the filler is the key composition in the land treatment eatment.its performance can determine the quality of the effluent.the size,struture,organic content and mineral of the filler are the main factors in the breakdown of the contaminant in the sewage.even the nature soil can deal with the sewage well,but can not content the demands in the scale and quality.it can be easily colgged and take lots of speace.while the new filler and the manmade soil enhance the sewage treatment and to solve some problems of n...