一种新型复合碳源的脱氮效能及工程应用

Nitrogen Removal Efficiency and Engineering Application of a New Composite Carbon Source

碳源不足是污水处理厂普遍存在的问题,低成本高效碳源对提升污水脱氮效能以及降低污水处理成本至关重要。文章对一种新型乙二醇复合碳源(EGC)在污水反硝化脱氮进行了实验室小试和实际工程应用研究。结果表明:EGC反硝化速率与乙酸钠相当,能促进反硝化的彻底进行。在污水处理厂实际应用中,EGC的使用能够保持出水总氮(TN)和化学需氧量(CODCr)的稳定达标排放,使用过程中污泥松散附着的胞外聚合物(EPS)由碳源替换前的23.14 mg/(g SS)降低至9.16 mg/(g SS),污泥容积指数(SVI)从121 mL/g下降至71 mL/g。相关性研究表明L-EPS含量与SVI变化呈正相关关系,相关性曲线为y=2.72x+63.51(R2=0.689),表明长期使用EGC不会导致污泥沉降性能降低和诱发污泥膨胀等问题。EGC的实际使用成本平均仅为0.04元/m^(3),较葡萄糖降低86.2%,污泥平均产率仅为0.70 g/g,较替换前降低17.6%,表现出优异的经济适用性,具有良好的大规模应用前景。

Insufficient of carbon sources is a common problem in wastewater treatment plants(WWTPs).Low-cost and efficient carbon sources are essential for improving effluent nitrogen removal efficacy as well as reducing wastewater treatment costs.This paper has investigated the waste water denitrification effciency and economy of a new type of ethylene glycol composite carbon source(EGC)through laboratory trial and practical engineering application.The results show that the denitrification rate of EGC is comparable to that of sodium acetate and it can promote complete denitrification.In the practical application of WWTP EGC can maintain the effluent of total nitrogen(TN)and chemical oxygen demand(CODCr)stable discharge.The sludge L-EPS decreased from 23.14 mg/(g SS)before carbon source replacement to 9.16 mg/(g SS)after replacing with EGC,and the sludge volume index(SVI)decreased from 121 mL/g to 71 mL/g.The correlation study shows a positive correlation between the L-EPS content and the change of SVI with a correlation curve of y=2.72x+63.51(R2=0.689),which indicates that the long-term use of the EGC carbon source does not lead to the reduction of sludge settling performance or induce sludge swelling and other Problems.Furthermore,the average cost of using the EGC carbon source is only 0.04 yuan/m^(3),86.2%lower than that of glucose,and the average sludge yield is only 0.70 g/g,17.6%lower than before replacement,showing excellent economic applicability and promising prospects for large-scale application.