonas putida. The efficiency of PAM degradation was 31.1% in 7 days and exceeded 45% under optimum culture condition (pH 7.2, 39 °C and 100 rpm). The addition of yeast extract and glucose improved the bacterial growth and PAM degradation. The degraded PAM samples were analyzed by gel-filtration chromatography, Fourier transform infrared and high-performance liquid chromatography. The results showed that high-molecular-weight PAM was partly cleaved to small molecular oligomer derivatives and part of the amide groups of PAM had been converted to carboxyl groups. The biodegradation did not accumulate acrylamide monomers. Based on the SDS-PAGE and N-terminal sequencing results, the PAM amide groups were converted into carboxyl groups by a PAM-induced extracellular enzyme from the aliphatic amidase family. PMID:25893998

  13. Comparison of two dynamic measurement methods of odor and odorant emission rates from freshly dewatered biosolids.

    PubMed

    Wang, Tingting; Sattayatewa, Chakkrid; Venkatesan, Dhesikan; Noll, Kenneth E; Pagilla, Krishna R; Moschandreas, Demetrios J

    2011-06-01

    Odor and odorant emission rates from freshly dewatered biosolids in a dewatering building of a Water Reclamation Plant (WRP) are measured using the EPA flux chamber and wind tunnel methods. Experimental results are compared statistically to test whether the two methods result in similar emission rates when experiments are performed under field conditions. To the best of our knowledge the literature is void of studies comparing the two methods indoors. In this paper the two methods are compared indoors where the wind velocity and air exchange rate are pertinent field conditions and can be measured. The difference between emission rates of odor and hydrogen sulfide measured with the two methods is not statistically significant (P values: 0.505 for odor, 0.130 for H(2)S). It is concluded that both methods can be used to estimate source emissions but selection of the most effective or efficient method depends on prevailing environmental conditions. The wind tunnel is appropriate for outdoor environments where wind effects on source emissions are more pronounced than indoors. The EPA flux chamber depends on the air exchange rate of the chamber, which simulates corresponding conditions of the indoor environment under investigation and is recommended for estimation of indoor pollution sources. PMID:21552636

  14. Occurrence and Fate of Trace Contaminants during Aerobic and Anaerobic Sludge Digestion and Dewatering.

    PubMed

    Guerra, Paula; Kleywegt, Sonya; Payne, Michael; Svoboda, M Lewina; Lee, Hing-Biu; Reiner, Eric; Kolic, Terry; Metcalfe, Chris; Smyth, Shirley Anne

    2015-07-01

    Digestion of municipal wastewater biosolids is a necessary prerequisite to their beneficial use in land application, in order to protect public health and the receiving environment. In this study, 13 pharmaceuticals and personal care products (PPCPs), 11 musks, and 17 polybrominated diphenyl ethers were analyzed in 84 samples including primary sludge, waste activated sludge, digested biosolids, dewatered biosolids, and dewatering centrate or filtrate collected from five wastewater treatment plants with aerobic or anaerobic digestion. Aerobic digestion processes were sampled during both warm and cold temperatures to analyze seasonal differences. Among the studied compounds, triclosan, triclocarban, galaxolide, and BDE-209 were the substances most frequently detected under different treatment processes at levels up to 30,000 ng/g dry weight. Comparing aerobic and anaerobic digestion, it was observed that the levels of certain PPCPs and musks were significantly higher in anaerobically digested biosolids, relative to the residues from aerobic digestion. Therefore, aerobic digestion has the potential advantage of reducing levels of PPCPs and musks. On the other hand, anaerobic digestion has the advantage of recovering energy from the biosolids in the form of combustible gases while retaining the nutrient and soil conditioning value of this resource. PMID:26437100

  15. InSAR Identifies Mine-Dewatering Associated Bedrock Compaction and Subsidence in North- Central Nevada

    NASA Astrophysics Data System (ADS)

    Katzenstein, K. W.; Bell, J. W.; Watters, R. J.

    2007-12-01

    During the last decade, InSAR has been used extensively for the delineation of aquifer-system response to heavy groundwater pumping. A number of studies have demonstrated the vastly improved spatial resolution afforded by InSAR relative to traditional surveying techniques in detecting groundwater-related effects, including subsidence. This has allowed for further understanding of the complexity of subsidence bowls and the role of secondary factors such as structure, aquifer material properties and other previously unforeseen factors. In the western U.S., ground subsidence related to mine dewatering is a common occurrence due to the very large volumes of water (as high as 100,000 acre-ft/yr) that are typically pumped in order to lower the local groundwater table to facilitate the excavation of open pit and underground mines. Several gold mines located along the Carlin Trend of Central Nevada have produced distinct InSAR-identified subsidence signals of greater aerial extent and magnitude than most municipal groundwater signals, including signals partly or entirely within bedrock. One signal in particular shows a minimum of 54 cm of cumulative dewatering related subsidence between June 1, 1992 and September 21, 2000. Our study has produced many (>50) interferograms, each covering different time intervals, allowing a better understanding of how the subsidence signal has evolved in response to varied pumping rates from dewatering wells. Since the spatial resolution of the InSAR is much better than that of the monitoring well locations, the complexity of the signal is better delineated. The aerial extent of the subsidence feature is impressive as it extends as far as 20 km away from the location of the extraction wells used for dewatering. The area of maximum subsidence correlates well with the area of maximum groundwater drawdown, however the subsidence signal extends well beyond (as much as 8-10 km) the observed groundwater drawdown pattern. This suggests a much

  16. Evaluation of hyperbaric filtration for fine coal dewatering. Fifth quarterly technical progress report, October 1, 1993--December 31, 1993

    SciTech Connect

    Parekh, B.K.; Hogg, R.; Fonseca, A.

    1993-12-31

    The main objectives of the project are to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20 percent moisture. The program consist of three phases: model development; laboratory studies; and field testing. The Pennsylvania State University is leading efforts in Phase I, the University of Kentucky in Phase II, and Consol Inc. in Phase III of the program. All three organizations are involved in all the three phases of the program. The Pennsylvania State University is developing a theoretical model for hyperbaric filtration systems, whereas the University of Kentucky is conducting experimental studies to investigate fundamental aspects of particle-liquid interaction and application of high pressure filter in fine coal dewatering. The optimum filtration conditions identified in phase I and 11 will be tested in a Consol Inc. coal preparation plant using an Andritz Ruthner portable hyperbaric filtration unit. In this report, dewatering model development and laboratory studies are presented.

  17. Reducing the moisture content of clean coals. Volume 4, Aiding the dewatering and classifying of fine coal with an ultrasonic tray: Final report

    SciTech Connect

    Raleigh, C.E.

    1992-11-01

    Volume four contains the results of an Empire State Electric Energy Research corporation and Electric Power Research Institute (EPRI) funded investigation to evaluate the effects and economics of applying ultrasonic waves to commercial-scale dewatering and classifying of fine coal. Pre-treating minus 28 mesh Upper Freeport Seam coal using an ultrasonic tray device improved subsequent dewatering by a vacuum disc filter after thickening in a cyclone, but it did not improve dewatering by a screen-bowl centrifuge after cycloning. Dewatering of Pittsburgh Seam coal also improved when the coal was ultrasonically treated, but it only manifested during thickening in the cyclone. Cycloning also increased the removal of fine, high-ash content clay particles from Pittsburgh Seam coal. In contrast, ultrasonically-treating Upper Freeport Seam coal did not improve subsequent classifying by a rapped sieve bend. Based on a specific example of results in this test work for Upper Freeport Seam coal, using an ultrasonic tray to aid dewatering of finely-sized coal can be economically beneficial. For other coals and dewatering devices, however, the economics for using ultrasonic trays to enhance fine coal dewatering will differ.

  18. A study of a solvent/binder combination for viscosity reduction of Orimulsion in fine coal dewatering

    SciTech Connect

    Kan, S.W.; Wilson, J.W.; Dharman, T.; Aksoy, B.S.

    1998-07-01

    To effectively liberate finely disseminated minerals from a coal matrix, a pulverization operation is needed. In this process fine coal particles are formed that possess large surface areas that are difficult to dewater, and create transportation, storage and handling problems at coal cleaning and utility plants. Using both laboratory and pilot scale models, research work conducted at the Department of Mining Engineering at University of Missouri-Rolla (UMR) on a single-state fine coal dewatering and briquetting technique, has shown the potential of briquetting to enhance the handling, transportation, and storage of fine coal. The operation uses a hydrophobic binder as the dewatering and briquetting agent and requires a compaction device, specifically, a commercial-scale briquetting machine. In the single-state dewatering-briquetting process, a bitumen-in-water emulsion (Orimulsion), which has high viscosity even at room temperature, was selected as the binder. Due to the tacky nature of the binder, it was felt that by reducing its viscosity using a solvent, the binder could more effectively coat the fine coal surfaces. This study investigated the efficiency of a solvent/binder combination for reducing the viscosity of the Orimulsion for the dewatering of fine coal, and making robust briquettes from predominantly -400 mesh coal particles. Preliminary results indicated that by adding a solvent to the binder, it reduced the viscosity of the Orimulsion, which in turn provided a more efficient use of the binder and resulted in a better coating of the ultra-fine coal particles. Using multiple-variable linear regression analyses, it was possible to establish basic relationships between the change in moisture of coal pellets and several operating variables. The model showed that the compaction pressure, as well as the type and amount of solvent used in conjunction with Orimulsion, influenced the moisture content of the coal pellets produced.

  19. Consolidation theory and its applicability to the dewatering and covering of uranium-mill tailings

    SciTech Connect

    Gates, T.E.

    1982-11-01

    This report is a review and evaluation of soil consolidation theories applicable for evaluating settlement during dewatering and subsequent covering of uranium-mill tailings. Such theories may be used to predict both consolidation and water flow related effects in uranium-mill tailings during drainage, following sluicing into burial pits. A consolidation theory to be useful must consider the effect of time-dependent loads, nonhomogeneous soil mass, nonlinear variation of soil properties with the stress-state parameters, large strain, and saturated and unsaturated flow. Constitutive relations linking the stress-deformation-state variables with void ratio should be adopted for predicting both consolidation and fluid-flow interaction in unsaturated uranium-mill tailings.

  20. Earthworms facilitate the stabilization of pelletized dewatered sludge through shaping microbial biomass and activity and community.

    PubMed

    Fu, Xiaoyong; Cui, Guangyu; Huang, Kui; Chen, Xuemin; Li, Fusheng; Zhang, Xiaoyu; Li, Fei

    2016-03-01

    In this study, the effect of earthworms on microbial features during vermicomposting of pelletized dewatered sludge (PDS) was investigated through comparing two degradation systems with and without earthworm E isenia fetida involvement. After 60 days of experimentation, a relatively stable product with low organic matter and high nitrate and phosphorous was harvested when the earthworms were involved. During the process, earthworms could enhance microbial activity and biomass at the initial stage and thus accelerating the rapid decomposition of PDS. The end products of vermicomposting allowed the lower values of bacterial and eukaryotic densities comparison with those of no earthworm addition. In addition, the presence of earthworms modified the bacterial and fungal diversity, making the disappearances of some pathogens and specific decomposing bacteria of recalcitrant substrates in the vermicomposting process. This study evidences that earthworms can facilitate the stabilization of PDS through modifying microbial activity and number and community during vermicomposting. PMID:26514568

  1. UV-Initiated Polymerization of Cationic Polyacrylamide: Synthesis, Characterization, and Sludge Dewatering Performance

    PubMed Central

    Zheng, Huaili; Sun, Yongjun; Tan, Mingzhuo; Chen, Wei; Liao, Yong

    2013-01-01

    P(AM-DAC-BA) was synthesized through copolymerization of acrylamide (AM), acryloyloxyethyl trimethyl ammonium chloride (DAC), and butylacrylate (BA) under ultraviolet (UV) initiation using response surface methodology (RSM). The influences of light intensity, illumination time, and photoinitiator concentration on the intrinsic viscosity [η] of P(AM-DAC-BA) were investigated. RSM model based on the influencing data was established for optimizing synthetic conditions. It was found that, at light intensity 1491.67 μw·cm−2, illumination time 117.89 min, and photoinitiator concentration 0.60‰, there was a better material performance achieved. Thus P(AM-DAC-BA) prepared under the above conditions showed excellent dewatering performance that, with 40 mg·L−1 P(AM-DAC-BA) at pH 7, the residual turbidity of supernatant and the dry solid content were up to 38 NTU, 28.5%, respectively. PMID:24459451

  2. POC-scale testing of an advanced fine coal dewatering equipment/technique. Quarterly technical progress report 6, January--March 1996

    SciTech Connect

    Tao, D.; Groppo, J.G.; Parekh, B.K.

    1996-05-03

    Froth flotation technique is an effective and efficient process for recovering of ultra-fine clean coal. Economical dewatering of an ultra-fine clean coal product to a 20% level moisture will be an important step in successful implementation of the advanced cleaning processes. This project is a step in the Department of Energy`s program to show that ultra-clean coal could be effectively dewatered to 20% or lower moisture using either conventional or advanced dewatering techniques. The cost-sharing contract effort is for 36 months beginning September 30, 1994. This report discusses technical progress made during the quarter from January 1- March 31, 1996.

  3. Effects of calcined aluminum salts on the advanced dewatering and solidification/stabilization of sewage sludge.

    PubMed

    Zhen, Guangyin; Yan, Xiaofei; Zhou, Haiyan; Chen, Hua; Zhao, Tiantao; Zhao, Youcai

    2011-01-01

    The high moisture content (80%) in the sewage dewatered sludge is the main obstacle to disposal and recycling. A chemical dewatering and stabilization/solidification (S/S) alternative for the sludge was developed, using calcined aluminum salts (AS) as solidifier, and CaCl2, Na2SO4 and CaSO4 as accelerators, to enhance the mechanical compressibility making the landfill operation possible. The properties of the resultant matrixes were determined in terms of moisture contents, unconfined compressive strength, products of hydration, and toxicity characteristics. The results showed that AS exhibited a moderate pozzolanic activity, and the mortar AS(0) obtained with 5% AS and 10% CaSO4 of AS by weight presented a moisture contents below 50%-60% and a compressive strength of (51.32 +/- 2.9) kPa after 5-7 days of curing time, meeting the minimum requirement for sanitary landfill. The use of CaSO4 obviously improved the S/S performance, causing higher strength level. X-ray diffraction, scanning electron microscopy and thermogravimetry-differential scanning calorimetry investigations revealed that a large amount of hydrates (viz., gismondine and CaCO3) were present in solidified sludge, leading to the depletion of evaporable water and the enhancement of the strength. In addition, the toxicity characteristic leaching procedure (TCLP) and horizontal vibration (HJ 557-2009) leaching test were conducted to evaluate their environmental compatibility. It was found that the solidified products conformed to the toxicity characteristic criteria in China and could be safely disposed of in a sanitary landfill. PMID:22125919

  4. Characteristics of dewatering induced drawdown curve under blocking effect of retaining wall in aquifer

    NASA Astrophysics Data System (ADS)

    Wu, Yong-Xia; Shen, Shui-Long; Yuan, Da-Jun

    2016-08-01

    For deep excavation pits that require the pumping of confined groundwater, a combination of a retaining wall and dewatering with large-diameter wells is usually adopted during excavation to improve safety. Since a retaining wall has a much lower hydraulic conductivity than the surrounding material in the aquifer, blocking of seepage to prolong the seepage path of the groundwater outside of the pit is effective. The retaining walls used during excavation dewatering cause hydraulic head drawdown inside the pit much faster than outside the pit. Thus, difference in hydraulic head between inside and outside of the pit increases. To investigate the mechanism of the blocking effect, numerical simulation using the finite difference method (FDM) was conducted to analyze the effects of pumping in the pit. The FDM results show that drawdown varies along the depth of the confined aquifer. The influence factors of drawdown inside and outside the pit include insertion depth of retaining walls, anisotropy of a confined aquifer and screen length of pumping wells. In addition, FDM results also show that the drawdown-time curve can be divided into four stages: in Stage I, drawdown inside the pit is very small and outside the pit it is almost zero; in Stage II, drawdown increases quickly with time; in Stage III, the drawdown curve is parallel to the Cooper-Jacob curve on semi-log axes; and in Stage IV, the drawdown becomes constant. These characteristics of the drawdown curve under the blocking effect of a retaining wall in an aquifer provide a way of estimating hydrogeological parameters according to pumping test results.

  5. Biodegradation of polyacrylamide by anaerobic digestion under mesophilic condition and its performance in actual dewatered sludge system.

    PubMed

    Dai, Xiaohu; Luo, Fan; Yi, Jing; He, Qunbiao; Dong, Bin

    2014-02-01

    Polyacrylamide (PAM) used in sludge dewatering widely exists in high-solid anaerobic digestion. Degradation of polyacrylamide accompanied with accumulation of its toxic monomer is important to disposition of biogas residues. The potential of anaerobic digestion activity in microbial utilization of PAM was investigated in this study. The results indicated that the utilization rate of PAM (as nitrogen source) was influenced by accumulation of ammonia, while cumulative removal of amide group was accorded with zeroth order reaction in actual dewatered system. The adjoining amide group can combined into ether group after biodegradation. PAM can be broken down in different position of its carbon chain backbone. In actual sludge system, the hydrolytic PAM was liable to combined tyrosine-rich protein to form colloid complex, and then consumed as carbon source to form monomer when easily degradable organics were exhausted. The accumulation of acrylamide was leveled off ultimately, accompanied with the yield of methane. PMID:24345566

  6. Transport phenomena in the crystallization of lysozyme by osmotic dewatering and liquid-liquid diffusion in low gravity

    NASA Technical Reports Server (NTRS)

    Todd, Paul; Sportiello, Michael G.; Gregory, Derek; Cassanto, John M.; Alvarado, Ulises A.; Ostroff, Robert; Korszun, Z. R.

    1993-01-01

    Two methods of protein crystallization, osmotic dewatering and liquid-liquid diffusion, like the vapor diffusion (hanging-drop and sessile-drop) methods allow a gradual approach to supersaturation conditions. The crystallization of hen egg-white lysozyme, an extensively characterized protein crystal, in the presence of sodium chloride was used as an experimental model with which to compare these two methods in low gravity and in the laboratory. Comparisons of crystal growth rates by the two methods under the two conditions have, to date, indicated that the rate of crystal growth by osmotic dewatering is nearly the same in low gravity and on the ground, while much faster crystal growth rates can be achieved by the liquid-liquid diffusion method in low gravity.

  7. POC-scale testing of an advanced fine coal dewatering equipment/technique. Quarterly progress report, July - September 1996

    SciTech Connect

    Tao, D.; Groppo, J.G.; Parekh, B.K.

    1996-10-01

    The advanced fine-coal cleaning techniques such as column flotation, recovers a low-ash ultra-fine size clean-coal product. However, economical dewatering of the clean coal product to less than 20 percent moisture using conventional technology is difficult. This research program objective is to evaluate a novel coal surface modification technique developed at the University of Kentucky Center for Applied Energy Research in conjunction with conventional and advanced dewatering technique at a pilot scale. The study which is in progress is being conducted at the Powell Mountain Coal Company`s Mayflower preparation plant located in St. Charles, VA. During this quarter laboratory dewatering studies were conducted using a 4-in diameter laboratory chemical centrifuge. The baseline data provided a filter cake with about 32% moisture. Addition of 0.3 kg/t of a cationic surfactant lowered the moisture to 29%. Addition of anionic and non-ionic surfactant was not effective in reducing the filter cake moisture content. In the pilot scale studies, a comparison was conducted between the high pressure and vacuum dewatering techniques. The base line data with high pressure and vacuum filtration provided filter cakes with 23.6% and 27.8% moisture, respectively. Addition of 20 g/t of cationic flocculent provided 21% filter cake moisture using the high pressure filter. A 15% moisture filter cake was obtained using 1.5 kg/t of non-ionic surfactant. Vacuum filter provided about 23% to 25% moisture product with additional reagents. The high pressure filter processed about 3 to 4 times more solids compared to vacuum filter.

  8. Crustal-scale fluid migration and dewatering of the Costa Rica subduction zone

    NASA Astrophysics Data System (ADS)

    Bangs, N. L.; McIntosh, K. D.; Kluesner, J. W.; Silver, E. A.

    2014-12-01

    crustal scale fluid migration system extends from the lower slope and across much of the shelf implying broad, active dewatering of the seaward most 50 km of the overriding plate. We interpret this large scale fluid migration system as an actively dewatering fold and thrust sequence driven by recent thickening of sediment sequences within the margin wedge.

  9. Improved dewatering behavior of clay minerals dispersions via interfacial chemistry and particle interactions optimization.

    PubMed

    McFarlane, Angus; Bremmell, Kristen; Addai-Mensah, Jonas

    2006-01-01

    Orthokinetic flocculation of clay dispersions at pH 7.5 and 22 degrees C has been investigated to determine the influence of interfacial chemistry and shear on dewatering and particle interactions behavior. Modification of pulp chemistry and behavior was achieved by using kaolinite and Na-exchanged (swelling) smectite clay minerals, divalent metal ions (Ca(II), Mn(II)) as coagulants and anionic polyacrylamide copolymer (PAM A) and non-ionic polyacrylamide homopolymer (PAM N) as flocculants. The pivotal role of shear, provided by a two-blade paddle impeller, was probed as a function of agitation rate (100-500 rpm) and time (15/60 s). Particle zeta potential and adsorption isotherms were measured to quantify the interfacial chemistry, whilst rheology and cryogenic SEM were used to investigate particle interactions and floc structure and aggregate network, respectively. Osmotic swelling, accompanied by the formation of "honeycomb" particle network structure and high yield stress, was produced by the Na-exchanged smectite, but not kaolinite, dispersions. Dispersion of the clay particles in 0.05 M Ca(II) or Mn(II) solution led to a marked reduction in particle zeta potential, complete suppression of swelling, honeycomb network structure collapse and a concomitant reduction in shear yield stress of smectite pulps. Optimum conditions for improved, orthokinetic flocculation performance of negatively charged clay particles, reflecting faster settling flocs comprised (i) coagulation, (ii) moderate agitation rate, (iii) shorter agitation time, and (iv) anionic rather than non-ionic PAM. The optimum dewatering rates were significantly higher than those produced by standard, manual-mixing flocculation techniques (plunging and cylinder inversion) commonly used in industry for flocculant trials. The optimum flocculation conditions did not, however, have a significant impact on the final sediment solid content of 20-22 wt%. Further application of shear to pre-sedimented pulps

  10. Estimated Fall Chinook Salmon Survival to Emergence in Dewatered Redds in a Shallow Side Channel of the Columbia River

    SciTech Connect

    McMichael, Geoffrey A.; Rakowski, Cynthia L.; James, B B.; Lukas, Joe

    2005-08-01

    Fall Chinook salmon (Oncorhynchus tshawytscha) often spawn in the tailraces of large hydroelectric dams on the Columbia River. Redds built in shallow habitats downstream of these dams may be periodically dewatered due to hydropower operations prior to the emergence of fry. To determine whether fall Chinook salmon redds were successful in a shallow area subjected to periodic dewatering downstream of Wanapum Dam on the Columbia River, we installed 7 redd caps and monitored fry emergence. Large numbers of live fry were captured from the redds between March 9 and May 18, 2003. Estimated survival from egg to fry for these redds, which were all subjected to some degree of dewatering during the incubation and post-hatch intragravel rearing period, ranged from 16.1 to 63.2 percent and averaged 27.8 percent (assuming 4,500 eggs/redd). The peak emergence date ranged from April 1 to 29, with the average peak about April 14, 2003. Mean fork length of fall Chinook salmon emerging from individual redds ranged from 38.3 to 41.2 mm, and lengths of fish emerging from individual redds increased throughout the emergence period.

  11. Engineering development of advanced physical fine coal cleaning for premium fuel applications: Subtask 3.3 - dewatering studies

    SciTech Connect

    Yoon, R. H.; Phillips, D. I.; Sohn, S. M.; Luttrell, G. H.

    1996-10-01

    If successful, the novel Hydrophobic Dewatering (HD) process being developed in this project will be capable of efficiently removing moisture from fine coal without the expense and other related drawbacks associated with mechanical dewatering or thermal drying. In the HD process, a hydrophobic substance is added to a coal-water slurry to displace water from the surface of coal, while the spent hydrophobic substance is recovered for recycling. For this process to have commercialization potential, the amount of butane lost during the process must be small. Earlier testing revealed the ability of the hydrophobic dewatering process to reduce the moisture content of fine coal to a very low amount as well as the determination of potential butane losses by the adsorption of butane onto the coal surface. Work performed in this quarter showed that the state of oxidation affects the amount of butane adsorbed onto the surface of the coal and also affects the final moisture content. the remaining work will involve a preliminary flowsheet of a continuous bench-scale unit and a review of the economics of the system. 1 tab.

  12. Membrane-Based Energy Efficient Dewatering of Microalgae in Biofuels Production and Recovery of Value Added Co-Products

    SciTech Connect

    Bhave, Ramesh R; Kuritz, Tanya; Powell, Lawrence E; Adcock, Kenneth Dale

    2012-01-01

    The objective of this paper is to describe the use of membranes for energy efficient biomass harvesting and dewatering. We have evaluated the dewatering of Nannochloropsis sp. with polymeric hollow fiber and tubular inorganic membranes to demonstrate the capabilities of a membrane-based system to achieve microalgal biomass of >150 g/L (dry wt.) and ~99% volume reduction through dewatering. The particle free filtrate containing the growth media is suitable for recycle and reuse. For cost-effective processing, hollow fiber membranes can be utilized to recover 90-95% media for recycle. Tubular membranes can provide additional media and water recovery to achieve target final concentrations. Based on the operating conditions used in this study and taking into scale-up considerations, it can be shown that an integrated hollow fiber-tubular membrane system can process microalgal biomass with at least 80% lower energy requirement compared to traditional processes. Backpulsing was found to be an effective flux maintenance strategy to minimize flux decline at high biomass concentration. An effective chemical cleaning protocol was developed for regeneration of fouled membranes.

  13. Fundamental study for improvement of dewatering of fine coal/refuse. Annual report, June 1979-June 1980. Part I

    SciTech Connect

    Chiang, S.H.; Fulton, P.F.; Klinzing, G.E.; Tierney, J.W.; Chao, J.; Gala, H.; Kakwani, R.; Riquelme, G.; Roy, R.

    1980-07-01

    The particle size distribution of constituent coal samples was determined by the microscopic technique using the Omnicon Alpha Image Analyzer. Shape factors of non-spherical and irregular shaped particles were determined by stereology. Consolidated filter cake samples were prepared using vacuum impregnation techniques. After polishing these samples, the pore size analysis was carried out using the Omnicon Alpha Image Analyzer. These processes of preparing a consolidated cake and analyzing it with the image analyzer are standardized. The basic structure of a computer oriented network model for studying dewatering of fine coal has been specified. The model uses an idealized three dimensional representation of the pore space which consists of a set of nodes with interconnecting bonds. The model consist of four separate modules at present: (i) the network module determines the state of the network at a given fraction of bonds which can be opened; (ii) the breakthrough condition module determines the minimum fraction of open bonds which gives a continuous path across the network; (iii) the equilibrium desaturation module determines the equilibrium moisture content as a function of increasing pressure; and (iv) the dewatering rate module determines the rate of dewatering as a function of filtration parameters. 20 refs.

  14. Evaluation of hyperbaric filtration for fine coal dewatering. Tenth quarterly technical progress report, January 1, 1995--March 31, 1995

    SciTech Connect

    Parekh, B.K.; Leonard, J.W.; Hogg, R.; Fonseca, A.

    1995-09-01

    The main objectives of the project are to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20 percent moisture. The program consist of three phases: Phase I, model development; Phase II, laboratory studies; and Phase III, field testing. The Pennsylvania State University is leading efforts in Phase I, the University of Kentucky in Phase II, and Consol Inc. in Phase III of the program. All three organizations are involved in-all the three phases of the program. The Pennsylvania State University is developing a theoretical model for hyperbaric filtration systems, whereas the University of Kentucky is conducting experimental studies to investigate fundamental aspects of particle-liquid interaction and application of high pressure filter in fine coal dewatering. The optimum filtration conditions identified in Phase I and II will be tested in a Consol Inc. coal preparation plant using an Andritz Ruthner portable hyperbaric filtration unit. Accomplishments are discussed for all three phases of study.

  15. Evaluation of hyperbaric filtration for fine coal dewatering. Fourth quarterly technical progress report: June 1, 1993--September 30, 1993

    SciTech Connect

    Parekh, B.K.; Hogg, R.; Fonseca, A.

    1993-12-31

    The main objectives of the project are to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20 percent moisture. The program consist of three phases, Model Development, Laboratory Studies, and Field Testing. The Pennsylvania State University is leading efforts in Phase 1, the University of Kentucky in Phase 2, and Consol Inc. in Phase 3 of the program. All three organizations are involved in all the three phases of the program. The Pennsylvania State University is developing a theoretical model for hyperbaric filtration systems, whereas the University of Kentucky is conducting experimental studies to investigate fundamental aspects of particle-liquid interaction and application of high pressure filter in fine coal dewatering. The optimum filtration conditions identified in phase 1 and 2 will be tested in a Consol Inc. coal preparation plant using an Andritz Ruthner portable hyperbaric filtration unit.

  16. A comprehensive insight into the combined effects of Fenton's reagent and skeleton builders on sludge deep dewatering performance.

    PubMed

    Liu, Huan; Yang, Jiakuan; Zhu, Nairuo; Zhang, Hao; Li, Ye; He, Shu; Yang, Changzhu; Yao, Hong

    2013-08-15

    Conditioning sewage sludge with Fenton's reagent and skeleton builders has been proved to be an effective mean to achieve deep dewatering. This work aimed to give a comprehensive insight into the mechanism involved. The results show that significant synergistic effect existed between Fenton's reagent and skeleton builders. With the optimum dosage, water content of dewatered sludge cake could be reduced to 49.5±0.5%. Furthermore, raw sludge existed in the form of zoogloea and its flocs surface was plate-like. After Fenton oxidation, partial of extracellular polymeric substances (EPS) was destroyed and the amounts of protein and polysaccharide dissolved in filtrate increased. Meanwhile, sludge flocs turned into smaller ones. After adding skeleton builders, constantly-changing environment promoted senescence and death of microorganism. A large area of plate-like structure disappeared, instead of which were holes. Irregular non-living things inlayed or pierced microbial cells, promoting the conversion from bound water to free water as well as further reduction of the sludge particle size. Additionally, these irregular substances could form a rigid porous structure under high pressure, which could transmit the stresses to the sludge internal parts and provide outflow channels for free water. Consequently, conditioned sludge was suitable for high pressure deep dewatering. PMID:23721731

  17. Evaluation of hyperbaric filtration for fine coal dewatering. Ninth quarterly technical progress report, October 1--December 31, 1994

    SciTech Connect

    Parekh, B.K.; Leonard, J.W.; Hogg, R.; Fonesca, A.

    1995-04-01

    The main objectives of the project are to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20% moisture. The program consists of three phases, namely: model development; laboratory studies; and field testing. The Pennsylvania State University is leading efforts in Phase 1, the University of Kentucky in Phase 2, and Consol Inc. in Phase 3 of the program. The Pennsylvania State University is developing a theoretical model for hyperbaric filtration systems, whereas the University of Kentucky is conducting experimental studies to investigate fundamental aspects of particle-liquid interaction and application of high pressure filter in fine coal dewatering. The optimum filtration conditions identified in Phase 1 and 2 will be tested in a Consol Inc. coal preparation plant using an Andritz Ruthner portable hyperbaric filtration unit. Results to date from all three phases are discussed.

  18. Enhanced dewatering of sludge with the composite of bioflocculant MBFGA1 and P(AM-DMC) as a conditioner.

    PubMed

    Guo, Junyuan; Nengzi, Lichao; Zhao, Jing; Zhang, Yuzhe

    2015-04-01

    Bioflocculant MBFGA1 was investigated to be used as a conditioner for sludge dewatering, and the response surface methodology (RSM) was employed to study the enhancing performance of the dewatering process by the composite of MBFGA1 and poly(acrylamide [2-(methacryloyloxy)ethyl]-trimethylammonium chloride) (P(AM-DMC)). Results showed that dry solids (DS) and specific resistance to filtration (SRF) of sludge treated by MBFGA1 alone appeared as 21.7 % and 3.6 × 10(12) m kg(-1), respectively, which were much better than FeCl3, Al2(SO4)3, and polyaluminum chloride (PAC), but poorer than P(AM-DMC) in sludge dewatering. Apart from this, the optimized conditioning process for improving the dewaterability of the sludge conditioned by the composite is MBFGA1 of 1.4 g L(-1), P(AM-DMC) of 0.13 g L(-1), CaCl2 of 56.1 mg L(-1), pH value of 7.5, and agitation speed of 149 rpm. Under this optimal condition, DS and SRF appeared as 29.9 % and 2.2 × 10(12) m kg(-1), respectively. Thus, it is feasible and meaningful to enhance the dewaterability of the sludge by the compound uses of MBFGA1 and P(AM-DMC). PMID:25634018

  19. Evaluation of hyperbaric filtration for fine coal dewatering. First quarterly technical progress report, September 1, 1992--November 30, 1992

    SciTech Connect

    Parekh, B.K.; Hogg, R.; Fonseca, A.

    1992-12-31

    Most of the coal presently used by the utility industry is cleaned at preparation plants employing wet processes. Water, while being the mainstay of coal washing, is also one of the least desirable components in the final product. Coarse coal (+3/4 inch) is easily dewatered to a 3--4 percent moisture level using conventional vibrating screens and centrifuges. However, the main problem of excess product moisture occurs in fine (minus 28 mesh) coal and refuse. Even though fines may constitute only about 20 percent of a contemporary cleaning plant feed, they account for two-thirds of the product surface moisture. This high surface moisture offsets many of the benefits of coal cleaning, and can easily undercut the ongoing programs on recovery of fine clean coal from refuse as well as producing an ultra-fine super clean coal fuel. Currently, most of the coal preparation plants utilize vacuum disk type technology for dewatering of the fine coal, providing dewatered product containing about 25 percent moisture. The coal industry would prefer to have a product moisture in the range of 10 to 15 percent, thereby avoiding thermal drying of coal. Hyperbaric filtration. has shown potential in lowering moisture in fine coal to about 20 percent level. This project will develop fundamental information on particle-liquid interaction during hyperbaric filtration and apply the knowledge in developing optimum conditions for the pilot plant testing of the hyperbaric filter system.

  20. Evaluation of hyperbaric filtration for fine coal dewatering. Eleventh quarterly technical progress report, April 1, 1995--June 30, 1995

    SciTech Connect

    Parekh, B.K.; Hogg, R.; Fonseca, A.

    1995-12-01

    The main objectives of the project are to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20 percent moisture. The program consist of three phases, namely Phase I - Model Development, Phase II - Laboratory Studies, Phase III - Field Testing. The Pennsylvania State University is leading efforts in Phase I, the University of Kentucky in Phase II, and Consol Inc. in Phase III of the program. All three organizations are involved in all the three phases of the program. The Pennsylvania State University is developing a theoretical model for hyperbaric filtration systems, whereas the University of Kentucky is conducting experimental studies to investigate fundamental aspects of particle-liquid interaction and application of high pressure filter in fine coal dewatering. The optimum filtration conditions identified in Phase I and II will be tested in a Consol Inc. coal preparation plant using an Andritz Ruthner portable hyperbaric filtration unit.

  1. Evaluation of hyperbaric filtration for fine coal dewatering. Twelfth quarterly technical progress report, July 1, 1995--September 30, 1995

    SciTech Connect

    Parekh, B.K.; Hogg, R.; Fonseca, A.

    1996-02-01

    The main objectives of the project are to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20 percent moisture. The program consist of three phases, namely: (1) Phase I Model Development; (2) Phase II Laboratory Studies; and (3) Phase III Field Testing. The Pennsylvania State University is leading efforts in Phase I, the University of Kentucky in Phase 11, and Consol Inc. in Phase III of the program. All three organizations are involved in all the three phases of the program. The Pennsylvania State University is developing a theoretical model for hyperbaric filtration systems, whereas the University of Kentucky is conducting experimental studies to investigate fundamental aspects of particle-liquid interaction and application of high pressure filter in fine coal dewatering. The optimum filtration conditions identified in Phase I and II will be tested in a Consol Inc. coal preparation plant using an Andritz Ruthner portable hyperbaric filtration unit.

  2. Membrane-based energy efficient dewatering of microalgae in biofuels production and recovery of value added co-products.

    PubMed

    Bhave, Ramesh; Kuritz, Tanya; Powell, Lawrence; Adcock, Dale

    2012-05-15

    The objective of this paper is to describe the use of membranes for energy efficient biomass harvesting and dewatering. The dewatering of Nannochloropsis sp. was evaluated with polymeric hollow fiber and tubular inorganic membranes to demonstrate the capabilities of a membrane-based system to achieve microalgal biomass of >150 g/L (dry wt.) and ∼99% volume reduction through dewatering. The particle free filtrate containing the growth media is suitable for recycle and reuse. For cost-effective processing, hollow fiber membranes can be utilized to recover 90-95% media for recycle. Tubular membranes can provide additional media and water recovery to achieve target final concentrations. Based on the operating conditions used in this study and taking into scale-up considerations, an integrated hollow fiber-tubular membrane system can process microalgal biomass with at least 80% lower energy requirement compared to traditional processes. Backpulsing was found to be an effective flux maintenance strategy to minimize flux decline at high biomass concentration. An effective chemical cleaning protocol was developed for regeneration of fouled membranes. PMID:22510094

  3. Dewatered sewage biosolids provide a productive larval habitat for stable flies and house flies (Diptera: Muscidae).

    PubMed

    Doud, C W; Taylor, D B; Zurek, L

    2012-03-01

    Species diversity and seasonal abundance of muscoid flies (Diptera: Muscidae) developing in biosolid cake (dewatered biosolids) stored at a wastewater treatment facility in northeastern Kansas were evaluated. Emergence traps were deployed 19 May through 20 October 2009 (22 wk) and 27 May through 18 November 2010 (25 wk). In total, 11,349 muscoid flies were collected emerging from the biosolid cake. Stable flies (Stomoxys calcitrans (L.)) and house flies (Musca domestica (L.)), represented 80 and 18% of the muscoid flies, respectively. An estimated 550 stable flies and 220 house flies per square-meter of surface area developed in the biosolid cake annually producing 450,000 stable flies and 175,000 house flies. Stable fly emergence was seasonally bimodal with a primary peak in mid-July and a secondary peak in late August. House fly emergence peaked with the first stable fly emergence peak and then declined gradually for the remainder of the year. House flies tended to emerge from the biosolid cake sooner after its deposition than did stable flies. In addition, house fly emergence was concentrated around midsummer whereas stable fly emergence began earlier in the spring and continued later into the fall. Biosolid age and temperature were the most important parameters affecting emergence for house flies and stable flies, whereas precipitation was not important for either species. This study highlights the importance of biosolid cake as a larval developmental habitat for stable flies and house flies. PMID:22493845

  4. Water based demulsifier formulation and process for its use in dewatering and desalting crude hydrocarbon oils

    SciTech Connect

    Merchand, P.; Lacy, S. M.

    1985-11-05

    Oil is dehydrated and/or desalted by the influence of a dewatering and desalting formulation which can be characterized as an admixture of (i) a demulsifier preferably an alkylene oxide aklyl phenol-formaldehyde condensate such as a poly ethoxylated nonylphenol-for-maldehyde condensate and (ii) a deoiler which is usefully a polyol such as ethylene glycol or poly (ethylene glycol) of Mw ranging from 106 to 44,000 and preferably ethylene glycol. The aqueous formulation may usefully contain a cosolvent such as isopropanol. The surface active agent composition is admixed with the salt-containing oil which has been emulsified with water, and heated whereby the formulation of surface active agents aids in breaking of the emulsion and transfer of salts to the aqueous phase preferably after passage through an electric coalescer whereby a clean oil product suitable for use in refining operations is recovered with remarkably low oil carry under with the effluent water when ethylene glycol is formulated into the system as the deoiler.

  5. Dewatering of Chlorella pyrenoidosa using diatomite dynamic membrane: filtration performance, membrane fouling and cake behavior.

    PubMed

    Zhang, Yalei; Zhao, Yangying; Chu, Huaqiang; Zhou, Xuefei; Dong, Bingzhi

    2014-01-01

    The diatomite dynamic membrane (DDM) was utilized to dewater Chlorella pyrenoidosa of 2 g dry weight/L under continuous-flow mode, whose ultimate algae concentration ranged from 43 g to 22 g dry weight/L of different culture time. The stable flux of DDM could reach 30 L/m(2) h over a 24 h operation time without backwash. Influences of extracellular organic matters (EOM) on filtration behavior and membrane fouling were studied. The DDM was divided into three sub-layers, the slime layer, the algae layer and the diatomite layer from the outside to the inside of the cake layer based on components and morphologies. It was found that EOM caused membrane fouling by accumulating in the slime and algae layers. The DDM intercepted polysaccharides, protein-like substances, humic-like substances and some low-MW organics. Proteins were indicated the major membrane foulants with increased protein/polysaccharide ratio from the slime layer to the diatomite layer as culture time increased. This method could be applied to subsequent treatment of microalgae coupling technology of wastewater treatment or microalgae harvesting for producing biofuel. PMID:24148755

  6. Strategies for Treating and Dewatering Contaminated Soils and Sediments Simultaneously - 13389

    SciTech Connect

    Bickford, Jody; Foote, Martin

    2013-07-01

    MSE Technology Applications, Inc. (MSE) was asked to perform a series of treatability studies by Global Technologies, Inc. (Global) and M{sup 2} Polymer Technologies, Inc. (M{sup 2} Polymer) using Global's metal treatment agent, Molecular Bonding System (MBS) and M{sup 2} Polymer's super-absorbent polymer, Waste Lock 770 (WL-770). The primary objective of the study was to determine if the two products could be used as a one-step treatment process to reduce the leachability of metals and de-water soils and/or sediments simultaneously. Three phases of work were performed during the treatability study. The first phase consisted of generating four bench-scale samples: two treated using only MBS and two treated using only WL- 770, each at variable concentrations. The second phase consisted of generating nine bench-scale samples that were treated using MBS and WL-770 in combination with three different addition techniques. The third phase consisted of generating four intermediate-scale samples that were treated using MBS and WL-770 simultaneously. The soils used in the treatability study were collected at the Mike Mansfield Advanced Technology Center in Butte, Montana. The collected soils were screened at 4 mesh (4.75 millimeters (mm)) to remove the coarse fraction of the soil and spiked with metallic contaminants of lead, cadmium, nickel, mercury, uranium, chromium, and zinc. (authors)

  7. Enhanced dewatering of waste-activated sludge by composite hydrolysis enzymes.

    PubMed

    Wu, Boran; Chai, Xiaoli; Zhao, Youcai

    2016-04-01

    The feasibility of composite hydrolysis enzymes in enhanced dewatering of waste-activated sludge (WAS) was verified in this study. A Pearson correlation analysis was conducted to explore the roles of different extracellular polymeric substance (EPS) fractions on WAS dewaterability. The results indicated that tightly bound EPS (TB-EPS) was released into the liquid phase consistently during enzymatic hydrolysis to form soluble EPS (S-EPS) and loosely bound EPS and that the TB-EPS content was positively correlated with the capillary suction time of WAS. A kinetic analysis was carried out to gain further insights into the kinetic variation in TB-EPS removal. It was found that TB-EPS reduction fit a first-order kinetic model and that mild temperature (25-30 °C) and a slightly acidic condition were favorable for the improvement of enzyme activity. Solid phase extraction combined with UV-Vis spectroscopy analysis was used to characterize the processes of migration and transformation of the hydrophobic (HPO), transphilic and hydrophilic (HPI) fractions in EPS during the enzymatic process. The results revealed that HPO and HPI were mainly composed of PN and PS, respectively, and that the enzymatic hydrolysis could enhance the transformation of HPI from TB-EPS to S-EPS, which was the dominant mechanism of improving WAS dewaterability. PMID:26815556

  8. Cr and Ni recovery during bioleaching of dewatered metal-plating sludge using Acidithiobacillus ferrooxidans.

    PubMed

    Rastegar, S O; Mousavi, S M; Shojaosadati, S A

    2014-09-01

    This study determined the optimal conditions required to attain maximum metal recovery in the bioleaching process of dewatered metal-plating sludge using Acidithiobacillus ferrooxidans (A. ferrooxidans). Adaptation of this strain was carried up to 1% (w/v) of the sample. Three factors including initial pH, initial Fe(3+) concentration and pulp density were selected as the effective factors and were optimized using a central composite design of response surface methodology. An initial pH of 1, pulp density of 9 g/l and initial Fe(3+) concentration of 1g/l were determined to be optimum values by the statistical models. The highest extractions for Cr and Ni under optimal conditions were 55.6% and 58.2%, respectively. Bioleaching kinetics was investigated using a modified shrinking core model to better understand the mechanism of the leaching reaction. The model predictions indicate that the diffusion step controlled the overall dissolution kinetics and is the rate controlling step. PMID:24971945

  9. Compressional rheology: A tool for understanding compressibility effects in sludge dewatering.

    PubMed

    Stickland, Anthony D

    2015-10-01

    Water and wastewater treatment sludges exhibit compressible behaviour due to flocculation and aggregation. At a critical solids concentration called the gel point, which is as low as 1-2 v/v%, a continuous interconnected network of particles is formed that can resist an applied load. The applied load (mechanical filtration pressure or buoyancy in settling for example) must exceed the network strength in order to consolidate the network. The network strength increases with solids concentration such that the equilibrium extent of consolidation is a function of the applied load. Improved understanding of the nature of compressible suspensions can have a significant impact through optimising design and operation of sludge handling and dewatering processes. This work gives an overview of compressional rheology, which has proven to be a useful tool for describing the solid-liquid separation of compressible systems. This is followed by three examples where compressibility effects must be taken into account, namely the extraction of material properties for extremely compressible materials, consolidation and crust formation during constant rate evaporation, and the effect of bed height in thickening. PMID:26304591

  10. Mining nutrients (N, K, P) from urban source-separated urine by forward osmosis dewatering.

    PubMed

    Zhang, Jiefeng; She, Qianhong; Chang, Victor W C; Tang, Chuyang Y; Webster, Richard D

    2014-03-18

    Separating urine from domestic wastewater promotes a more sustainable municipal wastewater treatment system. This study investigated the feasibility of applying a forward osmosis (FO) dewatering process for nutrient recovery from source-separated urine under different conditions, using seawater or desalination brine as a low-cost draw solution. The filtration process with the active layer facing feed solution exhibited relatively high water fluxes up to 20 L/m(2)-h. The process also revealed relatively low rejection to neutral organic nitrogen (urea-N) in fresh urine but improved rejection of ammonium (50-80%) in hydrolyzed urine and high rejection (>90%) of phosphate, potassium in most cases. Compared to simulation based on the solution-diffusion mechanism, higher water flux and solute flux were obtained using fresh or hydrolyzed urine as the feed, which was attributed to the intensive forward nutrient permeation (i.e., of urea, ammonium, and potassium). Membrane fouling could be avoided by prior removal of the spontaneously precipitated crystals in urine. Compared to other urine treatment options, the current process was cost-effective and environmentally friendly for nutrient recovery from urban wastewater at source, yet a comprehensive life-cycle impact assessment might be needed to evaluate and optimize the overall system performance at pilot and full scale operation. PMID:24564179

  11. Ground-water conditions and effects of mine dewatering in Desert Valley, Humboldt and Pershing Counties, northwestern Nevada, 1962-91

    USGS Publications Warehouse

    Berger, D.L.

    1995-01-01

    Desert Valley is a 1,200-square-mile, north- trending, structural basin, about 30 miles northwest of Winnemucca, Nevada. Unconsolidated basin-fill deposits exceeding 7,000 feet in thickness constitute the primary ground-water reservoir. Dewatering operations at an open-pit mine began in the Spring of 1985 in the northeast part of Desert Valley. Ground-water withdrawal for mine dewatering in 1991 was greater than three times the estimated average annual recharge from precipitation. The mine discharge water has been allowed to flow to areas west of the mine where it has created an artificial wetlands. This report documents the 1991 hydrologic conditions in Desert Valley and the change in conditions since predevelopment (pre-1962). It also summarizes the results of analyzing the simulated effects of open-pit mine dewatering on a basin-wide scale over time. Water-level declines associated with the dewatering have propagated north and south of the mine, but have been attenuated to the west due to the infiltration beneath the artificial wetlands. Maximum water-level declines beneath the open pits at the mine, as of Spring 1991, are about 300 feet. Changes in the hydrologic conditions since predevelopment are observed predominantly near the dewatering operations and the associated discharge lakes. General ground-water chemistry is essentially unchanged since pre- development. On the basis of a ground-water flow model used to simulate mine dewatering, a new equilibrium may slowly be approached only after 100 years of recovery from the time mine dewatering ceases.

  12. Model development and evaluation of methane potential from anaerobic co-digestion of municipal wastewater sludge and un-dewatered grease trap waste.

    PubMed

    Yalcinkaya, Sedat; Malina, Joseph F

    2015-06-01

    The performance of anaerobic co-digestion of municipal wastewater sludge with un-dewatered grease trap waste was assessed using modified biochemical methane potential tests under mesophilic conditions (35°C). Methane potentials, process inhibition and chemical behavior of the process were analyzed at different grease trap waste feed ratios on volatile solids basis. Nonlinear regression analyses of first order reaction and modified Gompertz equations were performed to assist in interpretation of the experimental results. Methane potential of un-dewatered grease trap waste was measured as 606 mL CH4/g VS(added), while methane potential of municipal wastewater sludge was only 223 mL CH4/g VS(added). The results indicated that anaerobic digestion of grease trap waste without dewatering yields less methane potential than concentrated/dewatered grease trap waste because of high wastewater content of un-dewatered grease trap waste. However, anaerobic co-digestion of municipal wastewater sludge and grease trap waste still yields over two times more methane potential and approximately 10% more volatile solids reduction than digestion of municipal wastewater sludge alone. The anaerobic co-digestion process inhibitions were reported at 70% and greater concentrated/dewatered grease trap waste additions on volatile solids basis in previous studies; however, no inhibition was observed at 100% un-dewatered grease trap waste digestion in the present study. These results indicate that anaerobic co-digestion of un-dewatered grease trap waste may reduce the inhibition risk compared to anaerobic co-digestion of concentrated/dewatered grease trap waste. In addition, a mathematical model was developed in this study for the first time to describe the relationship between grease trap waste feed ratio on volatile solids basis and resulting methane potential. Experimental data from the current study as well as previous biochemical methane potential studies were successfully fit to this

  13. POC-scale testing of an advanced fine coal dewatering equipment/technique. Quarterly technical progress report 3, April--June 1995

    SciTech Connect

    Groppo, J.G.; Parekh, B.K.

    1995-08-05

    Economical dewatering of an ultra-fine clean coal product to a 20% or lower level moisture will be an important step in successful implementation of the advanced fine coal cleaning processes. The main objective of the proposed program is to evaluate a novel surface modification technique, which utilizes the synergistic effect of metal ions-surfactant combination, for dewatering of ultra-fine clean coal on a proof-of-concept (POC) scale of 1 to 2 tph. The novel surface modification technique developed at the UKCAER will be evaluated using vacuum, centrifuge, and hyperbaric filtration equipment. Dewatering tests will be conducted using the fine clean coal froth produced by the column flotation units at the Powell Mountain Coal Company, Mayflower Preparation Plant in St. Charles, Virginia. The POC-scale studies will be conducted on two different types of clean coal, namely, high sulfur and low sulfur clean coal. The Mayflower Plant processes coals from five different seams, thus the dewatering studies results could be generalized for most of the bituminous coals. During this quarter, addition of reagents such as ferric ions and a novel concept of in-situ polymerization (ISP) was studied in the laboratory. Using the ISP approach with vacuum filtration provided 25% moisture filter cake compared to 65.5% moisture obtained conventionally without using the ISP. A series of dewatering tests were conducted using the Andritz hyperbaric pilot filter unit with high sulfur clean coal slurry.

  14. Metagenomic Comparison of Antibiotic Resistance Genes Associated with Liquid and Dewatered Biosolids.

    PubMed

    McCall, Crystal A; Bent, Elizabeth; Jørgensen, Tue S; Dunfield, Kari E; Habash, Marc B

    2016-03-01

    Municipal biosolids (MBs) that are land-applied in North America are known to possess an active microbial population that can include human pathogens. Activated sludge is a hotspot for the accumulation of antibiotics and has been shown to be a selective environment for microorganisms that contain antibiotic resistance genes (ARGs); however, the prevalence of ARGs in MBs is not well characterized. In this study, we enriched the plasmid metagenome from raw sewage sludge and two CP2 MBs, a mesophilic anaerobic digestate and a dewatered digestate, to evaluate the presence of ARGs in mobile genetic elements. The CP2-class biosolids are similar to Class B biosolids in the United States. The CP2 biosolids must meet a microbiological cut off of 2 × 10 colony-forming units (CFU) per dry gram or 100 mL of biosolids. The enriched plasmid DNA was sequenced (Illumina MiSeq). Sequence matching against databases, including the Comprehensive Antibiotic Resistance Database (CARD), MG-RAST, and INTEGRALL, identified potential genes of interest related to ARGs and their ability to transfer. The presence and abundance of different ARGs varied between treatments with heterogeneity observed among the same sample types. The MBs plasmid-enriched metagenomes contained ARGs associated with resistance to a variety of antibiotics, including β-lactams, rifampicin, quinolone, and tetracycline as well as the detection of extended spectrum β-lactamase genes. Cultured bacteria from CP2 MBs possessed antibiotic resistances consistent with the MBs metagenome data including multiantibiotic-resistant isolates. The results from this study provide a better understanding of the ARG and MGE profile of the plasmid-enriched metagenome of CP2 MBs. PMID:27065392

  15. A new model of coal-water interaction and relevance for dewatering. Final report

    SciTech Connect

    Suuberg, E.M.; Yun, Y.; Lilly, W.D.; Leung, K.; Gates, T.; Otake, Y.; Deevi, S.C.

    1995-02-01

    This project was concerned with developing an improved understanding of how moisture is held in coals. There is a concern that the historically held view, that capillary condensation in pores plays a significant role, could not be correct, since the coal shrinks and swells in response to moisture loss and gain. Thus there is no well-defined pore system for holding the moisture. This appears true for a range of ranks from lignite to high volatile bituminous coal. Instead, it appears that something more like classical swelling of coals in solvents is responsible. This study examined this hypothesis by various means, considering both the mixing thermodynamics of coal and water (or coal and other swelling solvents) and by examining coal`s elastic response. The conclusion is that water does indeed behave like many other swelling solvents, but is a somewhat poor swelling solvent. The structure of the water swollen coal appears to remain fairly glassy, implying that many non-covalent crosslinks remain unbroken. The water interacts with coal only at certain types of adsorption sites. This is consistent with a second historical view that polar functionality is responsible for water retention. The filling of these sites, somewhat surprisingly, appeared to involve a strong enthalpic driving force, rather than the entropic driving force that characterizes solvent swelling in other solvents. The practical importance of these results for thermal dewatering processes is that the historical view is supported. That is, that pyrolytic polar group removal is necessary. An alternative suggestion, based upon attempts to further crosslink coal, has not received support.

  16. Sludge dewatering and stabilization in drying reed beds: characterization of three full-scale systems in Catalonia, Spain.

    PubMed

    Uggetti, Enrica; Llorens, Esther; Pedescoll, Anna; Ferrer, Ivet; Castellnou, Roger; García, Joan

    2009-09-01

    Optimization of sludge management can help reducing sludge handling costs in wastewater treatment plants. Sludge drying reed beds appear as a new and alternative technology which has low energy requirements, reduced operating and maintenance costs, and causes little environmental impact. The objective of this work was to evaluate the efficiency of three full-scale drying reed beds in terms of sludge dewatering, stabilization and hygienisation. Samples of influent sludge and sludge accumulated in the reed beds were analysed for pH, Electrical Conductivity, Total Solids (TS), Volatile Solids (VS), Chemical Oxygen Demand, Biochemical Oxygen Demand, nutrients (Total Kjeldahl Nitrogen (TKN) and Total Phosphorus (TP)), heavy metals and faecal bacteria indicators (Escherichiacoli and Salmonella spp.). Lixiviate samples were also collected. There was a systematic increase in the TS concentration from 1-3% in the influent to 20-30% in the beds, which fits in the range obtained with conventional dewatering technologies. Progressive organic matter removal and sludge stabilization in the beds was also observed (VS concentration decreased from 52-67% TS in the influent to 31-49% TS in the beds). Concentration of nutrients of the sludge accumulated in the beds was quite low (TKN 2-7% TS and TP 0.04-0.7% TS), and heavy metals remained below law threshold concentrations. Salmonella spp. was not detected in any of the samples, while E. coli concentration was generally lower than 460MPN/g in the sludge accumulated in the beds. The studied systems demonstrated a good efficiency for sludge dewatering and stabilization in the context of small remote wastewater treatment plants. PMID:19369066

  17. Pilot Scale Single Stage Fine Coal Dewatering and Briquetting Process. Technical report, March 1, 1996 - May 31, 1996

    SciTech Connect

    Wilson, J.W.; Honaker, R.Q.; Ding, Y.; Ho, K.

    1996-12-31

    The primary goal for this ICCI coal research project is to effectively liberate coal from fnely disseminated minerals for Illinois Basin coal by using fine grinding and cleaning processes. However, because of the large surface area generated during the cleaning processes, it is difficult and uneconomic for conventional techniques to dewater the coal fines. In addition, these coal fine pose transportation, storage and handling problems at cleaning and utility facilities. The objective of this research is to combine dewatering and briquetting processes into a single stage operation that will solve the problems mentioned above. To build on the promising results obtained from the previous studies, a pilot scale commercial briquetting machine was used to evaluate this technique. The primary objective of the research in this reporting period is to determine the effectiveness of a single stage dewatering and briquetting technique using a commercial briquetting device. Two types of samples were prepared and the results of the -28 x 100 mesh samples are presented in this report. Modifications were made to the machine in an attempt to solve the back drainage problem. A total of six experiments were conducted and the results indicate that water resistance of coal briquettes increased as curing time increased. However, due to a deficiency of fine particles to bridge the gaps between the coarse particles, the wear resistance of the products declined. Also, at high roll speeds and compaction pressures, the coal briquettes produced tended to have higher moisture content and lower strength. On the other hand, at high feed rates, because of the screw extrusion effect, coal briquettes were produced with lower moisture content and higher strengths.

  18. Study of de-watering from the gelatinous precipitate formed during co-precipitation of Nd-YAG powder

    SciTech Connect

    Karmakar, Sanjib; Sharma, Rachna; Pathak, S. K.; Gupta, S. M.; Gupta, P. K.

    2013-02-05

    Neodymium doped Yttrium Aluminium Garnet (Nd:YAG) ceramics have been synthesised using coprecipitation technique and high temperature vacuum sintering. Gelatinous like precipitates were obtained when precursors of Nd, Al and Yb-nitrate solutions are co-precipitated using ammonia co-precipitant. De-watering from the gelatinous like precipitates is a big challenge and it possesses difficulty in filtration. Evaporation of water by heating resulted in strong agglomerated powder. Different agents were used to ease the filtration process, which is correlated with the phase in the calcined powder.

  19. POC-scale testing of an advanced fine coal dewatering equipment/technique. Quarterly technical progress report, No. 4, July 1995--September 1995

    SciTech Connect

    Groppo, J.G.; Parekh, B.K.

    1995-11-06

    Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 {mu}m) clean coal. Economical dewatering of an ultra-fine clean coal product to a 20 percent level moisture will be an important step in successful implementation of the advanced cleaning processes. This project is a step in the Department of Energy`s program to show that ultra-clean coal could be effectively dewatered to 20 percent or lower moisture using either conventional or advanced dewatering techniques. The cost-sharing contract effort is for 36 months beginning September 30, 1994. This report discusses technical progress made during the quarter from July 1 - September 29, 1995.

  20. POC-scale testing of an advanced fine coal dewatering equipment/technique. Quarterly technical progress report 2, January 1995--March 1995

    SciTech Connect

    Groppo, J.G.; Parekh, B.K.

    1995-05-05

    Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 {mu}m) clean coal. Economical dewatering of an ultra-fine clean coal product to a 20 percent level moisture will be an important step in successful implementation of the advanced cleaning processes. This project is a step in the Department of Energy`s program to show that ultra-clean coal could be effectively dewatered to 20 percent or lower moisture using either conventional or advanced dewatering techniques. The cost-sharing contract effort is for 36 months beginning September 30, 1994. This report discusses technical progress made during the quarter from January 1 to March 31, 1995.

  1. POC-scale testing of an advanced fine coal dewatering equipment/technique. Quarterly technical progress report, April 1996--June 1996

    SciTech Connect

    Tao, D.; Groppo, J.G.; Parekh, B.K.

    1996-07-31

    Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 {mu}m) clean coal. Economical dewatering of an ultra-fine clean coal product to a 20 percent level moisture will be an important step in successful implementation of the advanced cleaning processes. This project is a step in the Department of Energy`s program to show that ultra-clean coal could be effectively dewatered to 20 percent or lower moisture using either conventional or advanced dewatering techniques. The cost sharing contract effort is for 36 months beginning September 30, 1994. This report discusses technical progress made during the quarter from April 1 - June 30, 1996.

  2. Field evaluation of gas-lift and progressive-cavity pumps as effective dewatering methods for coalbed methane wells. Final report, April 1984-December 1985

    SciTech Connect

    Graves, S.L.; Hollingsworth, F.C.; Beavers, W.M.

    1986-03-01

    Field evaluations of gas-lift and progressive-cavity pumps were conducted to determine their effectiveness as dewatering techniques for coalbed-methane wells in the Warrior Coal Field. AMPCO installed a gas-lift system in AMPCO Well No. 6. Problems included poor performance of all gas-lift valve designs and higher instantaneous water production rates than anticipated due to heading and unloading. The test provided the conclusion that gas lift is an effective start-up dewatering tool for initial removal of large amounts of water and solids but that in use as a long-term dewatering tool, needs additional evaluation relative to capital cost, valve design, and extended performance.

  3. Poc-Scale Testing of an Advanced Fine Coal Dewatering Equipment/Technique

    SciTech Connect

    B.K. Parekh; D. Tao; J.G. Groppo

    1998-10-21

    In the last quarterly report, it was noticed that the baseline dewatering data varied significantly. This abnormality was attributed to the use of house vacuum which varied significantly during the testing. This quarter tests were repeated using a portable vacuum pump which provided a constant vacuum of 25 inches of mercury. Using 30 secs cake drying time and 30 secs cake formation time, the high- and low-porosity ceramic leaf filters provided 21.5% and 18.0% filter cake moistures, respectively. The solids loading on the high- and low-porosity filters were 0.8 Kg/m 2 and 0.44 Kg/m 2 , respectively. Addition of 10 g/t of an anionic flocculant lowered the filter cake moisture from 22.0% to 14.0% using the high-porosity filter, and 18.0% to 13.5% using the low-porosity filter. Addition of 15 g/t of a cationic flocculant lowered filter cake moisture from 18.0% to 16.0% using the low-porosity filter. High-porosity filter did not provide any lowering of filter cake moisture, however, the solids loading increased from 1.5 kg/m 2 to 5.8 kg/m 2 at a flocculant dosage of 25 g/t. This high solids loading indicated thicker filter cake which would retain a high moisture. Among the three surfactants studied, only the non-ionic and the cationic were effective in lowering the filter cake moisture. 0.4 kg/t of a non-ionic surfactant (octyl phenoxy polyethoxy ethanol) lowered filter cake moisture from 19.5% to 16.8%; and 1 kg/t of the cationic surfactant CPCL, lowered the filter cake moisture from 19.0% to 15.8%. Addition of 0.4 kg/t of copper ions or 0.3 kg/t of aluminum ions lowered the filter cake moisture from 20.5% to 17.0%, using the low-porosity filter. The high-porosity filter which showed increase solids loading (thicker filter cakes) did not provide any lowering of the filter cake moisture. Low-porosity filter was found to be more effective in lowering the filter cake moisture than high-porosity ceramic filter. However, high-porosity was more effective in providing higher

  4. Decolorization and biodegradation of the Congo red by Acinetobacter baumannii YNWH 226 and its polymer production's flocculation and dewatering potential.

    PubMed

    Li, Ruijing; Ning, Xun-an; Sun, Jian; Wang, Yujie; Liang, Jieying; Lin, Meiqing; Zhang, Yaping

    2015-10-01

    The strain Acinetobacter baumannii YNWH 226 was utilized to degrade Congo red (CR) under aerobic conditions. CR was employed as the sole carbon source to produce extracellular polymeric substances (EPS) used as potent bioflocculants in this strain. A total of 98.62% CR was removed during the 48-h decoloration experiments using CR (100 mg/L). A total of 83% bioadsorption and 65% biodegradation were responsible for the decoloration and degradation of CR through the strain. The bioflocculant showed high flocculation activity and dewaterability on textile dyeing sludge. A maximum flocculation of 78.62% with a minimum SBF of 3.07×10(9) s(2)/g and a CST of 58.4 s were achieved. We investigated the internal relationship between the decolorization efficiency of YNWH 226 and the flocculation activity and dewatering capacity of its EPS. The components and structure of the EPS highly influenced the decolorization efficiency of CR and the flocculation activity and dewatering capacity on sludge. PMID:26207869

  5. [Single-stage autotrophic nitrogen removal reactor with self-generated granular sludge for treating sludge dewatering effluent].

    PubMed

    Cao, Jian-ping; Du, Bing; Liu, Yin; Qin, Yong-sheng

    2009-10-15

    Single-stage autotrophic nitrogen removal (SANR) has been observed in a long-term operated nitrosation air-lift reactor for treating digested sludge dewatering effluent from sewage wastewater treatment plant. A kind of so called self-generated granular sludge which undertake the SANR reaction has oriented formed. The performance of SANR reactor cultivated above sludge for treating sludge dewatering effluent has been tested and better results have been reached. When the influent total nitrogen (TN) was kept about 350 mg/L (mainly ammonium nitrogen), the average TN removal efficiency and nitrogen removal load were 74.8% (maximum 86.92%) and 0.68 kg x (m3 x d)(-1) [maximum 0.9 kg x (m3 x d)(-1)] respectively. The operation stability and nitrogen removal efficiency have been enforced after adding a certain quantity powered activated carbon. The influent ammonium concentration, nitrogen load and aeration rate have a great effect on SANR reactor as well as the influent organic compound, pH, alkalinity have a relatively low effect. The parameters such as the ratios of aeration rate/deltaTN, aeration rate/deltaNH4+ -N, deltaALK/deltaTN can be used for better controlling the reaction. PMID:19968119

  6. Survival and behaviour of juvenile unionid mussels exposed to thermal stress and dewatering in the presence of a sediment temperature gradient

    USGS Publications Warehouse

    Archambault, L.; Cope, W. Gregory; Kwak, Thomas J.

    2014-01-01

    Our findings suggest that rising stream water temperature and dewatering may directly impact freshwater mussel abundance by causing mortality and may have indirect impacts via sublethal effects. Reduced burrowing capacity may hamper ability to escape predation or unfavourably high or low flows, and decreased byssus production may inhibit attachment and dispersal capabilities in juveniles.

  7. Enhanced dewatering of excess activated sludge through decomposing its extracellular polymeric substances by a Fe@Fe2O3-based composite conditioner.

    PubMed

    He, Dong-Qin; Luo, Hong-Wei; Huang, Bao-Cheng; Qian, Chen; Yu, Han-Qing

    2016-10-01

    Efficient sludge dewatering methods are highly desired by municipal wastewater treatment plants. In this study, Fe@Fe2O3 nanomaterial, combined with polydiallyldimethylammonium chloride (PDMDAAC) and H2SO4, was used for sludge dewatering. This composite conditioner exhibited an excellent dewatering capability. By using uniform design, the optimized dosages of Fe@Fe2O3, H2SO4 and PDMDAAC were determined to be 40, 136 and 4.8mg/gDS (dry solids), respectively. The moisture content of sludge cake decreased from 78.1% to 64.8%, and the capillary suction time from 56 to 21s. The sludge extracellular polymeric substances (EPS) were decomposed, resulting in greater conversion of the bound water into free water and the release of free water. The electron spin resonance results show that the molecular oxygen activation process induced by Fe@Fe2O3 produced hydroxyl radicals, which were mainly responsible for the EPS decomposition. In this way, an efficient composite conditioner for enhancing sludge dewatering was developed. PMID:27395000

  8. POC-scale testing of an advanced fine coal dewatering equipment/technique: Quarterly technical progress report No. 9, October 1996--December 1996

    SciTech Connect

    Tao, D.; Groppo, J.G.; Parekh, B.K.

    1997-01-21

    The advanced fine-coal cleaning techniques such as column flotation, recovers a low-ash ultra-fine size clean-coal product. However, economical dewatering of the clean coal product to less than 20 percent moisture using conventional technology is difficult. This research program objective is to evaluate a novel coal surface modification technique developed at the University of Kentucky Center for Applied Energy Research in conjunction with conventional and advanced dewatering technique at a pilot scale at the Powell Mountain Coal Company`s Mayflower preparation plant located in St. Charles, VA. During this quarter in the laboratory dewatering studies were conducted using copper and aluminum ions showed that for the low sulfur clean coal slurry addition of 0.1 Kg/t of copper ions was effective in lowering the filter cake moisture from 29 percent to 26.3 percent. Addition of 0.3 Kg/t of aluminum ions provided filter cake with 28 percent moisture. For the high sulfur clean coal slurry 0.5 Kg/t of copper and 0.1 Kg/t of aluminum ions reduced cake moisture from 30.5 percent to 28 percent respectively. Combined addition of anionic (10 g/t) and cationic (10 g/t) flocculants was effective in providing a filter cake with 29.8 percent moisture. Addition of flocculants was not effective in centrifuge dewatering. In pilot scale screen bowl centrifuge dewatering studies it was found that the clean coal slurry feed rate of 30 gpm was optimum to the centrifuge, which provided 65 percent solids capture. Addition of anionic or cationic flocculants was not effective in lowering of filter cake moisture, which remained close to 30 percent for both clean coal slurries.

  9. Effects of sludge retention time on oxic-settling-anoxic process performance: Biosolids reduction and dewatering properties.

    PubMed

    Semblante, Galilee U; Hai, Faisal I; Bustamante, Heriberto; Price, William E; Nghiem, Long D

    2016-10-01

    In this study, the effect of sludge retention time (SRT) on oxic-settling-anoxic (OSA) process was determined using a sequencing batch reactor (SBR) attached to external aerobic/anoxic reactors. The SRT of the external reactors was varied from 10 to 40d. Increasing SRT from 10 to 20d enhanced volatile solids destruction in the external anoxic reactor as evidenced by the release of nutrients, however, increasing the SRT to 40d did not enhance volatile solids destruction further. Relatively short SRT (10-20d) favoured the conversion of destroyed solids into inert products. The application of an intermediate SRT (20d) of the external reactor showed the highest sludge reduction performance (>35%). Moreover, at the optimum SRT, OSA improved sludge dewaterability as demonstrated by lower capillary suction time and higher dewatered cake solids content. PMID:27474952

  10. Chemical sludge conditioning in combination with different conventional and alternative dewatering devices: chamber filter press, decanter and Bucher press.

    PubMed

    Schaum, Christian; Cornel, Peter; Faria, Pedro; Recktenwald, Michael; Norrlöw, Olof

    2008-11-01

    The Kemicond process for sludge conditioning consists of chemical treatment with sulphuric acid and hydrogen peroxide at a pH-value of approximately 4 followed by a dewatering unit. It is shown that chemical treatment can improve the dewaterability of ferruginous digested sludge. It is concluded that the Fenton process as well as the oxidation of organics and the formation of iron hydroxo complexes are important reaction mechanisms. Furthermore, the organic matter changes through the acidic oxidative process. With the improvement in dewaterability, it is possible to achieve an increase in TS concentration, which affects a reduction of the sludge volume. Cost savings for sludge disposal can amortize the additional investment and operational costs for chemical treatment. PMID:18821238