scholarly journals Membrane filtration technology in water works. Development of membrane filtation system combined with advanced treatment (upflow dual-layer filtration system of manganese sand and granulated active carbon ).

1996 ◽  
Vol 25 (4) ◽  
pp. 240-243
Author(s):  
Yoshikazu ITOH
Author(s):  
V. Kofman

Технология гравитационной мембранной фильтрации предусматривает использование плоских полимерных ультра- и микрофильтрационных мембран (с размером пор от нескольких нанометров до нескольких сотен нанометров), расположенных на 40 100 см ниже уровня воды, т. е. работающих под гидростатическим напором 40 100 мбар в качестве движущей силы мембранной фильтрации в тупиковом режиме. Бактериальное сообщество исходной воды вызывает образование слоя биопленки на поверхности мембраны. В то же время присутствие эукариотных организмов в слое биопленки, характеризующихся хищническим поведением, обусловливает возникновение своего рода эффекта биологической чистки , приводящей к уменьшению сопротивления фильтрации биопленки за счет образования пустот и развития ее гетерогенности. В результате динамического развития подобной системы происходит ее стабилизация и соответствующее достижение относительного постоянства потока пермеата на уровне 2 10 л/(м2ч). Стабильный водный поток в режиме гравитационной мембранной фильтрации сохраняется в течение многих месяцев без проведения чистки мембраны. Система обеспечивает удаление из воды органических веществ и патогенных микроорганизмов. Проведены разного масштаба испытания системы гравитационной мембранной фильтрации для децентрализованной обработки речной воды, для обработки дождевой воды и серых сточных вод в локальных очистных системах с получением воды, пригодной для непитьевого потребления, при очистке сточных вод для безопасного их сброса и при предварительной обработке морской воды перед опреснением. В настоящее время известны примеры практического применения данной системы фильтрации.Gravity membrane filtration technology involves the use of flat polymer ultrafiltration and microfiltration membranes with pore sizes from several nanometers to several hundred nanometers submerged in water at 40-100 cm, i.e. operating under a hydrostatic head of 40 100 mbar as a driving force of the membrane filtration in deadlock mode. The bacterial community of the source water induces the formation of a biofilm layer on the membrane surface. At the same time, the presence of eukaryotes in the biofilm layer that are characterized by predatory behavior produces a kind of biological purification effect that provides for decreasing the filtration resistance of the biofilm due to the formation of voids and development of its heterogeneity. As a result of the dynamic development of such a system, its sustainability and relative continuity of the permeate flow at the level of 2 10 l/(m2h) are achieved. Sustainable water flow in the gravity membrane filtration mode is maintained for many months without cleaning the membrane. The system ensures the removal of organic substances and pathogenic microorganisms from water. Different-scale testing of the gravity membrane filtration system has been carried out: for decentralized river water treatment, for stormwater and gray wastewater treatment in local treatment systems to produce water suitable for non-potable consumption, in wastewater treatment for safe discharge, and for seawater pretreatment before desalination. Currently, examples of the practical application of this filtration system are known.


2005 ◽  
Vol 5 (5) ◽  
pp. 1-8 ◽  
Author(s):  
K.Y. Choi ◽  
B.A. Dempsey

The objective of the research was to evaluate in-line coagulation to improve performance during ultrafiltration (UF). In-line coagulation means use of coagulants without removal of coagulated solids prior to UF. Performance was evaluated by removal of contaminants (water quality) and by resistance to filtration and recovery of flux after hydraulic or chemical cleaning (water production). We hypothesized that coagulation conditions inappropriate for conventional treatment, in particular under-dosing conditions that produce particles that neither settle nor are removed in rapid sand filters, would be effective for in-line coagulation prior to UF. A variety of pre-treatment processes for UF have been investigated including coagulation, powdered activated carbon (PAC) or granular activated carbon (GAC), adsorption on iron oxides or other pre-formed settleable solid phases, or ozonation. Coagulation pre-treatment is often used for removal of fouling substances prior to NF or RO. It has been reported that effective conventional coagulation conditions produced larger particles and this reduced fouling during membrane filtration by reducing adsorption in membrane pores, increasing cake porosity, and increasing transport of foulants away from the membrane surface. However, aggregates produced under sweep floc conditions were more compressible than for charge neutralization conditions, resulting in compaction when the membrane filtration system was pressurized. It was known that the coagulated suspension under either charge-neutralization or sweep floc condition showed similar steady-state flux under the cross-flow microfiltration mode. Another report on the concept of critical floc size suggested that flocs need to reach a certain critical size before MF, otherwise membranes can be irreversibly clogged by the coagulant solids. The authors were motivated to study the effect of various coagulation conditions on the performance of a membrane filtration system.


2021 ◽  
Vol 8 (3) ◽  
pp. 711-722
Author(s):  
Katherine E. Greenstein ◽  
Matthew R. Nagorzanski ◽  
Bailey Kelsay ◽  
Edgard M. Verdugo ◽  
Nosang V. Myung ◽  
...  

Electrospun carbon nanofibers with integrated titanium dioxide nanoparticles are used for water treatment in a photoactive membrane filtration system.


Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 369
Author(s):  
Shengji Xia ◽  
Xinran Zhang ◽  
Yuanchen Zhao ◽  
Fibor J. Tan ◽  
Pan Li ◽  
...  

The membrane separation process is being widely used in water treatment. It is very important to control membrane fouling in the process of water treatment. This study was conducted to evaluate the efficiency of a pre-oxidation-coagulation flat ceramic membrane filtration process using different oxidant types and dosages in water treatment and membrane fouling control. The results showed that under suitable concentration conditions, the effect on membrane fouling control of a NaClO pre-oxidation combined with a coagulation/ceramic membrane system was better than that of an O3 system. The oxidation process changed the structure of pollutants, reduced the pollution load and enhanced the coagulation process in a pre-oxidation-coagulation system as well. The influence of the oxidant on the filtration system was related to its oxidizability and other characteristics. NaClO and O3 performed more efficiently than KMnO4. NaClO was more conducive to the removal of DOC, and O3 was more conducive to the removal of UV254.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Yeit Haan Teow ◽  
Meng Teck Chong ◽  
Kah Chun Ho ◽  
Abdul Wahab Mohammad

AbstractAiming to mitigate wastewater pollution arising from the palm oil industry, this university-industry research-and-development project focused on the integration of serial treatment processes, including the use of moving bed biofilm reactor (MBBR), pre-treatment with sand filters and activated carbon filters, and membrane technology for aerobically-digested palm oil mill effluent (POME) treatment. To assess the potential of this sustainable alternative practice in the industry, the developed technology was demonstrated in a pilot-scale facility: four combinations (Combinations I to IV) of unit operations were developed in an integrated membrane-filtration system. Combination I includes a MBBR, pre-treatment unit comprising sand filters and activated carbon filters, ultrafiltration (UF) membrane, and reverse osmosis (RO) membrane, while Combination II excludes MBBR, Combination III excludes UF membrane, and Combination IV excludes both MBBR and UF membrane. Life cycle assessment (LCA) was performed to evaluate potential environmental impacts arising from each combination while achieving the goal of obtaining recycled and reusable water from the aerobically-digested POME treatment. It is reported that electricity consumption is the predominant factor contributing to most of those categories (50–77%) as the emissions of carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen oxides, and volatile mercury during the combustion of fossil fuels. Combination I in the integrated membrane-filtration system with all unit operations incurring high electricity consumption (52 MJ) contributed to the greatest environmental impact. Electricity consumption registers the highest impact towards all life cycle impact categories: 73% on climate change, 80% on terrestrial acidification, 51% on eutrophication, and 43% on human toxicity. Conversely, Combination IV is the most environmentally-friendly process, since it involves only two-unit operations – pre-treatment unit (comprising sand filters and activated carbon filters) and RO membrane unit – and thus incurs the least electricity consumption (41.6 MJ). The LCA offers insights into each combination of the operating process and facilitates both researchers and the industry towards sustainable production.


2018 ◽  
Vol 19 (3) ◽  
pp. 855-863 ◽  
Author(s):  
T. Miyoshi ◽  
Y. Takahashi ◽  
T. Suzuki ◽  
R. Nitisoravut ◽  
C. Polprasert

Abstract This study investigated the performance of a hybrid membrane filtration system to produce industrial water from highly-colored surface water. The system consists of a membrane filtration process with appropriate pretreatments, including coagulation, pre-chlorination, and anion exchange (IE) process. The results of the pilot-scale experiments revealed that the hybrid system can produce treated water with color of around 5 Pt-Co, dissolved manganese concentration of no more than 0.05 mg/L, and a silt density index (SDI) of no more than 5 when sufficient coagulant and sodium hypochlorite were dosed. Although the IE process effectively reduced the color of the water, a moderate increase in the color of the IE effluent was observed when there was a significant increase in the color of the raw water. This resulted in a severe membrane fouling, which was likely to be attributed to the excess production of inorganic sludge associated with the increased coagulant dosage required to achieve sufficient reduction of color. Such severe membrane fouling can be controlled by optimising the backwashing and relaxation frequencies during the membrane filtration. These results indicate that the hybrid system proposed is a suitable technology for treating highly-colored surface water.


Water SA ◽  
2005 ◽  
Vol 31 (1) ◽  
Author(s):  
Xuejun Chen ◽  
Zhemin Shen ◽  
Xiaolong Zhu ◽  
Yaobo Fan ◽  
Wenhua Wang

2001 ◽  
Vol 1 (5-6) ◽  
pp. 357-364 ◽  
Author(s):  
Y. Jimbo ◽  
K. Goto

The design standards of the iron and manganese removal system by membrane filtration were investigated. The membrane filtration after pre-chlorination could remove iron completely and could remove around 70% of manganese. In the case of manganese concentration being more than 0.05 mg/l, the membrane filtration could remove them completely after the deposition in the oxidation tank. The concentrations of iron and manganese were reduced more than 90% by the oxidation tank and were reduced until under the detection limit after the membrane filtration. The economic comparisons between the rapid sand filtration system and this membrane filtration system in a small capacity and a middle capacity were investigated. The 15 years total costs of the membrane filtration system were estimated to be smaller than or around equal to the rapid sand filtration system in both capacities.


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