催化还原法深度处理污水中硝态氮的研究

Study on advanced treatment for removing nitrate in wastewater through chemical catalytic reduction

为有效降低城市污水处理厂出水硝态氮的含量,减轻氮素污染,依次进行了基础性试验和验证性试验.基础性试验以Fe0为还原剂,以配置的KNO3溶液为试验用水对分别添加H+、Fe2+、Cu2+、Pd/Al2O3等后的脱氮效果进行了对比研究.试验结果表明,系统p H值为2.1,Fe2+、Cu2+投加量分别为1000mg/L时,系统均可获得较好的脱氮效果,分别为92%、41%、61%,产物均以氨氮为主;当投加10g/L催化剂Pd/Al2O3,调节系统p H值为3.02时,系统脱氮率可达48%,且其产物以氮气为主,副产物较少.在此基础上,验证性试验以北京市某污水处理厂出水为试验用水,对上述各方法的脱氮效果进行了试验验证,并对其可行性进行了分析.结果表明,在一定条件下,各方法均可达到理想的脱氮效果,其去除率分别可达到87%、36%、50%、46%.但综合脱氮效果、产物分析、出水水质等考虑,相比较而言,添加催化剂的化学催化还原法在去除污水中的硝态氮时具有更好的可行性.

In order to effectively reduce the concentration of NO3--N in the effluent of the municipal wastewater treatment plant, the basic experiments and proving tests were conducted in order. The KNO3 solution prepared was sampled for evaluating NO3-- N removal efficiency by adding H＋、Fe2＋、Cu2＋ and Pd/Al2O3, respectively. Results showed that certain removal performances could get（92%、41%、61%）, when the p H was 2.1, or with the dosage of 1000mg/L for Fe2＋ and Cu2＋, respectively; one thing we could not neglect was that NH4＋-N dominated in the products. However, 48% removal efficiency could be reached and N2 was predominant in the products with dosage of 10g/L of the catalysts（Pd/Al2O3） and p H of 3.02. The effluent of the wastewater treatment plant was used for the proving tests. It can be concluded that under certain condition, ideal efficiency could be obtained through the above mentioned ways. Taking nitrate removal efficiency, byproducts, water properties into consideration, the chemical catalytic reduction of nitrate in wastewater could be more practicable.