畜禽养殖场地下水氮素污染修复研究
发布时间：2018-10-21 12:09
【摘要】：我国畜禽养殖场周边地下水环境氮素污染状况不断恶化,但氮素污染修复技术相对落后,亟需对畜禽养殖场周边地下水环境氮素污染状况进行详细勘察并开展相关修复技术的研究工作。本研究以受浙江某养殖场养殖废水污染的地下水为研究对象,研究适合我国南方养殖场地下水氮素污染的修复技术,取得的主要研究结果如下：(1)场地土壤成分以粘土为主,渗透性极差,含水层渗透系数不足2 cm/d,地下水埋深不足1m,地下水埋深较浅和土壤通气性较差不利于氨氮向硝态氮的转化；地下水受氨氮污染极为严重,氨氮浓度最高区域可达500 mg/L,而硝态氮污染相对较轻,整体上地下水环境中硝态氮含量不足10 mg/L；由于修复的地下水属潜水层,受外界影响较大,氨氮和硝态氮污染羽时空分布都极不均匀,整体上靠近氧化塘区域浓度偏高,丰水期氮素污染物浓度偏低；场地地下水环境属于弱碱性条件,pH范围在7-8之间；水体碳氮比偏低且不稳定,丰水期时大多数区域碳氮比不足1：1,不利于脱氮作用进行。场地地下水流速过慢、且污染较重的实际情况,不利于开展原位修复,而适于开展异位修复。(2)从氧化塘底泥及地下水中筛选出了4株土著反硝化菌,分别是恶臭假单胞菌、阴沟肠杆菌、羽扇豆苍白杆菌和鹰嘴豆苍白杆菌；在硝酸盐去除对比实验中,在以柠檬酸钠或葡萄糖为单一碳源的条件下,4株反硝化菌中,恶臭假单胞菌去除硝酸盐的效果最佳；在固体碳源的筛选实验中,使用麸皮和豆粉混合物作为固体碳源对水体中的硝酸盐去除效果最佳,在初始硝酸盐浓度为50 mg,/L时,出水中基本检测不到硝酸盐,但是该混合物也会向水体中释放10 mg/L以上的氨氮,在后期工程中需要配合其它填料使用。(3)修复系统利用含有沸石与有机质的多介质层与脱氮菌,先将污水中的氨氮通过吸附、硝化转化为硝态氮,再通过反硝化作用将硝态氮转化为氮气。修复工程建成并投入试运行后,氨氮去除率都在90%以上,随后由于系统堵塞失效,且出水中硝态氮浓度始终较高(高于100mg/L),对系统进行了重新装填,并安装了用于疏通介质层的反冲装置,有利于系统长期运行。再次运行后氨氮的去除率在80%以上,出水浓度低于5 mg/L；出水中硝态氮含量约为27 mg/L。出水氨氮和硝态氮含量分别满足畜禽养殖业污染物排放标准与地下水质量Ⅳ类农业用水标准。但系统长期处理效果有待进一步观察。
[Abstract]:The status of nitrogen pollution in groundwater around livestock and poultry farms in China is deteriorating, but the remediation technology of nitrogen pollution is relatively backward. It is urgent to investigate the nitrogen pollution of groundwater around livestock and poultry farms in detail and to carry out research on related remediation techniques. In this study, the groundwater polluted by aquaculture wastewater from Zhejiang province was taken as the research object, and the remediation technology suitable for nitrogen pollution of ground water in southern China was studied. The main results obtained were as follows: (1) the soil composition of the site was mainly composed of clay. The permeability of the groundwater is extremely poor, the permeability coefficient of the aquifer is less than 2 cm/d, the groundwater depth is less than 1 m, the groundwater depth is shallow and the soil aeration is poor, which is not conducive to the conversion of ammonia nitrogen to nitrate nitrogen, and the groundwater is seriously polluted by ammonia nitrogen. The highest concentration of ammonia nitrogen can be up to 500 mg/L, and the pollution of nitrate nitrogen is relatively light. On the whole, the content of nitrate nitrogen in groundwater environment is less than 10 mg/L; because the restored groundwater belongs to the phreatic layer and is greatly affected by the outside world. The distribution of ammonia nitrogen and nitrate nitrogen pollution plume is very uneven, the concentration of nitrogen pollutant near the oxidation pond is relatively high, the concentration of nitrogen pollutant is low in the high water period, the ground water environment belongs to the weak alkaline condition, the pH range is 7-8; The ratio of carbon to nitrogen in water is low and unstable, and the ratio of carbon to nitrogen in most regions is less than 1: 1 in the high water period, which is not conducive to denitrification. The ground water flow rate is too slow and polluted seriously, which is not conducive to carrying out in situ remediation, but is suitable for ectopic remediation. (2) four strains of indigenous denitrifying bacteria were screened from the bottom mud and groundwater of the oxidation pond, respectively, as Pseudomonas odour. Enterobacter cloacae, Pseudomonas pallidus and Bacillus chickenii; in nitrate removal experiments, four denitrifying bacteria were used as a single carbon source, with sodium citrate or glucose as a single carbon source. In the screening experiment of solid carbon source, the mixture of wheat bran and soybean powder was used as the best solid carbon source to remove nitrate in water, and when the initial nitrate concentration was 50 mg,/L, the effect of nitrate removal was the best when the initial nitrate concentration was 50 mg,/L. Nitrate can not be detected in the effluent, but the mixture also releases ammonia nitrogen to the water for more than 10 mg/L, which needs to be used with other fillers in the later stage of the project. (3) the remediation system uses multi-media layers containing zeolite and organic matter and denitrifying bacteria. The ammonia nitrogen in the wastewater was first adsorbed and nitrided into nitrate nitrogen, and then the nitrate nitrogen was converted to nitrogen by denitrification. After the restoration project was completed and put into trial operation, the removal rate of ammonia nitrogen was above 90%, then the system was reloaded because of the system blockage and failure, and the concentration of nitrate nitrogen in the effluent was always higher (higher than 100mg/L). A recoil device is installed for dredging the dielectric layer, which is beneficial to the long-term operation of the system. After rerunning, the removal rate of ammonia nitrogen is more than 80%, and the effluent concentration is lower than 5 mg/L;. The nitrate nitrogen content in effluent is about 27 mg/L.. The effluent ammonia nitrogen and nitrate nitrogen content meet the pollutant discharge standard of livestock and poultry industry and the agricultural water standard of groundwater quality 鈪，
本文编号：2285054
[Abstract]:The status of nitrogen pollution in groundwater around livestock and poultry farms in China is deteriorating, but the remediation technology of nitrogen pollution is relatively backward. It is urgent to investigate the nitrogen pollution of groundwater around livestock and poultry farms in detail and to carry out research on related remediation techniques. In this study, the groundwater polluted by aquaculture wastewater from Zhejiang province was taken as the research object, and the remediation technology suitable for nitrogen pollution of ground water in southern China was studied. The main results obtained were as follows: (1) the soil composition of the site was mainly composed of clay. The permeability of the groundwater is extremely poor, the permeability coefficient of the aquifer is less than 2 cm/d, the groundwater depth is less than 1 m, the groundwater depth is shallow and the soil aeration is poor, which is not conducive to the conversion of ammonia nitrogen to nitrate nitrogen, and the groundwater is seriously polluted by ammonia nitrogen. The highest concentration of ammonia nitrogen can be up to 500 mg/L, and the pollution of nitrate nitrogen is relatively light. On the whole, the content of nitrate nitrogen in groundwater environment is less than 10 mg/L; because the restored groundwater belongs to the phreatic layer and is greatly affected by the outside world. The distribution of ammonia nitrogen and nitrate nitrogen pollution plume is very uneven, the concentration of nitrogen pollutant near the oxidation pond is relatively high, the concentration of nitrogen pollutant is low in the high water period, the ground water environment belongs to the weak alkaline condition, the pH range is 7-8; The ratio of carbon to nitrogen in water is low and unstable, and the ratio of carbon to nitrogen in most regions is less than 1: 1 in the high water period, which is not conducive to denitrification. The ground water flow rate is too slow and polluted seriously, which is not conducive to carrying out in situ remediation, but is suitable for ectopic remediation. (2) four strains of indigenous denitrifying bacteria were screened from the bottom mud and groundwater of the oxidation pond, respectively, as Pseudomonas odour. Enterobacter cloacae, Pseudomonas pallidus and Bacillus chickenii; in nitrate removal experiments, four denitrifying bacteria were used as a single carbon source, with sodium citrate or glucose as a single carbon source. In the screening experiment of solid carbon source, the mixture of wheat bran and soybean powder was used as the best solid carbon source to remove nitrate in water, and when the initial nitrate concentration was 50 mg,/L, the effect of nitrate removal was the best when the initial nitrate concentration was 50 mg,/L. Nitrate can not be detected in the effluent, but the mixture also releases ammonia nitrogen to the water for more than 10 mg/L, which needs to be used with other fillers in the later stage of the project. (3) the remediation system uses multi-media layers containing zeolite and organic matter and denitrifying bacteria. The ammonia nitrogen in the wastewater was first adsorbed and nitrided into nitrate nitrogen, and then the nitrate nitrogen was converted to nitrogen by denitrification. After the restoration project was completed and put into trial operation, the removal rate of ammonia nitrogen was above 90%, then the system was reloaded because of the system blockage and failure, and the concentration of nitrate nitrogen in the effluent was always higher (higher than 100mg/L). A recoil device is installed for dredging the dielectric layer, which is beneficial to the long-term operation of the system. After rerunning, the removal rate of ammonia nitrogen is more than 80%, and the effluent concentration is lower than 5 mg/L;. The nitrate nitrogen content in effluent is about 27 mg/L.. The effluent ammonia nitrogen and nitrate nitrogen content meet the pollutant discharge standard of livestock and poultry industry and the agricultural water standard of groundwater quality 鈪，
本文编号：2285054
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