| With the intensive animal husbandry development, scale transformation, livestock and poultry wastewater treatment plant sludge disposal will be more and more important, because if the sludge was not properly handled, serious ecological environment pollution would occur. Vermicomposting is a kind of low carbon biological treatment way in sludge resource utilization because it can implement effectively and be cheaper in waste and sludge reduction, innocuity, stabilization and recycling. In this paper, livestock and poultry wastewater treatment plant sludge and different poultry and animal feces were used in separately single compost, which purpose is to explore the efficiency of vermicompost and the appropriate time that the compost can be utilized by earthworms; Different mixing proportions of manure and sludge were selected in earthworm breeding to find the optimal proportion in a series of experiments; Finally, with wormcast, sludge, clay as raw material, sweet potato root culture experiment was also carried out, then the optimum adding proportions of wormcast adoped in plant root culture were discovered. The main research conclusions are as follows:(1)The composting indices of pig dung, cow dung, rabbit manure, chicken manure, and sludge single material compost after 28 d were as following:The content of water, TC and C/N reduced in each treatment; The pH of sludge also reduced, but other indices rose. The total nitrogen content:those of rabbit manure, pig, cow dung increased, sludge and chicken manure reduced. After 28 d, compost of rabbit manure had met curing standards, those of pig manure was close to standards, but cow muck, chicken manure, sludge compost were bad.(2) Earthworms have strong selectivity to sludge and dung. Earthworms have strong inclination to sludge and cow dung, but prefer the most to sludge, then rabbit manure and pig manure, however, no any earthworm was fund in chicken manure. According to the result of earthworm choice experiment, some conclusions are summed as follows:the maximum quantity of earthworm that choose to turn into the sludge and cow dung on the 14th day and 28th day after respectively in composting; the maximum quantity of earthworm in the rabbit manure after being composted for 14 days; the pig manure and chicken manure are difficult to be accepted by the earthworm when they were composted, so, they must be mixed with sludge or cow dung to breed earthworm.(3)After raising two weeks with different waste and sludge compost, the average weight gain of earthworm was calculated. The Compost time of rabbit manure, sludge, pig manure, cow dung, chicken manure to maximize the earthworm weight were at the 0th day, the 7th day, the 14th day, the 21th day, the 28th day, and the chicken manure is not suitable for directly using in vermicompost because of it leading to a negative result. The order of individual earthworm weight in the end is as follows:Cow dung group(306.41 mg)> sludge group (253.02 mg)> rabbit dung group(170.53 mg)> pig manure group (156.38 mg)> chicken manure group (31.95 mg).(4) All of the different mixing proportion of "pig manure+sludge" and "cow dung +sludge" have good treating effect. After breeding for 60 days, All of the processing’s TC, NH4+-N reduced and available phosphorus, total phosphorus increased significantly. The pH of pig and cow dung rose, but those of other treatments decreased, and the pH value changed in the range of 5.8～7.33 during composting period. In the end material volume of each group became less, compost got softer and odourless.(5) Earthworms could grow well and get the expected weight in the material of the different combination proportion of "pig manure+sludge" and "cow dung+sludge". With the increase of breeding time, earthworm individual average weight. increased then decreased and finally reached the maximum weight at the 30th day. Among the three material of pig manure, cow dung and sludge,-the weight gain of the earthworm was the best in the pig manure, while the earthworm s weight gain was lowest in the sludge, and the weight gain of the earthworm in pig manure and sludge has a significant difference (P <0.05). From the whole, sludge adding cow or pig manure can significantly increase the individual average weight gain of earthworms, and the group of adding pig manure achieved the best result. The better effect could get if pig manure was added to the sludge according to the following commendated proportion:20%～50%(dry weight), and 40% is the best(weight gain:428.78 mg); The adding proportion of cow dung is 30%～50%(dry weight) to Sludge, and 50% is the best (the average weight gain:328.62 mg).(6) In the aspect of fertility of earthworm, Among the three material of pig manure, cow dung and sludge, the fertility of earthworm in the sludge was the best, and the fertility of earthworm in the pig manure was the lowest. while the breeding effect of the earthworm in pig manure, cow dung and sludge was significantly lower than "sludge+ cow dung" and "sludge+pig manure " treatment groups (P<0.05), and "sludge+cow dung" got better performance than "sludge+pig manure " treatment group. With the increasing of feeding time, the total number of earthworm and cocoon increased, and the earthworm’s biggest proliferation ratio was found in the 45th day. The "60% sludge+ 40% cow dung" group was the best in the whole experiment period. Adding cow dung or pig manure in sludge can improve the fertility of earthworm, the better adding proportion of cow dung is 30%～50%(dry weight) in the sludge, and the fertility of earthworm is the best when the sludge contained 40% cow dung; the better adding proportion of pig manure is 20%～40%(dry weight) in the sludge, and the fertility of earthworm is the best when the sludge contained 20% pig manure.(7) The result of sweet potato root culture experiments are as follows:to add soil 10%～50% by volume to the vermicompost or 10%～30% by volume to the sludge can improve the sweet potato seedling root weight and bud growth. "70% soil+30% wormcast" and "70% soil+30% sludge" group in root culture achieve the best root growth of sweet potato, and adding the same proportion of wormcast is better than adding sludge in the soil. |
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