Study On Aerobic Composting And Earthworm Treatment Of Residual Sludge

As China’s rapid economic development, urban sewage is also a marked increase in the number, which led to urban sewage treatment plant sludge volume also increased significantly. The sewage sludge is the necessary product of wastewater treatment and it is very difficult to be treated because of the great volume and complicated substances. The traditional treatment can not use the organic components of the sludge. Aimed at this situation, this experiment uses the aerobic composting and the earthworm to treat the sludge, and compare the two treatments with fertility and heavy metals and other factors.Use the sludge of a sewage treatment plant in Chongqing city. 1) using a self-designed aerobic composting device for composting fermentation, and using sawdust, bran shell of conditioning agents to carry out the medium temperature composting fermentation;2) using earthworms to treat the sludge directly .Make comparison of treated sludge by the two methods of fertilizer and heavy metals and other relevant indicators. Experiments reached the following conclusions:1、With the designed sewage sludge composting plant, using sawdust and bran mixed conditioner in Chongqing city sludge in a sewage treatment plant after a period of 19 days of aerobic composting, moisture content, VS content showed significant downward trend, pile temperature above 42℃in 5 days, consistent with low organic sludge composting requirements. TP, TN, TK levels are decreased; heavy metals also declined;2、With water content, temperature, pH value changes in input variables, VS as output, the use of BP neural network, the data simulated to obtain the simulated values and the relationship between the real value was found between the good linear relationship, so as to arrive, VS changes in the maturity degree of sludge can be used as evaluation index. Using SPSS software, moisture content, temperature, pH, VS principal component analysis, come VS, pH can reflect the sludge aerobic compost decomposition process and reflected by the calculated aerobic composting process integrated model :F = 0.24AX1 +0.17 AX2-0.19AX3 +0.12 X4;3、Using of wooden waste treatment sludge plant as earthworms. To ensure normal life in the activities of earthworms under investigation pH、VS sludge moisture content changes. After the earthworm treatment, the color of them becomes dark into light yellow; the sludge change into no odor; earthworm body color by a pink to dark red, indicating that the enrichment of heavy metals in the sludge. After processing the sludge by earthworms TP content increased, TN,TK have declined; heavy metals have different levels of decline;4、Sludge DOM UV spectrum of products and content, can reflect the sludge by aerobic composting and earthworms in the process of dealing directly with changes in organic matter, organic matter and can explain the observed changes. Lilac application of compost on the growth of clinker plays a catalytic role, and as Earthworm Casts and phosphorus content is high, affecting the normal growth of lilac, the growth is not ideal. Through different approaches cloves Mosaic tablets N, P, K elements have different content, but generally speaking, applying compost to make clinker plant grow.