Yijing Environmental Protection is a professional company that has been engaged in the water treatment industry for a long time. In recent years, it has also conducted extensive research on sludge treatment technology generated during the water treatment process, and has hired foreign consultants with rich experience in sludge anaerobic treatment technology to provide technical support. After several years of effort, Yijing Company has now completed and operated a sludge anaerobic fermentation project at OKI Pulp and Paper Mill under the Indonesian APP Group, and a sludge anaerobic treatment demonstration project at Yixing Qingyuan Wastewater Treatment Plant.

The current research hotspot is how to effectively utilize sludge as a resource and turn waste into treasure. In recent years, sludge has gradually been used for resource utilization in the production of biogas, agricultural fertilizers, building materials, and other aspects. After anaerobic digestion, sludge is concentrated, dehydrated, and naturally air dried before being directly used for farmland or building materials. This method has a simple process and produces biogas that can be comprehensively utilized, making it suitable for enterprises with large residual sludge production in sewage treatment processes.

At present, the sludge generated by the biochemical system is treated by dewatering and landfill. Biological sludge dewatering is difficult and requires a large amount of PAM. In the biochemical treatment system, nutrients need to be added to ensure biological growth. Nutrients are usually added to the biochemical system in a ratio of BOD: N: P=100:5:1. The use of anaerobic digestion to treat residual sludge has the following advantages:

1. Biomass biogas is a renewable energy resource.

2. Anaerobic digestion reduces the amount of biochemical sludge, thereby reducing polymer consumption and sludge treatment costs during subsequent sludge dewatering.

3. After anaerobic digestion treatment, the dewatering performance of biochemical sludge has been improved, and dry sludge with a sludge content of 60% can be achieved through pressure filtration, thereby reducing the sludge volume by about 70%.

4. After biodegradation, nutrients are released in the form of N and P. The clear liquid after anaerobic digestion and dehydration can be directly used as circulating nutrients in the biochemical system.