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Impact statementA symposium at the 2023 American Fisheries Society meeting highlighted collaborations among biologists, policymakers, and Native American tribes addressing conservation for native lampreys. We present key findings from the symposium and related research and an example of grassroots effort to protect and restore Pacific Lamprey. [ABSTRACT FROM AUTHOR]

Objective: Dewatering of fine sediments in rivers and streams can kill many thousands of larval lampreys (order Petromyzontiformes) that are burrowed in these habitats. The larval life stage for lampreys lasts 3–10 years, and because larvae often aggregate in large numbers, negative impacts from dewatering could potentially deplete local populations and affect multiple year‐classes. Larval lampreys have not traditionally been considered during instream projects, but recent efforts to increase awareness of lamprey habitats have resulted in guidance on dewatering approaches to limit impacts to lampreys. Salvage efforts to rescue and relocate lampreys aim to mitigate losses, but a lack of understanding of lamprey responses limits the optimization of dewatering and salvage procedures. Methods: We summarize the state of the science for nine factors that influence larval lamprey (Entosphenus and Lampetra spp.) responses to dewatering, including burrowing depth, the prevalence and timing of emergence, movements, survival, shoreline slope, dewatering rate, light, and lamprey size. Result: Research suggests that (1) shoreline slope influences movement capability, (2) hot and sunny conditions increase the risk of mortality, (3) salvage activities cause minimal direct mortality, and (4) smaller larvae are especially vulnerable to negative impacts from dewatering because they are more likely to emerge and are less capable of movement. Critical uncertainties associated with dewatering include cues that drive emergence, the influence of sediment composition and stratigraphy, vertical distribution of larvae in natural settings, use of the hyporheic zone, the scale of predation losses, and the effectiveness and impacts of salvage activities. Conclusion: Balancing investments in salvage operations and lamprey exclusion efforts (e.g., screening) and developing field survey approaches to evaluate lamprey use of the hyporheic zone are identified management implications and research needs. Addressing the critical uncertainties discussed here and providing updated, science‐based guidance on dewatering and salvage practices are suggested management actions to support lamprey conservation. Impact statementLarval lampreys live burrowed in fine sediments and are often not considered during instream projects that dewater these habitats. This paper synthesizes what is known about lamprey responses to dewatering to provide updated, science‐based guidance on dewatering approaches to minimize negative impacts to lamprey and support conservation efforts. [ABSTRACT FROM AUTHOR]

The filling of landfilled municipal sludge (LMS), which is typical of high water content and low strength, poses great challenges for the landfill expansion and its mechanical stability. This study proposed a synergistic method to treat the LMS using ferrous sulfate (FS)-conditioning and cementitious materials (e.g., lime, fly ash, and cement) solidification. A series of water content, unconfined compressive strength (UCS), pH, and toxicity leaching tests were conducted to evaluate the dewatering/solidification performance of this synergistic method. The results showed that this synergistic method was effective in LMS dewatering and solidification. For the LMS tested, the proposed optimum dosage was 7 % FS, 4 % lime, 5 % fly ash, and 10 % cement, which is a much lower usage than similar studies in the literature. At this dosage, the treated LMS after 28 days of curing exhibited water content of 57.8 %, UCS of 279.1 kPa, pH value below 10.0, and no leaching toxicity, which satisfied the landfill disposal requirement by Chinese standard GB/T 23485–2009. Microscopic analyses (e.g., optical microscope, bound water measurement, scanning electron microscopy, and X-ray diffraction) revealed that FS-conditioning destroyed the colloidal agglomerate in the sludge and released the bound water to become free water; then, the cementitious materials reacted with the free water and generated cementation products (e.g., ettringite, and calcium silicate/aluminate hydrate), which significantly improved the sludge strength. The novelty of this work is that the proposed synergistic use of FS and cementitious materials, relative to the traditional method, is more effective in sludge dewatering and solidification and yet has a lower cost. [Display omitted] • FS is an effective and economical chemical conditioner for LMS conditioning. • The solidified LMS can easily meet the requirements for landfill disposal. • The proposed method shows substantial superiority over other similar methods. [ABSTRACT FROM AUTHOR]

Backfilling technology is recognized as a consensus to achieve green and safe developing of mineral resources that could effectively fill the underground goafs using mine waste and tailings. As one of indispensable means of efficient solid-liquid separation, the deep cone thickener (DCT) has become an important gripper for treatment of mine wastes consist of waste rocks, mineral processing tailings and metallurgical slags, which eventually obtaining stable, high concentration paste backfilling slurry. However, it still faces tricky problems in industrial operations such as poor stability of underflow concentration and excessive frequent system structural failure. To further explore the scientific understanding and regulation, this paper focuses on the sedimentation, thickening, and dewatering mechanisms in DCT, systematically reviews the breakthroughs of particles feeds migration, collision and agglomerates, discusses the multi-scale morphological features of flocs growth, analyses the structural features of DCT (rake frame, feed well, etc.) and its influence on underflow concentration, explores mathematical modelling and the prediction of key parameter distribution (shear forces, solid concentration, fluid velocity, turbulence, etc.) inside DCT, and proposes the optimization and controlling methods in DCT operations. These discussions proposed in this paper further deepening the understanding of tailing thickening procedure via DCT, which could give some reference to related the researches of future generations. [Display omitted] • Understanding of sedimentation, thickening, and dewatering mechanisms inside DCT are proposed. • Multi-scale detection, properties and modelling predictions of DCT thickening are reviewed. • Mechanisms of key parameters and its potential optimization methods of DCT are discussed. [ABSTRACT FROM AUTHOR]

Municipal sludge treatment in urban contexts faces significant challenges, especially when dealing with sludge characterized by exceptionally high water content and organic content. This study investigates the application of sodium persulfate oxidation activated by ferrous ions (Fe2+/SPS) in conjunction with waste steel slag as a conditioning agent for municipal sludge, capillary suction time and specific resistance filtration experiments were conducted on conditioned sewage sludge, along with dewatering tests under ultrahigh pressure conditions. Additionally, to investigate the potential underlying mechanisms, Scanning Electron Microscopy analysis, Zeta potential measurements, and comprehensive sample analyses were performed. The research reveals substantial improvements in sludge dewatering performance when steel slag is combined with Fe2+/SPS treatment. This combined treatment introduces additional ferrous ions into the sludge, generating radicals that disrupt the structure of extracellular polymeric substances and cells within the sludge. Steel slag also acts as a skeleton builder material, creating larger drainage pathways within the sludge cake under ultrahigh pressure, enhancing permeability, and accelerating moisture release. This combined treatment method holds promise for achieving deep sludge dewatering, under ultrahigh filtration pressure, with water content reduced to below 40%. The study not only highlights the advantages of using steel slag in combination with Fe2+/SPS treatment for sludge dewatering but also provides insights into the underlying mechanisms. This comprehensive treatment method reduces the excessive use of ferrous ions and costs while significantly enhancing dewatering performance, offering a promising solution for municipal sludge treatment and management. [Display omitted] • Steel slag in combination with Fe2+/Na 2 S 2 O 8 for sludge conditioning is firstly proposed. • Ultrahigh filtration pressure reaches 30 MPa. • Steel slag reduces the excessive use of ferrous ions. • Larger drainage pathways within the sludge cake under ultrahigh pressure are created by steel slag. • The bound water was released and reduced significantly. [ABSTRACT FROM AUTHOR]

Steady population growth has resulted in increasing the land prices which led to construction of deep excavation pits, necessary for tall buildings and underground spaces. One of the most important issues in the design of deep foundations and underground spaces is how to deal with the groundwater. Considering the difficulty of excavation and construction under wet condition, in most of the projects the groundwater level is preferred to be dropped under the construction level, the operation called 'dewatering'. However, the dewatering operation has its own issues such as ground settlement and environmental impacts. In this research, the amounts of settlements due to excavation and dewatering were calculated separately using analytical and numerical models for Taklar 2 excavation pit located at the north-eastern part of Tehran city, as a case study. The analytical and numerical data were compared with some settlement data measured directly at the field. The results of this study confirmed that the numerical finite element method is appropriate for simulation of the settlement around excavation pits. The portion of settlement due to dewatering was estimated to be about 30 per cent of the total settlement during excavation operations. [ABSTRACT FROM AUTHOR]

One of the methods for in-site soil treatment is the use of electro-osmosis process. The other method is pre-fabricated vertical drains (PVD). In this research, these two methods combined and used in a soil mass that was subjected to improvement process under three different voltages for 24 days. Changing the soil temperature, moisture content, and pH during the process, at the end of the electro-osmosis, the surrounding soil of the anode and the cathode were subjected to consolidation and XRF test to evaluate and determine the quantity and quality of the elements on the anode and cathode sides, separately. The results showed that with lower voltage, the moisture loss rate of the soil, especially in the early days of the experiment, is significantly reduced, and subsequently the rate of improvement decreased. However, increasing the voltage did not necessarily improve the soil at the anode and the cathode side. Abbreviations: PVD: pre-fabricated vertical drains; pH: potential of Hydrogen [ABSTRACT FROM AUTHOR]

• A hybrid dewatering and air-preheating system mounted to coal-fired boiler was investigated. • New attainable ideal and unavoidable cases for combustion process were identified. • Improved potential of combustion system was conducted as 74.4%. • The critical dewatered moisture content was found as 20%. • A saving of about 29.54% in fuel consumption was determined. In this study, a parametric advanced exergy analysis was conducted for the waste heat recovery of a pulverized coal-fired power plant. In this aim, a new attainable ideal and the technically available unavoidable case for the combustion process were identified. Under the identified improved potential term, different unavoidable cases were parametrically investigated for the hybrid dewatering and air preheating process to improve the combustion process. In this aim, different removed moisture contents, air preheating conditions, and effectiveness of both internal and external heat exchangers were thermodynamically evaluated in terms of the combustion process. The improved potential was calculated as 74.4% for the whole combustion system. The critical moisture removal ratio was calculated as 20%. The effects of rehabilitation on improved potential were found as 2.80 points per 1% of effectiveness increase for the self (internal) heat exchangers of the boiler, 1.68 points per 1% of effectiveness increase for HE-I and HE-II (external heat exchangers), and 0.62 points per 1% increase of dewatered moisture ratio. Besides, a saving of about 29.54% was determined in fuel consumption for the most appropriate unavoidable condition. [Display omitted] [ABSTRACT FROM AUTHOR]

When pumping is conducted in confined aquifer inside excavation pit (waterproof curtain), the direction of the groundwater seepage outside the excavation changes from horizontal to vertical owing to the existence of the curtain barrier. There is no analytical calculation method for the groundwater head distribution induced by dewatering inside excavation. This paper first analyses the mechanism of the blocking effects from a close barrier in confined aquifer. Then, a simple equation based on analytical solution is proposed to calculate groundwater heads inside and outside of the excavation pit with waterproof curtain (hereafter refer to close barrier) in a confined aquifer. The distribution of groundwater head is derived according to two conditions: (i) pumping with a constant water head, and (ii) pumping with a constant flow rate. The proposed calculation equation is verified by both numerical simulation and experimental results. The comparisons demonstrate that the proposed model can be applied in engineering practice of excavation. Image 1 • Analyze mechanism of the blocking effects from the barrier in confined aquifer. • Propose analytical models to calculate head distribution inside and outside of the pit in confined aquifer. • Calculate distribution of head for two scenarios of pumping with constant head and constant flow rate. • Analytical solutions verified by numerical simulation and experimental field tests. [ABSTRACT FROM AUTHOR]

Soft-sediment deformation structures (SSDS) including slumped beds and dewatering and diapiric structures are relatively common in the youngest part of the Triassic succession exposed on the English south coast between Seaton, Devon and Lyme Regis, Dorset. They have been attributed to fluidisation as a result of slope failure or shockwaves caused by earthquakes, storm waves or bolide impact. Few of these structures can be proved to be the result solely of a seismic event. However, diapiric structures that are restricted to a single bed and over a small area in the oldest (Rhaetian, Triassic) part of the Blue Lias formation at Pinhay Bay, Lyme Regis are morphologically similar to structures developed in present-day sediments in seismically active areas. The Pinhay Bay examples appear to have been initiated by a single event: some of them are associated with minor movements along fractures in the underlying beds. They are interpreted as the result of a small local earthquake, the last in a series of minor tectonic events in the latest Triassic that were related to the opening of the English Channel. [ABSTRACT FROM AUTHOR]

The performance of the immobilized lysozyme and the native lysozyme on enhancing the excess sludge dewaterability was investigated. The results indicated that the specific resistance to filtration (SRF) decreased by 62.8% for native lysozyme and 53. 6% for immobilized lysozyme at the enzyme dosage of 9 mg/g (dry sludge). Correlation analysis was carried out to explore the role of different extracellular polymeric substance (EPS) fractions on excess sludge dewaterability. The results illustrated that the SRF negatively correlated with protein, polysaccharide from soluble EPS (S-EPS) and loosely bound EPS (LB-EPS) and positively correlated with that from tightly bound EPS (TB-EPS). Three-dimensional excitation emission matrix (3D-EEM) fluorescence analysis combined with the scanning electron microscope (SEM) images, revealed that sludge floc structure and microbial cells were destroyed by enzymatic treatment, and that the enzymatic hydrolysis could help to improve the transformation of hydrophilic groups from TB-EPS and the performance of the excess sludge dewatering process. The assessment of hydrolysis using the immobilized enzyme provided a new insight for the safe disposal of the sludge. [ABSTRACT FROM AUTHOR]

Abstract In recent times, there has been a rise in interest on the applications of electro-technology based food processing methods. With drying in food industries being an energy intensive process with huge environmental impacts, the objective of this study was to design and develop a purpose-built laboratory system, for experimentally characterising an energy efficient electro-osmosis dewatering system. Electro-osmosis is a unique dewatering technique in which, moisture in food materials are removed by the application of low electric field (5-30 V). Different food materials namely, yogurt, orange pulp and egg whites were tested using electro-osmosis at 15 V and 30 V over 15 min and 30 min, respectively. The energy consumption (kWh), carbon footprint (kgCO 2 e) and cost indices (£/kg dried food) were also evaluated and compared with thermal drying. [ABSTRACT FROM AUTHOR]

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Highlights • A green catalyst was synthesized and immobilized inside a tubular quartz reactor. • C:N:TiO2 nano particles have unique light harvesting features in visible region. • H2O2 and ClO- combination provided excellent electron transfer in PST. • O2 was the main active specie and OH also contributed to sludge remediation. • Sludge drying rate enhanced by the applied method under visible light irradiation. Abstract In this research, carbon and nitrogen doped TiO 2 nano-particles were successfully synthesized and immobilized onto inner surface of a tubular thin film reactor (TTFR). CO 3 -N x O y -TiO 2 nano-composite thin films (NCTF(s)) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Characterization results indicated that the CO 3 -N x O y -TiO 2 NCTF has a broad adsorption edge in the visible light region. Decorated TTFR was used to observe the impacts of visible light irradiation on sludge dewatering characteristics and organic structure. In the experiments, H 2 O 2 , NaOCl and their various gravimetric combinations were added to the sludge as electron acceptor combination (EAC). Obtained experimental results revealed a photocatalytic synergy between hydrogen peroxide and chlorite molecules. The optimum H 2 O 2 and OCl mixing dosage for photocatalytic and photolytic experiments was determined to be 0.02 g H 2 O 2 g−1 DS and 4 × 10-3 g−1 NaOCl g−1 DS, respectively. The pseudo-first order kinetic constants (k obs) for volatile solids (VS) removal observed in EAC 3 (with NCTF), EAC 2 (with NCTF) and photolysis were 0.140 min−1, 0.045 min−1 and 0.025 min−1, respectively. The average VS removal rate depending on the applied unit photonic power to unit TTFR area was 218 ± 14 mgVS removed W−1 h−1 cm−2. Experimental results obtained using different EAC(s) dosage schemes revealed that O 2 was the main active specie and HO radicals also contributed to sludge treatment. Naphthalene, pyrene, anthracene and phenanthrene were detected in raw sludge and removed 87 ± 1% by the method. [ABSTRACT FROM AUTHOR]

Abstract Dewatering and handling of pulp and paper mill sludge is challenging and often comprises more than half of the overall wastewater treatment costs at a mill. Primary sludge is usually more dewaterable than biosludge (waste activated sludge), and the ratio between both types of sludge largely determines the dewaterability of the sludge mix. This study has quantified the benefits of adding primary sludge to biosludge to enhance the dewaterability in terms of cake solids and filtrate/pressate solids content. Furthermore, the effects of the particle size distribution and the monovalent to divalent cation ratio of the various types of sludge were investigated. Biosludge and three types of primary sludge from a Canadian pulp and paper mill were mixed at various ratios and tested for dewaterability using a Crown Press®, a bench-scale device which simulates industrial belt press dewatering. Results show that after addition of primary sludge at up to 40% mass proportion (dry solids basis) the dewatered cake solids content increased substantially, from 10.4% to 18.7–19.9%, depending on the type of primary sludge added. Further addition of primary sludge led to comparably only small improvements. Primary sludge addition also resulted in decreased total suspended solids (TSS) concentrations in the combined gravity filtrate / Crown Press pressate. Primary sludge content of only 10% in the sludge mix was sufficient to decrease the TSS concentration from 1.8 g /L to 0.2 – 0.4 g /L. The study shows that only less than half of the sludge mix needs to consist of primary sludge, in order to achieve adequate dewaterability. This opens up the possibility of retaining more primary fiber within the pulping process, without compromising downstream sludge dewatering. [ABSTRACT FROM AUTHOR]

Highlights • Flocculation using AFlok-BP1 was effective than alum to harvest marine microalgae Nannochloropsis sp. at acidic pH 5. • More than 90% efficiency was obtained using AFlok-BP1. • Bridging mechanism is involved in flocculation of Nannochloropsis sp. as supported by the reduction of zeta potential value to −0.33 ± 0.27 mV. Abstract Harvesting, a challenging step of microalgae processing appears to be promising using flocculation method by the addition of tannin based natural biopolymer, AFlok-BP1. In this study, marine microalgae Nannochloropsis sp. was flocculated using AFlok-BP1 to evaluate its effectiveness in terms of flocculation efficiency, pH and dosages used, zeta potential, floc morphology characterization with comparison to the uses of aluminium sulphate and alkaline-induced pH. Oleaginous marine microalgae Nannochloropsis sp. was found to work effectively using AFlok-BP1 at an acidic pH 5 with more than 90% efficiency obtained at 160 mg/L. The finding was further supported with great instability of microalgae surface charge of -0.33 ± 0.27 mV, hence maximum destabilization of microalgae was believed to occur. The use of alum also effective to harvest Nannochloropsis sp. at neutral pH 7 with comparable efficiency as AFlok-BP1, but high dosage needed for more than 300 mg/L was at major concerns. Similarly, improved efficiency was observed for alkaline-induced pH for almost 100% efficiency. This would provide a better alternative for marine microalgae flocculation however, high concentration of minerals in the harvested biomass due to pH increase in need of further evaluation. To summarize, AFlok-BP1 would be a viable option to harvest marine microalgae Nannochloropsis sp. for the production of valuable compounds as it is an environmental friendly flocculant and provide no potential toxicity to the harvested biomass. [ABSTRACT FROM AUTHOR]

The present work focuses on the application of pH-induced sedimentation combined with dynamic filtration for microalgae culture concentration at pilot scale. Concentrations were performed on cultures of two microalgae species: Dunaliella tertiolecta and Chlorella sorokiniana . The objective of the combined process was to reduce microalgae dewatering costs. It is true that sedimentation reduces operation costs considerably, but the results of membrane filtration offer a total rejection and high final concentrations, at even a cheaper cost than centrifugation. When using the two technologies in series, high concentration factors with values up to 207.4 for Dunaliella tertiolecta and 245.3 for Chlorella sorokiniana were achieved. The final concentration of Dunaliella tertiolecta was 184.58 g L −1 with 81.5% of water content in the sludge. The concentrations obtained were high enough to dispense with further operations for the sludge to be ready for a cell disruption step using steam explosion. Analytic techniques used were dry weight and optical density. For the filtration, experiments were performed using both commercially available and self-prepared membranes, manufactured from Acrylonitrile Butadiene Styrene: a novel polymer in membrane technology, selected to reduce costs. Each of them could perform in a similar way to commercial membranes in a pilot scale high-shear stress membrane module. [ABSTRACT FROM AUTHOR]

Microalgal biomass is processed into products by two main process steps: 1) harvesting and dewatering; and 2) extraction, fractionation and conversion. The performance of unit operations for harvesting and dewatering is often expressed in qualitative terms, like “high energy consumption” and “low in operational cost”. Moreover, equipment is analysed as stand-alone unit operations, which do not interact in a chain of operations. This work concerns a quantitative techno-economic analysis of different large-scale harvesting and dewatering systems with focus on processing cost, energy consumption and resource recovery. Harvesting and dewatering are considered both as a single operation and as combinations of sequential operations. The economic evaluation shows that operational costs and energy consumption are in the range 0.5–2 €·kg − 1 algae and 0.2–5 kWh·kg − 1 of algae, respectively, for dilute solutions from open cultivation systems. Harvesting and dewatering of the dilute systems with flocculation results in the lowest energy requirement. However, due to required chemicals and loss of flocculants, these systems end at the same cost level as mechanical harvesting systems. For closed cultivation systems the operational costs decrease to 0.1–0.6 €·kg − 1 algae and the energy consumption to 0.1–0.7 kWh·kg − 1 algae. For all harvesting and dewatering systems, labour has a significant contribution to the total costs. The total costs can be reduced by a high level of automation, despite the higher associated investment costs. The analysis shows that a single step operation can be satisfactory if the operation reaches high biomass concentrations. Two-step operations, like pressure filtration followed by spiral plate technology or centrifugation, are attractive from an economic point of view, just as the operation chain of flocculation followed by membrane filtration and a finishing step with spiral plate technology or centrifugation. [ABSTRACT FROM AUTHOR]

The harvesting of microalgae for biofuel production consists of a primary concentration step, followed by a separation step to isolate the microalgal biomass from its aquatic environment. Recent research focussed mainly on the technological feasibility of various separation processes. However, to what extent these innovative harvesting strategies have been commercialized and therefore have led to actual innovation in the current microalgae biotech industry by the creation of intellectual property, has remained unexplored. This study reviews the scientific literature based on technological, economical and environmental criteria of 13 primary and 8 secondary harvesting methods. Commercial deployment was evaluated via patent analysis. Auto- and co-flocculation, as well as sedimentation, overall scored best for economic (CAPEX and OPEX) and environmental (energy and GHG) criteria, while belt filters scored the highest on the technological criteria (TSS). Hence, only 4 patents based on auto-/co-flocculation, sedimentation and only two for belt filtration are still in force. Technologies based on organic, electrolytic and magnetic flocculation seem to be more successfully patented. Since patenting involves making the technology freely available for others, small but sometimes crucial improvements in low-tech systems may be often kept as a company secret instead. So far, no single harvesting process with superior feasibility has emerged for application on a large commercial scale. This is mainly due to the difference in relative importance of technological, economical and environmental criteria for each harvesting process dependent on the used strain and the final products. [ABSTRACT FROM AUTHOR]

Anaerobic digestion coupled with dewatering is a common and widely used sludge treatment methods in a wastewater treatment plant (WWTP). Many researchers have employed adaptive neuro-fuzzy logic inference system (ANFIS) successfully to optimize the output of anaerobic digesters. However, there is no published work on the application of ANFIS to optimize the performance of the dewatering section of a WWTP. In this study, ANFIS was applied to model the relationship between biosolid quality (total solid content in biosolid) to total solid, volatile solid content, volatile fatty acid of digested sludge and polymer dose. Historical data on various physico-chemical process parameters such as total solid, volatile solid, volatile fatty acid content of digested sludge, total solid content of biosolid and polymer dose from the dewatering section of a WWTP over a period of four years was used for the analysis. The modelling study showed that the optimum total solid content (DS TS) was in the lower DS TS range of 1.3–1.5% w/w and the optimum volatile solid content (DS VS) was also in the lower DS VS range of 70–75% of TS of the digested sludge. The Optimum polymer dose range of 20 to 60 kg/ton of dry solid (kg/TDS) showing better biosolid capture compared to higher polymer dose ranges for the same total solid and volatile solid content. It was found that lower total solid and volatile solid concentration coupled with relatively low polymer dose yield higher biosolid capture rate. ANFIS based predictive model are useful for determination of optimum polymer dose in efficient dewatering performance. [ABSTRACT FROM AUTHOR]

Sludge dewatering is an important process in municipal wastewater treatment and critically influences the subsequent transportation and disposal. Thermal treatment coupled with other chemical processes has been widely used to improve sludge dewaterability. However, information about the response of sludge extracellular polymeric substances (EPS) to thermal treatment and its role in sludge dewatering is still limited. In this work, the effects of thermal treatment on anaerobic and aerobic sludges were investigated with an emphasis on the colloid properties of released EPS in sludge dewatering process. The results indicate that sludge dewaterability became deteriorated with the increased temperature in the range of 30–170 °C, which was ascribed to the disintegration of sludge flocs and change of EPS characteristics. Disintegrated sludge induced the release of the negatively charged EPS, resulting in the weakened bridging interaction and lower compactness. After thermal treatment, the EPS with a higher average molecular weight and stretched coil configuration retained more water. In addition, difference in dewaterability between anaerobic and aerobic sludges was found to be attributed to their different contents and structures of EPS components. These results provide an insight into thermal-dependent sludge dewatering process and are useful to facilitate water-sludge separation. [ABSTRACT FROM AUTHOR]

Microalgae are an excellent source of sustainable biofuels. However, the current microalgal growth using traditional liquid-based culture is not economically viable as the price of microalgal biofuel is still higher compared to its fossil fuel counterpart. In fact, microalgal dewatering requires substantial energy and represents a major bottleneck limiting the industrial microalgal mass production. Compared to conventional planktonic microalgae growth systems, the attached growth or biofilm-based growth represents several advantages such as higher biomass content compared to liquid culture and lower capital costs, which has a great potential to help microalgal fuels reach economic viability. However, despite the many advantages of biofilm-based growth, limited work has been reported on their use to mass produce microalgal biofuels or bioproducts. This review discusses the factors affecting microalgal biofilms growth as well as the challenges that hinder their large-scale production. Several parameters such as the microalgal strain, the microalgal adhesion to the substrate, operation conditions, and physico-chemical properties of the substrate are outlined in depth. This review highlights the current challenges in microalgal biofilm development and identifies strategies to improve biofilms growth, to optimize the economics of microalgal biomass production and downstream processing, and to promote the commercial industrialization of algal biofilm. A preliminary economic assessment of Chlorella sp. , Spirulina sp. and Scenedesmus sp. biofilms compared to liquid cultivation is evaluated, showing that the biomass production costs for biofilm-based cultivation system are 8–10 times lower than that of suspension-based cultivation system. [Display omitted] • The conventional biofuel production from microalgae is not economically viable. • Microalgal biofilms offer several advantages over conventional suspended cultivation. • The factors affecting biofilm growth are outlined in depth. • An economic study comparing biofilm growth to the liquid cultivation is evaluated. [ABSTRACT FROM AUTHOR]

This article addresses an innovative pit design and sludge dewatering in rural areas in developing countries. The innovative pit design which also function as sludge dewatering system is low cost, easy to implement and highly efficient. The system uses a mobile metal cage lined with a filter bag to collect the sludge. Based on this design, emptying the pit and transporting the dewater sludge is far much cheaper and easier than current practice (using vacuum trucks). The dewatering technique uses time instead of pressure to dewater the sludge. The results showed that a pit with 4 m 3 capacity can save the owner the cost of emptying the pit and 83% the cost of transporting the sludge via current method. It also saves the water treatment plant around $50 cost of dewatering the sludge from a single pit using dewatering machines. [ABSTRACT FROM AUTHOR]

The management of the huge amount of dredged sediments is an important issue to be solved worldwide, and dewatering is by far the most critical step when fine grained sediments are involved. Different technologies have been proposed in time to speed up the process. Even though electro-kinetic treatment is in principle one of them, it has not been implemented yet at an industrial scale, and only few trial applications are known. For such a reason, a multidisciplinary research activity is ongoing at the University of Napoli Federico II in the framework of the EU commitment ROSE with the aim to analyse the effectiveness and feasibility of such a technology from the lab to the site scale. In this paper, some evidences stemming from lab tests are presented. The results indicate that the application of low voltages improves the mechanical behaviour of the tested soil. In this case, however, the improvement is due more to a change in microstructure than to a decrease in void ratio. [ABSTRACT FROM AUTHOR]

The article presents the basic characteristics of composition and formation of combined sludges of steel mills, machine and metalworking factories. The principal issues of use of flocculants in dewatering of combined sludges of industrial wastewaters are stated. The article dwells upon the issues of a flocculant selection for treatment of industrial wastewaters of machine factories, and creation of optimal conditions for flocculation sludges processing. The problems of handling and disposal of sludges produced by industrial wastewaters treatment facilities are considered. The main purpose of this research is assessment of the possibility of advanced flocculation technique application for the treatment of combined sludges. [ABSTRACT FROM AUTHOR]

Whenever thickening, filtering and clarifying concentrates or residues, the question is: “What is the best equipment to choose?” This presentation gives guidelines to help evaluate equipment options. [ABSTRACT FROM AUTHOR]

In the process of urban construction, a large number of mud is produced. But the current treatment and disposal method of building mud has low efficiency and high cost. In order to facilitate the effective treatment of the subsequent mud, mud dewatering need to reduce the processing cost and realize the goal of sludge reduction as an important pre process to meet the requirements of national environmental protection. From the analysis of comprehensive index of energy consumption, investment operation cost of technology and economy, sludge hot-pressing drying technology will be one of the key development areas. Through the analysis of the composition and the dewatering performance of the building mud, the inorganic components were mainly SiO 2 and Al 2 O 3 , which was similar to the clay and was difficult to deal with. The pilot test was conducted with the method of heating, pressure, adding filter aid, etc. Research showed that the main factors affecting the height of mud cake formation were the mud particle size, the dynamic viscosity, the initial sludge concentration, etc. The effect of heating and pressing was remarkable. By using the similar amplification principle, the mud treatment equipment, which was based on hot-pressing drying technology, was designed. And the mud water content was controlled within 30%. [ABSTRACT FROM AUTHOR]

Recently, the disposal of dredged soil has become a worldwide problem. In order to utilize high water content soil material, it is essential to dewater and increase the soil strength. There are urgent demands for developing an alternative new method to dewater the dredged soils in more economical and environment friendly standpoint. Furthermore, by using adsorption effect of porous material such as granular blast furnace slag, there is possibility to establish purification technology of contaminated soil. In this paper, the siphon method is proposed to dewater the high water content dredged soil with horizontally installed plastic board drain and filter material. In order to investigate the availability and effectiveness of this method, series of tests were conducted to investigate the dewatering behaviour and strength of dredged soil with vacuum and siphon methods by using different materials as filter, such as Toyoura sand, zeolite, granular blast furnace slag. High water content dredged soil can be consolidated by using siphon method with saturated filter material such as Toyoura sand. However, it was impossible to dewater dredged soil by using siphon method with unsaturated porous filter material. The water retention tests of soil by using centrifuge method was performed to clarify the mechanism of preventing consolidation dredged soil. The test cannot find an accurate soil-water retention curve of dredged soil because of volume change. The water retention test by suction method was performed and clarify the mechanism that prevents consolidation dredged soil. The cause that prevents consolidation of dredged soil has been presumes by clarifying the air entry value. In addition, degree of saturation and suction in dredged soil and filter material has been clarified by using aquameters. The examination whether consolidation of dredged soil on various conditions focused on height of dredged soil and filter material is performed based on the revealed mechanism. [ABSTRACT FROM AUTHOR]

Acid mine drainage (AMD), specifically from opencast lignite mining, contains large quantities of dissolved iron, can be strongly acidic, and may emerge in high volume flows. In addition, AMD can contain heavy metals and toxic elements in high concentrations. Aquifers can be contaminated by the diffuse input of these pollutants. In conjunction with rising groundwater level, in particular during reclamation, the surrounding rivers and lakes may be infiltrated and thus water quality can deteriorate. To reduce the environmental impact, hoisted waters from operating lignite mines are currently treated in complex pit water purification systems. Thereby, water pH is raised and dissolved iron precipitates as gelatinous iron hydroxide, which hardly settles. To remove precipitates more efficient, a rotating microfiltration membrane module was tested as alternative process step in the current process. The present study investigates the performance of a 2.0 μm ceramic compact rotating disc (CRD) out of α-Al 2 O 3 . Through the rotary motion, the layer formation on the membrane surface shall be minimized. Furthermore, the solid content of the AMD water should be raised simultaneously. The experiments were carried out in cross-flow and dead-end set-up at transmembrane pressures between 1.2 and 1.9 bar. The experimental results show that retention of iron was higher than 99.9% if AMD water was treated with a precipitant. Moreover, the permeate flux was raised by a factor of 5.9 if the precipitated iron hydroxide was treated with a polymeric flocculant. In addition, the solid content was increased maximally by a factor of 10 to over 15% in the dead-end set-up at a stable and still considerable permeate flux. The achieved solid content can be compared to mechanical dewatering devices but operational costs may be lowered. On basis of the experimental results, the technical integration of a rotating membrane module can be suggested to remove iron hydroxide and enhance the solid content. [ABSTRACT FROM AUTHOR]

Microalgae are promising renewable feedstocks for producing biodiesel as an alternative to conventional diesel. However, the major bottleneck in microalgal biodiesel production is a rather high energy consumption and production costs, which limit the economic feasibility and industrial commercialization. In microalgal downstream processing, biomass dewatering and drying constitute the major challenge in terms of cost and energy. In this regard, several techniques have been developed to produce biodiesel from wet biomass, but the cost of biodiesel production is still higher than that of diesel. To date, reviews in this field generally focus on methods of producing biodiesel from wet microalgae and do not compare the different methods in terms of operation and efficiency. Here, we investigated and summarised different biodiesel production techniques from wet microalgae, and reviewed factors affecting cell wall disruption, lipid extraction, and lipid conversion. Further, challenges that hinder the industrial-scale production of biodiesel from wet microalgae are critically analysed in terms of production costs, production processes, and environmental concerns. We also provided a critical and in-depth insight into the challenges of microalgal biodiesel production and identified pragmatic strategies to put forward with the current research for economical biodiesel production from microalgae. [Display omitted] • Microalgal dewatering and drying are the major bottleneck in biodiesel production. • The conventional biodiesel production from microalgae is not economically viable. • Biodiesel production from wet microalgae is promising. • In situ biodiesel production is more efficient than other existing processes. • Current research and challenges of wet in-situ transesterification are critically discussed. [ABSTRACT FROM AUTHOR]

Groundwater and stone are intensively exploited in Wallonia (southern region of Belgium). The water table located in the mined geological formation might be reached when the quarry is deepened. Dewatering is therefore performed to depress the water table below the pit bottom in order to continue the activity in dry conditions. This affects the regional hydrogeology and the productivity of the nearby water catchments for the public distribution. In order to recommend an adequate feasibility study and minimize the impact on the environment, an interaction index, based on the equation used in the assessment of natural disasters, was developed. [ABSTRACT FROM AUTHOR]

Twenty-five natural and synthetic cationic polymers of different molecular weights and charge densities were evaluated for microalgae flocculation. Tanfloc is a natural low molecular weight tannin polymer whereas Zetag and Flopam are both synthetic high molecular weight polyacrylamide polymers. Five exponential concentrations (0.55, 1.66, 5, 15 and 45 mg L − 1 ) were tested for freshwater Chlorella vulgaris and marine Nannochloropsis oculata . All polymers were efficient (> 90% at ≥ 1.66 mg L − 1 ) for C. vulgaris . However, for N. oculata , only Tanfloc was effective. Charge density positively influenced flocculation decreasing the required polymer dosage. Restabilization was observed only for synthetic polymers when overdosed. Natural polymers performed similarly for both species. Overall, Tanfloc SL and Flopam FO 4990 SH were the most efficient polymers for microalgae flocculation though Tanfloc is a more economical option (US$37 per ton − 1 of biomass) and environmentally friendly than Flopam (US$171 per ton − 1 of biomass). [ABSTRACT FROM AUTHOR]

The turbidimetric and capillary suction time (CST) methods were used for the assessment of some properties (e.g., filtration process, water uptake etc.) of diatomite–bentonite based conditioners for dewatering of effluents from digestate of a biogas plant. These physical conditioners were prepared based on natural porous highly dispersible systems such as bentonite and diatomaceous earth. A characterization of the materials was performed by scanning electron microscopy (SEM) and fluorescence of X-rays spectrometry (XRF). A cationic polyacrylamide polymer (ZETAG ® 9014) was added prior to the dewatering process of the anaerobic digestion residue and an optimal dose of the mineral conditioner and the polymer was determined. It was suggested the formula, by means of which the amount of separated water was identified as water retention capacity (WRC). A favorable filterability region was determined with WRC between 1.5 and 4.4 (high level of WRC) and 1.5 and 2.9 (low level of WRC) in terms of the percentage of polymer in the dry cake. [ABSTRACT FROM AUTHOR]

Residential areas of Kuwait have been affected by rising groundwater levels for many years. The main reason for this problem is the increased recharge derived from the excessive irrigation of gardens and parks, and leaks from sewage networks, where the hydraulic characteristics of the lithology play an important role in intensifying the impacts of this phenomenon at local scale. The objective of this paper is to assess the hydrological conditions of Al-Qurain residential area to identify the extent and the causes of the water rise problem. A total of 25 wells of various depths were drilled, constructed and sampled at the study area. Water level loggers installed in the drilled wells indicated that water levels are fluctuating on daily bases and increasing up to 50 cm during winter months due to the reduction of evapotranspiration and recharge from rainfall. Combining the water level records and the results of the isotopic, chemical and biological analysis, it was concluded that the top 20 m of the aquifer water is made up of mostly irrigation, waste and rain water in addition to the aquifer groundwater. It was also observed that the intruding water from lower Dammam aquifer is dominating the aquifer beneath 40 m depth. This conclusion along with the steep topography of the area explained why this area is naturally prone to water rise. The study recommended the utilization of integrated system of dewatering wells along with desalination units to lower the water level and re-utilize the groundwater. On the prevention side, it is recommended to conduct an awareness campaign that educate the residents of the impacts of over use of water on their own properties. [ABSTRACT FROM AUTHOR]

This paper is devoted to analysis of oil treatment technology in the case of complex industrial process realization and further selection of technological mode. Mathematical modelling method is used to improve the efficiency of dewatering and desalting processes. The simulation system based on module modelling principle is developed. Every module is described in terms of appropriate combination of phenomena and processes. Problems of oil treatment analysis of complex structured technological scheme and searching of effective dewatering and desalting processes technological modes are solved. [ABSTRACT FROM AUTHOR]

Mining is located in Rosia Jiu Rovinari mining basin and its activity lignite exploitation by mining method combined with partial transport and internal transport tailings dump dump partial interior based extraction flow technology continuous large-capacity machines . Mining contributes to environmental pollution by large quantities of waste they produce and their diversity . It is necessary to loosen formations or aquifer dewatering, drainage and waste water that is inside masses of rock and coal for operations in normal conditions. For quantitative assessment of pollution levels produced in the quarry dewatering works Rosia Jiu, were sampled from environmental factors ael, surface water and air, the methods established by the regulations in force. Samples were analyzed according to STAS sites in force and as the results were given grades of creditworthiness for each medium. To assess the impact on the environment, we used the method of evaluation of the state of global environmental pollution by calculating IPG. [ABSTRACT FROM AUTHOR]

Mining is located in Rosia Jiu Rovinari mining basin and its activity lignite exploitation by mining method combined with partial transport and internal transport tailings dump dump partial interior based extraction flow technology continuous large-capacity machines. Mining contributes to environmental pollution by large quantities of waste they produce and their diversity. It is necessary to loosen formations or aquifer dewatering, drainage and waste water that is inside masses of rock and coal for operations in normal conditions. For quantitative assessment of pollution levels produced in the quarry dewatering works Rosia Jiu, were sampled from environmental factors ael surface water and air, the methods established by the regulations in force. Samples were analyzed according to STAS sites in force and as the results were given grades of creditworthiness for each medium. To assess the impact on the environment, we used the method of evaluation of the state of global environmental pollution by calculating IPG [ABSTRACT FROM AUTHOR]

Abstract: The manufacture of deinked pulp generates large amounts of waste for disposal. The yield loss in the production of recycled paper can be up to 25%. The use of landfills for waste disposal is very expensive and will be prohibited in Europe in the next few years. Thus, there is a great pressure to improve the material efficiency and to reduce the amount of waste that is produced at deinked pulp mills. However, the issue is complex because an improvement of the material efficiency at one process unit may deteriorate the performance of other stages. For example, the attempts to increase the fibre yield in the deinking processes can lead to poor sludge dewatering properties, resulting in that there are no added advantages for the mill anymore. This work aims to determine the limitations between the sludge dewatering properties and the improvements in material efficiency at a deinked pulp mill by investigating the dewatering properties of sludge samples that contained variable amounts of fine screening and flotation froth rejects. The results show that the deinked pulp mill material efficiency can be increased without weakening the sludge dewatering properties if the fibre content is not reduced below a certain limit. The material efficiency can be increased either by (1) recovering fibres at an acceptable quantity where the fibre content does not decrease below the limiting point or by (2) recovering fine materials simultaneously with fibres in a way that maintains the fibre content above a limiting point. The first method provides an opportunity for deinking mills to increase the yield, even though the increase is less than 2 percentage units. With the simultaneous recovery of fibres and fine materials using the second method, it would be possible to improve the material efficiency at the deinked pulp mill by approximately 5 percentage units without affecting the dewatering of the combined sludge. [Copyright &y& Elsevier]

Abstract: The purpose of this study is to find a solution for the groundwater uprising in Al-Fustat area – Old Cairo, Egypt. A 3-D finite Difference Model (Visual MODFLOW-Ver. 3.1) has been used to simulate the impact of different alternative solutions in order to select the best suitable one. The result of geophysical survey, twenty bore holes data, hydro-geological data and satellite images were used to construct and calibrate the numerical model of Al-Fustat city. Finally, the recommended solution is a combination of pumping wells and tile drains. The results of this solution indicate that using pumping rate of 200m3/day achieves 2–3m drawdown which meets the target. [Copyright &y& Elsevier]

Taking the deep excavation engineering of an office building for example, the key technology of design, construction and monitoring for the deep excavation project close to existing running tunnels of track traffic was discussed. The cautions in the construction process were also introduced. The results can provide the reference for other similar projects in Suzhou. [ABSTRACT FROM AUTHOR]

Abstract: With the increasing of sludge emissions and people''s increasing demand for better dwelling environment, resource utilization of sludge receives much concern in recent years. Currently, the co-processing of sludge in cement kiln has been considered as a sustainable way to dispose sludge in Japan as well as Europe and the United States. Huaxin has begun the co-processing of sludge in cement kiln since 2008. So far, 65000 tons of sludge has been successfully disposed. This paper focus on 3 ways of co-processing sludge in cement kiln through certain project examples. [Copyright &y& Elsevier]

The aim of this study is to investigate the efficiency of an innovative constructed wetland system planted with Phragmites australis in dewatering and treatment of sewage sludge. Six months of laboratory-scale experimental results indicated that the system in this study promotes sludge dewatering, as well as sludge water purification. The sludge water content and VS tend to decrease with increasing sludge retention time. The final product is sludge with a water content of around 40%; and the VS average removal rate was 48.2%. Approximately 392 L of fresh sludge was introduced totally and 10.3 L dewatered sludge accumulated during the experimental period, corresponding to sludge volume reduction of 97.4%. The sludge depth was 5.23 cm at the end with an increasing rate about 0.87 cm per month. Based on the sludge loading rate of 20.0 L/m2 d and an intermittently loaded model, the system could achieve a constant nutrient removal rate, with average percentages of removal being 75.2%, 97.3% and 78.4% for TN, TP and COD, respectively. The results showed that on-site treatment of sewage sludge with this uncomplicated, low-maintenance ecology technology can offer an alternative to conventional sludge treatment. [ABSTRACT FROM AUTHOR]

The effectiveness of two regeneration methods (i.e. improvement of the papermaking potential) for ive different grades of recycled fibres was investigated in present work. In the first method, only the reining operation was used, and in the second, removal of fines and subsequent reining were applied. The dewatering ability of every regenerated pulp (measured by the SR test) and basic strength properties of papers made from these pulps were tested. The results show that it was possible to increase the papermaking potential of all pulps tested; however , higher effectiveness was achieved when the removal of fines was followed by the reining operation. Further analysis of the results also indicates that recycled pulp grades based on kraft paper have sufficiently high papermaking potential, and in many cases they do not need additional regeneration. Pulp regeneration is strongly recommended in the case of pulps based on LWC, SC and Newsprint papers. Experiments have also proved that the selection of an optimal method for improved papermaking potential always has an individual character , and the method always has to be adjusted to a specific pulp grade and the paper grade made from it. [ABSTRACT FROM AUTHOR]

Abstract: Groundwater model as a tool is being used for various engineering applications. However, it is difficult to develop a groundwater model to truly represent a site condition with complex hydrogeological/geological conditions. A few aspects are addressed in this study: 1) multiple model layers should be used for a single hydrogeological unit in order to obtain more accurate solution to a groundwater flow system under certain conditions such as vertical hydraulic gradient are obvious and significant aquitards are present; 2) when the topographic surfaces changes sharply across the model domain, very fine and multiple layers can be used with flat model layer elevations that do not follows the natural unit surfaces as long as the hydraulic properties of various formation can be properly implemented in the model in the 3D domain. This approach proved to be numerically stable and more efficient using MODFLOW; and 3) multiple lines of evidences for model calibrations should be investigated when modeling groundwater flow systems with complex conditions to ensure the accuracy and representation of the model. [Copyright &y& Elsevier]

Abstract: Paper presents results of experimental dewatering of stabilized sludge analysis and study. The experiments were carried out at a small waste water treatment plant (15,000 population equivalent). Experiment focused on impact of consumption of flocculant and centrifuge load on quality of dewatered sludge and centrate. Dry solids in dewatered sludge and content of undissolved particles in the centrate were observed in particular for proper evaluation of the experiment. It was proven that specific consumption of flocculant has greater impact on centrate quality than on dry solids content in dewatered sludge. It was possible to increase dry solids content in dewatered sludge only by 10% at most. However, amount of undissolved particles dropped more than ten-fold. Regarding quality of dewatered sludge and centrate, optimum specific consumption of flocculant during the experiment amounts to 8g/kg of dry solids of sludge with flocculant concentration being 0.16% and centrifuge load reaching 110kg/h of dry solids. Specific consumption of flocculant amounting to 5.4g/kg of dry solids of sludge (calculated value) under identical operational conditions proves to be the best economical option. [Copyright &y& Elsevier]

Thickening is the first step in the design of sustainable (cost effective, environmentally friendly, and socially viable) tailings management solutions for surface deposition, mine backfilling, and sub-aqueous discharge. Slurries are converted to materials with superior geotechnical properties by adding polymers. Given the tailings composition, a high settling rate alongside high solids content is achieved by optimizing the various polymers parameters: ionic type, charge density, molecular weight, and dosage. This paper developed a statistical model to understand the dewatering behavior of polyacrylamide- modified tailings by fitting laboratory test data using the method of least squares. A newly devised polymer characteristic coefficient (Cp) that combined the various PAA parameters correlated well with the observed behavior as the R² equaled 0.99 for void ratio and 0.98 for hydraulic conductivity. Tailings dewatering widely varied (e = 7.5 to e = 34 and k = 10 cm/sec to k = 10-4 cm/sec) at low o′ = 0.001 kPa that corresponded to sedimentation of the feed slurry. The compressibility was found to converge to e = 2.8 ± 0.2 at o′ = 100 kPa pertaining to a thickened slurry and to e = 2±0.1 at o′ = 1000 corresponding to consolidated tailings. The hydraulic conductivity did not converge and was found to be 10-5 cm/sec at e = 3 and 10-6 cm/sec at e = 2. The liquid limit (o′ = 2 kPa) can be used to differentiate between sedimentation and consolidation. The slurry behaves like a liquid (dominated by the microstructure and seepage through inter-floc voids) for o′ < 2 kPa and as a solidifying material (affected by pore pressure dissipation through intra-floc voids) at o′ > 2 kPa. The constitutive equations describing the thickening process were found to be power laws of the form e = a o′b and k = 10 (c + e d), respectively, where a, b, c, and d are functions of the polymer parameters. [ABSTRACT FROM AUTHOR]

Abstract: With the increasing of mechanization of coal mining, the fine coal content in raw coal is more and more, which makes the work of dewatering difficult. The constant voltage and constant current electro-osmosis, combined with vacuum filtration were adopted to dewater the fine coal. The dewatering efficiency can be improved and the moisture of cake can be reduced when the electric field was imposed. When the initial electric field strength is less than 40 V/cm, the precipitation rate of constant voltage electro-osmosis dewatering (EOD) higher than the constant current EOD, can reach 30%. When the initial electric field higher than 40 V/cm, the Precipitation rate of constant current EOD higher than the constant voltage EOD, can reach 55%. [Copyright &y& Elsevier]

Abstract: Dewatering of fine clean coal and refuse slurry is one of the most important aspects of coal cleaning scenario. It is also adds significant cost to the price of clean coal. This article summarizes the current state-of-the art of dewatering being practiced around the world and discuses some of the upcoming novel dewatering technologies. Hyperbaric filter provides a low moisture product for fine coal slurries. For fine coal refuse slurries the Deep Cone Thickener provides dewatered product containing 50 percent solids. The article also discusses economics of dewatering, which is about $3.30/t for fine clean coal slurries. [Copyright &y& Elsevier]