Enhancing biodegradability of industrial park wastewater by packing carriers and limited aeration in the hydrolysis process

This study aims to ameliorate effects of packing carriers, filling ratio, temperature and limited aeration on hydrolysis performance in a chemical industrial park wastewater treatment plant. Illumina-MiSeq sequencing was applied to compare microbial community structure between biofilm attached on carriers and activated sludge in a full-scale hydrolysis tank. Packing carriers intensified the plentifulness of microbial community, enriched hydrolytic bacteria (Betaproteobacteria, Gammaproteobacteria, Sphingobacteria, Clostridia, Bacteroidia), and enhanced biodegradability of organics in the wastewater. Rising carriers filling ratio increased first-order kinetic constant of hydrolysis from 0.015 to 0.080 h⁻¹, and decreased fractions inert to hydrolysis. Rising temperature stimulated enzymatic activity for hydrolysis with activation energy of 80.22 kJ/mol. Limited aeration further enriched hydrolytic bacteria, inhibited sulfate-reducing bacteria and intensified biodegradability of organic substances. Variations of fluorescent organic substances and ammonia nitrogen release during hydrolysis confirmed that hydrolysis was strengthened by packing carriers, increasing filling ratio, enhancing temperature and introducing limited aeration. Packing carriers and limited aeration were techno-economic methods for enhancing hydrolysis performance in the chemical industrial park wastewater treatment plant by enriching hydrolytic bacteria and stimulating their activities.