摘要
农村生活污水具有处理量小,分散,日变化系数大等特点,分散处理成为农村污水处理的首要选择。该研究采用AAO工艺与BAF组成的双污泥反硝化除磷系统(anaerobic anoxic oxic-biological aerated filter,AAO-BAF)处理农村生活污水,探讨了氨氮容积负荷对该系统BAF单元硝化性能及出水悬浮物(SS)的影响。通过改变水力负荷和有效滤料容积(即方式1和方式)2种方式,氨氮容积负荷在0.43-1.21 kg/(m3·d)之间变化。试验结果表明,随着氨氮容积负荷的增加,氨氮去除率呈现先缓慢降低后急剧减小的趋势,不同的是,出水SS对方式1(即水力负荷的变化)更敏感。当氨氮容积负荷在0.43-1.12 kg/(m3·d)时,氨氮去除率大于81%;当氨氮容积负荷大于1.12 kg/(m3·d),氨氮去除率急剧降低,氨氮容积负荷为1.21 kg/(m3·d),2种运行方式的氨氮去除率分别为65%和68%。当氨氮容积负荷小于0.74 kg/(m3·d)时,出水SS小于10 mg/L;当氨氮容积负荷大于0.74 kg/(m3·d)时,出水SS急剧增加,但方式1增加得更快,氨氮容积负荷增加到1.21 kg/(m3·d)时,方式1和方式2的出水SS分别为21.8和14.2 mg/L。所以,为保证BAF出水水质达到国家一级A排放标准,其氨氮容积负荷应小于0.74 kg/(m3·d)。
The universal features of rural domestic wastewater were small quantity, scattered distribution, and great diurnal variation, etc. So it was difficult to centralize, treat, and reuse such wastewater. However,discharging such untreated rural domestic sewage with the characteristics of comparatively high nitrogen and phosphorus concentration to the environment brought about seriously eutrophication. Therefore, it was necessary to research and develop a treatment process which has the advantages of relatively high efficiency, less land occupied, investigated savings, and also easy management and maintenance for nutrient removal from the rural sewage. On the basis of these considerations above, an enhanced denitrifying phosphorus removal system, that is,a two-sludge process integrating anaerobic/anoxic/oxic(AAO) reactor with biological aerated filter(BAF)( AAO-BAF for short), was developed to treat domestic sewage, especially the decentralized sewage in rural areas. In this innovation system, the AAO unit, consisting of nine compartments in sequence, was used mainly for the removal of organic compounds and nutrients without ammonium oxidation, while the BAF unit was mainly responsible for nitrification. The BAF unit, an important component of the two-sludge system, was 1.8m in height and 10cm in diameter, with a light-weight ceramic filled in it. Nine sampling ports were placed along the BAF, marked as B1 to B9 from bottom to top in turn. In this study, a series of experiments were carried out to research the effect of the ammonium volumetric loading on nitrifying characteristics and effluent SS of the BAF. The ammonium volumetric loading, by changing the hydraulic loading(marked as mode 1) and adjusting the effective volume of the BAF unit(marked as mode 2), was varied from 0.43 kg/(m3·d) to 1.2 kg/(m3·d). Mode1 lasted for 90 d, during which hydraulic loading soared from 1.53 m3/(m2·h) to 4.37 m3/(m2·h). Mode 2 ran for60 d, and during that period BAF effective volume decreased from 9.8 L to 2.7 L, while hydraulic load maintained 1.53 m3/(m2·h). Throughout the total experimental period, the sludge reflux ratio was 100% maintained, with a nitrification reflux ratio of 300%, and the air-water ratio of BAF unit was set at 3:1-4:1.The results showed that,with the increase of ammonium volumetric loading, the ammonia nitrogen removal efficiency showed a tendency of slowly decreasing first and sharply dropping later during two operating modes. Effluent SS was more sensitive to changes in mode 1 than that in mode 2, which was the most significant difference between the two operating modes. When ammonia volumetric loading varied from 0.43 kg/m3·d to 1.12 kg/(m3·d), the nitrogen removal efficiency was over 81%; and when ammonia volumetric loading increased to 1.21 kg/(m3·d), ammonia removal efficiency decreased sharply to 65% and 68%, respectively. When the ammonia volumetric loading was below 0.74 kg/(m3·d), both effluent SS were lower than 10mg/L; and when ammonia volumetric loading varied from0.74 kg/(m3·d) to 1.21 kg/(m3·d), effluent SS soared much more sharply during mode 1, at the ammonia volumetric loading of 1.21 kg/(m3·d), effluent SS was 21.8 mg/L and 14.2 mg/L respectively. These findings determined that, to meet the first class of A standard, namely, the standard of ammonia nitrogen concentration less than 5 mg/L, and effluent SS lower than 10 mg/L, BAF unit should be operated at the condition of ammonium volumetric loading below 0.74 kg/(m3d).
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2013年第21期194-200,共7页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家863计划项目(2012AA063406)
北京市教委科技创新平台项目
关键词
农村地区
污水处理
氨
氮
双污泥反硝化除磷系统
容积负荷
水力负荷
rural areas
sewage treatment
ammonia
nitrogen
two-sludge denitrifying phosphorus removal process
volumetric loading
hydraulic load