Sequential Application of Plastic Media- Trickling Filter and Sand Filter for Domestic Wastewater Treatment at Low Temperature Condition.

Present research was aimed towards designing and construction of efficient plastic media-trickling filter (TF) for the treatment of domestic wastewater. The hydraulic flow rate through the TF was maintained at 80±2 ml/min at a temperature range of 5-15ºC by selecting treatment time of 12, 24, 36 and 48 hrs. Parameters like COD, BOD5, TSS, turbidity, NO3, NO2, SO4, PO4 and pathogenic indicator microbes were monitored after treatment of 12, 24, 36 and 48 hrs. The efficiency of the TF was improved with increase of time from 12 to 48 hrs. Maximum efficiency of TF was observed after 48 hrs treatment viz. 93.45, 93, 86.25, 57.8, 63.15, 25, 32.43, 99.95 and 86.3% reduction from the zero time value for BOD5, COD, TSS, PO4, SO4, NO3, NO2, turbidity and fecal coliforms respectively. Finally 48 hrs treated sample was passed through sand filter (SF) for further final polishing and approximately, 95.72, 95, 100, 73.5, 65.8, 58.3, 37.83, 100 and 91.5% reduction in BOD5, COD, TSS, PO4, SO4, NO3, NO2, turbidity and fecal coliforms was observed. This study showed that plastic media-trickling filter along with sand filter is a promising technology for wastewater treatment and can be scaled up for small communities in the developing countries.

Operação de filtros biológicos percoladores pós-reatores UASB sem a etapa de decantação secundária / Operation of trickling filters post-UASB reactors without the secondary sedimentation stage

A pesquisa teve por objetivo avaliar filtros biológicos percoladores (FBP) pós-reatores UASB operando sem a etapa de decantação secundária, em termos da remoção da demanda bioquímica e química de oxigênio (DBO e DQO) e sólidos suspensos totais (SST). O aparato experimental consistia em um reator UASB que alimentava quatro FBP em paralelo, preenchidos com diferentes materiais suporte. O reator UASB operou em regime hidráulico permanente, e três condições operacionais foram impostas aos FBP durante o período experimental. Em geral, os sistemas UASB/FBP foram capazes de promover o atendimento aos padrões de lançamento. Em condições de baixas cargas orgânicas volumétricas (COV), o uso de materiais de enchimento de maior área superficial específica não proporcionou ganhos expressivos em termos de desempenho. Contudo, o uso de meio suporte baseado em espumas de poliuretano propiciou melhoria significativa na qualidade do efluente final. O uso de sistemas UASB/FBP sem decantadores secundários parece ser uma promissora alternativa para a simplificação operacional da tecnologia, e uma importante estratégia para o tratamento de efluentes domésticos em países em desenvolvimento. No entanto, o sucesso do emprego desta tecnologia fica condicionado ao correto gerenciamento do lodo anaeróbio do reator UASB, a fim de que sejam evitadas sobrecargas nos FBP.

The research aimed at evaluating the operation of trickling filters (TF) post-UASB reactors without the secondary sedimentation stage, in terms of biochemical and chemical oxygen demand (BOD and COD) and total suspended solids (TSS) removal. The experimental apparatus consisted of one UASB reactor followed by four TF in parallel, each one filled with a different packing media. The UASB reactor was operated at a permanent hydraulic regime, while three operational conditions were imposed to the TF during the experimental period. In general, the UASB/TF systems were able to comply with the discharge standards. At low organic loading rates (OLR), no improvements in terms of organic matter removal, with the use of higher surface area packing media were observed. However, the use of a sponge-based packing media provided significant improvements on final effluent quality. The use of UASB/TF systems without secondary sedimentation can constitute an attractive alternative in terms of operational simplification of this technology, and an important strategy for domestic wastewater treatment in developing countries. However, the success of this technology is strictly connected to the correct anaerobic sludge management of the UASB reactor, in order to avoid overloads on the TF.

APPLICATION OF TRICKLING FILTERS IN TREATMENT OF WASTEWATER FROM GAS-GENERATING WITH HEAVY OIL / 微生物学通报

A research combined trickling filter system and active sludge aeration system was applied in the treatment of industrial wastewater from gas-generating with heavy oil. The wastewater contained both high contents of NH+4-N and mixed hydrocarbons including various PAHs. Its BOD5/COD ratio was less than 0.3 and belongs to recalcitrant, toxic wastewater. The results showed a touch-growth biofilms system was formed on the porous packing material and it played a key role in the decrease of toxicity of the influent. It could also improve the biodegradability of the wastewater.