Anaerobic digestion in mesophilic and room temperature conditions： Digestion performance and soil-borne pathogen survival

• Published in: Journal of environmental sciences (China) 2016-05, Vol.43 (5), p.224-233
• Main Authors: Chen, Le, Jian, Shanshan, Bi, Jinhua, Li, Yunlong, Chang, Zhizhou, He, Jian, Ye, Xiaomei
• Format: Article
• Language: English
• Subjects: ambient temperature; anaerobic digesters; Anaerobic digestion; Anaerobiosis; Biofuels; biogas; Bioreactors; biosafety; digestion; Digestion performance; Fatty Acids, Volatile - metabolism; feedstocks; Fruit and vegetable wastes; Lycopersicon esculentum; Pathogen inactivation; pathogen survival; Phytophthora - physiology; Phytophthora capsici; quantitative polymerase chain reaction; Ralstonia - physiology; Ralstonia solanacearum; Refuse Disposal - methods; Soil - chemistry; Soil - parasitology; Soil Microbiology; survival rate; Temperature; tomatoes; volatile fatty acids; wastes; 中温; 厌氧反应器; 厌氧消化; 土传病原菌; 常温条件; 挥发性脂肪酸; 消化性能; 辣椒疫霉菌
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2015.11.013

Tomato plant waste（TPW） was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carried out for TS（total solid） concentrations of 2%, 4% and 6% respectively, at mesophilic（37 ± 1°C） and room（20–25°C） temperatures. Results showed that higher digestion performance was achieved under mesophilic digestion temperature and lower TS concentration conditions. The biogas production ranged from 71 to 416 L/kg VS（volatile solids）. The inactivation of anaerobic digestion tended to increase as digestion performance improved. The maximum log copies reduction of R. solanacearum and P. capsici detected by quantitative PCR（polymerase chain reaction） were 3.80 and 4.08 respectively in reactors with 4% TS concentration at mesophilic temperatures. However, both in mesophilic and room temperature conditions, the lowest reduction of R. solanacearum was found in the reactors with 6% TS concentration, which possessed the highest VFA（volatile fatty acid） concentration. These findings indicated that simple accumulation of VFAs failed to restrain R. solanacearum effectively, although the VFAs were considered poisonous. P. capsici was nearly completely dead under all conditions. Based on the digestion performance and the pathogen survival rate, a model was established to evaluate the digestate biosafety.