Black water treatment by an upflow anaerobic sludge blanket (UASB) reactor: a pilot study

Abstract

Decentralized sanitary wastewater treatment has become a viable and sustainable alternative, especially for developing countries and small communities. Besides, effluents may present variations in chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total nitrogen values. This study describes the feasibility of using a pilot upflow anaerobic sludge blanket (UASB) reactor to treat wastewater with different organic loads (COD), using black water (BW) and sanitary wastewater, in addition to its potential for preserving nutrients for later recovery and/or reuse. The UASB reactor was operated continuously for 95 weeks, with a hydraulic retention time of 3 days. In Phase 1, the reactor treated simulated BW and achieved 77% CODtotal removal. In Phase 2, treating only sanitary wastewater, the CODtotal removal efficiency was 60%. Phase 3 treated simulated BW again, and CODtotal removal efficiency was somewhat higher than in Phase 1, reaching 81%. In Phase 3, the removal of pathogens was also evaluated: the efficiency was 1.96 log for Escherichia coli and 2.13 log for total coliforms. The UASB reactor was able to withstand large variations in the organic loading rate (0.09–1.49 kg COD m−3 d−1), in continuous operation mode, maintaining a stable organic matter removal.

Up-Flow Anaerobic Sludge Blanket (UASB) Technology for Energy Recovery: A Review on State-of-the-Art and Recent Technological Advances

“…High efficiency blackwater treatment was reported also in [ 109 ], where an OLR of 4.1 kg COD/m 3 d was applied (HRT of 2.6 d), obtaining a COD removal efficiency of 84% and a good methane production of 0.68 m 3 CH 4 /m 3 d. The positive reported outcome was related to the prevalence of H 2 /CO 2 methanogenic pathway [ 109 ]. To compare the effect of diverse influent streams, UASB was used to treat both blackwater and sanitary wastewater in the work in [ 112 ], highlighting a higher COD abatement when treating blackwater (77% versus 60%). The good COD removal was maintained despite the fluctuating OLR, coupled with a moderate E. coli (1.96 log) and Total Coliforms (2.13 log) removal [ 112 ].…”

“…To compare the effect of diverse influent streams, UASB was used to treat both blackwater and sanitary wastewater in the work in [ 112 ], highlighting a higher COD abatement when treating blackwater (77% versus 60%). The good COD removal was maintained despite the fluctuating OLR, coupled with a moderate E. coli (1.96 log) and Total Coliforms (2.13 log) removal [ 112 ]. In a coherent way, a recent notable research proved that different blackwater types (coming from conventional and vacuum toilets) enriched distinct microbial consortia in UASB treatment, probably due to the diverse sulfate and ammonia loadings [ 113 ].…”

Investigation on Recycling Dry Toilet Generated Blackwater by Anaerobic Digestion: From Energy Recovery to Sanitation

“…Anaerobic digestion is an energy-efficient method for blackwater treatment to recover energy and nutrients [9]. However, the stability of anaerobic digestion is susceptible to fluctuations in substrate composition (such as total solids, chemical oxygen demand, C/N ratio, and total organic carbon), accumulation of toxic substances, sludge aging and other factors [10].…”

Reator anaeróbio-aeróbio-nitrificante-anóxico (RAANA) com zonas biológicas sobrepostas, seguido de desinfecção: tratamento de esgoto sanitário para remoção de matéria orgânica, nitrogênio, sulfeto e microrganismos indicadores

“… A metanogênese gera alcalinidade devido à remoção dos ácidos voláteis e geração de bicarbonato. Com relação ao pH é normal ocorrer aumento devido à remoção dos ácido orgânicos voláteis e geração de bicarbonato (SLOMPO et al, 2019). Deve ser considerado a contribuição da amonificação e sulfetogênese via propionato (LENS et al, 1998).…”

“…efluente a DQOf foi igual a 54,7 ± 13 mg.L -1 . O desempenho global verificado na zona anaeróbia foi igual a 77 ± 10 % e o RAANA piloto alcançou remoção média de 88 ± 4 % para o período monitorado (Figura 30).O desempenho verificado na primeira semana de monitoramento foi típico de reator UASB que já passou por período de partida Slompo et al, (2019). investigaram um reator UASB que tratou mistura entre esgoto sanitário e água residuária da suinocultura, durante o período em que o reator UASB foi alimentado apenas com esgoto sanitário a remoção de DQO foi igual a 60 %.…”