Biological drinking water treatment processes, with special reference to mutagenicity

Many researches have demonstrated that the use of biological processes in the production of drinking water has many advantages over conventional alternatives. One possibility is that biological processes will result in lower levels of genotoxic by-products in the drinking water. This possibility was investigated in the present study, which compares the levels of such by-products following either chemical or biological treatments. Water samples, collected at the main steps of the two key stages of both treatments were passed over XAD2/8 resins, to concentrate micropollutants, included by-products, for subsequent analysis using the microsome/Salmonella assay (TA98 and TA100 +/- S9). The results showed that biological treatment, avoiding break-point chlorination, limits by-product formation and associated mutagenic generation. It follows that, in this respect, biological processes seem to have significant advantages over conventional water treatments. (C) 2000 Elsevier Science Ltd. All rights reserved.