COMPARISON OF PREFABRICATED BIOGAS DIGESTER AND TRADITIONAL BIOGAS DIGESTER - BASED ON LIFE CYCLE ASSESSMENT

China plays a leading role in the worldwide development and dissemination of household-based biogas technology, no matter traditional biogas digester or prefabricated biogas digester (PBD). Life cycle assessment of traditional onsite-constructed (OC) digester, glass fibre reinforced plastics (FRP) digester and plastic soft (PS) digester with the same volume of 8 m(3) was implemented. The environmental impact of OC digester is the highest while the environmental impact of PS digester is the lowest. The environmental impact comprehensive indexes (EICIs) of OC digester, FRP digester and PS digester within the lifetime are 8.6 x 10(-2), 6.72 x 10(-2) and 6.16 x 10(-3), respectively. The EICI is 3.23 x 10(-4) for each m3 biogas production while the EICI is 6.45 x 10(-4) for each kg dry matter digestate production. The EICIs of 1 ton digestate application and chemical fertiliser application are -2.14 and 0.127, respectively. In order to reduce the environmental impact of PBD which adopts chemical materials, it is suggested that environment-friendly material be used.