超滤在乙醇厌氧沼液资源化回用中的应用

厌氧沼液经资源化处理后回用于生产，可有效解决传统乙醇生产过程耗水量大和废水处理成本高等突出问题。鉴于超滤是去除厌氧沼液中微生物的常用手段，该方法对管式超滤膜用于处理乙醇厌氧沼液的可行性开展了研究。结果表明：在沼液温度50 ℃、膜面流速为4.5 m·s-1、产水率30%的最佳条件下，膜通量达到174 L·(m2·h)-1；膜污染包括无机污染和有机污染，无机污染主要有Ca2+、Mg2+和Fe3+等，有机污染较为复杂，包括烃、脂肪酸及其衍生物以及腐殖酸、富里酸等；最佳清洗策略是先用柠檬酸和NaClO清洗，然后用NaOH进行清洗，膜通量恢复率达到了98%以上。超滤可以有效去除厌氧沼液中的微生物，避免拌料粉浆的酸化。

Application of ultrafiltration in treatment of ethanol anaerobic digestion effluent for recycling use

Recycling the treated anaerobic digestion effluent (ADE) for use in ethanol production process can alleviate some problems such as large water consumption in production process and the subsequent expensive wastewater treatment for standardized discharge. Considering that ultrafiltration (UF) membrane is instrumental for the removal of microorganisms contained in the ADE, this method focused on the feasibility of tubular ultrafiltration (UF) membrane to treat the ADE for the future recycling use. Results showed that the reasonable condition was the ADE temperature of 50 °C, membrane surface velocity of 4.5 m·s-1 and water production rate of 30%. Under the controlled condition, a desired membrane flux was obtained to be 174 L·(m2·h)-1. Further, the membrane fouling was taken into consideration. It was found that the pollutants should be divided into inorganic compounds, mainly consisting of metal elements Ca2+, Mg2+, Fe3+, and organic substances, i.e., hydrocarbons, fatty acids and their derivatives, humic acid and fulvic acid. Exploration of membrane washing method showed that these foulants were removed using citric acid and sodium hypochlorite solution, followed by sodium hydroxide solution. With this membrane washing method, the membrane flux recovered above 98%. These results indicate that the UF treatment can effectively remove the microorganisms living in the ADE to avoid the slurry acidification in the ethanol production process.