废铁屑对剩余污泥厌氧消化特性的影响

为探明废铁屑（RSI）对中温厌氧消化特性的影响，利用RSI为外源添加剂研究其投加对剩余污泥厌氧消化水解酸化、产气效率以及污泥表面形态的影响.结果表明:①剩余污泥酸化水解产物VFAs的主要成分是乙酸，其含量随RSI投加量的增加呈先升后降的趋势.②RSI投加量适中（不超过20 g/L）时可促进乙、丁酸型发酵，抑制丙酸型发酵，进而提高剩余污泥厌氧消化效率.③当RSI投加量分别为0、1、5、10、20和30 g/L时，累积甲烷产率分别为135.4、141.9、159.2、178.9、209.3和180.7 mL/g（以VS计），甲烷含量分别为51.2%~56.4%、53.9%~58.6%、58.1%~62.5%、59.5%~68.3%、61.1%~71.2%和51.9%~61.4%.RSI最佳投加量为20 g/L，与空白组相比，累积甲烷产率和甲烷含量分别提升了54.6%和23.0%.④结合扫描电镜-X射线能谱（SEM-EDX）分析方法发现，在厌氧消化过程中微生物可促进RSI的溶解，且随RSI投加量的增加，消化污泥表面的铁元素含量也随之增加.⑤RSI的投加会提高蛋白酶和纤维素酶的活性，但若投加量过高则会产生负面效应.研究显示，外源添加剂RSI投加量适中（不超过20 g/L）时可促进剩余污泥厌氧消化效率. 

Influence of Rusty Scrap Iron on Anaerobic Digestion Performance of Waste-Activated Sludge

In this study, a series of tests were conducted to explore the exogenous RSI effects on anaerobic digestion of mesophilic waste-activated sludge (WAS) from the perspectives of hydrolysis and acidification efficiency, biogas production and surface morphological variation of digested sludge. The results showed that: (1) Acetic acid was the major hydrolytic-acidogenic intermediate product during WAS digestion. The concentration increased at low dosage but decreased at high level of RSI. (2) The medium addition of RSI (no more than 20 g/L) promoted the acetate and butyrate fermentation but inhibited the propionate fermentation. The anaerobic digestion efficiency of WAS was thereby improved. (3) The cumulative methane yield at RSI concentrations of 0, 1, 5, 10, 20 and 30 g/L were 135.4, 141.9, 159.2, 178.9, 209.3 and 180.7 mL/g, and the corresponding methane content was 51.2%-56.4%, 53.9%-58.6%, 58.1%-62.5%, 59.5%-68.3%, 61.1%-71.2% and 51.9%-61.4%, respectively. The optimal RSI dosage was 20 g/L. Compared with the blank group, the cumulative methane yield and methane content increased by 54.6% and 23.0%, respectively. (4) The SEM-EDX analysis showed that the microbial metabolism contributed to the dissolution of RSI. The iron content on the surface of digested sludge increased with the increment of RSI dosage. (5) The activities of protease and cellulose were promoted by moderate amount of RSI, but was suppressed by excessive RSI dose. Overall, the results demonstrated that the anaerobic digestion efficiency of WAS was improved by moderate RSI doses (no more than 20 g/L).