Remoção de matéria orgânica, sólidos suspensos e indicadores bacteriológicos em lagoas de estabilização em escala real.

Abstract

The objective of this work was to study the stabilization pond systems of the cities of Guarabira - PB Í6 ° 51'18 "S and 35 ° 29'24" 0; 98m anm) and Sapé - PB <7 ° Ô6'00 "S and 35 ° 13'48" 0 »lmm) through the characterization of the mean flow rate to the ETE's, the monitoring of the physical-chemical and microbiological quality of the raw sewage and effluents from each pond and the analysis of the efficiency of the systems in the removal of matter suspended solids and bacteriological indicators. The TTE of the city of Guarabira is formed by two modules in parallel, each with two lagoons in series, being anaerobic <3.7 m) - AiG, followed by a facultative one (2, Sm) - FiG, totaling an area of 1 * 92 ha. The research was developed only in one of the modules. In the city of Sapé the treatment of sewage is done through a primary facultative pond - F1S, with E, m depth and a total area of ​​E, 6 ha. The samples were taken at Sh, every fortnight, and the processing was done at the maximum 4 hours after collection. Fieldwork was carried out from September 1991 to July 1992 at the TTE of Guarabira and from September 1991 to June 1992 at the SSE of Sapé, continuing the monitoring studies of these systems (Florentino, 1992 3 Florentino, 1993i Tejo, 1993). The analyzed parameters were temperatures pH, dissolved oxygen, BOD5, COD, suspended solids, fecal coliforms and streptococci fecal diseases. The mean inflows to the systems were 8.0 l / s and 10.2 l / s, respectively, for the Guarabira TSS and the Sapé trough. These values ​​allowed the calculation of the volumetric and superficial organic loads of the lagoons. At the Guarabira ETE, the volumetric loads for AiG and FIG were 60 and 1.2 gDBO .m ~ 3. The primary fac- tory reactor at Sapé had volumetric and surface loads of 11 gDB05, m-3 d-1 and 234 kg DM-ha " 1. d-1, respectively. Throughout the Lagoa series of the Guarabira TEE, the observed reductions were 93% for BOD5 (327-22 m g / l), 36 '/. for COD (1029-655 m g / l), 79% for SS (296-63 m g / l), 9, B10J for CF (2.9 x 107 - 5.5 x 10 * cfu / 100 ml) and 99.913% for EF (4.3 x 106 - 3.7 x 103 cfu / 100ml). In the primary facultative pond of the Sapé TEE, the reductions were 94% for BOD5 (689 - 44 mg / l), 76% for COD (3745-885 mg / l), 75% for SS (752 - 187 mg / l), 99.388 (8.5 x 10 7 - 5.2 x 10 4 cfu / 100 ml) and 99.831% for EI (1.6 x 107 - 2.7 x 10 6 / ml). The monitoring showed that the treatment systems of the cities of Guarabira and Sapé are functioning satisfactorily, presenting efficiency compatible with the existing configurations. However, the final effluent from the systems does not meet the recommended standard for discharging into the environment, as these can cause serious health risks.