- The composting of two kinds of advanced dewatered sludge cakes treated with bioleaching and chemical conditioning methods: A full-scale study
- 南京农业大学资源与环境科学学院, 南京 210095
- 南京农业大学资源与环境科学学院, 南京 210095
- 无锡新利环保生物科技有限公司, 无锡 214000
- 摘要：利用生物沥浸法和以添加石灰与三氯化铁为代表的化学法对污泥进行调理，继而采用隔膜厢式压滤机深度脱水是目前在我国应用较为广泛的工艺，但系统比较两种工艺所产生的污泥的堆肥效果的研究还很鲜见.为此，本试验分别对相同来源的污泥用两种方法进行调理后再用机械脱水，将获得的污泥饼进行工程化高温好氧堆肥，并以相同来源的常规脱水污泥（CS，指含水率80%左右的污泥）作为对照，探究其堆肥过程及产品性质的差异.结果表明，采用条垛式堆肥（条垛底宽2.8 m、高1.2 m、长10 m），生物沥浸污泥（BS）和石灰调理污泥（LS）堆肥所需辅料仅为CS的9.1%.尽管BS堆体中的NH4+-N含量始终最高，但其氨气挥发量仅为LS堆体的9.7%和CS堆体的31.4%.42 d时各堆体的CO2释放速率和水溶性C/N相比堆肥前均明显下降，说明堆体均已腐熟.LS堆肥产品的种子发芽指数（GI）仅为57.3%，而BS堆肥产品和CS堆肥产品的GI均为90%左右，显然后两者对种子的毒害已完全消除.此外，BS堆肥产品中的养分含量（N+P2O5+K2O）明显高于LS堆肥产品和CS堆肥产品，总养分分别高出28.5%和73.0%；其速效养分指标WSN亦分别高出40.6%和102%.综上所述，较之LS堆肥或CS堆肥，采用BS高温堆肥不仅可以显著减少辅料的添加量，且其堆肥过程中的氨气损失少，堆肥产品腐熟度好，养分含量高，因此，污泥生物沥浸处理-高温发酵技术是对推动堆肥后土地利用极有帮助的深度脱水工艺和资源化方法.
- Abstract：Bioleaching involving in A. ferrooxidans and chemical conditioning by jointly adding lime, FeCl3, and PAM have been widely adopted for improving sludge dewaterability in China. However, little information is available on the comparison of the composting as well as the compost product qualities of the advanced dewatered sludge cakes with moisture content of about 60% or below from two kinds of above-mentioned conditioning method. Here we reported the composting performance of bioleached sludge cake (BS) and lime conditioned dewatered sludge cake (LS) with comparison to conventional dewatered sludge cakes (CS). Three sludge cakes were collected from the same origin, with about 60% moisture for the first two sludges and 80% moisture for the last one. Three full-scale windrow composting with pile bottom width of 2.8 m, height of 1.2 m, and length of 10 m were performed for BS, LS, and CS in Wuxi Lucun Sludge Composting Plant, Wuxi City, Jiangsu Province, China. The results showed that the amount of bulking agent requirement in composting of BS and LS was only 9.1% of CS composting owing to much lower moisture content in the first two piles. Although the content of NH4+-N in BS pile was significantly and consistently higher than other two piles during the whole period, the cumulative ammonia volatilization in BS pile was unexpectedly about 9.7% and 31.4% of LS and CS piles, respectively. The temperature dynamics of piles and the lower CO2 production rate and water-soluble C/N ratio in three piles at day 42 of composting indicated that three composting products have become mature after 42 d composting. Moreover, the germination index (GI) of both of BS and CS compost products increased to 90%, but the GI of LS compost product merely reached 57.3%, implying the phytotoxicity of the latter wasn't yet eliminated completely. Furthermore, the total nutrient content (N+P2O5+K2O) and available N of BS compost product were obviously higher than the other two products, as exhibiting that total nutrient content of BS compost product was 28.5% and 73.0% higher than that of LS and CS compost products, respectively. Also, water-soluble N of BS product was 40.6% and 102% higher than LS and CS compost products, respectively. Therefore, BS compost is deserved to be widely applied because it has many advantages including reducing bulking agent amount drastically and improving the quality of composting products.