Wastewater pretreated by electrocoagulation and flotation

Wastewater pretreated by electrocoagulation and flotation

News and Views MF s y s t e m for removing algae at Hungarian power plant A c o n t i n u o u s mlcrofiltration (CMF) system, designed to remove al...

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News and Views

MF s y s t e m

for

removing algae at Hungarian power plant A c o n t i n u o u s mlcrofiltration (CMF) system, designed to remove algae from water before treatment b y reverse osmosis, h a s u n d e r g o n e precommissioning trials at Memcor's Wirksworth, UK, factory. The CMF system, worth over £350 000, is due to be delivered to the Bokod Power Plant in H u n g a r y u n d e r a contract placed by Zenon Systems Kft, a H u n g a r i a n water treatment company, part of Zenon Environmental Inc of Canada. The water at the power station is taken directly from the cooling lake which suffers from high turbidity, primarily due to algae blooms. To meet the feedwater s t a n d a r d s required for reverse osmosis, conventional p r e t r e a t m e n t m e t h o d s can be complex, requiring several stages. This MF system is able to remove s u s p e n d e d solids a n d algae down to 0.2 microns in a one-barrier filtration step. In this system, M I 0C m e m b r a n e modules from Memcor will be used. TWo 36M10C MF units will be capable of treating a m a x i m u m flow rate of 44 m 3 / h r in d u t y / s t a n d b y configuration or 88 m 3 / h r in parallel configuration.

Further Information from: Jayne Allsop, Memcor Ltd, Derby Road, Wlrksworth, Derbyshire DE4 4EP, UK. Tel: 0629 823811.

EuroMembrane 9 5 --- Call for

papers E u r o M e m b r a n e 95 will be held over three days, from 18-20 September 1995, in Bath, UK. It continues the series of conferences organized by the E u r o p e a n Society of Membrane Science a n d Technology, a n d participants are now invited to submit abstracts in the following areas: •

physicochemical fundamentals;



fluid m e c h a n i c s a n d transportation;



engineering design;



process integration;



materials a n d formation;



biomedical applications;



environmental applications;

Membrane Technology No. 48



p h a r m a c e u t i c a l a n d chemical applications;



gas separations; a n d



competing technologies, economics a n d business. Abstracts should be submitted on a single sheet of A4 b y 15 December 1994.

Further Information from: Marie Salter, EuroMembrane 95, Centrefor Continulng Eduction, University of Bath, Claverton Down, Bath BA2 7AY, UIC

Wastewater

pretreated by electrocoagulation and flotation A paper on the u s e of a combined electrocoagulation a n d aeroflotatlon m e t h o d for p r e t r e a t m e n t of wastewater prior to microflltratlon h a s been published in Filtration & Separation, May 1994, following its presentation at the Flltech E u r o p a 93 Conference in Karlsruhe, Germany, on 20 October 1993. The u s e of cross flow mlcroflltratlon in wastewater treatment is limited b e c a u s e of m e m b r a n e fouling as a result of the colloidal fraction. All types of treatment depend on a preliminary conversion of the colloidal a n d soluble pollution into particulate pollution prior to a final clarification. The paper presented describes the role of electrochemical destabilization of the wastewater prior to CFMF. Industrial development of the process depends on the particular flow of permeate p r o d u c e d a n d regeneration of the m e m b r a n e . In the experiment, the s u s p e n s i o n was pretreated with a n aeroflotation unit combined with electrocoagulation. The treated water was mixed with recirculated water, pressurized a n d s a t u r a t e d with air, a n d t h e n introduced into the separation chamber. Fine gas bubbles are released which c a u s e s the water particles to float, a process which is e n h a n c e d b y the release of gas from electrolysis of water. Results showed that pretreatment: •

reduced the fall in permeate o u t p u t with time; a n d



increased the m i n i m u m level of filtrate significantly compared to levels obtained with u n t r e a t e d water a n d decanted u n t r e a t e d water. The a u t h o r s concluded that although direct treatment of municipal wastewater by microfiltration is not a n economic possibility, it is ij~oss~le to obtain permeate flows a p p r o a c h i n g 0.35 m ~ / m ' / h by combining this filtration with a preliminary electrochemical destabilization. The technique then b e c o m e s a possible treatment process, especially as virtually total disinfection of the effluent can be achieved with a cutoff threshold of 0.1 ~la.

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News and Views Further Inforrnatlon from: M-F Pouet and A Grasmlck, Groupe de Genie d e s Procedes, Unlversltd de MontpeUier II, place Eugene BatalUon, F-34095 MontpeUler Cedex 5, France.

resulting in low extractables and cleaner filtrate. Each cartridge is 100% integrity tested by diffusional flow during m a n u f a c t u r e e n s u r i n g high p r o d u c t reliability a n d quality says the company.

Membranes directory published An international directory giving information of over 200 m e m b r a n e companies h a s been published in the May 1994 issue of Filtration & Separation. The directory features companies that m a n u f a c t u r e or supply m e m b r a n e s a n d related equipment - including materials a n d the m a i n m e m b r a n e types. Full contact details a c c o m p a n y each directory entry. Further Informatlon from: Filtration & Separation, Elsevier A d v a n c e d Technology, PO Box 150, Kidllngton, Oxford OX5 1AS, UK. Tel: 0865 843848. Fax: 0865 843971.

HtFIow Sol-Vent cartrldge fllter. Further Informatlon from: Gelman Sciences, 600 South Wagner Road, A n n Arbor, MI 48106, USA. Tel: +1 313 665 0651.

New product cat ogue from Amicon

Removing

Amicon h a s Just published its 1994 product catalogue. Included are details of over 600 products for microfiltratlon, m e m b r a n e filtration and chromatography. Membrane filtration products offered include spiral-wound a n d hollow fibre cartridges and systems. Further Information from: Amlcon Inc, 72 Cherry Hill Drive, Beverly, MA 01915, USA. Tel: + 1 508 777 3622. Fax: +1 508 777 6204.

Biological nitrogen removal u n d e r low temperature in a m e m b r a n e separation bioreactor for on-site domestic wastewater treatment h a s been studied by researchers in J a p a n , a n d the results are presented in Wat. Scl. Tech., 28, pp 325--333, 1993. At low temperatures, biological treatment plants suffer from both loss of nitrifying activity a n d nitrifying bacteria from the system. The purpose of these studies was to examine the effect of complete biomass retention in a m e m b r a n e separation bioreactor against the severe conditions at low temperature. The bioreactor was operated u n d e r intermittent aeration of a 180-minute operational cycle to achieve simultaneous nitrification a n d denitriflcation for nitrogen removal. Temperature was initiaUy controlled at 25°C a n d reduced by 5°C stepwise at every 2 weeks duration to 5°C. Nitrogen removal started to deteriorate as temperature dropped to 10°C a n d from more t h a n 90°C at 25°C reached 20 ° at 5°C. Increasing oxygen s u p p l y by increasing aeration time in the operational cycle could completely recover nitrification at 10°C. High nitrogen removal was again achieved by the introduction of a non-aeratlon period.

0.05

rating

for HiFLO filter Gelman Sciences is now offering its HiFLO Sol-Vent TM cartridge filter with a O.05~u-n rating, specifically designed for high purity filtration of critical process fluids for the chemical a n d microelectronic industries. The filter is m a n u f a c t u r e d with Just two materials of construction, PTFE m e m b r a n e a n d polypropylene. The cartridge materials are thermally-bonded,

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n i t r o g e n at low temperature

M e m b r a n e T e c h n o l o g y No. 4 8