不同产酸类型餐厨酸化液作为污水反硝化碳源的性能研究

Food Waste Acidification Liquid as Carbon Source for Wastewater Denitrification

摘要:

餐厨酸化液有机酸含量高，作为碳源应用于污水反硝化脱氮过程潜力巨大，可缓解我国城市污水处理厂普遍面临的碳源不足的问题。基于全混式厌氧发酵反应器，探究在连续运行条件下不同pH值、有机负荷(OLR)和停留时间(HRT)对餐厨废弃物厌氧产酸特性的影响，通过调控厌氧产酸类型，获取不同产酸类型的酸化液，评估其作为外加碳源的反硝化性能。结果表明，中温条件下，控制pH值为6.0，OLR为15.0g/(L·d)时获得最大TVFAs产量，为50.05g/L，产酸类型为丁酸型发酵；控制pH值为5.0时，产酸类型为乙酸型发酵，具有最佳反硝化速率，为7.62mg/(g·h)，介于葡萄糖(5.39mg/(g·h))和乙酸钠(9.47mg/(g·h)) 之间；同等COD下，餐厨酸化液的反硝化能力(0.21g/g)相当于乙酸钠的84%。因此，餐厨酸化液作为一种新的、可持续的、低成本的碳源具有巨大的市场和应用潜力。

关键词:餐厨废弃物;产酸发酵;外加碳源;反硝化脱氮

Abstract:

The acidified liquid of food waste had a high concentration of organic acids, providing an additional carbon source for the denitrification process in wastewater treatment, potentially alleviating the common problem of carbon source scarcity in urban sewage treatment plants in China. Based on fully mixed anaerobic fermentation reactors, the effects of different pH values, organic loading rates (OLR), hydraulic retention times (HRT) on the anaerobic acidification characteristics of food waste under continuous operation were investigated. By regulating the types of anaerobic acid production, different types of acidification liquids were obtained to evaluate their performance as additional carbon sources for wastewater denitrification. The results indicated that controlling the pH value at 6.0 and the OLR at 15.0g/(L·d) yielded the maximum production of TVFAs at 50.05g/L, with butyric acid fermentation being predominant. When the pH value was controlled at 5.0, acetate-type fermentation occurred, exhibiting the optimal denitrification rate of 7.62mg/(g·h), which was between that of glucose (5.39mg/(g·h)) and sodium acetate (9.47mg/(g·h)). At equivalent COD levels, the denitrification capability of the acidified liquid of food waste (0.21g/g) was 84% of that of sodium acetate. Therefore, food waste acidification liquid represented a sustainable, low-energy and cost-effective renewable carbon source with significant market and application potential.

Key words:food waste;acidogenic fermentation;additional carbon source;denitrification