“三池两坝”多级组合工艺对内陆池塘养殖尾水的处理

Treatment of inland pond aquaculture tail water by multi-stage combined process of“three ponds and two dams”

针对内陆淡水池塘养殖尾水分布及污染特点,采用沉淀池+过滤坝+曝气池+过滤坝+生态池(简称“三池两坝”)多级组合处理工艺对池塘养殖尾水进行处理。考察组合工艺对低污染、中污染、高污染类型对应的3个示范点尾水主要污染物指标去除效果及各单元的沿程去除情况,并对工程建设投资及运行费用进行分析。结果表明:3个示范点对TSS、CODMn、TN、TP和NH+4-N的去除率分别为48.1%~60.7%、50.4%~60.7%、52.5%~59.2%、64.2%~71.5%和72.1%~80.5%,水质净化效果明显,均能稳定达到SC/T 9101—2007《淡水池塘养殖水排放要求》;该组合工艺夏季处理效果最好,其次是春秋季,冬季该系统仍能正常稳定运行,保障出水水质达标;沉淀池对TSS去除效果最好,为21.3%,曝气池对CODMn和NH+4-N的去除贡献最大,为18.7%和28.7%,生态池对TN和TP的去除贡献最大,为16.3%和28.8%,过滤坝则对各水质指标均具有良好的去除效果,去除率为7.5%~11.8%;3个示范点养殖池塘尾水工程建设费用分别为1.370万、2.775万和1.304万元/hm^2,每年分摊到养殖池塘运行维护费用分别为0.325万、0.387万和0.400万元/hm^2。

According to the distribution and pollution characteristics of aquaculture wastewater from inland fresh ponds,the multistage combined treatment system of“sedimentation pond+filter dam+aeration pond+filter dam+ecological pond”(referred to as“three ponds and two dams”)was adopted to purify the aquaculture wastewater.The removal effect of the combined process on the main pollutant indexes of wastewater and the removal contribution rate of each unit along the way of three demonstration sites corresponding to low pollution,medium pollution and high pollution types were investigated.The project construction investment and operation cost were analyzed.The results showed that the average removal rates of TSS,CODMn,TN,TP and NH+4-N in the three demonstration sites ranged from 48.1%to 60.7%,50.4%to 60.7%,52.5%to 59.2%,64.2%to 71.5%and 72.1%to 80.5%,respectively.Water quality at the outlets was improved obviously and met the standard of Requirement for Water Discharge from Freshwater Aquaculture Pond(SC/T 9101-2007)stably.The treatment effects of combined system in summer were the best,followed by spring and autumn.Even in winter,the system could still run normally and stably to ensure that the water quality reach the standard.Sedimentation pond had the best purifying effects on TSS with the removal rate of 21.3%.Aeration pond had the largest contribution to CODMn and NH+4-N with the removal rates of 18.7%and 28.7%,respectively.Ecological pond had the largest contribution to TN and TP removal rates with 16.3%and 28.8%,respectively.The filter dam had good removal effect on all water quality indexes,and the removal range was 7.5%to 11.8%.The construction cost of the aquaculture pond tail water projects were 13700,27750 and 13040 yuan/hm^2 for the three demonstration sites.The annual operating and maintenance costs allocating to the ponds every year were 3250,3870 and 4000 yuan/hm^2,respectively.