[Objective] This study aimed to make use of the limited filamentous sludge bulking characteristics to purify water quality and save energy. [Method] The effects of dissolved oxygen （DO） on sludge bulking were explored by changing the DO con- centration in the aerobiotic pool of NO system from the low load （0.25 kg COD/（kg MLSS.d）） and the medium to high load （0.55 kgCOD/（kg MLSSod））. [Result] In the NO activated sludge system, when the sludge load was 0.25 kg COD/（kg MLSS.d）, DO=1.5 mg/L, the sludge index was at around 250, while when the sludge load- ing was 0.55 kg COD/（kg MLSS.d）, DO=1.5 mg/L, the sludge index was close to 300, occurring the limited filamentous bulking. The bulked sludge still showed high removal rates to COD, SS, nitrogen and phosphorus. [Conclusion] It could improve the oxygen transfer rate and reduce the aeration rate at low DO conditions to achieve energy-saving.
An engineering technology for the comprehensive treatments of sewage sludge and mine wastewater in smal town was introduced. As fil ing materials, gangue to fil in the col apse basin, construction waste, household refuse and ex-cess sludge as wel as clay were mixed with water into organic fil ing soil, turning the waste sludge into useful soil matrix, which solved the difficulties in growing plants in the reclaimed land that lack of organic soil. The col apse basin was de-signed into oxidation pond, wetland and land infiltration system to treat industrial wastewater and domestic wastewater, realizing the up-to-standard release after sewage treatment.
