【摘要】：我國畜禽養(yǎng)殖場周邊地下水環(huán)境氮素污染狀況不斷惡化,但氮素污染修復(fù)技術(shù)相對落后,亟需對畜禽養(yǎng)殖場周邊地下水環(huán)境氮素污染狀況進(jìn)行詳細(xì)勘察并開展相關(guān)修復(fù)技術(shù)的研究工作。本研究以受浙江某養(yǎng)殖場養(yǎng)殖廢水污染的地下水為研究對象,研究適合我國南方養(yǎng)殖場地下水氮素污染的修復(fù)技術(shù),取得的主要研究結(jié)果如下：(1)場地土壤成分以粘土為主,滲透性極差,含水層滲透系數(shù)不足2 cm/d,地下水埋深不足1m,地下水埋深較淺和土壤通氣性較差不利于氨氮向硝態(tài)氮的轉(zhuǎn)化；地下水受氨氮污染極為嚴(yán)重,氨氮濃度最高區(qū)域可達(dá)500 mg/L,而硝態(tài)氮污染相對較輕,整體上地下水環(huán)境中硝態(tài)氮含量不足10 mg/L；由于修復(fù)的地下水屬潛水層,受外界影響較大,氨氮和硝態(tài)氮污染羽時(shí)空分布都極不均勻,整體上靠近氧化塘區(qū)域濃度偏高,豐水期氮素污染物濃度偏低；場地地下水環(huán)境屬于弱堿性條件,pH范圍在7-8之間；水體碳氮比偏低且不穩(wěn)定,豐水期時(shí)大多數(shù)區(qū)域碳氮比不足1：1,不利于脫氮作用進(jìn)行。場地地下水流速過慢、且污染較重的實(shí)際情況,不利于開展原位修復(fù),而適于開展異位修復(fù)。(2)從氧化塘底泥及地下水中篩選出了4株土著反硝化菌,分別是惡臭假單胞菌、陰溝腸桿菌、羽扇豆蒼白桿菌和鷹嘴豆蒼白桿菌；在硝酸鹽去除對比實(shí)驗(yàn)中,在以檸檬酸鈉或葡萄糖為單一碳源的條件下,4株反硝化菌中,惡臭假單胞菌去除硝酸鹽的效果最佳；在固體碳源的篩選實(shí)驗(yàn)中,使用麩皮和豆粉混合物作為固體碳源對水體中的硝酸鹽去除效果最佳,在初始硝酸鹽濃度為50 mg,/L時(shí),出水中基本檢測不到硝酸鹽,但是該混合物也會向水體中釋放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)修復(fù)系統(tǒng)利用含有沸石與有機(jī)質(zhì)的多介質(zhì)層與脫氮菌,先將污水中的氨氮通過吸附、硝化轉(zhuǎn)化為硝態(tài)氮,再通過反硝化作用將硝態(tài)氮轉(zhuǎn)化為氮?dú)�。修�?fù)工程建成并投入試運(yùn)行后,氨氮去除率都在90%以上,隨后由于系統(tǒng)堵塞失效,且出水中硝態(tài)氮濃度始終較高(高于100mg/L),對系統(tǒng)進(jìn)行了重新裝填,并安裝了用于疏通介質(zhì)層的反沖裝置,有利于系統(tǒng)長期運(yùn)行。再次運(yùn)行后氨氮的去除率在80%以上,出水濃度低于5 mg/L；出水中硝態(tài)氮含量約為27 mg/L。出水氨氮和硝態(tài)氮含量分別滿足畜禽養(yǎng)殖業(yè)污染物排放標(biāo)準(zhǔn)與地下水質(zhì)量Ⅳ類農(nóng)業(yè)用水標(biāo)準(zhǔn)。但系統(tǒng)長期處理效果有待進(jìn)一步觀察。
[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，

本文編號：2285054