Caracterização dos esgotos domésticos e efluentes das ETE's de Campina Grande, Guarabira e Sapé-PB.

Abstract

The present work had the objective of characterizing the domestic sewage of the cities; Campina Grande, Guarabira and Sapé (PB), and the comparison of the physical-chemical and microbiological quality of the effluents produced by the three treatment systems. In Campina Grande the sewage treatment is done through two lagoons in series, designed to operate with mechanical aeration, with 3.5m depth and total area of 3.09ha. The TTE of the city of Guarabira is formed by two modules in parallel, each with two lagoons in series, being anaerobic (3.7m) followed by a facultative (2.2m) totaling an area of 1.92ha. The research was developed only in one of the modules. A primary facultative pond, with a depth of 2.20m and a total area of 2.6ha, makes up the TEE of the city of Sapé. Samples collected from the raw sewage and effluent from the lagoons were carried out at 8 o'clock on a fortnightly basis, from January to September 1991 (Campina Grande) and from January to October of the same year in Guarabira and Sapé. Analyzes were initiated no later than two hours after collection. 24 hour profiles of the three systems were also performed. The parameters analyzed were: Temperature, pH, Dissolved Oxygen (OD), DBOc, COD, Total Solids (ST), Total Fixed Solids (STF), Total Volatile Solids (STV), Suspended Solids (SS), Suspended Solids (SS), Fecal Coliform (CF), (APHA, 1989), and counting the number of helminth eggs for EB and anaerobic lagoon effluent (WHO, 1989), and for effluents from facultative lakes (Ares et al., 1989). The results of BOD 5 (108 mg / L) and COD (226 mg / L) indicated that EB was relatively weak, with marked fluctuations, being the lowest values found in the winter months and corresponding to the season of rainfall in the region. The mean pH was slightly alkaline (mean 7.7). The mean values ​​for SS, ST, CF and numbers of A. lumbricoides eggs were 99 mg / L, 935 mg / L, 1.3x10 7 CF / 100ml and 497 eggs / L, respectively. The pond aerators were not working, and the first reactor was heavily silted due to lack of maintenance of the litter box. These conditions did not promote the expected removals of some analyzed parameters. The efficiencies were 34% for BOD5 T (108 - 71mg / L); 31% for COD (226 - 155 mg / L) and 47% for SS (99-52 mg / L); 10% for ST (935-840 mg / L): 36% for CF (1.3x10 7-8.3 X 10-6 CF / 100 mL) and 68% for A. lumbricoides eggs (497-158 eggs / L). The final effluent, of poor quality, significantly compromises the receiving body in which it is released, making its use inappropriate for irrigation and animal watering. The raw sewage of Guarabira was classified as medium concentration based on the mean values ​​of BOD5 (338 mg / L), COD (549 mg / L), ST (977 mg / L), SS (249 mg / L). The mean concentration of FC was 4x10 7 CF / 100ml and 558 eggs / L For A. lumbricoides. The pond series removed 94% from BOD 5 (338-20 mg / L), 77% COD (549-125 mg / L), 8T877 (977-567 mg / L), 99.7% CF (4x10 7 - 1x10 5 CF / 100mL), and 100% A. lumbricoides eggs (558-0 eggs / L). The crude sewage from the Sapé TEE was classified as strong, due to the high average concentrations of BODs (725 mg / L), COD (1,567 mg / L), ST (1,777 mg / L), SS (985 mg / L). The mean concentration of CF was 2.2x10 ° CF / 100mL and there was a high average number of A. lumbricoides eggs (2,180 eggs / L). The primary facultative pond was responsible for the reduction of 947. of BOD, (725-44 mg / L), 84% COD (1,567-245 mg / L), 597. ST (1,777-730 mg / L) , 87% of the SS (9,985 - 127 mg / L), 99,75% (2, 10 x 10 - 5 x 10 5 CF / 100 mL) and 100% A. lumbricoides eggs (2,180 - 0 eggs / L). The data showed that the treatment systems of the cities of Guarabira and Sapé are functioning satisfactorily. Removal of CF from Guarabira (99.55%) And Sapé (99.76%) was compatible with the configuration of the respective systems. However, the final effluent is not suitable for discharge into the environment, which can cause serious health risks.