Performance evaluation of a natural treatment system for small communities, composed of a UASB reactor, maturation ponds (baffled and unbaffled) and a granular rock filter in series

Abstract

Post-treatment of anaerobic reactor effluent with maturation ponds is a good option for small to medium-sized communities in tropical climates. The treatment line investigated, operating in Brazil, with an equivalent capacity to treat domestic sewage from 250 inhabitants, comprised a upflow anaerobic sludge blanket reactor followed by two shallow maturation ponds (unbaffled and baffled) and a granular rock filter (decreasing grain size) in series, requiring an area of only 1.5 m inhabitant. With an overall hydraulic retention time of only 6.7 days, the performance was excellent for a natural treatment system. Based on over two years of continuous monitoring, median removal efficiencies were: biochemical oxygen demand = 93%, chemical oxygen demand = 79%, total suspended solids = 87%, ammonia = 43% and Escherichia coli = 6.1 log units. The final effluent complied with European discharge standards and WHO guidelines for some forms of irrigation, and appeared to be a suitable alternative for treating domestic sewage for small communities in warm areas, especially in developing countries.

Stratification and equalization cycles in shallow maturation ponds with different operational configurations and at different periods of the year

“…The system was designed to serve an equivalent population of 250 inhabitants, receiving approximately 40 m 3 day À1 of inflow. Recent research about the performance of the system can be seen in Dias et al (2018).…”

Remoção de nutrientes em lagoas de polimento de bateladas sequenciais no pós-tratamento do efluente de reator UASB

“…Diversos trabalhos têm relatado que parâmetros operacionais podem interferir no funcionamento das lagoas de polimento, como o regime de alimentação, o tempo de detenção hidráulica, a profundidade e a sazonalidade (CAVALCANTI, 2009;OLIVEIRA, 2010;SUTHERLAND et al, 2018). No que se refere ao regime de alimentação, vários estudos versam sobre a utilização de lagoas de polimento de fluxo contínuo (LPFC) no pós-tratamento de UASB ( LETTINGA, 1994;CAVALCANTI et al, 2001;MASCARENHAS;CHERNICHARO, 2004;BASTOS et al, 2010;OLIVEIRA, 2010;KHAN et al, 2011;ASSUNÇÃO;VON SPERLING, 2013;PONTES;SOUSA;LEITE, 2017;DIAS et al, 2018).…”

The impact of hydraulic retention time on the performance of two configurations of anaerobic pond for municipal sewage treatment

“…Currently, the costs associated with the extensive land requirements are the largest single barrier to uptake of APs [17][18][19], with hydraulic retention times (HRTs) ranging from 1 and 4 days but most commonly between 2 and 3 days [8]. Reduction of land requirement, through shorter HRTs, improves the economic viability of APs whilst also offering process improvements.…”