Microfiltration of water-based paint effluents

• Published in: Advances in environmental research : an international journal of research in environmental science, engineering and technology engineering and technology, 2004-03, Vol.8 (3), p.455-466
• Main Authors: Dey, B.K, Hashim, M.A, Hasan, S, Sen Gupta, B
• Format: Article
• Language: English
• Subjects: Microbial contamination; Microfiltration; Water recycling; Water-based paint
• ISSN: 1093-0191; 1093-7927
• DOI: 10.1016/S1093-0191(02)00122-3

The major hurdle associated with water recycling in water-based paint manufacturing processes is microbial contamination and related deterioration of product quality and shelf life. The common problems associated with microbial degradation are change in viscosity, pH, colour and loss of surface adhesion properties. Owing to these reasons, water recycling is not widely practised in water-based paint manufacturing processes. The present study focuses on tertiary treatment of effluent by chemical coagulation and cross-flow microfiltration (0.2 μm pore size) to produce water of sufficient quality for reuse in various stages of water-based paint manufacturing. The coagulation and flocculation were carried out in a ‘jar test’ rig at a controlled pH, and coagulant dosage was optimised by turbidity and zeta potential measurements. The filtrate was subjected to cross-flow microfiltration and permeate was tested for necessary quality attributes. Screening of aerobic microbes and fungi were conducted by streaking the samples on nutrient agar and malt extract agar, respectively. Iron sulfide agar tubes were used for screening anaerobic microbes or the sulfate reducing bacteria. The tests showed that permeate was free from microorganisms. The process was implemented in a paint manufacturing plant in Malaysia, which resulted in 55% reduction in water consumption.