title: Anaerobic co-digestion of source segregated brown water (feces-without-urine) and food waste: for Singapore context.
abstract: The objective of this study was to evaluate the feasibility of anaerobic co-digestion of brown water (BW) [feces-without-urine] and food waste (FW) in decentralized, source-separation-based sanitation concept. An effort has been made to separate the yellow water (urine) and brown water from the source (using no-mix toilet) primarily to facilitate further treatment, resource recovery and utilization. Batch assay analytical results indicated that anaerobic co-digestion [BW+FW] showed higher methane yield (0.54-0.59 L CH(4)/gVS(added)) than BW or FW as a sole substrate. Anaerobic co-digestion was performed in the semi-continuously fed laboratory scale reactors viz. two-phase continuous stirred-tank reactor (CSTR) and single-stage sequencing-batch operational mode reactor (SeqBR). Initial 120 d of operation shows that SeqBR performed better in terms of organic matter removal and maximum methane production. At steady-state, CODs, CODt, VS removals of 92.0±3.0, 76.7±5.1 and 75.7±6.6% were achieved for SeqBR at 16d HRT, respectively. This corresponds to an OLR of 2-3 gCOD/L d and methane yield of about 0.41 L CH(4)/gVS(added). Good buffering capacity did not lead to accumulation of VFA, showing better process stability of SeqBR at higher loading rates. The positive findings show the great potential of applying anaerobic co-digestion of BW+FW for energy production and waste management. In addition, daily flush water consumption is reduced up to 80%. Decentralized, source-separation-based sanitation concept is expected to provide a practical solution for those countries experiencing rapid urbanization and water shortage issues, for instance Singapore.
authors.affiliation: Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, #06-08 CleanTech One, 1 Cleantech Loop, 637141 Singapore. rrajinime@yahoo.co.in
authors.forename: Rajinikanth
authors.initials: R
authors.lastname: Rajagopal
authors.forename: Jun Wei
authors.initials: JW
authors.lastname: Lim
authors.forename: Yu
authors.initials: Y
authors.lastname: Mao
authors.forename: Chia-Lung
authors.initials: CL
authors.lastname: Chen
authors.forename: Jing-Yuan
authors.initials: JY
authors.lastname: Wang
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D005502:Food; D006801:Humans; D006863:Hydrogen-Ion Concentration; D017404:In Situ Hybridization, Fluorescence; D012722:Sewage; D012846:Singapore; D014873:Water Pollutants / Q000378:metabolism*
chemical_list: D012722:Sewage; D014873:Water Pollutants