Influência do tempo de detenção na eficiência de lagoas facultativas secundárias, tratando esgotos domésticos.

Abstract

The objective of the present study is to determine the basic kinetics of secondary facultative ponds treating domestic sewage in the Northeastern region of Brazil. An attempt has also been made to evaluate the effectiveness of secondary facultative ponds under the specific regional conditions. The experimental results reported herein have been carried out in the Experimental Station for the Biological Treatment of Sewage EXTRABES in Campina Grande. Two pilot scale ponds were operated independently fron june 1977 to march 1979. Each pond was integrated to a series of ponds, this forming two systems. The sistems were as follows: Sistem I I I comprises an anaerobic pond (A2) followed by another anaerobic pond (A3) and a secondary facultative pond (F6). Sistem IV consist of an anaerobic pond (A4) followed by a secondary facultative pond ( F 7). During the experimental period, organic loading and detention time were different for each system. It was verified that an increase in the detention time of a secondary facultative pond, wich implies an increase of its area, does not promote a proportional increase in its efficiency on the removal of BOD5 and Feacal Coliforms.