Digestion Enhancement with Thermal Hydrolysis Pretreatment at Beijing's Gaobeidian Water Reclamation Plant - Operating Experience and Challenges

摘要

The advanced digestion system at the GBDWRP has been successfully operated for 15 months. With thermal hydrolysis pre-treatment, BDC has recovered two valuable resources from GBDWRP's sludge: energy and "organic soil nutrient" (dewatered cake) which are beneficially reused. The Cambi THP process resulted in enhanced digestion performances, as evidenced by a higher degree of VSD and more digester gas production. The additional gas will be used to produce energy for plant use; it is projected that 75% of the power needed to operate the GBDWRP could be derived from the additional gas. The cake from sludge dewatering was relatively odor free and had high total solids (averaged 48%). The cake quality met and exceeded all relevant Chinese standards governing sludge disposal as well as U.S. EPA's Class A biosolids specifications. The cake is used on up to 1,600 hectares of forestland in the vicinity of Beijing.