初始pH对原污泥厌氧发酵产氢的影响

Effects of initial pH on bio-hydrogen production from raw municipal sludge

市政污泥（简称污泥）厌氧发酵产氢既可解决污泥的出路问题,又能产生清洁能源——氢气,是一种较为理想的处理处置方式。调节污泥适合的初始pH值能够提高污泥的产氢效率。为了考察不同初始pH值对污泥厌氧发酵产氢的影响,将未经任何预处理污泥（原污泥）的初始pH分别调到2.0~12.0,用于批式实验。研究表明：调节原污泥初始pH,适当条件下能促进氢气的生成。初始pH为强酸性条件时,污泥基本不产氢;初始pH在4.0~11.0,污泥总体产氢量也很低;初始pH=12.0条件下,污泥总体产氢量最高,比产氢率达到3.39 m L·（g VS）-1。不同初始pH下污泥的降解均以蛋白质降解为主。酸性条件下,蛋白质及糖类物质有一定降解;中性条件下,蛋白质及糖类物质都得到较好的降解,浓度均较低;碱性条件下,糖类物质的酸化较微弱,但蛋白质却得到较好的降解,降解蛋白质生成的TVFA由于甲烷菌受到抑制而产生积累。

Hydrogen production by anaerobic fermentation of municipal sludge is a prominent way of reducing sludge pollution and producing clean energy. Adjusting the initial pH of the sludge to a suitable level can improve the efficiency of hydrogen production; therefore,this research focuses on the influence of the initial pH on bio-hydrogen production. The initial pH of municipal sludge was adjusted to values between 2 and 12 before it was used as substrates for batch experiments. When the initial pH of sludge was below 4,there was almost no hydrogen production. At initial pH of 4. 0 ~ 11. 0,the corresponding hydrogen production was still relatively low.However,at an initial pH of 12. 0,the sludge gave the highest hydrogen production,with a corresponding specific hydrogen yield of 3. 39 m L·（ g VS）-1. Protein was the main substrate that degraded during fermentation at various initial pH levels. Under acidic conditions,both protein and saccharide underwent little degradation.When the initial pH was close to neutral,both protein and saccharide degraded well,meaning that the concentration of protein and saccharide remaining was low. Under alkaline conditions,the acidification of saccharide was weak but the acidification of the protein was strong,so the total volatile fatty acid level increased due to methanogen inhibition at high pH values.