Cross-Flow Ultrafiltration Used in Algal High Rate Oxidation Pond Treatment of Saline Organic Effluents with the Recovery of Products of Value
An algal high rate oxidation ponding process for treating organic s present in saline effluents has been described. The extreme halophile Dunaliella salina can be made to predominate in the system by manipulating salinity, producing products of value together with a waste treatment function. Application in treating tannery saline organic wastes was examined. Techniques appropriate for the harvesting of micro-algae from this and other algal production systems presents a limiting factor in the development of algal biotechnology. Cross-flow filtration was evaluated as a technique for micro-algal cell separation. Both microfiltration and ultrafiltration were found to produce effective algal removal from the medium, Cross-flow ultrafiltration with a polyethersulfone coated tubular filter produced effective separation with the production of cell concentrates in a viable condition. Flux rates of 30 - 40 LMH fall within acceptable levels for application in industrial processes. Cell shattering observed with microfiltration precludes its use for recovering whole or viable cell concentrates.