Effect of varying volumes of anaerobic microbial inoculum on biodegradation and biogas production from black water

• Published in: Journal of the Indian Chemical Society 2024-11, Vol.101 (11), p.101426, Article 101426
• Main Authors: Bera, Sounak, Ela-a Justina, D., Chatterjee, Soumya, Vairale, Mohan G., Devi, Rashmi Rekha, Acharya, Somen, Pal, Vijay, Gupta, Rajeev, Kamboj, Dev Vrat
• Format: Article
• Language: English
• Subjects: Anaerobic treatment; Biogas; Black water; COD; Sanitation
• ISSN: 0019-4522
• DOI: 10.1016/j.jics.2024.101426

Unfettered discharge of untreated black water is one of the raging environmental issues which needs to be addressed especially in many developing and third-world countries. Black water is rich in organic compounds, elements such as nitrogen and phosphorous, and harmful faecal coliforms which makes it a major threat to the environment. The present study focuses on the use of an inhouse anaerobic microbial inoculum for the treatment of black water with an emphasis on decentralized treatment systems. The effects of varying volumes of inoculum (5 %, 10 %, 20 % & 30 %) for the treatment of black water was studied. Various parameters such as pH, total solids (TS), volatile solids (VS), chemical oxygen demand (COD) and biogas production were recorded. 10 % inoculum yielded the maximum amount of biogas. The biogas volume varied from 1046 mL–1180 mL depending on the experiments carried out using either fresh inoculum or acclimatized old inoculum. The inoculum could also be reused for sustained biodegradation and biogas production process which makes its use economic and apt as inoculum for reactors used in decentralized treatment processes. An attempt was also made in this work to reduce the input COD imparted via the inoculum itself by letting the larger and heavier solids to settle. Nevertheless, it was observed that the best working inoculum was the 10 % whole inoculum in terms of biogas production and COD removal. [Display omitted] •Experiments were performed for optimization of black water biodegradation.•Various inoculum volumes were tested for the optimal concentration of the inoculum.•Batch repetition studies were carried out with the optimal inoculum volume.•Studies were also carried out for scaling down the input COD load imparted by the inoculum.