Guizhou: Sludge Transforms into Organic Nutrient Soil

On a seemingly ordinary morning, the sewage in the city is purified layer by layer and transformed into clear water flowing into the river, but did you know? The byproduct produced in this process - sludge - is also undergoing a magical journey of counterattack. They have transformed from symbols of urban pollution to organic nutrients that nourish life, writing a new chapter in the green cycle of the Earth.

With the rapid advancement of urbanization, the amount of sewage treatment has surged, producing a large amount of sludge. Sludge is mainly composed of various microorganisms and organic and inorganic particles, as well as harmful substances such as heavy metals, organic pollutants, pathogenic microorganisms, and parasitic eggs. If sludge is not effectively treated, it is easy to cause secondary pollution to the environment. However, these seemingly useless sludge are actually valuable resources rich in organic matter and nutrients. They can be scientifically processed and transformed into organic nutrient soil, achieving resource recycling.

There are a total of 34 domestic sewage treatment plants in the central urban area of Guiyang, which produce about 900 tons of sludge every day. Sludge treatment has always been a headache. There are three traditional methods for sludge treatment, namely landfill method, incineration method, and biofuel method, but these methods have problems such as difficult environmental protection standards and high treatment costs.

For this reason, from 2021, Guizhou Business Area of China Water Environment Group, Institute of Geochemistry of the Chinese Academy of Sciences, Guizhou University and other units began to carry out research and test on sludge recycling technology, make full use of organic carbon and nutrient elements in sludge, develop efficient sludge compost fermentation and organic nutrient soil preparation technology, and promote sludge recycling. This process technology is to efficiently break down the cell wall of sludge, reduce the water content of sludge to below 60%, and achieve preliminary reduction; Then, through the backend high-temperature fermentation equipment, combined with fermentation auxiliary materials, mixed fermentation is carried out to effectively kill pathogenic microorganisms and roundworm eggs in the sludge, ultimately transforming the sludge into organic nutrient soil. The entire process technology takes about 21 days. The organic nutrient soil produced has been tested by a third-party quality supervision and inspection station, and its organic matter and heavy metal indicators fully comply with national standards. It can be used in fields such as landscaping, mine restoration, and home gardening, truly achieving the reuse of urban organic waste.

The Guiyang Xinzhuang Reclaimed Water Plant (Phase I) is located on Shuidong Road in Gaoxin Community, Wudang District, Guiyang City. It can process 250000 tons of domestic sewage per day and produce approximately 130 tons of sludge per day. Through aerobic fermentation treatment, it can produce 30-40 tons of organic nutrient soil. Nowadays, after aerobic composting treatment, it has been used as organic nutrient soil in multiple scenarios such as Xinzhuang Reclaimed Water Plant (Phase I) and Jinyang Reclaimed Water Plant (Phase III) Ground Park. The lush vegetation and vibrant daisies adorn the factory area with bright colors, with a gentle breeze blowing over it and no odor of sludge, filled with the fragrance of osmanthus.

The counterattack journey of sludge is a green revolution about environmental protection, technology, and resource recycling. It reminds us that behind every drop of sewage lies the possibility of life. Under the illumination of technology, the former waste has been reborn and become a precious resource that nourishes the earth. This revolution not only improved the urban environment, but also opened up new paths for environmental protection. Let us all look forward to a greener and more sustainable future quietly growing on every inch of land where sludge is transformed.