Improvement of Humus Soil on Activated Sludge Properties Under Condition of Thermophilic Anaerobic Digestion

Abstract:

This study aims to improve the dewater ability and the stability of the activated sludge with the sludge production being reduced. The parameters, such as capillary suction time (CST), elemental compositions, distribution of organic matter molecular weights and Fourier transform infrared spectrum were investigated to study the influence of humus soil on activated sludge properties under the condition of thermophilic anaerobic digestion (at 55 °C). The CST results show that humus soil can greatly improve dewater ability of the sludge. The Mw/Mn of FAs isolated from activated sludge decreases according to the dosage of humus soil, and the micromolecular proportion raises from 50% to 70%. All HAs isolated from activated sludge show similar spectra with different intense absorbance during the region of 1 654, 1 540, 2 925 cm-1 which suggests that humus soil improves the aromatization degree and the stability of activated sludge. Similar results are also found in organic elemental and total organic carbon analysis.