Treatment Of Earthworm Culture Bed To Sludge And The Preliminary Applications Of Its Products

With the increase of wastewater’s treatment capacity, the sludge produced by sewage treatment plants is getting much more than before. The untreated sludge will cause serious environmental problems such as water pollution, air pollution and soil pollution. In recent years, man) researchers focus on the methods of sludge disposal. This research is based on the earthworms’characteristic of digesting rotten food to treat sludge. The objective of this paper is to try out a new method of sludge disposal, using earthworm culture bed to decompose sludge and applying their products in agriculture, to achieve the goal of sludge resources. The main results and conclusions are as follows:The optimized conditions on the growth and reproduction of earthworm as well as the matrix processing rate as follows:the quality ratio of sludge and straw was 9:1, the sludge matrix was added 400g every time and once every 12 days, the matrix for the culture bed composed of 10cm bottom soil,5cm buffer matrix and sludge matrix, and used dust as the bottom soil.The appearance of sludge matrix in culture bed could be changed significantly by the activities of earthworm. Earthworm could transform sludge into vermicompost. The culture bed which had inoculated earthworm could obviously improve the removal rates of TN (total nitrogen), TP (total phosphorus), OM (organic matter) and the rate of bacteria inactivation.The activities of earthworm could change the distribution of TN and TP in culture bed. At beginning, TN and TP in culture bed were well-distributed. At the end of the test, the content of TN and TP decreased both in sludge matrix and buffer matrix, and increased in soil.Adding vermicompost in the soil could promote the growth of impatiens and pepper. Moreover, the higher ratio of vermicompost in the soil, the better growth of impatiens and pepper would be. Compared to the vegetable seeds sowed in soil, when the seeds were sowed in mixture substrate composed of freshly dewatering sludge and soil, the final seed germination ratio reduced 32.5%. However, when the seeds sowed in soil mixed with vermicompost, the final seed germination ratio increased 10.9%.