摘要
采用连续搅拌釜式反应器(CSTR)成功启动了餐厨垃圾与剩余污泥混合发酵平行系统,重点探究了不同污泥停留时间(SRT)缩减幅度对于餐厨垃圾和剩余污泥混合发酵系统的影响.结果表明,较大幅度地缩减SRT(> 8. 3 d)提升反应器运行负荷,不利于反应器的稳定运行;随着反应器运行负荷的增加,SRT缩减幅度应逐渐降低(5~0. 9 d),能够取得餐厨垃圾和剩余污泥混合发酵系统的高负荷稳定运行.经过282 d的运行,CSTR混合发酵系统能够在SRT为9. 1 d,进料负荷(以COD计)为(12. 9±1. 5) g·(L·d)~(-1)的条件下稳定运行,相应的甲烷产量为3. 94~4. 25 L·(L·d)~(-1),甲烷产率(以COD计)为288~302 m L·g-1,p H和挥发性脂肪酸(VFA,以COD计)分别稳定在7. 80~7. 83和0. 32~0. 39 g·L-1.此外,还探究了高负荷条件下餐厨垃圾和剩余污泥混合发酵污泥特性,结果表明,餐厨垃圾和剩余污泥混合发酵系统甲烷转化途径以乙酸转化途径为主,具有较高的乙酸、丙酸、丁酸和戊酸的产甲烷活性和辅酶F420的质量摩尔浓度.
Two parallel digestion systems of food waste( FW) and waste-activated sludge( WAS) were successfully initiated using a continuous stirred-tank reactor( CSTR),and the effect of different reduction extents of sludge retention time( SRT) on the co-digestion of FW and WAS was investigated. SRT Reduction extents longer than 8. 3 d were not conducive to the stable operation of the codigestion system when the organic load rate( OLR) was increased. The reduction extent of SRT should be reduced gradually from 5 d to 0. 9 d to achieve high load and stable operation of the co-digestion of FW and WAS. After a long-term operation( approximately 282 d),the co-digestion reached stable operation at SRT of 9. 1 d and OLR( calculated by COD) of( 12. 9 ± 1. 5) g·(L·d)~(-1). The corresponding methane production,methane yield( calculated by COD),p H,and volatile fatty acid( VFA,calculated by COD) were3. 94-4. 25 L·(L·d)~(-1),288-302 m L·g-1,7. 80-7. 83,and 0. 32-0. 39 g·L-1,respectively. Additionly,the sludge characteristics of the co-digestion of FW and WAS under a high loading rate were also investigated. The results showed that the primary pathway of methane conversion was through acetic acid during the co-digestion of FW and WAS. Meanwhile,higher methanogenic activity of acetic acid,propionic acid,butyric acid,valeric acid,and coenzyme F420 concentration were also measured.
引文
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