Fate of Arsenic during Biological Treatment of High Strength Wastewater–Case Study
The paper presents the results of treatability study on highly contaminated wastewater with phenols (300 mg/l), thiocyanate (210 mg/l), ammonia (800 mg/l) and arsenic up to 11 mg/l. The study was conducted in two sequencing batch reactors (SBRs) using biomass from coke plant. After two months of acclimatization the biomass was able to remove ammonia to below 1 mg/l and phenols and thiocynate below detection limits. Partial arsenic removal was also achieved. Removal of arsenic was substantially improved by addition of 40 mg/l of ferric chloride during react cycle. Aeration tests with the biomass indicated that, approximately 5% of arsenic is transfered during biological treatment into volatile compounds.