基于秸秆材料的生物基质系统对养殖废水污染物去除效果研究

采用人工湿地处理养殖废水具有良好的去除效果和资源化利用优势,但畜禽养殖废水浓度较高,直接排入人工湿地易导致湿地植物死亡,采取措施适度降低废水污染物浓度是生态治理的重要前提。因此,本研究选取稻草和芦苇两种秸秆材料,设置稻草、芦苇和对照三个处理,利用三级生物基质消纳系统,开展为期6个月的野外控制试验,对比分析稻草和芦苇对养殖废水主要污染物的去除效果及其自身的降解特征,探讨生物基质系统对养殖废水中主要污染物的去除效果。结果表明,稻草和芦苇对主要污染物指标化学需氧量(COD)、氨氮(NH_4~+-N)、总氮(TN)和总磷(TP)均有良好的去除效果,其中稻草对NH_4~+-N、TN和TP的去除率相对较高,分别为44.9%、39.2%和39.6%,去除负荷分别为17.38、19.84和3.02 g/(m~3·d);芦苇对COD的去除率相对较高,为50.6%,去除负荷为87.28 g/(m~3·d)。NH_4~+-N和TN的去除效果与Eh呈显著正相关(P0.05),而与pH值呈显著负相关(P0.05);TP的去除则受环境因素的影响较小。稻草的降解速率显著快于芦苇,半年内的月平均降解率分别为8.0%和3.6%。稻草总体去除效果好于芦苇的原因可能与其主要成分纤维素、半纤维素和木质素的降解速率相对较快有关,但是芦苇作用的持续时间则相对较长。

Study on removal effect of swine wastewater pollutants by straw material biological substrate system

Constructed wetlands (CWs) can high efficiently remove pollutants in swine wastewater, and have advantages in resource utilization. However, this can easily lead to plant death when swine wastewater directly discharged into CWs. Therefore, reducing pollutant concentration is an important premise of ecological treatment. To explore the effect of biological substrate system on major pollutants removal efficiency in swine wastewater, rice straw and reed straw were selected as straw materials in three-stage biological substrate system. Three treatments including rice straw, reed straw, and control were assigned in the 6-month field experiment. This paper analyzed major pollutants removal efficiencies and degradation characteristics of materials between rice straw and reed straw for treating swine wastewater, and discussed its influencing factors. Results showed that high removal effects on chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total nitrogen (TN) and total phosphorus (TP) by rice and reed straw were observed. The removal efficiencies of NH4+-N, TN and TP were relatively higher with values of 44.9%, 39.2% and 39.6%, respectively for rice straw, while the corresponding removal loads were 17.38, 19.84 and 3.02 g/(m3·d), respectively. The removal efficiency of COD was relatively higher with values of 50.6%, while removal load was 87.28 g/(m3·d) by reed straw. The removal efficiencies of NH4+-N and TN were positively correlated with Eh (P<0.05), while were negatively correlated with pH (P<0.05). The removal of TP was less affected by environmental factors. The degradation rate of rice straw was significantly faster than that of reed straw with monthly average degradation rates 8.0% and 3.6%, respectively, in the six months. The pollutant removal efficiency in rice straw was generally better than that in reed straw, while the effective duration of reed straw was relatively longer than that of rice straw. The primary reason might be that cellulose, hemicellulose, and lignin degradation rate was faster in rice straw than that in reed straw.