Methanogenic granular sludge formation in an upflow anaerobic sludge blanket reactir treating synthetic methanolic waste

A laboratory upflow anaerobic sludge blanket reactor, seeded with fine, suspended, bacterial floc with 1.76 g volatile suspended solids/l, was used to treat synthetic methanolic waste. After 180 days of continuous peration, granular sludge with discrete granules of 1 to 2 mm diam. was formed, with 52 g volatile suspended solids/l. Granules were brown, relatively soft and had a settling velocity of 1.61 cm/s. Extracellular polymeric matter extracted from the granular sludge had high carbohydrate content but low nucleic acid content. The ash of the granular sludge contained Na⁺, K⁺ and Mg²⁺ up to 15.0, 11.7 and 3.75 mg/g, respectively. Scanning and transmission electron microscopy revealed that the granular sludge was dominated by methanogens resembling Methanosarcina.The authors are with the Department of Environmental Engineering, Faculty of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565, Japan     

Cultivation of oyster mushrooms (<Emphasis Type="Italic">Pleurotus</Emphasis> spp.) on various lignocellulosic wastes

Cultivation of speciality mushrooms on lignocellulosic wastes represents one of the most economically and cost-effective organic recycling processes. Three species of Pleurotus, namely P. columbinus, P. sajor-caju and P. ostreatus were experimentally evaluated on untreated organic wastes including chopped office papers, cardboard, sawdust and plant fibres. Production studies were carried out in polyethylene bags of about 1 kg wet weight with 5% spawning rates of substrate fresh weight in a custom-made growth room especially designed for spawn run and cropping. The conversion percentage from dry substrate weight to fresh mushroom weight (biological efficiency) was determined. The highest biological efficiency was noted with P. columbinuson cardboard (134.5%) and paper (100.8%), whereas P. ostreatus produced maximum yield on cardboard (117.5%) followed by paper (112.4%). The overall yield of P. sajor-cajuwas comparatively low (range 47–78.4%). The average number of sporophore flushings ranged between 5 and 6 times. The findings that P. columbinus and P. ostreatus are superior to P. sajor-caju are consistent with previous reports elsewhere. Further evaluation of P. columbinus alone on different bagging systems containing partially pasteurized office papers as a growing substrate revealed that polyethylene bags resulted in 109.4% biological efficiency in contrast to pottery (86%), plastic trays (72%) or polyester net (56%). The above findings reveal an opportunity for commercial implication of oyster mushroom especially P. columbinus for utilization of different feasible and cheap recyclable residues.     

Synergetic effect of pH and biochemical components on bacterial diversity during mesophilic anaerobic fermentation of biomass-origin waste

Aims: To investigate the synergetic effect of pH and biochemical components on bacterial community structure during mesophilic anaerobic degradation of solid wastes with different origins, and under acidic or neutral conditions. Methods and Results: The bacterial community in 16 samples of solid wastes with different biochemical compositions and origins was evaluated during mesophilic anaerobic degradation at acidic and neutral pH. Denaturing gradient gel electrophoresis (DGGE) and single‐strand conformation polymorphism (SSCP) were used to compare the communities. Multivariate analysis of the DGGE and SSCP results revealed that most of the dominant microbes were dependent on the content of easily degradable carbohydrates in the samples. Furthermore, the dominant microbes were divided into two types, those that preferred an acid environment and those that preferred a neutral environment. A shift in pH was found to change their preference for medium substrates. Although most of the substrates with similar origin and biochemical composition had similar microbial diversity during fermentation, some microbes were found only in substrates with specific origins. For example, two microbes were only found in substrate that contained lignocellulose and animal protein without starch. These microbes were related to micro‐organisms that are found in swine manure, as well as in other intestinal or oral niches. In addition, the distribution of fermentation products was less sensitive to the changes in pH and biochemical components than the microbial community. Conclusions: Bacterial diversity during anaerobic degradation of organic wastes was affected by both pH and biochemical components; however, pH exerted a greater effect. Significance and Impact of the Study: The results of this study reveal that control of pH may be an effective method to produce a stable bacterial community and relatively similar product distribution during anaerobic digestion of waste, regardless of variation in the waste feedstocks.     

Factors in the determination of methanogenic potential of manure

The influence of the substrate concentration, the micro and macro nutrients and buffer requirements, the sludge origin (biomass that is acclimatized or not acclimatized to waste) and the inoculum/substrate ratio (ISR) were studied to determine their effects in the methanogenic potential of turkey manure, which is a solid waste. According to the results obtained, the methane production determination does not require the addition of nutrients (additional to the contents in the waste) and a buffer for this type of assay. The methane yield (Y_CH4) performance is given by the substrate concentration and the sludge origin, therefore it is better to carry out the assay with biomass that is already adapted to the waste. The methanogenic potential of this type of waste is not determined by the amount of sludge and it does not need an external inoculum (external to the waste contents).     

Comparison of methods for total community DNA extraction and purification from compost

The differences on DNA yield and purity of three different DNA extraction protocols were compared with regard to the use for PCR and other molecular analyses. Total DNA was extracted from compost by the three protocols, and then was purified by spin-bind cartridges after being precipitated by PEG8000. The detection performed on a nucleic acid and protein analyzer showed that all three methods produced high DNA yields. The agarose gel electrophoresis showed that the fragments of crude and purified DNA had a length of about 23 kb. A eubacterial 16S rRNA gene-targeted primer pair was used for PCR amplification, and full length 16S rDNAs were amplified from all the purified DNA samples. After being digested by restriction endonucleases, the restriction map of amplified rDNA showed identical genetic diversity. The products of PCR using primer pair GC341F and 907R were also used for denaturing gradient gel electrophoresis analysis. The results indicated that high-quality DNA was extracted from compost by the three protocols, and each of the protocols is adapted to extract microbial genome DNA from compost expediently and cheaply.     

Comparison of Different Standard Methods to Evaluate the Total Concentrations of Heavy Metals in Waste Rock

The mining industry is a very rapidly increasing production sector in Finland. Many new mines have been opened recently and others are in the planning phase. Mining legislation has been recently revised and compilation of an ID-directive (Industrial Emission Directive, 2010) required to implement environmental law revision is in progress. The aim of this study was to compare different digestion methods recommended by the Finnish Environmental Administration for threshold and guideline value determinations in the Finnish PIMA Decree (214/2007) and Government Decree (591/2006) concerning recovery of certain wastes in earth construction. Altogether six methods were tested, of which five were microwave-assisted acid digestion methods: ISO 11466, EPA Method 3051A (aqua region), EPA Method 3051A (HNO₃), EPA Method 3051A (HNO₃/HCl), and SFS-EN 13656, while one was a fusion method with lithium tetraborate (ASTM C 1391 - 95). The results showed that concentrations of heavy metals (As, Cd, Co, Cu, Ni, Pb, Sb, V, and Zn) can be determined reproducibly with standard methods, but the chemical method used can have a significant impact on the results. This conclusion is very important, because the measured heavy metal values can affect the classification and processing of waste materials, and thereby can significantly impact the cost of treatment.     

餐厨垃圾高温好氧生物减量菌种的筛选及特性

【背景】随着餐厨垃圾产生量的逐步提高,如何实现其快速降解,成为餐厨垃圾处理亟待解决的问题。餐厨垃圾的高温好氧生物减量技术是一种可以快速降解餐厨垃圾的有效方法。【目的】筛选能够适应餐厨垃圾环境且具有高效降解餐厨垃圾中有机物能力的菌株,以提高餐厨垃圾的降解效率和减量效果。【方法】采用温度梯度耐受性实验和餐厨垃圾浸出液高油高盐耐受性实验进行菌种初筛,并利用产酶培养基复筛及餐厨垃圾生物减量实验验证。【结果】通过初筛、复筛和功能验证,最终获得4株生物减量效果优良的菌株N3-1、C7、N3-3和G6-1,其对餐厨垃圾挥发性固体(volatile solid,VS)的降解率分别为36.95%、33.23%、32.83%和31.91%,是对照组的3.02、2.71、2.68和2.61倍。经鉴定,这4株菌分别属于热嗜油地芽孢杆菌(Geobacillus thermoleovorans)、史氏芽孢杆菌(Bacillus smithii)、热解木糖地芽孢杆菌(Geobacillus caldoxylosilyticus)和立陶宛地芽孢杆菌(Geobacillus lituanicus)。【结论】筛选出的4株菌均具有较强的餐厨垃圾原料适应性和高效的生物降解能力,为开发餐厨垃圾高温好氧复合菌剂奠定了基础,并为实现餐厨垃圾减量化、无害化处理和资源化利用提供了技术支持。     

Implementing Extended Producer Responsibility Legislation

The goal of this article is to contribute to the understanding of how the multiple, and sometimes conflicting, stakeholder perspectives and prevailing conditions (economic, geographic, etc.) in the implementation locality shape extended producer responsibility (EPR) “on the ground.” We provide an in‐depth examination of the implementation dimension of EPR in a specific case study by examining concrete activities at the operational front of the collection and recycling system, and probing the varying stakeholder preferences that have driven a specific system to its status quo. To this end, we conduct a detailed case study of the Washington State EPR implementation for electronic waste. We provide an overview of various stakeholder perspectives and their implications for the attainment of EPR policy objectives in practice. These findings shed light on the intrinsic complexity of EPR implementation. We conclude with recommendations on how to achieve effective and efficient EPR implementation, including improving design incentives, incorporating reuse and refurbishing, expanding product scope, managing downstream material flows, and promoting operational efficiency via fair cost allocation design.     

Strategies for PHA production by mixed cultures and renewable waste materials

Production of polyhydroxyalkanoates (PHA) by mixed cultures has been widely studied in the last decade. Storage of PHA by mixed microbial cultures occurs under transient conditions of carbon or oxygen availability, known respectively as aerobic dynamic feeding and anaerobic/aerobic process. In these processes, PHA-accumulating organisms, which are quite diverse in terms of phenotype, are selected by the dynamic operating conditions imposed to the reactor. The stability of these processes during long-time operation and the similarity of the polymer physical/chemical properties to the one produced by pure cultures were demonstrated. This process could be implemented at industrial scale, providing that some technological aspects are solved. This review summarizes the relevant research carried out with mixed cultures for PHA production, with main focus on the use of wastes or industrial surplus as feedstocks. Basic concepts, regarding the metabolism and microbiology, and technological approaches, with emphasis on the kind of feedstock and reactor operating conditions for culture selection and PHA accumulation, are described. Challenges for the process optimization are also discussed.     

不同填埋工艺对填埋气产生动态变化的影响

依据厌氧、准好氧填埋原理构建了填埋试验装置,对准好氧填埋CH₄、O₂浓度的动态变化进行了监测,并与厌氧填埋结构CH₄的浓度变化进行了比较.结果表明,准好氧填埋方式下、厌氧填埋方式下CH₄的平均浓度变化范围分别为7%～13%、35%～50%;准好氧填埋结构有利于减少CH₄气体的产生;CH₄浓度在准好氧填埋、厌氧填埋方式下都表现出明显的空间层次效应,呈现出下层>中层>上层的规律性;准好氧填埋结构的O₂浓度呈现上层>中层>下层的规律性.