对当今城市污水处理厂污泥农肥化关键技术的研究
【摘要】 作为污水处理过程的副产品,城市污水处理厂污泥是包含水、泥沙、纤维及动植物残体等的复杂多相体系,含水率高(>98%),体积庞大,含有激素类物质(E1、E2等)、毒性有机物(苯、氯酚等)、重金属(Cd, Cr等)以及各种无机盐等污染物,这些污染物具有长期毒性和不可降解性,若无序排放,将成为危险的二次污染源,通过环境介质进入食物链,造成严重的生态风险,影响人类健康。同时,城市污泥中的有机质和有用元素含量高,是一类可利用性极高的二次资源。污泥堆肥后进行土地利用,是一种较好的资源化方式,也是未来污泥处理的主流发展方向。本研究以新加坡联合国祯水处理(辽阳)有限公司污泥为研究对象,通过堆肥化实验,系统探讨了利用污泥制备生物复合肥或土壤改良剂的可行性,在探讨好氧条件下堆体微生物学特征的基础上,初步获得了污泥好氧堆肥的基础性数据。具体内容如下：首先,自行设计了一套适合于小体积堆肥化处理的发酵装置,并设计了能够对堆肥发酵全过程进行分阶段、实时监测和调控的自控系统-CCS控制系统。对该实验平台进行了系统优化和参数修正。其次,研究了高温好氧发酵条件下,堆体含水率调整方式和堆肥调理剂筛选与添加方式,优化了堆肥营养配比参数,并通过对比实验,获得了堆肥过程的各项参数,对堆体温度、含水率、pH、电导率、挥发性固体、水溶性有机碳、氨态氮等指标的变化进行了动态监测。研究表明：室外通风晾晒,并与调理剂混合,有利于调整生污泥水分,促进堆肥顺利启动；锯末、稻壳及稻草秸秆三种调理剂的调理效果次序为锯末>稻草秸秆>稻壳,污泥、调理剂、回流污泥最佳混合比例为3：2：3。进而,利用堆肥产品进行种子发芽实验。通过与空白对照,计算了不同比例堆肥浸提液的发芽指数,分析了其对植物种子的毒性作用,研究了污泥堆肥的农田利用效果,并确定了本研究污泥堆肥适宜的施用量。最后,综合污泥堆肥产品的物理、化学及生物学指标,提出了一种判断污泥堆肥腐熟程度的方法。
【Abstract】 Sewage sludge is the byproduct of sewage treatment, with a lot of water, silt, fibers, residuals of animal and plant in it. Water content and volume of sewage sludge is high, also it contains hormones, toxic organics, heavy metals and different kinds of mineral wastes, all of which have a continuous toxicity. Once discharged wantonly it would enter the food chain easily and may cause serious secondary pollution to the environment and human beings. Whereas there are some organic and useful elements in sewage sludge and made it an available resource for secondary utilization. Land use after composting is a good choice of resource utilization and may be a main means of sludge disposal in the future.Thermophilic aerobic composting study is carried on based on the condition of the sludge from Liaoyang sewage treatment plant in order to find out whether the sludge can be used as biology compound fertilizer or soil amendment, and to achieve key technics of composting.First of all, the fermentation device and its control system are designed.Secondly, analysis the parameters such as temperature, water content, pH value, EC, VS, WSOC and NH4+-N of thermophilic aerobic composting process based on different humic content, different kinds of compost amendment and different adding ratios of the amendment. The investigation shows natural air-dried and then mixed with conditions is a better way of sludge dewatering. Among sawdust, rice husk and rice straw, after mixed with sawdust, the compost can achieve a better maturity, and the best adding http://www.51lunwen.org/nykj/2012/0301/lw201203010931274887.html ratio of sludge, sawdust and mature compost that returned is 3:2:3.Thirdly, evaluate the toxicity of the compost production of secondary fermentation according to the GI of comparative tests and try to find the best using quantity.At last, give the maturity determination of compost production based on the physical, chemical and biological indices.
【关键词】 城市污泥； 好氧堆肥； 水分调控； 调理剂； 腐熟度；
【Key words】 municipal sludge； aerobic composting； water content controlling； amendment； maturity index；
