Field test of methane fermentation system for treating swine wastes

• Published in: Water Science & Technology Vol. 45; no. 12; pp. 103 - 112
• Main Authors: Kataoka, N, Suzuki, T, Ishida, K, Yamada, N, Kurata, N, Katayose, M, Honda, K
• Format: Journal Article Conference Proceeding
• Language: English
• Published: England IWA Publishing 01.01.2002
• Subjects: Agriculture; Ammonia - analysis; Anaerobic Digestion; Animals; Bacteria, Anaerobic - physiology; Biogas; Bioreactors; Chemical oxygen demand; Composting; Composts; Dehydration; Density; Evaluation; Fermentation; Gases; Gravity; Ignition; Manure; Methane; Methane - metabolism; Moisture content; Oxidation; Oxygen - metabolism; Pretreatment; Refuse Disposal - methods; Removal; Sludge; Sludge digestion; Slurries; Specific gravity; Swine; Treated water; Urine; Wastes; Water content
• ISBN: 9781843394198; 1843394197
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2002.0415

A methane fermentation system for treating swine wastes was developed and successfully demonstrated in a field test plant (0.5 m3/d). The system was composed of a screw-press dehydrator, a methanogenic digester, a sludge separator, an oxidation ditch (OD) and composting equipment. A performance evaluation was carried out regarding physical pre-treatment using the screw-press dehydrator, methane fermentation for pre-treated slurry, and post-treatment for digested effluent by OD. Total solids (TS) and chemical oxygen demand (CODCr) removal by the screw-press pre-treatment were 38% and 22%, respectively. Properties of the screenings were as follows: water content 57%, ignition loss 93%, specific gravity 0.33. The pretreated strong slurry was digested under mesophilic conditions. Digestion gas (biogas) production rate was 25 m3/m3-slurry (NTP) and methane content of the biogas was 67%. CODCr removal of 65% with methane fermentation treatment of the slurry operating at 35 degrees C was observed. No inhibition of methane fermentation reaction occurred at the NH4(+)-N concentration of 3,000 mg/l or less during methane fermentation by the system. Mass balance from the present pilot-scale study showed that 1 m3 of mixture of excrement and urine of swine waste (TS 90 kg/m3) was biologically converted to 25 m3/m3-slurry (NTP) of biogas (methane content 67%), 100 kg of compost (water content 40%, ignition loss 75%), and 0.80 m3 of treated water (SS 30-70 mg/l).