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Рассмотрены разработанные компанией Alfa Laval инновационные технологические решения, воплощенные в декантерной центрифуге Aldec G3. Для обезвоживания осадков сточных вод компания Alfa Laval изготавливает два вида современных декантерных центрифуг (всего их более 12 типов для применения в различных сферах: от пищевой промышленности и биофармацевтики до обезвоживания нефтешламов или отвальных хвостов горнодобывающей промышленности). Использование декантерной центрифуги Aldec G3 обеспечивает максимальное сокращение совокупных издержек на обезвоживание осадков сточных вод. Описаны виды ремонтных работ декантерных центрифуг, осуществляемые в единственном на территории России сертифицированном по стандартам ISO сервисном центре Альфа Лаваль.

Faecal sludge dewatering is often a necessary step in many treatment and reuse processes, and it can decrease costs of transporting large volumes of high water content sludge. Common dewatering methods such as settling-thickening tanks and drying beds are not feasible in space-constrained areas such as urban informal settlements, therefore innovative dewatering methods are needed. This study evaluated permeable membranes as a dewatering method for a transfer station operated by Sanergy in Nairobi, Kenya. The objective was to determine if membranes could provide a sustainable and economically-feasible dewatering method within the constraints of Nairobi’s informal settlements by evaluating multiple variables, such as flocculant dosage and initial total solids content, and their relation to faecal sludge dewatering. Experiments were conducted with several membrane types including commercial geotextiles and locally-produced plastic woven bags (gunny sacks). Increasing the flocculant dosage within an optimal range was seen to increase dewatering rates, but had minimal effect on the final dewatered solids content. Sludge with initial total solids contents below 3% was seen to require longer dewatering times to allow for drainage, while sludge above 3% required a minimal drainage period before evaporation began. A settling step proved paramount for sludge with high water content where the supernatant was then decanted prior to dewatering through permeable membranes; however, this may not be recommended in all cases depending on the treatment objectives. Reuse of geotextile membranes may lead to a reduction in dewatering performance, and single-use, locally-produced membranes are a more cost-effective, though operationally intensive, option.

Urbanisation is putting enormous pressure on wastewater treatment plant facilities. Optimising the liquid and sludge process streams in existing plants is one way of prolonging the life span of such installations. Many Wastewater treatment plants (WWTP) have sludge dewatering installations where treated wastewater sludge is dewatered using belt filter presses amongst others, before final disposal. One of the most expensive inputs in these plants is the polymers used as flocculants. Controlling the optimum dosing in the dewatering process cannot currently be done in real-time. It has been shown that huge savings can be made by optimising the dosing rates of polymers based on the sludge rheology. An Ultrasound Velocity Profiling (UVP) and pressure drop (PD) measurement system was specially designed and commissioned for a WWTP. The system was installed in a WWTP to measure the rheological properties of sludge in-line and in real-time prior to mechanical dewatering using a belt filter press. This non-invasive in-line system was able to accurately measure the rheological parameters in real-time in a 100 mm stainless pipe. It was shown for the first time what the maximum in-line yield stress is that is required for optimum dewatering based on a relationship determined between the yield stress and the total suspended solids in the filtrate exiting the belt filter press.

Sludge dewatering is a prerequisite for the subsequent utilization of sludge. However, the existing mechanical dewatering cannot achieve satisfactory water content (< 60%). Herein, pressure and electric dewatering in alternate operation (P/EDWalt) was proposed to improve dewatering efficiency. Compared with conventional simultaneous mode, P/EDWalt performed better in sludge dewatering. Its optimal dewatering conditions were voltage of 30 V for 20 min in two electric dewaterings, and pressure of 0.04, 0.07 and 0.10 MPa in three pressure dewaterings. Such conditions, the water content of sludge was reduced from 83.7% to 53.3%, the dewatering efficiency was 36.3%, and the energy consumption was 0.138 kWh/kgtotal removed water. These phenomena such as electroosmosis, the ohmic heating and electrophoresis facilitated the removal of water in sludge, and the dewatered sludge has good reusability in incineration, landfill and agriculture. Therefore, P/EDWalt could serve as a promising method for the sludge dewatering.

High-solid anaerobic digestion (HS-AD) has been applied extensively during the last few decades for treating various organic wastes, such as agricultural wastes, organic fractions of municipal solid wastes, and kitchen wastes. However, the application of HS-AD to the processing of sewage sludge (SS) remains limited, which is largely attributable to its poor process stability and performance. Extensive research has been conducted to attempt to surmount these limitations. In this review, the main factors affecting process stability and performance in the HS-AD of SS are comprehensively reviewed, and the improved methods in current use, such as HS sludge pre-treatment and anaerobic co-digestion with other organic wastes, are summarised. Besides, this paper also discusses the characteristics of substance transformation in the HS-AD of SS with and without thermal pre-treatment. Research has shown that the HS effect is due to the presence of high concentrations of substances that may inhibit the function of anaerobic microorganisms, and that it also results in poor mass transfer, a low diffusion coefficient, and high viscosity. Finally, knowledge gaps in the current research on HS-AD of SS are identified. Based on these, it proposes that future efforts should be devoted to standardising the definition of HS sludge, revealing the law of migration and transformation of pollutants, describing the metabolic pathways by which specific substances are degraded, and establishing accurate mathematical models. Moreover, developing green sludge dewatering agents, obtaining high value-added products, and revealing effects of the above two on HS-AD of SS can also be considered in future.

Urban wastewater sludge is highly humid, large and poorly dehydrated. Dehydration of sludge in natural conditions has a number of shortcomings: low effi ciency, sludge areas require huge land areas, worsen the ecological situation, pollute groundwater, soil, etc. One way to eliminate the problem and improve the effi ciency of sludge dewatering in urban wastewater is to switch to mechanical dehydration using fl occulants. The work is devoted to the selection of the most eff ective fl occulant and was carried out on the natural sediments of the right-bank treatment facilities in Krasnoyarsk and the sewage treatment plants in the sett lement of Emelyanovo. The experiment showed that fl occulants Praestol 851BC and Zetag 7485 at a dose of 3 kg / t dry matt er of the precipitate have the greatest eff ectiveness.

These studies examined the concept of concentration and purification of several types of wastewater by freezing and thawing. The experiments demonstrated that freezing of contaminated liquid contributed to concentration of contaminants in solution as well as significant concentration and agglomeration of solid particles. A high degree of purification was achieved for many parameters. The results of comparative laboratory tests for single and multiple freezing are presented. It was found that there was a higher degree of concentration of pollutants in wastewater frozen as man-made snow than in bulk ice. Furthermore, the hypothesis that long storage time of liquid as snow and sufficient temperature gradient metamorphism allows for high efficiency of the concentration process was confirmed. It was reported that the first 30% of the melted liquid volume contained over 90% of all impurities. It gives great opportunities to use this method to concentrate pollutants. The results revealed that the application of this process in full scale is possible. Significant agglomeration of solid particles was also noted. Tests with clay slurry showed that repeated freezing and thawing processes significantly improve the characteristics of slurry for sedimentation and filtration.

Ultrasonic treatment is a good method of facilitating sewage sludge dewatering characteristics. It can also promote the potential of sludge electro-osmosis dewatering (EDW), which is an accepted method of deep dewatering, but the treatment method and optimizing conditions should be determined by performing experiments. In this study, we consider two treating methods: ultrasonic pre-treatment, which uses ultrasonic treatment as sludge pre-treatment before electro-osmosis dehydration, and ultrasonic coupling, which uses ultrasonic and electric fields simultaneously. Using sludge from the Tianjin Jizhuangzi sewage treatment plant, we analyze the influence of ultrasonic intensity and treatment time on sludge dewatering by performing two different methods. The results show that they effectively facilitated sludge EDW. Under the same conditions, i.e. 2 cm cake initial thickness, voltage of 60 V for 5 min, and 0.1 MPa mechanical pressure for 5.5 min, the optimum processing conditions for ultrasonic pre-treatment were found to be 0.510 W/cm

One of the most important facilities in Romania for the wastewater treatment is located near Bucharest. The paper focus on the final sludge dewatering line where the working environment has recently been deemed unsuitable for human exploitation due to different chemical compounds such as water vapour, hydrogen sulphide, ammonia and calcium oxide dust. To avoid problems, the company has to manage very careful the human activity with long breaks to protect their employees so they decided to change the ventilation solution, and to find the strategy of optimal air distribution. Our study defines the optimal solution for the general ventilation of the room for highly dehydrated sludge and for the improvement of technological parameters and working conditions. This solution obtained by means of numerical simulation generally adapts the existing ventilation system and prepares the implementation of local solutions to capture and treat the effluents of the treatment line. In order to propose a solution for the general ventilation system, we performed numerical simulations using Computational Fluid Dynamics models. The numerical models were calibrated and validated with measured data obtained in different experimental campaigns in situ.

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.

In the study the comparative analysis of test results of drainage of municipal wastewater sludge was conducted with the use of flocculant Praestol 855BS and the mixture of flocculant Praestol 855BS 50% + orange essential oil 50%, as the reagents supporting this process. It was also attempted to reduce unpleasant smells exuding from the drained sludge. The process of drainage of municipal wastewater sludge was conducted in the laboratory setting centrifuge of MPW-350 type. The variable independent parameters were centrifugation time, centrifugation speed, dosage of flocculant Praestol 855BS as well as dosage of mixture in the proportion of flocculant Praestol 855BS (50%) + orange essential oil (50%). The following parameters were subject to assessment: water content in the sludge, dry mass content in the reflux as well as time of maintenance of the oil’s smell in the sludge. The conducted tests demonstrated that the orange essential oil has an impact on drop in resultant quality parameters of the drainage process of municipal wastewater sludge. Batching of the orange essential oil has an impact on considerable reduction of odours exuding from drained wastewater sludge, and thus on improvement of work conditions connected with operation of centrifugal separators. Bearing in mind both the efficient drainage process of wastewater sludge as well as simultaneous reduction of unpleasant smells exuding from the sludge during this process it is assumed and recommended to simultaneously apply both reagents, that is flocculant Praestol 855BS (50%) and orange essential oil, also in the volume of 50%.

Sludge disposal is becoming an issue at the municipal solid waste incinerator (MSWI), especially for environmental and economic reasons. This paper describes a case study of the optimization of the sludge management (SM) system at the MSWI in the Czech Republic. The original concept of SM at MSWI was designed as waste-free. However, the present operation indicates that there is a need to carry out regular extraction and disposal of sludge settling at the bottom ash tank and the bottom of the retention basin. The current status of SM causes problems not only in terms of operation but it also entails significant financial costs given the necessary regular cleaning of tanks. The aim of the applied research presented in this paper is SM optimization by a mobile sludge dewatering (DW) press unit with optimal polymer combination for DW. Nakládání s kalem se stává problémem na spalovně komunálního odpadu, zejména z pohledu ekologických a ekonomických důvodů. Tento článek popisuje případovou studii optimalizace kalového hospodářství na spalovně komunálního odpadu v České republice. Původní koncept kalového hospodářství na spalovně komunálního odpadu byl navržen jako bezodpadový. Současný stav však naznačuje, že je zapotřebí provádět pravidelné odsávání a likvidaci sedimentů kalu v nádržích jímky škvárové vody a retenční jímky. Současný stav kalového hospodářství způsobuje problémy nejen z hlediska provozu, ale přináší také významné finanční náklady vzhledem k nezbytnému čištění nádrží. Cílem aplikovaného výzkumu prezentovaného v tomto příspěvku je optimalizace kalového hospodářství mobilním odvodňovacím zařízením s optimální kombinací polymerů pro odvodněný kal.

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.

Digested sludges generally exhibit poorer dewaterability than activated sludges. This study investigated the effects of acidification and oxidation on EPS properties and dewaterability of anaerobic digested sludge in Fenton treatment in order to unravel the underlying mechanism of sludge conditioning. The results indicated that sludge dewatering property was improved after acidification treatment. Meanwhile, fluorescence analysis revealed that the protein-like substances were effectively removed from sludge bulk after acidification treatment. Acidification and Fenton oxidation showed a significant synergetic effect in enhancing sludge dewatering process. Solubilization and decomposition of bound EPS occurred synchronously during Fenton conditioning. Oxidation process is very likely to play a more important role in sludge conditioning than Fenton coagulation. According to pilot test, Fenton treatment performed much better in cake moisture content reduction than chemical conditioning with traditional inorganic coagulants. Additionally, full-scale application of Fenton conditioning will not have detrimental effects on performance of wastewater treatment system.

In urban and peri-urban areas of developing countries decentralized wastewater treatment using septic tanks as pretreatment is common. One challenge of decentralized wastewater treatment systems (DEWATS) is handling and utilization of the generated sludge. Sludge drying reed beds (SDRBs) are a robust method for dewatering and stabilization of sludge. Constructed wetlands (CWs) and SDRBs can be integrated to treat both wastewater and sludge. SDRBs require more area than most other sludge treatment options, but have low operational cost and energy requirements. The land area required for SDRB’s can be optimized by the selection of an appropriate loading rate, sludge application frequency and resting phase. This paper gives a review regarding the use of SDRB’s as well as presenting a pilot scale experiment comparing planted and unplanted sludge drying beds in Kathmandu. The planted beds showed a higher dewatering capability and higher reduction of volatile solids (VS). A short-term pilot-scale experiment can give valuable input to the design and operation of full-scale systems and for sub-tropical climate as that of Kathmandu Nepal, an initial sludge loading rate (SLR) of 100 kg total solids (TS)/m2/year is suggested with a gradual increase to up to 250 kg TS/m2/year.

Sludge Treatment Reed Beds (STRBs) are widely used in Northern Europe to dewater and mineralize surplus sludge from activated sludge systems used to treat urban domestic sewage. STRBs are low-technology, energy-efficient, and do not require addition of chemicals. They dewater and stabilize the sludge and produce a final product that can be safely used as a fertilizer for agricultural crops. Long-term sludge reduction takes place in the reed beds due to dewatering and mineralization of the organic matter in the sludge. Although, in theory, a simple technique relying largely on natural processes, experience has shown that it is very important to understand and respect the basic design and operation requirements of STRBs. This paper describes the basic design and operation requirements of STRBs, with special focus on pivotal requirements to respect in order to secure proper functioning. Also, the paper summarizes performance experience concerning final dry matter content, degree of mineralization, emission of greenhouse gases, and degradation of micro-pollutants in STRBs. There are still a number of outstanding issues that are not fully understood, particularly in relation to the importance of the sludge quality for the dewatering in an STRB. Therefore, extreme care should be taken when attempting to extrapolate the use of STRBs to applications and regions outside of their 'normal' and documented area of application.

Sewage treatment plants generate a large volume of waste sludge as a by-product with water content over 95%, which requires further treatment, volume reduction, dewatering, stabilization, and safe disposal. Sludge dewatering is a major issue in sewage treatment as dewatering consumes a large quantity of expensive synthetic chemical flocculants. Moreover, the commercial chemical flocculants create several environmental issues including generation of odor and release of toxic compounds. As an alternative to chemical flocculant-based dewatering, a sustainable and eco-friendly process is necessary. A number of studies have been reported on this aspect using flocculants produced by heterotrophic bacteria, chemolithoautotrophic bacteria, and fungi. A composite flocculant from iron-oxidizing bacteria has been found to be a promising flocculating agent. This chapter presents a comprehensive review of developments in biotechnological approaches to sludge flocculation and dewatering, which includes background on sewage treatment, sludge flocculation, and dewatering methods using microbial flocculants.

ABSTRACT: Sludges generated during purification of water for human consumption are produced in large volumes and have high environmental polluting potential. The sludge dewatering technique using geotextile closed systems has been used to reduce the sludge volume for final disposal. It is a system that allows encapsulation, insulation, dewatering and disposal of sludge, which allows control of the input and output variables of the system. Also known as geotextile tubes, geotextile containers and geotextile bags are a function of their size. This work presents a discussion about the main factors influencing this sludge dewatering technique and its applicability for sludges generated in a water treatment plant. The study includes tests with single filling and with refilling the small geotextile bags in equipment constructed to simulate control of operational conditions, such as flow rate and pumping pressure. The evaluated performance of this system according to parameters proposed in the literature is also presented. The results obtained indicate that the efficiency of the dewatering technique depends on both the characteristics of the sludge and the geotextile properties. This study indicates the importance and efficiency of the dewatering technique in geotextile closed systems in reducing the sludge volume for final disposal.

Wastewater characteristics and sludge generation potential of point source categories are reviewed critically. Novel industry-specific sludge dewatering/drying solutions necessary to establish a sustainable model are examined through a detailed literature survey. Knowledge of sludge properties is one of the most critical issues needed to design dewatering/drying equipment. This study focuses on industrial wastewater/sludge characterization. In addition, a comprehensive review of current drying models and technologies is also presented. A summary of the results derived from a novel thin-film-based photonic sludge dewatering/drying study is outlined as an alternative approach for industrial sludge control. Sludge was dried in a tubular quartz reactor (TQR), the inner surface of which was coated with a TiO2 thin film. The TQR was irradiated with UV A, UV B, and UV C lamps. The consumed and generated energy fluxes through endergonic and exergonic reactions driven by photolysis and photocatalysis were investigated. In addition, the variations in sludge dewatering/drying characteristics were also examined and compared with conventional methods to evaluate the energy requirements. © 2014, Copyright Taylor & Francis Group, LLC. 111Y209 This work is funded by The Scientific and Technological Research Council of Turkey TÜBİTAK (Project 111Y209) and C¸erkezköy Organized Industrial Management.

이 연구에서는 하수 처리 시 발생하는 잉여슬러지의 탈수성을 증대시켜 탈수 후 최종슬러지 케이크를 감소시키기 위해 초음파 적용 가능성을 검토하였다. 이번 연구에서 사용된 슬러지는 하수처리장에서 직접 채취한 탈수 전 잉여슬러지이며 여기에 초음파 조사시간과 조사강도를 달리 가하여 탈수성 변형특성을 고찰하였다. 실내외 실험을 동시에 수행하였으며 각각 용량이 다른 세 개(7리터, 1톤, 7톤)의 처리조를 제작 활용하였다. 초음파 처리 시간과 처리강도에 따라 탈수성 및 감량화 판단 인자로 사용되는 CST와 점도의 변화를 측정하였다. 연구결과 초음파 조사시간이 길어질수록 원 시료의 CST가 증가하는 경향을 보였으나 조사한 슬러지에 응집제를 첨가할 경우 도리어 초음파 강도와 조사시간에 따른 CST가 아주 낮게 최고점의 20%까지 측정되었다. 초음파에 의한 점도 변화는 최고점의 40%까지 감소하였다. 또한 원심력에 따른 슬러지의 침하를 분석하였는데 초음파를 가하고 응집제를 첨가한 슬러지의 초기 침하속도가 더 빠르며, 최종침하량에도 더 빨리 도달한 것으로 나타났다. 연구결과 초음파 조사시간과 초음파 강도가 탈수성에 큰 영향을 주는 것으로 나타났으며 연구결과를 현장에 도입할 경우 잉여슬러지의 탈수능 향상과 최종 탈수케이크 감량화에 유용하게 사용될 수 있을 것으로 기대된다. 가능성 평가를 위하여 대형 처리조를 처리장에 설치 운영하여 탈수케이크의 CST 및 함수율 변화를 고찰하였으며 실험실과 유사한 결과(최고 50% 감소)를 도출하였다. 【This study examined the effectiveness of ultrasound on enhancing the dewaterability and volume reduction of bio solids from a waste treatment plant. The test specimen was obtained from a storage tank immediately before the dewatering process at a local treatment plant. The test conditions included the energy levels of ultrasonic waves and treatment time. The tests were undertaken using three types of different treatment processors (7 liter, 1 ton, 7 ton container). The capillary suction time (CST) and the viscosity of sludge, which is one of the influencing factors for dewaterbility, were obtained under various test conditions. The results showed that ultrasound increases the CST of the raw specimens, whereas a significant reduction (20 % of the maximum value) of CST occurred in the sample with ultrasound and flocculent. The decrease in viscosity reached 40 % of the maximum value. A centrifugal test was performed to examine the characteristics of the sludge settlement. The settling rate and time required to reach the final values were both enhanced by the ultrasonic energy. An ultrasonic treatment is potentially useful tool for reducing the amount of released sludge. To examine the possible use of field application, the real scale sonic processor was designed and operated. The results were similar (50 % of the maximum value) to those of laboratory experiments.】

So far, the most common method of conditioning to increase the efficiency of sludge dewatering is by adding chemicals (polyelectrolytes). This method effectively increases dewatering, thus causing the possibility of getting into the environment of hazardous chemicals. The use of physical conditioning methods (thermal, ultrasonic field) or a combination one (so-called hybrid conditioning) is an alternative to chemical methods for sludge preparing. A preliminary modification of excess sludge before the fermentation process affects the stabilization process, thereby changing the parameters characterizing the efficiency of sewage sludge dewatering. The article presents a study determining the impact of pre-conditioning of excess sludge before anaerobic stabilization on the final efficiency of their dewatering. Sludge conditioning methods of thermal and ultrasonic pre-treatment and combination of these two methods (hybrid conditioning) were used. The ability of sludge dewatering was determined on the b...

The ability of selected bacteria: Myxococcus xanthus, Bacillus pumilus, Halobacterium salinarum, and Brevibacterium antiquum to produce phosphorus bio-mineral in settled wastewater and sludge dewatering centrifuge liquors was investigated. B. pumilus and B. antiquum were capable of growing and producing bio-minerals identified as struvite that reached up to 250 µm in size within ten days. This study opens a completely new route to remove and recover phosphorus as struvite from wastewater, with advantages such as being able to use streams with variable phosphorus concentrations of (7–30 mg/L) and no need for external chemicals.

The characterization and use in sludge dewatering of a novel bioflocculant M-C11 produced by Klebsiella pneumoniae was investigated. The purified M-C11 was composed of 91.20% sugar, 4.61% protein and 3.91% nucleic acids (w/w). Fourier transform infrared (FT-IR) spectroscopy of purified M-C11 confirmed the presence of carboxyl, hydroxyl, methoxyl and amino groups. The sludge resistance to filtration (SRF) decreased remarkably from 11.64×1012 m/kg to 4.66×1012 m/kg under the optimum conditions (pH=6, 3 mL bioflocculant and 4 mL CaCl2 dosage), after being conditioned with bioflocculant M-C11, which was more efficient than inorganic flocculants. Results showed that M-C11 could serve as a substitute for chemical conditioners and a promising alternative to the sludge treatment industries.

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.

The oily sludge was more serious polluted to the environment, it is necessary to harmless treatment. Analysised the composition of the oily sludge. Three ways to deal with oily sludge included chemical treatment, biological degradation and resource utilization. Elaborated the application of three ways, dicussed the pros and cons, thought waste utilization was the most effective way.

The present experimental investigation examined the applicability of fry-drying technology for municipal dewatered sludge by using waste engine oil for frying. The process was studied in a 100180 degrees C temperature range for 2 to 20min frying times. The cakes were shaped in a diameter range of 1 to 3cm with 3-cm-length prior to the frying. Experimental points were determined by the BoxWilson experimental method. Statistical analysis was employed for determining the response function coefficients for variables. The response functions were as dry solids content (DS), volatile solids content (VS), and low heating value (LHV). Experimental and predicted results indicated good agreement with high correlation coefficients. The results showed that fry-drying is an alternative, fast process for sludge drying. In addition, it makes fry-dried sludge as a product with noteworthy LHV. This study provides further insight into the fry-drying of municipal dewatered sludges.

Biological sludge dewatering is a crucial step in industrial wastewater treatment processes. There are always challenges as these sludges tend to form highly compressible cakes and the sludge properties are continually changing. In this work, a method was developed to optimize the selection and design of a dewatering process for these highly compressible materials and a case study was used to demonstrate this methodology. A Capillary Suction Time (CST) method was shown to be effective in the initial screening of pretreatment methods. Laboratory pressure filtration can show general trends of the dewatering behavior but cannot match plant-scale operation due to dissimilarities in the equipment configuration and operating procedures. A pilot filter press equipped with both chamber and diaphragm plates was found to work well for this evaluation. It was demonstrated that pressure filtration alone produces wetter cakes (30–34 wt% cake solids),but with the additional expression exerted by the diaphragm, drier (4...

The sludge should have conditioning to enhance the characteristic of dewatering belong to its bad dewatering performance. The means we always use is chemical conditioning which is adding flocculants to the sludge to cooperate the machine dewatering. The single use of inorganic flocculants will increase the weight of the filtered mud cake and the results are generally not good. The synthetic organic polymer flocculants usually have good results but also have harmful effects on environment. The natural modification polymer flocculants and microbial flocculants have small adverse impact on environment with good effect in sludge dewatering and their application will be more and more widely with the development to the depth.

Sludge treatment reed bed (STRB) systems have been used for dewatering and mineralisation of sludge in Europe since 1988. STRB systems provide substantial environmental, economic, and operational benefits compared to mechanical sludge dewatering solutions such as belt presses and centrifuges. They require less energy, no chemicals, reduce the sludge volume and produce bio solids with dry solid contents up to 20–40% under Danish climate conditions, depending on the sludge quality. Experience has shown that sludge treated in STRBs represents a high quality product with a low content of pathogens and hazardous organic compounds, qualities that make it suitable for recycling on agricultural land. The upfront capital cost for STRBs are often higher compared to mechanical dewatering devices. However, the operational expenses (OPEX) (including energy, chemicals, bio solid handling) are significantly lower compared to conventional mechanical dewatering devices, delivering an economic break-even of about 3–5 years. This paper provides an overview of the operation and maintenance costs and environmental benefits of a typical STRB based on the experiences gained from the operation of a large number of STRBs with yearly treatment capacities between 100 and 3,000 tonnes of dry solid up to approximately 250,000 PE in Denmark and Europe.

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.

This report is a synthesis of the technical assistance (TA) and recommendations, carried out by the World Bank water and sanitation program (WSP) since September 2014. To achieve the target of 100 percent improved sanitation, there is a national drive to improve fecal sludge management (FSM). This TA recognizes that to achieve the goals it is necessary to support the development of national FSM policies, regulations, and guidelines, while also improving capacity at the local level by supporting the implementation of improved FSM models in target cities. The objective of the TA was to provide government with tested advice on how to scale up improved septage management nationwide through: (i) improvement of septage management in three cities through the application of new management models (local level); and (ii) assistance to national government in training and capacity building and the formulation of policies and regulations to improve septage management at scale (national level). This report is structured as follows: chapter one is the executive summary; chapter two gives the background to sanitation in Indonesia and to fecal sludge management in particular; chapter three provides an overview of the TA approach; chapter four gives details of the implementation of the TA; chapter five summarizes the lessons learned; and chapter six outlines the recommendations and next steps.

Advanced Sludge dewatering system is investigated by the approaches of physical and chemical pretreatment process to improve sludge dewatering performance, based on the degree of difficulty or ease together with the relationship analysis of the existing form of the sludge water. Systems of sludge pre-treatment, sludge filter press and auto-control are elucidated significantly, with the aim that accomplishing the sludge deep dewatering, and making the moisture content of sludge below 55%. This approach can suit to the manipulating locally of the sludge in the sewage treatment plant a nd save the investment of sludge storage storehouse as well as the cost of transportation.

The potential benefits and mechanism of explosive explosion shockwave pretreatment on sludge dewatering treatments were investigated in this study. Water content of sludge cake after centrifugation was used to evaluate sludge dewaterability. Particle size, viscosity, turbidity, and micrograph were determined to explain the observed changes in the pretreatment process. The results indicated that the optimal pretreatment condition, generating the lowest water content of sludge cake, was 25 g explosive and 96.7% original sludge water content. This condition resulted in the reduced particle size and viscosity as well as increased turbidity. Particle size and viscosity significantly contributed to enhance sludge dewaterability. Micrograph investigation indicated that explosive explosion shockwave pretreatment could rupture sludge flocs, release physically bound water, and extracellular substances into the solution, consequently enhancing sludge dewaterability.

Mechanical compression is a traditional process for the dewatering of sewage sludge. However, the moisture content of the cake is still high, unfavorable for the sludge management. In this paper, the use of thermal compression to improve the sludge dewatering is investigated. The dewatering efficiency is affected by the applied temperature, pressure and the sludge mass. The bound water of the sludge is further reduced by thermal compression, improving the dewatering performance. The solid content of the cake obtained after 10 min mechanical compression and 60 min thermal compression at 120 oC and 4 MPa is 85.2%.

Purification of municipal wastewater generates huge amounts of sewage sludge, which contains large quantities of water, biomass, and extracellular polymeric substances. It is widely known that sewage sludge usually has a poor dewaterability. A large amount of water in sludge directly translates into high transport and handling costs; therefore, sludge treatment and disposal usually requires over 50% of the operation budget for wastewater treatment plants. The application of a low electric field through the sludge segment, called electro-dewatering, is considered to improve the liquid–solid separation, resulting in low water content in the sludge cake. However, prediction of dewatering enhancement for sewage sludge, in particular, offers a challenge due to variations in sludge pretreatment practices and the lack of harmonized testing methodologies. In this review article, the aspects that have an effect on sewage sludge electro-dewatering and its feasibility are discussed in the light of recent technologic...

The dewatering of municipal sewage sludge is a current problem due to the huge production of this waste. The bound water content in sludge is closely related to the sludge dewatering performance. By comparative analysis of the measurement methods of the bound water content in sludge, this article points out their respective advantages and disadvantages, as well as the respects which should be noted in practice.

To identify the key characteristics of cationic polyacrylamide (c-PAM) for evaluating sewage sludge dewatering performance, we examined the properties of 13 types of c-PAMs that come from different manufacturers via a laboratory assay. The sludge dewatering performance was determined through a full-scale test at a large wastewater treatment plant in Beijing. We checked the cationic degree, solution viscosity, dissolution time, and 1 mm sieve residue of c-PAM. The 1 mm sieve residue was found to affect the dissolution time, solution viscosity, and conductivity. The full-scale test indicated that the cationic degree is the most important factor that affects the dosage and treatment capacity of the belt filter press when the cationic degree ranges from 25% to 45%. However, the moisture content of sludge cake is mainly relevant to raw sludge organic content. The sludge dewatering performance of the 13 types of c-PAMs showed that the c-PAM should be selected based on cationic degree, solution viscosity, and 1 mm sieve residue. The dosage should then be adjusted at the appropriate time according to the status of the equipment and facilities during sludge dewatering.