Research On Stabilization Process In Laboratory Simulating Semi-Aerobic Landfill

Based on the simulated experiments, this paper integrality illustrates the mechanism of stabilization and studies the influence factors of the semi-aerobic landfill;builds the scientic index system and evaluation standard;the model based on BP neural network is applied to judge stabilization degree of simi-aerobic landfill.The results of laboratory simulated tests indicate that: the diameters of leacheate collection pipes and vent-pipes are important factors to influence the leachate quality degradation, and the results of different combination are different;the area of ventholes on the vent-pipe is also one of the important factors , the result of 7.85 cm2 is better than 3.93cm2 ; the settlement can be divided into 3 phase: the settlement due to the selfweightstress,the settlement due to the quickly degradation of the organic substance ,and the settlement due to slowly degradation of garbage.the settlement at the second phase accounts for 48%~56% of the initial height of garbage in the Iandfill,at this time the landfill is very unsteady.According to the results of the test and the theoretical analysis ,the paper reveals the selected principle of evaluation index ,and builds the index system from 3 aspect: leachate quality, contents of refuse components and the regular patterns of settlement,including COD,ammonia-N,TVS/TDS,BDM,settlement; at the 70th day,the density of ammonia-N has dropped to 10mg/l, when the indexs such as ammonia-N, BDM,settlement velocity ect become very little,the density of COD is still high(700-1600mg/l),the transformation of assessment index of semi-aerobic landfill is not in-phase,so the stabilization process is divided to unsteadiness-basic stabilization- absolute stabilization , through settlement is regarded as control index(the settlement hit 99.99% of sedimentation capacity) when semi-aerobic landfill is on basic stabilization,and COD(less than 10mg/l) is regarded as control index when it is on absolute stabilization, the paper foretells the evaluation standard, BP neural network is used to evaluate the stabilization level of simulating semi-aerobic landfill, seven simulating equipments are still in unsteadiness at the end of test ,while l#-6# simulating equipments turn into basic stabilization when it arrives at the 598th day.This paper provide a way of thinking for the semi-aerobic landfill,the evaluation index system and standard have important reference value for various landfill of our country.