复合填料地下渗滤系统的强化脱氮研究

Intensified Denitrification of Compound Mixed Subsurface Wastewater Infiltration System

为有效提高地下渗滤系统的运行水力负荷并强化其脱氮效果,建立了由55%煤渣、25%土壤与20%草炭全混合装填的地下渗滤装置,运行水力负荷为10cm·d-1,每天进水4次,通过改变不同运行条件来促进TN的去除.研究结果表明该装置对COD,NH4+-N,TN的平均去除率,在正常出水水位条件下运行,分别为73.4%,98.2%和20.1%;在提高出水水位条件下运行,分别为75.4%,79.1%和26.9%;在添加碳源条件下运行,分别为88.9%,88.5%和55.7%.说明草炭的添加并不能明显提高TN的去除率,而出水水位的提高,可促进系统内厌氧环境的形成从而有利于TN的去除,但同时也会降低氨氮的去除效果;添加碳源可明显提高TN的去除效果,使系统出水TN质量浓度由正常出水水位条件下的22.8mg·L-1下降到14.2mg·L-1,且对COD和NH4+-N去除效果的影响不大.因此,影响该系统去除TN的关键因素是碳源的缺乏.

In order to improve the hydraulic permeability and intensify denitrification of subsurface wastewater infiltration system,one apparatus was established in a pilot laboratory with the mediums of 55% cinder,25% soil and 20% grass carbon mixed completely.The apparatus was dosed 4 times daily with domestic wastewater at 10 cm·d-1.Operating conditions were changed in order to improve the removal efficiency of TN.The average removal efficiency of COD,NH＋4-N and TN were 73.3%,98.2% and 20.1%,respectively,when outlet location was at normal position.The average removal efficiency of COD,NH＋4-N and TN were 75.4%,79.1% and 26.9%,respectively,When outlet location was heightened 30 cm,the bottom of apparatus was submerged so that anaerobic environment was formed.The average removal efficiency of COD,NH＋4-N and TN were 88.9%,88.5% and 55.7%,respectively,when the apparatus was conducted in glucose added in domestic wastewater.The results show that the removal of TN is not improved by adding grass carbon in apparatus;outlet location raising can increase TN removal efficiency from 20.1% to 26.9%,but the action is limited; the glucose added can increase TN removal efficiency from 26.9% to 55.7%,and TN concentration of effluent decreases from 22.8 mg·L-1 to 14.2 mg·L-1; at the same time,the removal of COD,NH＋4-N is not affected.So the critical factor of the TN removal blocked is carbon absent.