| Sewage sludge contains abundant organic compounds,heavy metals and pathogens.It would cause significant pollution to the environment if they were not taken action control.In recent years, heavy metals in sewage slud,ge decreased obviously,greenbelt soil compost by swage sludge is a reasonable method for land use,which not only economize Chemical fertilizer,reduce the cost of cultivation,find a better way for sludge treatment,but also keep away from food chain,not influence human health,and has wider application than agricultural application of sewage sludge.Based on above reasons,study reasonable amount of compost is a main problem of sludge compost for greenbelt soil.The target of this study treated by aerobic from dewatered sludge in Chongqing sewage treatment plant,we divided into two groups for potted plant examinations according to sludge as substrates and fertilizer.For substrate examination,four treatments added sludge composting among seven treatments(mixed by volume ratios).For fertilizer examination,three treatments added sludge composting among five treatments,adopting the same nutrient content examination,Impatiens Balsamine and Carnation Flower were two target flowers.The results showed that content of organic matter,nitrogen,phosphorus and kalium in sludge compost of Chongqing was 478.60g/kg,11.56 g/kg,7.62 g/kg and 9.72 g/kg,respectively.Higher nutrient content indicated that this sludge was a favourable organic manure resource.The pH and CEC value were according with basic require of substrate,but the bulk density was just 0.17g/cm~3, and it was prone to lodge when planting as singleness substrate,which can add other substrates to increase bulk dentist.EC value was as high as 14.50mS/cm,it should be diluted or washed before using.Analysed the chemical and physical properties of seven treatments for substrate examination, consider from nutrient contents,heavy metals and bulk dentist,each mixed substrate were aerated, have good waterholding characteristic,bulk dentist and soil porosity were appropriate for planting. High content of organic compound,nitrogen and phosphorus but low content of heavy metals. Among them,mixed substrateâ…¦(sludge composting:perlite:vermiculite=3:1:1)was the best one according to theory,next was mixed substrateâ…¥(sludge composting:leaf mold:perlite:vermiculite =2:1:1:1). Results on pot experiment showed that plant grown better for substrate contains sludge compost, but restrain for Impatiens Balsamine when just containing sludge composting.Variance analysis was conducted of the data of increment for plant height and branch,florescence,maximum leaf length and leaf width,amount and fresh weight of flower,educed that excellent one was mixed substrateâ…¥(sludge composting:leaf mold:perlite:vermiculite=2:1:1:1).Substrateâ…¥elevated not only for Impatiens Balsamine,but also for Carnation Flower,which indicated that this one was applicable for general.Sludge composting for substrate,substitute for turfy soil,is a reasonable method.Analysed nutrient and heavy metals contents after planting,substrates contained sludge composting could reused.Result on from the experiments when sludge compost was used as fertilizer showed that, fertilized with sludge compost was better than Contrasted soil.Variance analysis was conducted of the data of increment for plant height and branch,florescence,maximum leaf length and leaf width, amount and fresh weight of plant educed that flower fertilized with sludge composting increased plant height and amount,predated initial time of flowering,improved ornamental value.Growth effect was worse than soil fertilized by chemical fertilizer contains the same nutrient content,but comparable when nutrient contents were twice.Sludge composting could educe the same effect with fertilizer so far as amount and ratio were appropriate. |
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