固相反硝化同时去除地下水中硝酸盐和阿特拉津的试验研究

EXPERIMENTAL STUDY ON THE SIMULTANEOUS REMOVAL OF NITRATE AND ATRAZINE FROM GROUNDWATER USING SOLID-PHASE DENITRIFICATION PROCESS

以稻草秸秆作为固相反硝化的碳源和载体,采用自行设计的有机玻璃反应柱研究固相反硝化对地下水中硝酸盐和阿特拉津同时去除的效果。结果表明,当硝酸盐初始浓度分别为50,100 mg/L时,出水硝酸盐浓度在5 d内均达到较高去除率。当硝酸盐的初始浓度提高至150 mg/L时,硝酸盐去除率降低至82.3%。系统反硝化作用稳定,且表现出了一定的耐冲击负荷能力。研究还发现,随着阿特拉津浓度的提升(1,5,10 mg/L),去除率由80%下降至30%。试验结果表明高浓度的阿特拉津更容易达到稻草秸秆的饱和吸附量,产生较多无法被吸附的阿特拉津剩余量。相较于硝酸盐,阿特拉津更容易受到水力停留时间变化的影响,硝酸盐去除率在试验中一直维持在80%以上。阿特拉津去除率随水力停留时间的延长而增加,在HRT为8 h时,稻草秸秆对阿特拉津达到吸附饱和,最大去除率为78.64%。试验表明,适宜的HRT对阿特拉津和硝酸盐的同时去除起着关键作用。

The effect of solid-phase denitrification on the simultaneous removal of nitrate and atrazine in groundwater was studied by using self-designed plexiglass reaction column with straw as carbon source and carrier of solid-phase denitrification.The results showed that when the initial concentration of nitrate was 50,100 mg/L,the change of nitrate concentration in the effluent was similar,and each of them reached a high removal rate within 5 days. When the initial concentration of nitrate rose to 150 mg/L,the removal rate of nitrate decreased to 82. 3%. Denitrification system worked stable,and showed a certain impact resistance load capacity. The study also found that with the increase of atrazine concentration（ 1,5,10 mg/L）,the removal rate decreased from about 80% to 30%. Experiments showed that high concentrations of atrazine were more easily to reach the adsorption saturation of straw,resulting in that more atrazine could not be adsorbed. Compared with nitrates,atrazine was more susceptible to change in hydraulic retention time,nitrate removal rate in the test has been maintained at 80% or more. Atrazine removal rate increased with the extension of hydraulic retention time. At HRT of 8 h,straw reached the adsorption saturation of atrazine,the maximum removal rate was 78. 64%. Experiments showed that suitable HRT played a key role in the simultaneous removal of atrazine and nitrate.