UK MONITORING STUDY ON THE REMOVAL OF LINEAR ALKYLBENZENE SULFONATE IN TRICKLING FILTER TYPE SEWAGE-TREATMENT PLANTS - CONTRIBUTION TO GREAT-ER PROJECT NUMBER-2

The results of a linear alkylbenzene sulphonate (LAS) monitoring exerc ise carried out during August and September, at six different tricklin g filter sewage treatment plants in the Are and Calder catchments in t he UK are described. The average LAS concentration in flow proportiona l, composite, crude sewage was 3.25 mg l(-1) and ranged from 1.10 to 5 .58 mg l(-1). Based on consumer usage data and boron measurements thes e results indicate that up to 60% of the LAS was removed in the sewers prior to reaching the sewage treatment plants. The concentration of L AS in flow proportional, composite final effluents from well-operated plants ranged from 4 to 460 mu g l(-1), with an average value of 240 m u g l(-1). Removal through the plants ranged from 70-99% with mean val ues of 90.7, 93.4, 93.0, 74.6, 97.3 and 92.4% for the six plants. A si mple model is described which can be used to accurately predict the di el variation in LAS concentrations in the final effluent when measured influent concentrations, flow and settling tank volumes are known. (C ) 1998 Elsevier Science B.V.