城市污泥施入土壤后对氮素淋溶影响的初步研究

Preliminary Study of the Nitrogen Leaching after the Municipal Sludge Application in Soil

通过土柱淋溶实验,研究不同淋溶液对城市污泥土壤利用后氮素溶出的影响及对周围环境的影响。通过3种不同淋溶液自来水、酸、十二烷基苯磺酸钠(LAS)对2种污泥(常州马杭污水处理厂污泥和常州江边污水处理厂污泥)和2种土壤(草坪土和树林土)混配形成的土柱系统进行淋溶,每4h收集一次淋溶液,共收集48h,对收集的淋溶液进行氮素测定。结果表明,随着时间推移,氮素淋出的量逐渐增多,但单个时间段淋出的氮素量逐渐降低并趋于稳定。3种淋溶液中LAS对土壤-污泥系统中氮素溶出的影响最大,其次是酸,最小的是自来水。最后通过氮磷指数法对淋出的氮素总量进行风险评价,评价结果显示为中等危险等级。

The nitrogen leaching was studied after municipal sludges were applied in the soils by soil column leaching experiment. Three different leaching solutions （tap water, acid and sodium dodecyl benzene sul- fonate） were used to leach the column systems mixed by two kinds of sludges （from Mahang sewage treat- ment plant and Jiangbian sewage treatment plant） and two kinds of soils （lawn soil and forest soil）. The leaching solutions were collected for twelve times every four hours. And the nitrogen contents of the leaching solution were determined and analyzed. The results showed that the amount of nitrogen leaching gradually increased along with the extended time. But the nitrogen concentration gradually decreased and tended to be stable in single period. The LAS leaching solution obviously effected the leaching of nitrogen in the sludge-soil systems. Moderate influence was produced by the acid and the least influence was the tap water. The risk assessment of the total nitrogen was evaluated by the nitrogen and phosphorus index method. And the evaluation results showed that the risk grade was medium.