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Research on Sludge Bio-Drying Process with Membrane Cover Technology: A Case Study of Engineering Practice in Guangze County

Author(s)

Hongxing Xiao, Ang Yu*

Affiliation(s)

College of Environment and Ecology, Xiamen University, Xiamen, Fujian, China *Corresponding Author

Abstract

To achieve efficient reduction and resource utilization of municipal sludge, this study combines metabolic heat generation by thermophilic bacteria with e-PTFE membrane cover technology in a full-scale sludge bio-drying engineering practice with a treatment capacity of 100 t/d in Guangze County, Fujian Province. The results show that the optimal mixing ratio is sludge: rice husk: recycled material = 1:1:0.1 (volume ratio). Under this condition, the maximum pile temperature reaches 88.9 °C, and the temperature above 70 °C can be maintained for more than 10 days. At the end of the bio-drying period (15 days), the moisture content of the product decreases from an initial 56% to 25%–30%, the weight reduction rate reaches 50%–70%, and the bulk density decreases from 0.7 t/m³ to 0.45 t/m³. The product has an organic matter content of 56.66%, total nutrients of 5.84%, a seed germination index (GI) of 0.725, a maturity index (E4/E6) of 2.66, and heavy metal contents below the national standard limits. Metagenomic analysis reveals that during the hyperthermophilic phase, the family Streptosporangiaceae (relative abundance 43%) within the phylum Actinobacteria becomes the core functional microbiota driving macromolecular organic matter degradation and biological heat production. This process requires no external heat source for maintenance and achieves deep dewatering, stabilization, and harmlessness of sludge within 15 days.

Keywords

Sludge Dewatering; Thermophilic Bacteria; Bio-Drying; Membrane Cover

References

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