Behaviour and biodegradation of sulfonamides (p-TSA, o-TSA, BSA) during drinking water treatment

Three sulfonamides - para-toluenesulfonamide (p-TSA), ortho-toluenesulfonamide (o-TSA) and benzenesulfonamide (BSA) - have recently been detected in groundwater within a catchment area of one drinking water treatment plant (DWTP), which is located downstream of a former sewage farm. The degradation pathways of p-TSA, o-TSA and BSA were investigated during drinking water treatment with incubation experiments and an experimental filter. Incubation experiments showed that p-TSA is removed during the treatment by microbiological processes. Removal of p-TSA is performed by adapted microorganisms only present in polluted groundwater. The elimination in an experimental filter of 1.6 m length applying filtration velocities from 2 to 6 m h−1 was ∼93% of p-TSA. The microbial degradation rates in the incubation experiment were ∼0.029 μg l−1 h−1 (zero order reaction). In the experimental filter, the reaction rate constants were around 0.0063 s−1 for all filtration velocities (1st order reaction). Drinking water treatment does not reduce the concentration of o-TSA and BSA under conditions encountered in Berlin. p-TSA, o-TSA and BSA were only measured in the low μg l−1 concentrations range in the purified water.