혐기성 소화 효율 증진을 위한 ATAD 및 알칼리 전처리 연구

Abstract

Abstract Pretreatment of waste activated sludge (WAS) results in an improved efficiency of the subsequent anaerobic biotransformation of the organic matter to volatile fatty acids. The pretreatment process has been carried out using alkaline treatment, ATAF treatment (Temperature from 45℃ to 60℃, HRT from 2d to 6d) and different combination of these two methods: alkaline followed by ATAF , as well as the combining method in which ATAF treatment is applied to WAS samples dosed with alkaline. The hydrolysis efficiency was evaluated based on the quantity of soluble COD (SCOD) and organic nitrogen in the pretreated WAS as well as the production of total volatile fatty acids (TVFA) in the following biochemical acid potential (BAP) test For WAS samples with described pretreatments, the released SCOD varied from 36% to 89% of the total COD (TCOD) and soluble organic nitrogen from 34% to 42%. For the alkaline pretreated WAS, the TVFA/TCOD ratio increased to 30%, and the following ATAF treatment enhanced the ratio 66%. Further, WAS samples pretreated using simultaneous ATAF and alkaline treatment in which ATAF was applied to WAS samples dosed with 40 meq/L NaOH for 14.4 sec/mL could achieve a maximum TVFA/TCOD ratio of 84% in 21 hours. Therefore, the combination of simultaneous alkaline and ATAF pretreatment is efficient in enhancing the production of volatile acids in WAS in order to achieve recovery of volatile fatty acids from the WAS. Key word: Alkaline, Autothermal, Aerobic digestion, Anaerobic digestion.