臭氧氧化-苦草深度处理猪场废水对无机营养盐的去除效果初探

The efficiency of combined treatment of ozonation and Vallisneria spiralis in removing inorganic nutrients in piggery wastewater

进行了经氧化塘和人工湿地处理的猪场废水的臭氧氧化-苦草深度处理研究,考察了不同浓度臭氧氧化处理无机营养盐(N、P)含量的变化,和臭氧氧化-苦草处理对去除无机营养盐的作用。结果表明,三个臭氧投加浓度(10、30、50 mg·L^(-1))分别使NO-2含量降低7.7%、17.6%和21.4%,使NO-3增加5.7、4.2和2.4倍,使PO3-4增加40.1%、26.0%和0.7%;臭氧氧化-苦草处理使TN、NH+4、NO-2、TP含量分别降低11.4%~15.7%、29.9%~34.2%、22.6%~40.7%和36.0%~38.0%,使NO-3含量增加0.4~1.0倍。结果表明,臭氧氧化可以使N、P的形态发生变化,且低浓度的臭氧投加就能达到显著效果,苦草显著促进臭氧氧化后猪场处理尾水中无机营养盐的去除。

Piggery wastewater contains a high concentration of inorganic nutrients, and piggery effluent from conventional biological treatment processes still contain nutrient-rich matters, which poses a significant threat to surface and groundwater and requires subsequent treatment. In this research, piggery wastewater pretreated from oxidation pond followed by the constructed wetland was further treated by ozona-tion and Vallisneria spiralis. We measured the changes of inorganic nutrients（N and P） content in the piggery wastewater after exposed to different concentrations of ozone（AO1 10mg·L^-1、AO2 30 mg·L^-1、AO3 50 mg·L^-1）for 30 min followed by growing Vallisneria spiralis for 4 weeks. We found that three levels of ozonation treatment decreased NO-2by 7.7%, 17.6% and 21.4%, respectively, and increased NO-3by 5.7, 4.2 and 2.4 times, and PO3-4by 40.1%, 26.0% and 0.7%, respectively. After the treatment of Vallisneria spiralis, TN, NH＋4, NO-2and TP were decreased by 11.4%～15.7%, 29.9%～34.2%, 22.6%～40.7% and 36.0%～38.0%, respectively, while NO-3was increased by 0.4～1.0times. Our results indicated that ozonation could lead to dramatic changes of the chemical forms of inorganic nutrients even at a low ozone concentration, and culture of Vallisneria spiralis could obviously reduce the concentration of inorganic nutrients in the ozone-treated piggery wastewater.