Ronaldo Stefanutti

Coconut shells as filling material for anaerobic filters

In rural areas of developing countries, there is a lack of sanitation services and the installation of such infrastructure is hampered by the high investment costs for initial implementation and by the limited availability of qualified personnel. An alternative to traditional sanitation services include an anaerobic filter, but the high cost of appropriate filling material can be an obstacle to its wide-spread implementation. To decrease this construction cost, the objective of this work was to study the use of coconut shells as filling material for anaerobic filters. Anaerobic filters were built and filled with the studied material and operated with up flow and hydraulic retention time of 9 hours. The reactors provided a removal of 79 ± 16% in BOD terms, indicating that the coconut shell filling had efficiency consistent with the literature data. In addition, the husks were found to retain their tensile strength following use in the reactors. Coconut husks have more empty bed volume than other low cost materials, such as crushed stone, nearing properties of traditional materials. The results of this study indicate that coconut husks may prove to be a low cost alternative to traditional fillers for anaerobic treatment in rural communities.

Pós-tratamento de efluente de filtros anaeróbios operados com baixo tempo de detenção hidráulica por escoamento superficial no solo

In this investigation the post-treatment of anaerobic filters operated with low hydraulic retention time (HRT) through overland flow system was studied. For that, it was built four reactors whose volume was 500 L, filled up with bamboos rings and a ramp with 40.0 m of length and inclination of 3.5%, covering with Tifton 85 (Cynodon sp) grass. It was evaluated the wastewater treatment from Limeira city (SP), operating anaerobic filters with 3 hour HRT and the effluent application in superficial drain of 0.10; 0.20; 0.30 e 0.40 m3.h-1.m-1 rates. In these operational conditions, the effluent was suitable to be discharged into receiving waters until the rate application of 0.20 m3.h-1.m-1. Over this value, there was a worse final quality in DBO and phosphorus concentration.