Measuring the environmental impact of waste flow management in Brazilian apartment buildings

As biodegradable material represents approximately 70% of household waste in Brazil, any strategy to divert appreciable waste quantities from landfills of necessity has to include valorization and recycling of this material. A societal change of attitude is required to perceive this challenge. Experiments in an urban apartment building are described that produced this change of attitude with a success factor of 80%. Divided waste collection was implemented that separated at the source biodegradable from inert material. Correct collection, handling and display procedures were established. Composting of biodegradable material was carried out under the rooftop of the building as an alternative to using it as animal feed. Half of the inert material entered the reverse logistics chain and was also diverted from the landfill. Waste related material flow through the building is completely quantified, food intake and waste production are related, diversion of both biodegradable and inert waste components from the landfill is measured and the composting process is described. The landfill diversion stands at 61%, mass reduction through the composting process is 80% and matured compost is returned to residents for use in flower cages. The system has been operational for two years and stands out as a precedent in successful decentralized household waste management supported by material flow analysis. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

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.     

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。     

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.     

添加剂对厨余垃圾堆肥中H_2S和NH_3排放的影响

以大类粗分后的厨余垃圾为研究对象,玉米秸秆作为调理剂,以不添加菌剂的处理作为对照(CK),以添加腐熟堆肥、鼠李糖脂和固体专用菌剂为3个处理,研究菌剂添加对厨余垃圾堆肥过程中H_2S和NH_3排放的影响。研究结果表明:菌剂添加促进了堆肥腐熟;添加腐熟堆肥更能有效地降低厨余垃圾堆肥过程中H_2S排放,而鼠李糖脂的添加更能有效控制NH_3的排放。从恶臭气体控制、堆肥腐熟并结合H_2S和NH_3的检知嗅阈,优选腐熟堆肥作为厨余垃圾堆肥过程中实现H_2S和NH_3同时减排的添加剂。     

磺胺抗性消长与堆肥进程的交互特征

基于添加和不添加磺胺药[m(磺胺二甲嘧啶SM2)∶m(磺胺-6-甲氧嘧啶SMM)=1∶1]的好氧堆肥试验,分析堆肥过程中鸡粪理化性质、微生物群落代谢特征、磺胺抗生素以及5种抗性基因变化,探明磺胺抗性消长与堆肥过程的交互特征.结果表明,磺胺药添加抑制了堆肥基础呼吸,延长了堆体达到高温的时间,减缓了养分转化速度,显著影响堆肥中期微生物群落结构特征.鸡粪中SMM和SM2在堆肥14 d内即可完全降解,且SMM降解速率高于SM2.随堆肥进行,sul1和sul2呈先下降后轻微回升的趋势,磺胺药添加对sul1和Int I1丰度无明显提高作用,但可促进sul2扩散.堆肥过程中,tet Q和tet W变化与磺胺抗性基因不同,但磺胺药添加亦增加tet Q和tet W相对丰度.冗余分析结果显示,温度与sul1、sul2和Int I1明显负相关,与tet Q和tet W无明显相关性;5种抗性基因相对丰度均与碳氮比和硝态氮含量负相关,与p H、含水率和铵态氮含量正相关.     

堆肥嗜热纤维素分解菌的筛选鉴定及其强化堆肥研究

对采集于农业堆肥高温期的微生物样品进行30d的高温驯化,驯化完成后从中筛选得到15株嗜热纤维素分解菌,经形态学特征、生理生化反应及16S rDNA序列同源性比对鉴定为:Bacillus sp3株,Paenibacillus sp1株,Bacillus licheniformis3株,Bacillus subtilis4株,Brevibacillus borstelensis1株,Bacillus coagulans3株.将筛选得到的菌种添加至高纤维素含量的堆体进行效果验证,结果表明添加嗜热纤维素分解菌对堆肥pH变化无显著影响,但可提高堆肥高温期温度、延长高温期并显著地降低堆肥产品的C/N和有机质含量,显著降低纤维素和半纤维素含量,加快堆肥腐熟.堆体有机质降解动力学结果表明,堆体接菌和不接菌处理的有机质最大降解度分别为62.5481%和61.7101%,速率常数分别为0.1250d-1和0.1051d-1,接菌处理的堆肥比对照堆肥提前6d达到稳定.研究表明,添加筛选的嗜热纤维素分解菌能缩短堆肥周期.     

不同来源生物质废弃物高温堆肥过程的物理化学及微生物性质研究

采用实验室小型堆肥系统对3种典型废弃物牛粪、食物残渣及污泥堆肥过程的物理化学及微生物特性进行了研究和比较.研究表明不同原料堆肥pH都能升到8以上,C/N在堆肥过程中有降低的趋势。不同水分调整材料稻秸(RS)、蛭石(V)、废纸(WP)及锯屑(SD)对堆肥过程的影响与不同堆肥原料相比要小的多.在3种不同原料中,食物残渣堆肥活性最高,14 d有机物降解率为47.2%～56.8%,代表微生物量的醌含量在堆肥后期可增加到359.7～472.3 μmol·kg^-1,但微生物群体的多样性较低,醌多样性指数DQ在堆肥后期增加到6.1～6.7.牛粪堆肥只在初始阶段活性较高,之后很快降低,其醌含量较低.在堆肥中期达到最大值为36.3～117.0 μmol·kg^-1,醌多样性指数DQ初始期为10.3～12.8,堆肥过程中逐渐升高至后期达18.1～22.7.污泥堆肥的各项特性介于食物残渣和牛粪之间.堆肥过程的不同主要是由于原料中各种有机成分的不同而导致.根据研究结果提出了对堆肥过程进行合理控制的建议.