Effect of stocking density and food quality on the growth and fecundity of an epigeic earthworm (<Emphasis Type="Italic">Eisenia fetida</Emphasis>) during vermicomposting

Physico-chemical characteristics of the feed and optimum worm density are important parameters for the efficient working of a vermicomposting system. Overcrowding of worms can affect the efficiency of a vermicomposting system even if all other parameters have been optimized. This article reports the effect of stocking density and feed quality on the growth and fecundity of Eisenia fetida under laboratory conditions. The feed mixtures contained cow dung and textile mill wastewater sludge in different ratios. Three feed mixtures and five stocking rates (1, 2, 4, 8, and 12) were tested for 12 weeks. The results showed that E. fetida growth rate was faster at higher stocking densities; however, biomass gain per worm was faster at lower stocking densities. Sexual maturity was attained earlier at higher stocking densities. Growth rate was highest in 100% cow dung at all the stocking densities when compared to textile mill wastewater sludge containing feed mixtures. A worm population of 27–53 worms per kg of feed was found to be the most favorable stocking density.     

堆肥化过程中微生物群落的动态

通过变性梯度凝胶电泳（DGGE）和平板计数法对堆肥化过程中微生物的区系动态变化进行了研究.结果表明,在堆肥化过程中,微生物数量总的趋势是细菌的数量最多,放线菌次之,真菌的数量最少,中温微生物的数量始终高于高温微生物.当发酵结束后,中温微生物的数量低于发酵初始水平,高温放线菌和高温真菌的数量试验结束后高于初始水平,高温细菌的数量在整个堆肥化过程中变化不大.通过DGGE分析表明,发酵过程中细菌的种类发生了明显的更迭现象.发酵初期Bdellovibrio、Clostridia bacterium、Bacillus、Clostridium等占优势,中期Beta proteobacterium、Petrobacter succinimandens、Nitrospirae bacterium、Clostridium等占优势,后期Clostridium、Beta proteobacterium、Paenibacillus等占优势,而在整个堆肥化过程中Clostridium都是优势种.     

Production of vermifertilizer from guar gum industrial wastes by using composting earthworm <Emphasis Type="Italic">Perionyx sansibaricus</Emphasis> (Perrier)

Efforts have been made to convert the guar gum industrial waste into a value-added product, by employing a new earthworm species for vermicomposting e.g. Perionyx sansibaricus (Perrier) (Megascolecidae), under laboratory conditions. Industrial lignocellulosic waste was amended with other organic supplements (saw dust and cow dung); and three types of vermibeds were prepared: guar gum industrial waste + cow dung + saw dust in 40: 30: 30 ratio (T₁), guar gum industrial waste + cow dung + saw dust in 60: 20: 20 ratio (T_2,), and guar gum industrial waste + cow dung + saw dust in 75: 15: 10 ratio (T₃). As compared to initial concentrations, vermicomposts exhibited a decrease in organic C content (5.0–11.3%) and C:N ratio (11.1–24.4%) and an increase in total N (18.4–22.8%), available P (39.7–92.4%), and exchangeable K (9.4–19.7%) contents, after 150 days of vermicomposting. A vermicomposting coefficient (VC) was used to compare of vermicomposting with the experimental control (composting). P. sansibaricus exhibited maximum value of mean individual live weight (742.8 ± 21.1 mg), biomass gain (442.94 ± 21.8 mg), growth rate (2.95 ± 0.15 mg day⁻¹), cocoon numbers (96.0 ± 5.1) and reproduction rate (cocoons worm⁻¹ day⁻¹) (0.034 ± 0.001) in T₂ treatment. In T₃ maximum mortality (30.0 ± 4.01 %) in earthworm population was observed. Overall, T₂ vermibed appeared as an ideal substrate to manage guar gum industrial waste effectively. Vermicomposting can be proposed as a low-input basis technology to convert industrial waste into value-added biofertilizer.     

城市污泥堆肥过程中气温对堆体温度影响的模拟

在静态垛堆肥过程中,气温的变化会对堆体温度造成影响,这对堆肥过程中的堆体温度控制具有重要意义．但迄今为止,对此问题仍缺乏研究．本文引入小波分析方法对气温和堆体温度数据进行去噪和压缩处理,提取出气温波动引起的堆体温度波动信号,然后对气温波动信号和堆体温度波动信号进行分周期拟合,获得一一对应的振幅和相位差．结果表明,对于强制通风静态垛堆肥,气温波动对堆体下层（75cm）的影响最大,最大值为0．186℃,最小值为0．132℃,平均值为0．159℃;对中层（50cm）的影响最小,但随着堆肥进程的持续有增大的趋势;对上层（25cm）影响的最大值为0．105℃,最小值为0．065℃,平均值为0．085℃．从相位差上看,堆体中层（50cm）的相位差始终最大,在堆肥的降温期呈现明显减小的趋势;上层（25cm）的相位差随着堆肥进程的持续有明显增大的趋势;下层（75cm）的相位差在整个堆肥进程中呈缓慢升高的趋势．通过影响强度和相位差综合分析发现,堆体上层物料和下层物料在热量散失过程中可能存在两种不同的热交换机制,即上层物料以稳态热传导和自然对流为主,而下层物料则以非稳态热对流为主．     

城市污泥好氧堆肥物料平衡计算分析

根据好氧堆肥机理和物料平衡关系研究城市污泥好氧堆肥过程,给出了污泥预处理过程中若干平衡方程,可用这几个方程计算调节剂添加量等参数,还分别建立了好氧堆肥过程中固、液、气三相平衡关系的计算方程,有助于好氧堆肥工程的设计。     

Influence of cow-dung amendment on glyphosate mobility in soil

Abstract

Sorption and desorption characteristics of glyphosate on native soil and soil amended with cow dung were investigated. Sorption was pH dependent and decreased with increasing pH. Glyphosate partition coefficient ranged from 275 to 16,200?L kg^?1 in native soil, but for soil amended with cow dung it was significantly lower, viz 180–1530?L kg^?1. Glyphosate partition coefficient showed strong negative correlation with cation exchange capacity and positive correlation with surface area. Phosphate in cow dung suppressed glyphosate sorption and enhanced desorption. This study revealed that cow-dung addition to soil could raise the mobility of glyphosate towards groundwater contamination due to the presence of phosphate.     

KOH活化法制备牛粪活性炭的研究

以牛粪为原料,采用KOH活化法制备活性炭,并考察了浸渍比、活化剂浓度、活化时间和活化温度等不同制备条件对牛粪活性炭样品性能的影响.实验结果表明,在浸渍比1∶4、KOH质量分数35%、活化时间60min、活化温度700℃条件下制备的活性炭性能最佳,制得的活性炭比表面积为979.8m2·g-1,碘吸附值可达796.37mg·g-1,亚甲基蓝吸附值可达150.30mg·g-1.最后,将制备的牛粪活性炭应用于对Cr(Ⅵ)的吸附,研究了最佳工艺条件下制备的活性炭吸附Cr(Ⅵ)的适宜条件.结果表明,在投加量为8g·L-1时、吸附时间90min、pH值为5和较低温度的适宜条件下,自制牛粪活性炭对Cr(Ⅵ)的吸附量最大.     

冷凝水回流对堆肥腐熟度和污染气体排放影响

为探究堆肥过程中高温水蒸气携带的冷凝水回流对腐熟度及温室气体排放的影响,本文以猪粪和厨余垃圾为堆肥原料,在60L密闭好氧堆肥反应器中进行48d的高温好氧堆肥实验.结果表明,堆肥高温期产生的饱和水蒸汽因发酵罐封闭体系不能及时排出,会在发酵罐壁形成冷凝水回流入堆体中,整个堆肥过程冷凝水产率为物料湿重的18%.此外,回流冷凝水中主要成分为NH₄⁺-N(11.40g/L)、溶解性有机碳(6.3g/L)以及无机盐离子,具有较高的EC值(41.05mS/cm)和pH值(9.22),而较高的NH₄⁺-N含量使冷凝水回流处理的堆肥产品种子发芽指数(GI)略达到腐熟(71.4%),与排出处理相比GI下降了25.5%.同时,冷凝水回流使NH₃和CH₄排放量分别增加了55.2%的60.2%,但是CO₂和N₂O排放量分别降低了16.8%的34.8%.研究表明,冷凝水回流可降低17.8%总温室效应.本文建议堆肥过程将高温水蒸气冷凝排出,一...     

Influence of dissolved organic matter on methylmercury transformation during aerobic composting of municipal sewage sludge under different C/N ratios

Current knowledge about the transformation of total mercury and methylmercury (MeHg) in aerobic composting process is limited. In this study, the composition and transformation of mercury and dissovled organic matter (DOM) in aerobic composting process of municipal sewage sludge were were comprehensively characterized, and the differences among the three C/N ratio (20, 26 and 30) were investigated. The main form of mercury in C/N 20 and 26 was organo-chelated Hg (F3, 46%-60%); while the main form of mercury in C/N 30 was mercuric sulfide (F5, 64%-70%). The main component of DOM in C/N 20 and 26 were tyrosine-like substance (C1, 53%-76%) while the main fractions in C/N 30 were tyrosine-like substance (C1, 28%-37%) and fulvic-like substance (C2, 17%-39%). The mercury and DOM varied significantly during the 9 days composting process. Compared to C/N 20 and 26, C/N 30 produced the less MeHg after aerobic composting process, with values of 658% (C/N 20), 1400% (C/N 26) and 139% (C/N 30) of the initial, respectively. Meanwhile, C/N 30 produced the best compost showed greater degree of DOM molecular condensation and humification. Hg fraction had been altered by DOM, as indicated by a significant correlation between mercury species and DOM components. Notably, C/N 30 should be used as an appropriate C/N ratio to control the methylation processes of mercury and degration of DOM.     

污泥和鸡粪生物炭制备及其老化过程中的碳损失

生物炭具有高度的碳(C)稳定性,是一种良好的固碳材料.污泥富含无机矿物质,热解制备生物炭过程中其内源矿物会富集,影响固碳能力.在500、 600和700℃下制备市政污泥生物炭(SZB)、药厂污泥生物炭(YCB)和鸡粪生物炭(JFB),并模拟其在土壤中70～100 a老化过程,利用元素分析、傅里叶红外光谱(FTIR)、 X射线荧光光谱(XRF)、离子质谱仪(ICP)和X射线衍射(XRD)等分析手段,测定其理化性质并计算C损失.结果表明,热解过程中,生物炭内源矿物种类和质量分数决定生物炭C损失,其中Ca和Mg是主要的C保护矿物,而Fe的存在会降低生物炭C稳定性,增加C损失.老化过程中,生物炭C的自身稳定性对其C损失起主要作用,矿物起辅助作用.研究揭示了生物炭内源C和矿物组分对其C损失的影响规律,为利用污泥和鸡粪生物炭土壤固碳提供参考.