饮用原水中微量NH_3-N的生物膜脱除

针对NH3-N浓度为1mg.l-1的饮用原水,分别以硅锰砂石和聚胺脂海绵作为硝化生物膜载体,考察了自制固定床生物膜反应器的脱氨效果.30d的连续运行结果表明,砂石载体系统达到95%—100%的NH3-N去除率,出水NH3-N浓度接近0,出水NO2--N浓度在0—0.02mg.l-1之间;而海绵载体系统虽然挂膜快,但运行阶段NH3-N去除率仅为10%—35%,出水NH3-N不能达标,且具有生物可降解性,反硝化过程优先导致NO2--N的积累.进一步考察了硅锰砂石生物膜系统稳定运行的最优参数,得出试验条件下,水力停留时间为6min,气水比为1:1,反冲洗周期为6d.硅锰砂石因其良好的孔隙率、粒径分布和密度等物理特性,以及化学稳定性和生物安全性,是含低浓度NH3-N原水生物膜净化的良好载体选择.

DEAMMONIA OF TRACE NH_3-N IN DRINKING WATER USING NITRIFYING BIOFILMS

Silicide-manganese sand and PU sponge were introduced as biofilm carriers in a self-manufactured fixedbed biofilm reactor(FBR),and removal effects of 1mg·l~(-1) ammonia nitrogen in drinking water were investigated.After one month's continuous running,the sand system reached an ammonia nitrogen removal rate between 95%-100%,with an output ammonia nitrogen concentration near zero and an output nitrite nitrogen concentration between 0-0.02 mg·l~(-1).While the sponge system had a shorter generation time but an ammonia nitrogen removal rate only between 10%-35%,the output ammonia nitrogen concentration could not achieve the standard; furthermore,sponge was biodegradable,the output nitrite nitrogen accumulated because of predomination of denitrifying process.In addition,working parameters of silicide-manganese sand biofilms system were discussed.Under optimal conditions,HRT was 6 min,gas-water ratio was 1 :1,and back wash period was 6 d.Silicide-manganese sand has favorable physical porosity,size distribution and density,as well as,good chemical stability and biological safety.It proves to be preferred nitrifying biofilms carrier choice for raw water purification containing trace ammonia nitrogen.