The Impact Of Compositing The Municipal Sewage Sludge With Sawdust As Substrate On The Seedling Grouth Of Perennial Ryegrass

As a kind of solid and liquid waste,urban sewage sludge contains a lot of harmful substa nces and heavy metal elements,but it also contains a lot of organic matter and nutrients.Garde n green space utilization is the most environmentally friendly treatment and the most promisin g way of urban sewage treatment.Because of the high water content and large volume of sludg e produced in the wastewater treatment plant,it is necessary to make a reasonable preliminary treatment.This study wil first wet air oxidation treatment of sludge and LIPP anaerobic digestion sludge with sawdust respectively,compound as a new eco-organic type cultivation substrate,study two kinds of sludge composite with sawdust in different ratio to seed perennial ryegrass,discuss the influence of the germination and growth of perennial ryegrass seedlings and the effects of the land utilization.The main results are as follows:1.Wet air oxidation and anaerobic digestion technology with LIPP are two different methods processing dehydrated sludge,the sludge volume smaller,more stable and harmful component content is reduced after the treatment,achieve the requirement of resource utilization.On the testing results show that: The two kinds of treated sludge are conforming to the standard(GB/T 23486-2009),which can be used on the land utilization.2.Through the determination and analysis of several major physical and chemical properties of the substrate which wet air oxidation treated sludge and LIPP anaerobic digested sludge composite with sawdust in different ratio,such as organic matter,p H value,EC value,bulk density and total porosity,in addition to a few groups of the compound substrates which applied large amount of sludge,The physical and chemical properties of other different proportions of the compound substrate are basically in accordance with the requirements of the common cultivation substrate.3.This experiment choose controlled trials with potting,then measure the germination,morphological index and physiological of perennial ryegrass.Experimental results show that,when the ratio of sludge and sawdust in wet air oxidation treatment was 20%,the effect on ryegrass germination and seedling growth is the best,the tiller number and the leaf length were the closest to the nutrient soil,the germination index,the root length,the fresh weight,the chlorophyll content,the soluble sugar content were higher than the nutrient soil control,the MDA content,relative conductivity values were lower than the nutrient soil control.Whenthe ratio of LIPP anaerobic digested sludge and sawdust was 40%,it had the best effect on the germination of ryegrass seeds,the germination percentage,the germination potential,the germination index,the vigor index were all higher than that of nutrient soil;In the ratio of50%,the growth of seedlings of ryegrass had the best effect,the tiller number and the leaf length were the closest to the nutrient soil,the fresh weight,the root length,the chlorophyll content,the soluble sugar content were all higher than the nutrient soil control,the MDA content and the relative conductivity value were lower than the nutrient soil.4.Experimental results show that,when the ratio of sludge and sawdust in wet oxidation treatment was 20%,the ratio of LIPP anaerobic digested sludge and sawdust was 50%,the tillering and leaf growth rate of ryegrass were delayed,but the root,fresh weight,chlorophyll content and soluble sugar content of ryegrass were increased.As a result,the ryegrass showed a short and strong form which can reduce the lodging lawn and the pruning times in the future maintenance of the lawn,and can reduce the cost of maintenance and management.