基于协同反硝化脱氮的光伏废水处理

Photovoltaic wastewater treatment based on a combined heterotrophic and sulfur-based autotrophic denitrification technology

以光伏废水为研究对象,利用启动成功的协同反硝化反应器,在进水F-浓度为800mg/L,NO_3^--N为350mg/L的条件下,控制进水C/N为0.7左右,实现反硝化过程无需酸碱调控,TN去除率为90%以上,TN去除速率为2.0~2.5kg/(m^3·d).除氟试验表明,通过投加Ca O初步除氟能将F-浓度降低至800mg/L,同时将p H提升至7.68,满足协同反硝化的p H范围(7.5~8.5)要求;二次除氟能有效降低废水中残余的F-及协同反硝化生成的SO_4^(2-).针对多数含F-浓度超过800mg/L的光伏废水,可采用先初步除氟、协同反硝化脱氮,最终二次除氟、除硫酸盐的工艺路线.相比于完全异养反硝化脱氮处理光伏废水,采用协同反硝化可节约脱氮成本0.82元/t.

Photovoltaic wastewater was used as the influent of a combined heterotrophic and sulfur-based autotrophicdenitrification reactor.When the influent F-concentration was800mg/L,NO3--N concentration was350mg/L,TOC/Nwas0.7,the nitrogen removal rate and denitrification efficiency of the reactor reached2.0~2.5kg/(m3·d)and90%abovewithout pH adjustment.Defluorination experiments indicated that F-concentration of photovoltaic wastewater wasdecreased to800mg/L by adding calcium oxide.Meanwhile,the pH of the wastewater was raised to7.68,which met thepH(7.5~8.5)requirement of the combined denitrification.The remaining F-and generated SO42-in combineddenitrification were removed effectively by secondary defluorination.Photovoltaic wastewater containing high F-concentration(800mg/L above)could be treated by preliminary defluorination,combined denitrification and secondarydefluorination.In terms of the cost of denitrification in photovoltaic wastewater treatment,the combined denitrificationcould save0.82yuan/t compared with unit cost of the heterotrophic denitrification.