Microwave Irradiation Pretreatment Effects on the Dewatering of Activated Sludge

Abstract:

In this study, we investigate the characteristics of activated sludge pretreated with microwave irradiation and the factors influencing the microwave effects. The pretreatment process was carried out using a lab-scale industrial microwave unit (2450 MHz frequency). Parameters such as the dewatering, settling, sludge volume index (SVI₃₀), water percent content, filterability, extracellular polymeric substances (EPS), microbe structure and others, were used to quantify the microwave effects. The SVI₃₀ and specific resistance to filtration (SRF) of sludge treated by 1000W microwave for 40s were reduced by 43.2 and 74.6%, respectively, compared to untreated sludge. The microwave field destroyed the structure of activated sludge, reducing the EPS levels and breaching the microorganism cell walls. Surprisingly, the optimum microwave irradiation time for removing EPS from activated sludge surface is also the optimum time required to improve its dewatering ability. The microwave output power was one of the most important factors for improving the dewatering of activated sludge when all other parameters of activated sludge and microwave frequency were held constant. The absorbed power and absorb ratio both increase with the output power of microwave, and absorb ratio of 1000w microwave reaches 21.93% in this study.

• Periodical: Advanced Materials Research (Volumes 518-523)
• Pages: 3155-3162
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.518-523.3155
• Online since: May 2012
• Authors: Lin Fang, Xu Xin Zhao, Na Na Yuan, Hong Yuan Sun, Rui Ma, Marcos A. Cheney
• Keywords: Activated Sludge, Dewatering, Extracellular polymeric substance, Microwave Irradiation, Setting

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