Ecology, Environment and Conservation Paper

PHYSICO-CHEMICAL CHARACTERISATION AND QUALITY IMPROVEMENT EVALUATION OF PRIMARY TREATED MUNICIPAL WASTE WATER IN THE CITY OF BAHIA BLANCA (ARGENTINA)

N.B. Tombesi, M.F. Pistonesi and R.H. Freije

Abstract

The objective of this study is to determine the physico-chemical characteristics of the primary treated municipal wastewater in Bahia Blanca (Province of Buenos Aires, Argentina), in different operating conditions and to evaluate the resulting improvement in quality. The effluent has recently begun to be treated by filtration through three Huber GmbH Ro-2 rotative filters, since until then raw wastewater had been dumped straight into the inner estuary of Bahia Blanca. The principal parameters studied were those related with suspended solids, organic matter and nutrients. Twenty- four hourly samples were taken in order to assess the variations within the day. Moreover seven samples—on a sample per day basis—were obtained at a manifest peak hour to analyse weekly behaviour. Finally three random samples of the retained and compacted solids were analysed to assess their composition. Obtained values for COD, Turbidity and SS show similar levels and behaviour both within the day and the week Nutrients show a predominance of ammonia, a low concentration of nitrites and an almost complete absence of nitrates. Total solids remotion is calculated at 23%, in relation to the addition of both suspended and retained solids.