低有机质污泥投加药剂联合低温热水解及后续厌氧发酵研究

Chemicalthermal pretreatment and subsequent anaerobic digestion of sludge with low organic content

污水厂污泥量日益增加,所含的有机物可用于厌氧发酵产甲烷,但目前多数污水处理厂多为低有机质污泥。本文围绕低有机质污泥投加不同药剂联合低温热水解对污泥溶解性物质变化及厌氧发酵规律的影响情况进行研究。结果表明,投加药剂联合低温热水解不仅有助于有机物[可溶糖、可溶蛋白和TVFA(挥发性有机酸)]的溶出与生成,而且有助于后续厌氧发酵产甲烷。在本实验所研究的低温热水解(污泥含固率为8%,热水解处理温度为90℃,处理时间为24 h)及药剂投加量[NaOH:0.018 g·(gDS)^(-1)、Ca(OH)_2:0.016 g·(gDS)^(-1)、CaCl_2:0.0375g·(gDS)^(-1)]的条件下,有机物溶出与生成的效果为NaOH>Ca(OH)_2>CaCl_2,其中热水解联合NaOH中可溶糖、可溶蛋白和TVFA浓度分别达到3051 mg·L^(-1)、10686 mg·L^(-1)和5740 mg·L^(-1)。对于产甲烷促进效果为NaOH>CaCl_2>Ca(OH)_2,其中投加NaOH后最大累积产甲烷量可达到101.9 ml·(gVS)^(-1)。

The large amounts of municipal sludge are generated from waste water treatment plants.The organic compounds in sludge are helpful for methane production. While the most of municipal sludge in China is of low organic matter. Thus this paper explored the effect of different additive agents combined with thermal hydrolysis on organics solubilization of sludge with low organic and subsequent anaerobic digestion. The results showed that additive combined with low temperature thermal hydrolysis is helpful not only for the dissolution and the production of organics, including soluble sugar, soluble protein and TVFA（total volatile organic acids） but also for anaerobic digestion. The effect of organic dissolution under the thermal pretreatment condition（the solid content, the temperature and the time were 8%, 90℃ and 24 h, respectively） and the additive concentration[the concentration of NaOH, Ca（OH）2 and CaCl2 were 0.018 g·（gDS）^-1, 0.016 g·（gDS）^-1 and 0.0375（g·gDS）^-1, respectively] was arranged in descending order, which were NaOH, Ca（OH）2 and CaCl2 in turn, namely the addition of NaOH had obvious effects on soluble sugar, soluble protein and TVFA, and the concentrations were 3051 mg·L^-1, 10686 mg·L^-1 and 5740 mg·L^-1 respectively. The ranking of efficiency of anaerobic digestion was NaOH, CaCl2 and Ca（OH）2 in turn, and the maximum gas production was acquired and up to 101.9 ml·（gVS）^-1with the addition of NaOH.