厌氧消化处理餐厨垃圾技术进展

结合了国内外餐厨垃圾厌氧消化的研究现状,主要介绍了餐厨垃圾的消化体系特点、添加剂、联合消化等工艺条件对餐厨垃圾厌氧消化的影响,旨在探讨更有效的餐厨垃圾厌氧消化工艺条件,实现餐厨垃圾减量化,从无害化转向资源化和能源化。     

循环经济模式下重庆市餐厨垃圾回收体系构建研究

随着人民生活水平的提高,生活节奏的加快,城市餐厨垃圾产生量也日益巨增,作为城市生活垃圾的重要组成部分,其餐厨垃圾的回收处置已经成为当前国内城市生活垃圾管理的重要课题。首先从餐厨垃圾的产生现状、收集现状、运输现状三方面分析重庆市餐厨垃圾处理存在的问题,其次,结合循环经济的理念及国内外餐厨垃圾的处理经验,构建政府建设—企业经营—产权转让的新型BOT餐厨垃圾回收模式,最后,对这种模式可能导致的经济行为进行情景假设分析,得出重庆市政府在BOT餐厨垃圾回收模式情景下,将更有利于美丽城市建设的结论。     

天津市餐厨垃圾回收现状与对策

餐厨垃圾是一种具有较高再生利用价值的资源,但是处置不当会给社会造成危害。天津市餐厨垃圾的回收包括规范化的再生资源回收企业回收、以养猪和炼制餐厨再生食用油为目的的非法回收商贩回收、城市普通生活垃圾收集处理系统回收等三种形式。以源头单独集中、清洁化单独收运、无害化处理和资源化利用为指导原则,开展城市餐厨垃圾的规范化回收符合发展循环经济的根本要求。从加强宣传教育、加大食用油监管力度、健全行政监管体系、完善餐厨垃圾规范化收集网络等角度,提出推动天津市餐厨垃圾回收规范化发展的对策。     

小型餐厨垃圾处理设备的应用研究

简要概述了餐厨垃圾的定义及其常规处理方法,介绍了小型餐厨垃圾处理设备的工艺流程和工作原理。此设备基于高温好氧发酵作用,主要利用微生物将餐厨垃圾中的有机物等分解,对过程中产生的废气利用生物+吸附联合净化,从而达标排放。通过对小型餐厨垃圾设备进行试验研究,结果表明,此设备的垃圾降解率约为80%,针对餐厨垃圾产生量小的场合较为适用。     

餐厨垃圾脱液预处理技术及装备设计

餐厨垃圾脱液预处理对餐厨垃圾的有效处置具有重要作用。利用螺旋挤压固-液分离技术对餐厨垃圾进行脱液处理研究,分析螺旋挤压过程中的影响因素对脱液过程的影响。对研究结果进行总结,设计一台用于处理餐厨垃圾的综合处理装备,并在样机设备上对实际餐厨垃圾进行螺旋挤压脱液处理,对比分析不同螺旋转速和物料状态对脱水过程的影响。实验研究结果和实际使用状况用于评价设备的使用效果。     

浅谈我国餐厨垃圾的回收与利用

随着我国经济发展及城镇化进程的加速,餐厨垃圾产生量近些年迅猛增长,餐厨垃圾的回收与资源化利用已成为解决城市环境问题的重要环节.对我国餐厨垃圾的回收与利用现状进行综述性分析,在此基础上提出了相应的对策和建议.     

浅谈上海市餐厨垃圾收运处置全程信息化监管设想及建议

针对当前实现餐厨垃圾全程监管的意义与必要性,结合餐厨垃圾产、收、运、处各环节特征,就目前尚在建设并试点的上海市餐厨垃圾收运处置全程信息化监管系统的构成、运行和技术手段等内容提出设想,并就未来信息化系统建设方向提出建议.     

城市餐厨垃圾资源化技术应用现状与展望

介绍了餐厨垃圾的主要特点,列举了国内外城市餐厨垃圾的处理现状和主要资源化利用技术,分析主要技术的优势和劣势,对主要技术综合环境效益、经济效益和能耗等方面进行比较,得出厌氧消化等综合处理工艺较适合用于处理城市餐厨垃圾的结论,最后就餐厨垃圾处理设施规划中3个关键问题,即技术设计、产品销路和物流供应作了相应讨论。     

发达国家餐厨垃圾回收利用经验及借鉴

介绍了发达国家回收处理和再利用餐厨垃圾的管理和技术,提出我国应借鉴发达国家经验,从技术、政策、法规等方面加强餐厨垃圾的再利用工作。     

餐厨垃圾对水稻秸秆中温两相厌氧发酵产酸和产气过程的影响

在发酵温度为35℃和原料干物质质量(TS计)固定的条件下,研究了餐厨垃圾的投加对水稻秸秆(稻秸)厌氧发酵过程中有机质溶出的影响。通过改变稻秸和餐厨垃圾的投加配比(TS/TS),寻求实验最优化参数,二者配比(TS/TS)为1∶0,0∶1,3∶1,4∶1,5∶1,同时研究了餐厨垃圾的加入对稻秸中温两相厌氧发酵系统运行及产气量的影响。结果表明:餐厨垃圾的存在对稻秸有机质的水解周期影响不大,但有利于提高稻秸酸化率和酸化速率。当稻秸与餐厨TS比为3∶1时,实验组酸化率高,单位TS的挥发性有机酸(VFA)溶出量为77.6 mg/g TS,纯稻秸组低,为42.0 mg/g TS。餐厨垃圾的投加还有利于产气时间的提前,且混合物料组系统的稳定性高于单一物料组。一次性投加方式产气量和相分离效果均优于其他各组,单位TS产气量为183.8 m L/g。     

Biodiesel from lignocellulosic biomass – Prospects and challenges

Biodiesel can be a potential alternative to petroleum diesel, but its high production cost has impeded its commercialization in most parts of the world. One of the main drivers for the generation and use of biodiesel is energy security, because this fuel can be produced from locally available resources, thereby reducing the dependence on imported oil. Many countries are now trying to produce biodiesel from plant or vegetable oils. However, the consumption of large amounts of vegetable oils for biodiesel production could result in a shortage in edible oils and cause food prices to soar. Alternatively, the use of animal fat, used frying oils, and waste oils from restaurants as feedstock could be a good strategy to reduce the cost. However, these limited resources might not meet the increasing demand for clean, renewable fuels. Therefore, recent research has been focused the use of residual materials as renewable feedstock in order to lower the cost of producing biodiesel. Microbial oils or single cell oils (SCOs), produced by oleaginous microorganisms have been studied as promising alternatives to vegetable or seed oils. Various types of agro-industrial residues have been suggested as prospective nutritional sources for microbial cultures. Since the most abundant residue from agricultural crops is lignocellulosic biomass (LCB), this byproduct has been given top-priority consideration as a source of biomass for producing biodiesel. But the biological transformation of lignocellulosic materials is complicated due to their crystalline structure. So, pretreatment is required before they can be converted into fermentable sugar. This article compares and scrutinizes the extent to which various microbes can accumulate high levels of lipids as functions of the starting materials and the fermentation conditions. Also, the obstacles associated with the use of LCB are described, along with a potentially viable approach for overcoming the obstacles that currently preclude the commercial production of biodiesel from agricultural biomass.     

Extrication of biodiesel feedstock from early stage of food waste liquefaction

Biodiesel is commonly produced from vegetable oils, mostly edible and more expensive than petroleum diesel. By considering the cost of the conversion processes, cheap feedstock such as triglycerides and fatty acids (FA) extracted from early stage of food waste liquefaction has become a better choice than vegetable oils, as it could provide high yield of biodiesel without any compromise to food supply and other resources. In this study, FA from early stage of food waste liquefaction was extracted and tested for use as feedstock for biodiesel synthesis. The raw material was not pretreated but extraction was done by dry and wet methods. It was found that wet method could minimized the lost of short and medium-chained FA as well as reducing the number of steps required, thus, yielding higher amount of FA as feedstock. The effects of mixing, methanol ratio, reaction time and catalyst content were investigated for the acid-catalyzed esterification. The maximum biodiesel conversion obtained was 97.4 %.     

Effect of mixing ratio of woody waste and food waste on the characteristics of carbonization residue

Biomass such as woody waste and food waste can be converted to a renewable energy source by means of carbonization processes. The basic characteristics of woody waste and food waste, such as proximate analysis and heating value, were evaluated before carrying out carbonization tests. Carbonization tests were carried out to obtain the basic characteristics of carbonization residue on changing the proportion of food waste from 0% to 30% in the mixture of woody waste and food waste. The effect of the food waste was estimated by basic characteristics of the residue such as the heating value, yield, and fuel ratio. As increased the food waste content, the bulk density, yield and chlorine content of the carbonization residue increased, but fuel ratio, the carbon content and heating value of the residue decreased. From the results of the basic characteristics of the residue, the optimum food waste content in carbonization tests was found to be 20%. Even if food waste is combined with woody waste at levels up to 30%, the sulfur and chlorine concentrations in the residue were much lower than the regulatory standard levels. From the results for the fuel ratio and heating value of the residue, the carbonization residue is suitable for use as a renewable energy source and can be categorized by the second grade level of solid fuel products.     

Bacterial Cellulose from Simple and Low Cost Production Media by Gluconacetobacter xylinus

Bacterial cellulose pellicles were produced by Gluconacetobacter xylinus using non conventional low-cost carbon sources, such as glycerol remaining from biodiesel production and grape bagasse, a residue of wine production. The carbon sources assayed showed their suitability for microbial cellulose production, with relatively high production values such as 10.0 g/l for the culture medium with glycerol from biodiesel as carbon source and corn steep liquor as nitrogen source; and 8.0 g/l for the culture medium containing grape bagasse and corn steep liquor. Glucose, commercial glycerol and cane molasses were also assayed as carbon sources for comparison. The bacterial celluloses produced were characterized by means of scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. Morphological analysis showed that bacterial cellulose microfibrils produced from the non-conventional media used were several micrometers long and had rectangular cross-sections with widths and thicknesses in the range of 35–70 and 13–24 nm, respectively. X-ray patterns showed crystallinity levels in the range of 74–79 % (area method), whereas both X-ray patterns and infrared spectroscopy evidenced the presence of peaks characteristic of Cellulose I polymorph. Besides thermal properties were similar to those found for the pellicle obtained from glucose. The study performed showed the suitability of using wine residues or glycerol remaining from increasing biodiesel production as cheap carbon sources for production of bacterial cellulose microfibrils, with similar characteristics as those obtained by use of more expensive carbon sources such as glucose or commercial glycerol. On the other hand, the low cost nitrogen sources used (corn steep liquor or diammonium phosphate) also contributed to the economy of the bioprocess.     

Recovery of different waste vegetable oils for biodiesel production: A pilot experience in Bahia State,Brazil

In Brazil, and mainly in the State of Bahia, crude vegetable oils are widely used in the preparation of food. Street stalls, restaurants and canteens make a great use of palm oil and soybean oil. There is also some use of castor oil, which is widely cultivated in the Sertão Region (within the State of Bahia), and widely applied in industry. This massive use in food preparation leads to a huge amount of waste oil of different types, which needs either to be properly disposed of, or recovered. At the Laboratorio Energia e Gas-LEN (Energy & Gas lab.) of the Universidade Federal da Bahia, a cycle of experiments were carried out to evaluate the recovery of waste oils for biodiesel production. The experiences were carried out on a laboratory scale and, in a semi-industrial pilot plant using waste oils of different qualities. In the transesterification process, applied waste vegetable oils were reacted with methanol with the support of a basic catalyst, such as NaOH or KOH. The conversion rate settled at between 81% and 85% (in weight). The most suitable molar ratio of waste oils to alcohol was 1:6, and the amount of catalyst required was 0.5% (of the weight of the incoming oil), in the case of NaOH, and 1%, in case of KOH.The quality of the biodiesel produced was tested to determine the final product quality. The parameters analyzed were the acid value, kinematic viscosity, monoglycerides, diglycerides, triglycerides, free glycerine, total glycerine, clearness; the conversion yield of the process was also evaluated.     

Bioconversion of dairy manure by black soldier fly (Diptera: Stratiomyidae) for biodiesel and sugar production

Modern dairies cause the accumulation of considerable quantity of dairy manure which is a potential hazard to the environment. Dairy manure can also act as a principal larval resource for many insects such as the black soldier fly, Hermetia illucens. The black soldier fly larvae (BSFL) are considered as a new biotechnology to convert dairy manure into biodiesel and sugar. BSFL are a common colonizer of large variety of decomposing organic material in temperate and tropical areas. Adults do not need to be fed, except to take water, and acquired enough nutrition during larval development for reproduction. Dairy manure treated by BSFL is an economical way in animal facilities. Grease could be extracted from BSFL by petroleum ether, and then be treated with a two-step method to produce biodiesel. The digested dairy manure was hydrolyzed into sugar. In this study, approximately 1248.6 g fresh dairy manure was converted into 273.4 g dry residue by 1200 BSFL in 21 days. Approximately 15.8 g of biodiesel was gained from 70.8 g dry BSFL, and 96.2 g sugar was obtained from the digested dairy manure. The residual dry BSFL after grease extraction can be used as protein feedstuff.     

Analyzing alternative bio-waste feedstocks for potential biodiesel production using time domain (TD)-NMR

Production of biodiesel is currently limited due to lack of economically beneficial feedstocks. Suitability of municipal wastewater sludge and olive mill waste as feedstocks for biodiesel production was evaluated. The various bio-waste sources were analyzed for their oil content and fatty acid composition using conventional analyses complemented with time domain (TD)-NMR analysis. TD-NMR, a rapid non-destructive method newly applied in this field, yielded good correlations with conventional methods. Overall biodiesel yields obtained by TD-NMR analysis were 7.05% and 9.18% (dry wt) for olive mill pomace and liquid wastes, and 11.92%, 7.07%, and 4.65% (dry wt) for primary, secondary, and anaerobically stabilized sludge, respectively. Fatty acid analysis indicated fundamental suitability of these agro-industrial waste resources for biodiesel production. Evaluation of bio-waste materials by TD-NMR revealed the potential of this tool to identify waste-oil sources cost effectively and quickly, supporting expansion of a sustainable biodiesel industry in Israel and other regions.     

Biodiesel production from waste frying oils and its quality control

The use of biodiesel as fuel from alternative sources has increased considerably over recent years, affording numerous environmental benefits. Biodiesel an alternative fuel for diesel engines is produced from renewable sources such as vegetable oils or animal fats. However, the high costs implicated in marketing biodiesel constitute a major obstacle. To this regard therefore, the use of waste frying oils (WFO) should produce a marked reduction in the cost of biodiesel due to the ready availability of WFO at a relatively low price.In the present study waste frying oils collected from several McDonald’s restaurants in Istanbul, were used to produce biodiesel. Biodiesel from WFO was prepared by means of three different transesterification processes: a one-step base-catalyzed, a two-step base-catalyzed and a two-step acid-catalyzed transesterification followed by base transesterification. No detailed previous studies providing information for a two-step acid-catalyzed transesterification followed by a base (CH₃ONa) transesterification are present in literature. Each reaction was allowed to take place with and without tetrahydrofuran added as a co-solvent. Following production, three different procedures; washing with distilled water, dry wash with magnesol and using ion-exchange resin were applied to purify biodiesel and the best outcome determined. The biodiesel obtained to verify compliance with the European Standard 14214 (EN 14214), which also corresponds to Turkish Biodiesel Standards.     

Performance and emission study of biodiesel from leather industry pre-fleshings

The possible use of pre-fleshing wastes from tanneries in the production of biodiesel fuel was examimed in our previous study in 2005. In this study, engine performance and emission values of biodiesel obtained from these wastes have been investigated and compared to petrodiesel fuel. The test results demonstrated that although the wheel force and power of biodiesel fuel is slightly lower than petrodiesel and the acceleration periods are accordingly longer, the emission values of hydrocarbons and particulate matter were found to be considerably lower with biodiesel. Thus, it has been shown that a waste byproduct can be utilized in the production of an environmentally friendly fuel, which can be used in some diesel engines without a need for major adjustment, providing economic and ecological benefits.