| With the development of economy and the improvement of people’s living standard, the urban sewage displacement increases day by day, the city as sewage treatment sludge by-products, production has greatly increased, at present the big city sewage sludge factory production has far exceeded the sludge treatment and disposal of plant sludge of ability, and because China’s sludge treatment technology start later, with the international advanced countries, the current our country still is in the sludge treatment process behind, equipment updating couldn’t keep up with the speed of stage, and sludge disposal sites contain ability is limited, the part of the untreated sludge piles up at will frequently occurred, not only because of the heavy metal element contains a lot of sludge caused soil environment and surface and underground water of heavy metal pollution, but also because the sludge can send out the strong bad odor, influence people’s normal life and work, therefore, how to reasonable treatment sludge become the urgent needs to solve the city of one of the urban environment problems.Various soil and water conservation measures is commonly used in one of the plants, drought resistance, alkali resistance is strong, likely to survive and grow strong, in this lab choose norms similar, plant height in23cm or so, base diameter is about0.6cm thick around in various YouZhu potted experiment, through the different pretreatment process will be finished and chao soil sludge respectively according to certain mixing ratio, compare different concentration of hot dry sludge, composting, sludge and lime dry sludge on the growth index and various of different heavy metal element enrichment and ability of the influence, and make use of BCR extraction of heavy metal form the analysis of sludge, according to different existence form of heavy metal activity introduced different toxic coefficient, using the formula separately calculated hot dry sludge, composting, sludge and lime dry sludge continuous application of20years of maximum seems to provide certain land use for sludge data to support. After experimental conclusion: A certain proportion of the hot dry sludge, composting, sludge and lime dry sludge will be the ability of heavy metal concentration of various play a role in promoting, according to the function size order for compost sludge> respectively hot dry sludge> lime dry sludge. From different group experimental plant in the total amount of metal accumulation situation, to various different kinds of heavy metal absorption ability has much difference, this already heavy metal elements in soil and the concentration of the size and the existing form, and plant growth for this element of the demand levels, Zn, Cu elements are elements needed to make plants grow metal elements, the root of the two kinds of element adsorption ability strong; Cd elements, Pb elements not needed to make plants grow metal elements, so plants of the two kinds of elements of the relative to Zn element enrichment capacity, Cu a lot weaker elements.Different sludge pretreatment technology of all kinds of heavy metals in the sludge the passivation effects of different intensity, from the overall perspective, compost and lime dry the pretreatment on the sludge Zn passivation effects than hot dry elements of pretreatment is obvious; Three kinds of pretreatment process of sludge Cu elements in the passivation effects no obvious difference, Cu elements are not used to the dross of state for the Lord; For Pb elements, hot, dry and compost pretreatment effect was significantly better than the lime dry; For Cd elements, the dry heat of the dry and lime treatment, most of the more stable to oxidation state can be and stable scraps existence state, and the compost processing results but after just the opposite, in sewage sludge Cd element active strengthening, stable combination state content decrease, level of unstable exchange state and carbonate combination state content increased.The traditional method of determining the applying sludge content just consider heavy metal type, and don’t pay close attention to the activity of existence because heavy metal form different soil environment to the influence of different size. This lab according to different forms of heavy metal environmental risk size into toxic sludge seems determined response coefficient compost, can exchange state toxic response coefficient for5, carbonate combination state response coefficient for toxic4, can also YuanTai toxic response coefficient of three, the oxidation state can be toxic response coefficient for2, scraps toxic response coefficient for the state1, hot dry sludge, composting sludge and lime dry sludge are under the control of the permission of4.93t/(hm2·a),6.01t/(hm2·a) and5.17t/(hm2·a). |
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