垃圾压实密度对模拟回灌型准好氧填埋场稳定进程影响的试验研究

Effect of garbage-compact density on the stabilizing process of laboratory-simulating semi-aerobic landfill with leachate recirculation

在室内模拟试验条件下,研究了不同垃圾压实密度对模拟回灌型准好氧填埋场稳定进程的影响。经过近630d的试验,对于压实密度分别为671.47kg/m3、524.02kg/m3和430.18kg/m3的2#、3#和4#模拟垃圾柱,其渗滤液COD值由试验前的50000mg/L分别降至试验结束时的2210mg/L、2790mg/L和2090mg/L,氨氮质量浓度由最高时的约1300mg/L分别降至45.1mg/L、12.1mg/L和4.96mg/L,垃圾柱累积表面沉降量分别为97.2cm、122.5cm和152.7cm。研究表明,回灌型准好氧填埋场具有加速沉降,改善渗滤液水质的优势;并且垃圾压实密度越小,模拟准好氧填埋场前期好氧反应进行得越激烈,垃圾体的温度越高,渗滤液水质(COD、氨氮)越快得到改善,填埋垃圾的沉降越快,稳定速率也越快。因此在进行该类填埋场的设计和运行时,要适当控制填埋垃圾的压实密度。

The present paper is concerned about our research results on the effect of garbage-compact density on the stabilizing process of laboratory-simulating semi-aerobic landfill with leaehate reeirculation. It is well known that sanitary landfill has a lot of advantages, such as simple operation and management, low cost and suitable for various types of garbage, it has become a major final disposal of solid garbage in many countries. In spite of this, there has been existing a big problem with this type of landfill, that is, its high content of organic pollutant and that of ammonia-N. To solve this problem, we have focused our research on the study of the influence of stabilization process of simulating semi-aerobic landfill with leaehate reeireulation for a long time in the laboratory conditions of different garbage com- paction densities. To be exact, we have classified the garbage-com- pact densities into 2 # , 3 # and 4 # simulating columns, which can be classified into three orders, that is, 671.47 kg/m^3, 524.02 kg/m^3 and 430.18 kg/m^3, respectively. After 630 days＇ test operation, COD concentration of leaehate would drop from about 50 000 mg/L to 2 210 mg/L, 2 790 mg/L and 2 090 mg/L; ammonia-N concentration decreases from 1 300 mg/L to 45.1 mg/L, 12.1 mg/L and 4.96 mg/L, with their accumulated surface settlements reduced to 97.2 cm, 122.5 cm and 152.7 cm, respectively. The results of our experiments indicate that laboratory simulating semi-aerobic landfill with leaehate reeireulation enjoys advantages in accelerating the garbage sedimentation and improving leaehate quality, The smaller the garbage compact density is, the sharper the previous aerobic reaction in simulating columns and the higher garbage temperature will be, and, in turn, the greater the leaehate quality improvement, the garbage sedimentation and stabilization rate. Therefore, controlling garbage compact density appropriately is of great importance during the design and operation of semi-aerobic landfill.