Utilization Of Solar Energy On Sewage Sludge Composting Fertilizer Effect And Application

With rapid development of urbanization of China，rate of urban sewage disposal isenhancing and output of sludge from urban sewage treatment plant are increasingtoo． Recent, a lot of work has been do in terms of sludge treatment. However, due toeconomic and technical reasons, our sludge treatment capacity is still very weak. Lowsludge treatment and technical flaws make a large number of sewage sludge withoutdisposed. These sludge accumulation occupy large land. Aerobic sludge composting is ancommonly sludge treatment now. Temperature is one of the most important control factorsof aerobic composting. However, at the beginning of the aerobic sludge composting, a lotof extra energy usually required in order to have better results.In order to make sludge composting work in high efficiency and use solar energyinstead of other additional energy, the use of solar energy and reasonable ratio of sludgeand additive in efficient aerobic composting were studied in this paper. The main contentsand results of the study were as follows:Based on the different characteristic of ordinary reactors, greenhouse reactors andsolar reactors, the three kinds of reactors were designed. To investigate the influence ofdifferent devices, temperature, pH, conductivity, nutrient elements C and N, GI edc. Weretested. The results showed that the use of solar energy can improve the efficiency ofaerobic compost.（1）Solar energy can provide a stable energy for high efficiency aerobiccomposting experiments. When nature temperature is low in autumn or spring, solarenergy compost can work at temperature35℃.(2) EC and pH值is related to ionconcentration. The EC of three groups were substantially the same. pH值eventuallyshowed weak alkaline.(3) With the help of solar energy, the TOC was degraded more andthe TN content was higher. At the end of experiment, the TOC of the solar groups weredegraded31.25k/kg. The greenhouse group was degraded20.07k/kg and the ordinaryone was degraded20.05k/kg.(4) GI rate can explain the degree of composting mostdirectly. The GI rate of these3groups reached maturity requirements80%, and the rate ofsolar energy group remain the highest. The effect on aerobic composting of different material ratio was researched toimprove the technology of aerobic composting. To investigate the influence of differentdevices, TOC, nutrient elements N, GI temperature edc. Were tested. At last flower seedswere grew with these composting sludge. The experimental results showed that:(1)Compost sludge made the compost temperature rise rapidly. Sawdust kept the compostsludge warm.(2)It showed that composting sludge make for nitrogen fixation and thedegradation of TOC. TOC of NO.1(Sludge+Sawdust+Compost sludge) was degraded14g/kg.(3) The GI rate of NO.1was the highest reached75.57%.(4) The plant grewwith NO.1compost sludge was the best. The plant grew faster and had more flowers.The result of this experiment is practical significance. It can provide a theoreticalbasis on large-scale aerobic sludge composting.