New process for the combined anaerobic-microalgae treatment of high-concentration organic wastewater

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New process for the combined anaerobic-microalgae treatment of high-concentration organic wastewater **Second Prize for Technical Invention. A COD concentration of over 2000 mg/L is considered to be that of high-concentration organic wastewater; 100% of livestock and poultry manure wastewater, as well as 70% of industrial wastewater, fall into this category. The main technical bottleneck in the treatment of high-concentration organic wastewater is that the COD concentration exceeds the range that conventional biological treatment can handle. The typical four-step process for treating high-concentration organic wastewater, both domestically and internationally, suffers from issues such as high reagent consumption, high energy usage, low resource efficiency, and severe secondary pollution. This project introduces for the first time at home and abroad a new process for the combined anaerobic-microalgae resource utilization treatment of high-concentration organic wastewater. Its key innovative aspects are as follows: 1. A new three-step resource recovery treatment process of “high-efficiency anaerobic fermentation + microalgae enrichment and purification + dynamic membrane advanced treatment” was developed, which addresses the issues of low resource utilization and severe secondary pollution associated with the four-step treatment method, thereby enabling a shift in the treatment of high-concentration organic wastewater from mere pollution control to resource recycling. 2. An efficient external circulation anaerobic reactor was invented to overcome the technical challenges associated with traditional anaerobic reactors, namely the tendency for poor sludge-water separation, as well as low shock resistance and stability of such systems. 3. A new method for the enrichment and selection of microalgae strains from anaerobic fermentation broth was invented, along with an efficient photobioreactor suitable for microalgae that can tolerate wastewater. This approach overcame the challenges related to symbiosis between bacteria and algae as well as organic pollution in the cultivation of microalgae in anaerobic fermentation broth, thereby enabling the use of microalgae cultivation for wastewater treatment as a viable alternative to traditional aerobic treatment methods. 4. A advanced treatment process for water resource reuse using dynamic membrane bioreactors was invented, enabling efficient advanced treatment of water from microalgae cultivation for reuse, thereby helping to alleviate the strain on water resources in China. The project has been granted 26 Chinese invention patents and 1 U.S. invention patent, 122 academic papers have been published (of which 86 are indexed by SCI), and 4 monographs have been published. Through industry-university-research collaboration, it has been widely applied in nearly 20 projects dealing with high-concentration industrial organic wastewater and over 200 projects for treating wastewater from farms in provinces and cities such as Shanghai, Zhejiang, Shandong, and Jiangxi. It has also been used in countries like Kenya and Algeria, indicating broad application prospects.