Estudo do desempenho de um sistema de lagoas de estabilização no tratamento de águas residuárias de bairros populares (Glória I, Glória II, Jardim América e Belo Monte) da cidade de Campina Grande, Paraíba.

Abstract

The operational performance of a sewage treatment plant during the acclimatization phase was analyzed from March to August 2007. The plant made up of preliminary treatment (bar screen, grit chamber), parshall flume, an anaerobic pond and a secondary facultative pond, was designed for treating wastewater predominantly domestic from four popular places situated in the peripheral zone of Campina Grande City (7° 13 11"South, 35°52 31"West), Paraiba state, northeast Brazil. Two of these places were areas not previously attended by the general sewerage system of Campina Grande and two others, new ones resulting from the transference of people from a slum. Routine monitoring comprised analyses of pH, temperature, BODs, COD, suspended solids, thermotolerant coliforms and helminth eggs in grab samples of raw sewage and effluents of both ponds and dissolved oxygen in the effluent of the facultative pond, being these samples collected between 8 and 10 a.m. Besides, a study on the variability of influent flow-rate and the characterization of the facultative pond effluent in terms of physicochemical variables diurnal profiles were carried out. The average influent flow-rate was estimated as 6.85 L.s"1 and volumetric organic loading in anaerobic pond and surface organic loading in secondary facultative pond were 75 gBOD5.n1 \d"' and 200.68 kgBODj.ha'.d"1, based, respectively, on BOD5 average values of 454 .mg.L"1 for raw sewage and 114 mg.L"1 for the anaerobic effluent. It was concluded that the operational performance of the series of ponds, during the acclimatization phase, was typical of systems with such a configuration. Despite being a very good performance with high removal efficiency of organic matter, the final effluent of the plant, as typical, did not have a good sanitary quality. In future, as already envisaged in project, new contributions will increase influent flow-rate and so, presumably, the operational characteristics would be critical affecting negatively the efficiency of the system.