coagulation Articles
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Flocs' re-growth characteristics in circulation coagulation–membrane filtration process
Membrane fouling can be significantly mitigated through circulating coagulation, floc breakage and re-growth under appropriate conditions. In this study, unified membrane filtration index (UMFI) was adopted to analyze the membrane fouling. The effect of circulating coagulation pretreatment on both flocs' average diameter and membrane fouling were investigated under different ...
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Membrane foulants and fouling mechanisms in microfiltration and ultrafiltration of an activated sludge effluent
Membrane fouling in microfiltration (MF) and ultrafiltration (UF) of an activated sludge (AS) effluent was investigated. It was found that the major membrane foulants were polysaccharides, proteins, polysaccharide-like and protein-like materials and humic substances. MF fouling by the raw effluent was governed by pore adsorption of particles smaller than the pores during the first 30 minutes of ...
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Effect of floc structure and strength on membrane permeability in the hybrid coagulation-microfiltration process
The relative importance of floc property on microfiltration and fouling mechanism remains a field of arguments. The effects of floc structure and strength on fouling rate of coagulation-microfiltration were investigated in dead-end microfiltration. Flocs varying in size, fractal structure and strength were prepared by AlCl3 and PACl (Polyaluminum Chloride) coagulation at various dosages followed ...
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Optimization study of a hybrid alum coagulation-membrane filtration system for virus removal
Due to the intrinsically small sizes of enteric viruses (20–100 nm) and their relatively high resistance to most disinfectants, detection of viruses in treated drinking water is not a rare phenomenon. This study therefore evaluates various aspects involved in a hybrid alum coagulation-ultrafiltration (UF) system for virus removal. Coagulant doses (0, 1 and 10 mg Al3+/L) and pH conditions relevant ...
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Effects of recycling flocculation membrane filtration on drinking water treatment
Recycling flocculation membrane filtration (RF-MF) and coagulation membrane filtration (C-MF) were investigated for removal of natural organic matter (NOM) from Luan river in this study. The effectiveness of recycling flocculation pretreatment on both NOM removal and membrane filtration were assessed under different concentrations of coagulant and reflux flocs. Under the conditions of coagulant ...
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Assessment of the value of NOM treatment processes based on a matter-element model
Research into natural organic matter (NOM) removal in drinking water treatment processes is mostly independent, distributed, disconnected and unable to meet the needs of technology application; therefore, an assessment of the value of NOM treatment processes is necessary. In this paper, a hybrid evaluation model based on rough set theory and a matter-element model was used to evaluate the ...
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Development of a model-based control system for membrane filtration process
Reduction of operational cost and certification of safety for treated water are required for the membrane filtration process for drinking water. Therefore a model-based control system is developed to reduce operational cost. A process model is used for the model-based control system that calculates the transmembrane pressure (TMP) in the future. This allows the model-based control system to ...
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Pre-coagulation and ultrafiltration of effluent impaired surface water for phosphorus removal and fouling control
The process combination of in-line coagulation and subsequent membrane filtration is a suitable advanced treatment stage to achieve higher quality standards regarding pathogens and phosphorus in biologically treated wastewater prior to its discharge into sensitive water bodies. In this study a membrane pilot installation (capacity of 6 m3/h) was operated in dead-end configuration to investigate ...
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The dye or humic acid water treatment and membrane fouling by polyaluminum chloride composited with sodium alginate in coagulation–ultrafiltration process
Composite flocculants have been extensively studied and applied in recent years in order to improve the water treatment efficiency. In this study, a new composite flocculant prepared by polyaluminum chloride (PAC) and sodium alginate (SA) was used to treat dye and humic acid water in the coagulation–ultrafiltration process. The subsequent effects of PAC/SA on ultrafiltration membrane ...
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Recycling of spent filter backwash water using coagulation-assisted membrane filtration: effects of submicrometre particles on membrane flux
Membrane separation technology has been widely used for recycling of spent filter backwash water (SFBW) in water treatment plant. Membrane filtration performance is subject to characteristics of the particles in the SFBW. A bench-scale microfiltration (MF) coupled with pre-coagulation was set up to evaluate the recovery efficiency of SFBW. Effect of particle size distribution and zeta potential ...
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Comparison of optional process configurations and operating conditions for ceramic membrane MF coupled with coagulation/flocculation pre-treatment for the removal of NOM in drinking water production
The increase of Natural Organic Matter (NOM) in natural water sources, partly caused by progressing climate change issues, is a growing concern for drinking water production. In recent years, membrane technology like Reverse Osmosis (RO) or Nanofiltration (NF) has been successfully applied as a robust solution for NOM removal to produce potable water. However, coagulation/flocculation ...
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Sewage pre-concentration for maximum recovery and reuse at decentralized level
Pre-concentration of municipal wastewater by chemically enhanced primary treatment (CEPT) was studied under controlled laboratory conditions. Both iron and aluminium-based coagulants were examined at gradually increasing concentrations (0.23, 0.35, 0.70 and 1.05 mmol/L). The CEPT sludge generated from different coagulation experiments was digested in batch anaerobic reactors, while the ...
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Experimental evaluations of water treatment systems using a pilot-scale plant for adaptations to a sharp increase in raw-water turbidity caused by climate change
One effect of climate change on the water supply systems in Japan may be a sharp increase in the raw-water turbidity following heavy rain. The objective of this study was to evaluate water treatment performance with a sharp increase in raw-water turbidity. This evaluation was carried out from the perspective of turbidity response by a pilot-scale plant using sand filtration and membrane ...
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Physicochemical treatment of office and public buildings greywater
The current study analyses the performance of deep sand filtration of greywater from an office building and the performance of a combined physicochemical process comprising of coagulation, sedimentation and filtration. Raw greywater quality exhibited very high variability with average turbidity of 35 NTU, and TSS, CODt, and BOD of 45, 240, 75 mg/l respectively. The stand-alone filter removed 50 ...
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7 Common Pitfalls when you choose a Chemical Coagulation Water Treatment System to Treat Your Water
Pretreatment processes in water treatment systems are often crucial to maintaining efficiency and longevity of the downstream equipment, such as membrane filtration. Many systems incorporate a coagulation step that will encourage small suspended solids to aggregate and fall out of solution. By eliminating the larger particles in the solution, filtration membranes won’t foul, tear or clog ...
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Pretreatment of concentrated leachate by the combination of coagulation and catalytic ozonation with Ce/AC catalyst
A raw concentrated leachate produced from membrane bioreactor-nanofiltration (MBR-NF) was taken from Chengdu Chang'an Waste Landfill Site, China. The major fraction of this concentrated leachate was large refractory humic substances. A coagulation–ozonation process was applied to treat this leachate, aiming at enhancing chemical oxygen demand (COD) removal efficiency and increasing its ...
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Using magnetic powder to enhance coagulation membrane filtration for treating micro-polluted surface water
The magnetic enhanced coagulation membrane filtration (MECMF) process was introduced into micro-polluted surface water treatment. The process was conducted by adding magnetic powder (MP) for enhancing coagulation. By contrasting the water quality parameters including dissolved organic carbon (DOC), UV254 and turbidity of permeates of MECMF and coagulation/flocculation membrane filtration ...
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Size fractionation characterisation of removed organics in reverse osmosis concentrates by ferric chloride
Reverse osmosis membrane separation is the leading method for manufacturing potable purified water. It also produces a concentrate stream, namely reverse osmosis concentrates (ROC), with 10–20% of the water, and almost all other compounds. One method for further treating this stream is by coagulation with ferric chloride. This study evaluates removed organics in ROC treated with ferric chloride. ...
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Corrugated Sheet Plant
The previous wastewater treatment was composed of the following chemicals: an acidic coagulant, caustic for pH adjustment, and an anionic polymer made down to 1% solution. The facility used 3-4 gallons of coagulant, 2-3 gallons of caustic, and 2-3 gallons of anionic flocculant (at a 1% solution) at a cost of $50/batch. The operator stated that they had low solids, they tended to overdose which ...
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Reduction of dissolved organic matter and trihalomethane formation potential in raw water supply reservoir by hybrid ultrafiltration process
Hybrid microfiltration (MF)–ultrafiltration (UF) and hybrid coagulation–ultrafiltration membrane processes were investigated and compared for dissolved organic matter (DOM) reduction in the low turbidity raw water supply from Sri-Trang Reservoir, Thailand. The coagulation process was operated with 20 mg/L polyaluminum chloride (PACl) at pH 7. The MF used had a pore size of 0.1 μm and the UF was ...
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