scholarly journals Membrane filtration technology in water works. Advanced water purification treatment by ceramic -film filtration system.

1996 ◽  
Vol 25 (4) ◽  
pp. 214-219
Author(s):  
Toshio KAWANISHI
Keyword(s):  
Water Purification ◽  
Membrane Filtration ◽  
Ceramic Film ◽  
Filtration System ◽  
Filtration Technology

Membrane Fouling and Hybrid Membrane Filtration System in Water Purification

MEMBRANE ◽  
2013 ◽  
Vol 38 (5) ◽  
pp. 207-214
Author(s):  
Yoshihisa Fujii ◽  
Sadaki Samitsu ◽  
Izumi Ichinose
Keyword(s):  
Water Purification ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Hybrid Membrane ◽  
Filtration System

Гравитационная мембранная фильтрация в схемах очистки воды и сточных вод (обзор)

2019 ◽  
pp. 48-55
Author(s):  
V. Kofman
Keyword(s):  
Wastewater Treatment ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Local Treatment ◽  
Predatory Behavior ◽  
Practical Application ◽  
Produce Water ◽  
Filtration System ◽  
Microfiltration Membranes ◽  
Filtration Technology

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.

Low-pressure membrane filtration with unconventional coagulation regimes

2005 ◽  
Vol 5 (5) ◽  
pp. 1-8 ◽  
Author(s):  
K.Y. Choi ◽  
B.A. Dempsey
Keyword(s):  
Activated Carbon ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Cross Flow ◽  
Chemical Cleaning ◽  
Sand Filters ◽  
Charge Neutralization ◽  
Floc Size ◽  
Filtration System ◽  
Pre Treatment

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.

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