#BiogasTreatment

To accelerate the research, development, and innovation of new technologies and equipment for the high-value utilization of biogas and biomethane, and to strengthen the promotion and application of advanced and practical technologies by enterprises as well as the demonstration and leadership of typical scenarios, the Society will, in due course, release a series of innovative technologies and typical case studies on the high-value utilization of biogas and biomethane. This initiative aims to expedite the formation of a pathway involving “technological breakthroughs—scenario validation—industrial application—system upgrades,” thereby providing strong support for promoting high-quality development in the biogas industry.

01 Overview:

High-temperature, high-load, continuous multi-stage anaerobic fermentation of mixed feedstocks is an integrated anaerobic fermentation model that uses various agricultural organic wastes—such as crop straw, livestock and poultry manure, and fruit and vegetable waste—as feedstocks. Through a series of dry and semi-dry anaerobic fermentation processes, it achieves continuous and efficient production of biogas and biomethane under high-temperature and high volumetric loading conditions. The front end employs high-efficiency pretreatment to leverage the complementary advantages of various feedstocks, while the back end is equipped with membrane purification equipment or combined heat and power (CHP) units to maximize the value of biogas. The digestate and digestate liquid are processed into organic fertilizer for application to farmland, forming a circular treatment system characterized by strong feedstock adaptability, low operating costs, and the co-production of energy and resources. Schematic Diagram of High-Temperature, High-Loading, Continuous Multi-Stage Anaerobic Digestion of Mixed Feedstocks 02 System Characteristics

Scenario Characteristics: First, high-temperature, high-load, high-efficiency fermentation. By employing a high-temperature anaerobic process and a combined dry fermentation reactor with a horizontal push-flow design, the system enhances anaerobic digestion rates and methane activity, accelerates the hydrolysis of fibrous materials such as crop straw, and improves acid production efficiency, resulting in a significantly higher volumetric gas yield compared to traditional processes. Second, a two-stage series process with strong feedstock adaptability. By employing a two-stage series fermentation process combining dry and semi-dry stages, the system can synergistically treat a variety of waste materials—including crop straw, livestock and poultry manure, and fruit and vegetable waste—addressing the issue of poor fermentation stability associated with single-feedstock systems and enabling complementary advantages across multiple feedstocks. Third, it enables the simultaneous production of energy and fertilizer, achieving full-cycle recycling. Biogas is used for biomethane purification or combined heat and power generation; digested residue is processed into organic fertilizer and seedling growing media; and digested liquid is converted into liquid fertilizer for application to farmland, realizing a closed-loop full industrial chain from “organic waste → clean energy → organic fertilizer → green agriculture.” 03 Suitable Regions

This process is suitable for regions with a wide variety of agricultural waste, close integration of crop and livestock production, and high demand for large-scale treatment. 04 Application Case

The Hubei Lvxin Yicheng Large-Scale Biogas Pilot Project was completed, commissioned, and has been operating stably since 2017. The project employs a continuous, multi-stage anaerobic digestion process using mixed feedstock in both dry and semi-dry modes. The entire project consists of three independent modules, each comprising two-stage CSTR reactors, with the three modules operating in parallel. In the primary reactors, the average solids content of the feedstock exceeds 35%; after mixing within the tank, the solids content reaches approximately 18%. The second-stage reactors operate in a semi-dry mode, with material transferred from the first stage to the second via custom-designed high-flow-capacity screw pumps. This effectively enhances production efficiency per unit of tank volume, optimally extends the fermentation retention time of the feedstock, and ensures the stability of the entire biogas production process. The project processes over 50,000 metric tons of various organic wastes annually, producing 5 million cubic meters of biogas, generating 6.4 million kilowatt-hours of electricity for the grid, and producing 30,000 metric tons of organic fertilizer annually, which fertilizes 35,000 mu of farmland.