Quantitative analysis of microbial biomass yield in aerobic bioreactor

We have studied the integrated model of reaction rate equations with thermal energy balance in aerobic bioreactor for food waste decomposition and showed that the integrated model has the capability both of monitoring microbial activity in real time and of analyzing biodegradation kinetics and thermal-hydrodynamic properties. On the other hand, concerning microbial metabolism, it was known that balancing catabolic reactions with anabolic reactions in terms of energy and electron flow provides stoichiometric metabolic reactions and enables the estimation of microbial biomass yield (stoichiometric reaction model). We have studied a method for estimating real-time microbial biomass yield in the bioreactor during food waste decomposition by combining the integrated model with the stoichiometric reaction model. As a result, it was found that the time course of microbial biomass yield in the bioreactor during decomposition can be evaluated using the operational data of the bioreactor (weight of input food waste and bed temperature) by the combined model. The combined model can be applied to manage a food waste decomposition not only for controlling system operation to keep microbial activity stable, but also for producing value-added products such as compost on optimum condition.     

Integrated model of reaction rate equations and thermal energy balance in aerobic bioreactor for food waste decomposition

The integrated model is composed of two basic parts: one is a reaction rate model of biodegradation in combination with bioenergetics and the other is a thermal engineering model of energy flow and balance in the bioreactor. Integrating these models provides possibility to estimate microbial activity using time course of physicochemical parameters such as bed temperature, bed weight, and/or C0₂ concentration during decomposition.     

Influence of biomass density and food to microorganisms ratio on the mixed culture type I methanotrophs enriched from activated sludge

Methanotrophic based process can be the remedy to offset the wastewater treatment facilities increasing energy requirements due to methanotroph's unique ability to integrate methane assimilation with multiple biotechnological applications like biological nitrogen removal and methanol production. Regardless of the methanotrophic process end product, the challenge to maintain stable microbial growth in the methanotrophs cultivation bioreactor at higher cell densities is one of the major obstacles facing the process upscaling. Therefore, a series of consecutive batch tests were performed to attentively investigate the biomass density influence on type I methanotrophs bacterial growth. In addition, food to microorganisms(F/M), carbon to nitrogen(C/N) and nitrogen to microorganisms(N/M) ratio effect on the microbial activity was studied for the first time. It was clarified that the F/M ratio is the most influencing factor on the microbial growth at higher biomass densities rather than the biomass density increase, whereas C/N and N/M ratio change, while using nitrate as the nitrogen source,does not influence methanotrophs microbial growth. These study results would facilitate the scaling up of methanotrophic based biotechnology by identifying that F/M ratio as the key parameter that influences methanotrophs cultivation at high biomass densities.     

厨余垃圾厌氧消化处理难点及调控策略分析

厨余垃圾产量大、有机物含量高、营养元素丰富,对其进行适当处理后资源化利用是厨余垃圾处理的发展方向。厌氧消化可实现生物质能的高效利用,是厨余垃圾资源化、无害化处理的主要方法之一。提升餐厨垃圾厌氧消化效率获得清洁能源及对消化产物的综合利用是目前研究的热点。介绍了厨余垃圾的基本特性、厌氧消化的机理,总结厨余垃圾厌氧消化各阶段面临的问题,分析对应的国内外调控策略的优缺点及研究进展,并对今后厨余垃圾厌氧消化的调控新策略及产物再利用进行展望。     

大庆市餐厨垃圾现状及处理技术探讨研究

在生活中,我们每个人每一天都会制造很多的生活垃圾,其中包括餐厨垃圾,它主要包括厨余和泔脚,二者的化学组成、物料结构以及初始微生物量均存在差异,并且餐厨垃圾会对人们的身体健康造成严重的影响,同时餐厨垃圾的乱倒乱扔,对于市容环境也存在一定的影响,严重时会影响到当地的生态平衡。本文对大庆市餐厨垃圾的来源、产生量、物理特征以及处理现状进行了认真的研究与分析,提出了适合大庆市市情的措施与对策,以实现餐厨垃圾的无害化、减量化和资源化。     

餐厨垃圾厌氧处理“碳中和”综合效益评价

为综合评估餐厨垃圾厌氧处理的环境影响与效益,对某餐厨垃圾厌氧处理工艺及其技术单元进行生命周期环境影响评价,并建立“碳中和”计算模型预测与验证实际碳排及耗能情况,综合“环境影响-碳排耗能-经济效益-社会效益”对实际案例进行评估.结果表明,沼肥加工和沼气提纯技术单元分别造成39%和59%总环境影响.另外,粗油提炼、沼气提纯以生物基产品回收形式大幅度削减碳排,分别占理论碳削减的9.7%和54.7%.餐厨垃圾处理厂需通过增加系统稳定性、完善气体监测体系、提高技术处理效率和优化设备额外耗能情况等方式,以减少理论与实际碳排能耗偏差.经综合评价,该餐厨垃圾处理厂模式具备实现“负碳”潜力,其工艺推广具有未来前景.     

微生物菌剂对堆肥功能微生物重构的影响

堆肥产品不仅可以作为有机肥或土壤改良剂,还可以在包气带土层防护地下水污染的过程中起到微生物载体的作用.在堆肥中接种菌剂能够加速堆肥进程,促进堆肥材料的腐熟,但是也有研究认为接种剂与堆肥土著微生物的竞争会导致菌剂无法发挥作用.为了阐明菌剂与土著微生物之间的相互作用,采用宏蛋白质组学方法,分析餐厨垃圾堆肥接菌组（木质纤维素混合菌剂）和对照组（未接菌）中功能微生物群落和碳水化合物代谢途径的变化.结果表明:接菌组中假单胞菌目（Pseudomonadales）和散囊菌纲（Eurotiomycetes）菌群的相对丰度比对照组分别提高了12.5%和22.0%,成为优势细菌和真菌,二者在碳水化合物代谢活性上也成为优势菌群.菌剂主要是由芽孢杆菌目（Bacillales）和散囊菌纲的曲霉（Aspergillus）组成,曲霉因具有堆肥系统所需的木质纤维素分解能力而成为优势真菌,而菌剂中的芽孢杆菌虽然数量较多,但是缺乏堆肥系统所需的功能而无法成为优势细菌.餐厨垃圾中易降解物质分解过程中产生的有机酸会导致酸性环境,对照组中能够适应酸性环境的芽孢杆菌目和酵母菌纲（Saccharomycetes）是优势群落,添加菌剂后,堆肥系统中土著的假单胞菌目和散囊菌纲具有较高的碳水化合物代谢活性和多种有机酸转化通路,因此在与菌剂中的芽孢杆菌目和土著的芽孢杆菌及酵母菌的竞争中成为优势菌群.研究显示,外源菌剂与土著微生物之间以及各土著微生物之间都会发生竞争作用,能否成为优势菌群取决于是否适应堆肥底物新陈代谢的变化,因此只要选择好菌剂的功能和接种时机,菌剂就能够发挥原有的作用.      

ANAMMOX流化床反应器性能的研究

直接以氨为电子供体的反硝化反应是一种新的生物反应，可实现对两种氮素污染物的同时去除．探索了用流化床反应器开发这一反应，以处理厌氧消化污泥压滤液的可行性．试验发现，用该技术处理，无需供氧，也无需中和，并可有效地避免基质的抑制作用；平均氨和亚硝酸容积负荷率为４２８８３和４６４９１ｍｇ／（Ｌ·ｄ），平均氨和亚硝酸去除率为８８４９％和９９０４％；由于ＡＮＡＭＭＯＸ混培物产率较低，需要较长的ＳＲＴ（＞１００ｄ），有必要进一步研究ＡＮＡＭＭＯＸ混培物的生长条件，以保证ＡＮＡＭＭＯＸ反应器长期稳定运行．     

SBR系统中投加三氯化铁辅助除磷试验研究

文章研究了向SBR系统中投加混凝剂三氯化铁对活性污泥系统的影响。试验结果表明:投加三氯化铁辅助除磷效果较好,但对COD和氮的去除有不利影响,且随投加期延长,不利影响加剧。PLFAs法测定结果证实了三氯化铁对活性污泥中微生物产生了毒害作用,污泥微生物群落的总生物量减少,但微生物群落结构基本没变化。     

基于厌氧膜生物反应器的剩余污泥-餐厨垃圾厌氧共消化性能

采用厌氧膜生物反应器(anaerobic membrane bioreactor,AnMBR)进行剩余污泥与餐厨垃圾的共消化,研究其有机物的去除特性、产气性能和微生物群落组成等运行性能.结果表明,反应器运行过程中有机负荷(organic loading rate,OLR,以VS计)稳定在0.59～0.64 kg·(m~3·d)~(-1),挥发性固体(volatile solids,VS)降解率由单消化17.5%上升至共消化40%,COD截留率为95.3%.消化液含固率提高了3.9倍,最终CH_4体积分数稳定在60%,CH_4产量(以COD_(added)计)为78.7 mL·g~(-1).跨膜压差(transmembrane pressure,TMP)和平均Flux分别维持在-3.1～-2.7 kPa和0.106 L·(m~2·h)~(-1),膜污染较轻.16S rRNA微生物多样性分析表明,AnMBR内部厌氧消化细菌主要是Proteobacteria(变形菌门)、Bacteroidetes(拟杆菌门)和Cloacimonetes(阴沟单胞菌门),产甲烷菌中的优势菌科为Methanobacterium(甲烷杆菌科),优势菌属为Methanosaeta(甲烷鬃毛菌属)和Methanolinea(甲烷绳菌属).这将为AnMBR处理污泥及其它高含固率废物流的稳定性和运行性能研究提供有力的理论参考依据,进而为生物质资源化和能源危机提供有效解决途径.     

餐厨垃圾的黑水虻处理中含钙矿物及微生物对油脂转化效率的影响

黑水虻处理是近年来发展起来的一种餐厨垃圾的有效资源化方法,但由于黑水虻的生理特性,油脂类物质经常不能被彻底降解和去除,残渣仍有酸败气味,需堆肥化二次处理.为了提高油脂类成分的降解效率,提升黑水虻富集油脂的资源化能力,本研究拟以含钙矿物和微生物为主要辅助手段,通过向餐厨垃圾中添加湿重比例为0~10%的CaCO₃、0~10%的Ca(OH)₂、5%CaCO₃和菌液的混合物及6种不同菌液,研究含钙矿物和微生物对于油脂减量化和虫油转化效率的影响.结果发现,向餐厨垃圾中添加含钙矿物,能够显著调节和缓冲黑水虻处理过程中的环境pH值,但对增加油脂的去除效率和黑水虻油脂的转化能力没有显著作用.而且添加7%~10% 的CaCO₃对于餐厨垃圾的减量化率和黑水虻的虫产率有负作用,添加5%~10%的Ca(OH)₂会导致显著的幼虫死亡率.同时添加CaCO₃和菌液对于油脂的去除不利.仅添加微生物菌液是提高垃圾油脂减量化率和黑水虻油脂富集率的最有效方法.枯草芽孢杆菌NJZ菌株、地衣芽孢杆菌NY菌株、植物乳酸杆菌RS72菌株和粪肠球菌L102菌株,是提高黑水虻油脂转化效率的有效菌株.添加微生物后,黑水虻的虫油产率由对照组的10.4%提升至12.8%~14.4%,虫油富集率由对照组的93.9%提升至116%~130%.虫油富集率超过100%,说明餐厨垃圾中碳水化合物、蛋白质等非油脂成分的一部分转化为黑水虻的体脂,而微生物的辅助降解可能是强化这一过程的主要因素.但即使在接种微生物以后,虫沙中仍然有29%~44%的油脂在处理结束时剩余,说明餐厨垃圾中的油脂较难被彻底降解和利用.未来研究中,可以继续筛选高效降解油脂的微生物,与黑水虻共同处理餐厨垃圾,实现油脂成分的资源化全利用.     

蒸汽爆破对污泥和餐厨垃圾联合厌氧消化的促进效果

鉴于蒸汽爆破（简称"汽爆"）预处理对污泥和餐厨垃圾联合厌氧消化的影响还鲜有报道,为探讨汽爆预处理对污泥和餐厨垃圾联合中温厌氧消化的促进效果及经济可行性,利用小型发酵罐在35℃下开展了未预处理污泥和餐厨垃圾联合消化、汽爆污泥单独消化、汽爆污泥和餐厨垃圾联合消化的试验,并进行能耗分析.结果表明,未预处理污泥与餐厨垃圾联合消化阶段,VS（挥发性固体）去除率为33.9%,沼气产率为311.0 mL/g（以投料VS计）;汽爆污泥单独消化阶段,VS去除率和沼气产率均略高于未预处理污泥与餐厨垃圾联合消化阶段,但反应器ρ（NH₄+-N）过高,影响产气稳定性,沼气φ（CH₄）较低.汽爆污泥与餐厨垃圾联合消化阶段,VS去除率和沼气产率分别达到49.5%和420.5 mL/g,显著优于未预处理联合消化阶段.能耗分析表明,预处理的升温过程使汽爆预处理整体能耗偏高,但若能有效回收70%的热量,则汽爆预处理可提高污泥-餐厨垃圾联合中温厌氧消化工艺3.34 kW·h/t（以污泥量计）的能量产率.研究显示,汽爆预处理可提高污泥和餐厨垃圾联合中温厌氧消化工艺35.2%的沼气产率,但由于预处理能耗较高,预处理过程中热能的有效回收是汽爆预处理应用于污泥和餐厨垃圾联合中温厌氧消化经济可行的关键.      

生物反应器填埋条件下垃圾生物质组分的初期降解规律

在经甲烷化填埋层渗滤后的渗滤液循环回灌的新鲜垃圾填埋层内,以生物质分类表征为基础,分析了新鲜垃圾填埋层内固相各生物质组分（总糖、蛋白质、脂肪、纤维素和木质素）的初期降解规律.结果表明,垃圾中原有总糖组分和蛋白质的快速水解发酵是新鲜垃圾填埋后产生高有机质浓度渗滤液的主要机制;脂肪和纤维素的降解产物不是填埋初期高有机质浓度渗滤液的主要来源;纤维素是填埋层稳定产甲烷阶段的主要碳源,其水解速率可能是甲烷化过程的限速步骤;纤维素/木质素之质量比可作为指示填埋垃圾稳定化的指标.各生物质组分的初期降解速率常数均在0.01至0.1之间,而填埋气体中甲烷体积分数在60d内达到45%.食品垃圾组分富集的生活垃圾,应用生物反应器填埋技术时,必须具备足够的降解容量以代谢填埋初期固相中总糖和蛋白质快速水解产生的酸性液相产物.     

生物质能利用技术-厌氧消化技术的研究新进展

厌氧消化技术是最重要的生物质能利用技术之一。厌氧消化技术是实现废物污染防治和能源回收利用的有效方法。本文综述了厌氧消化技术利用生物质废物回收利用生物质能的最新研究进展,分别介绍了生物质废物厌氧发酵产乳酸,氢气和甲烷的机理,研究现状和存在的问题,并对其进一步发展和未来的应用前景进行了分析和展望,为寻找适合中国的垃圾处理技术提供一些参考。     

微生物燃料电池中底物的研究进展

微生物燃料电池是一种利用可溶性有机废物和可再生生物质等原料萃取电能的装置,而底物作为能量转化的能源物质,是影响 微生物燃料电池产电能力的重要因素之一.能够充当底物的有机质种类十分丰富,如多种低浓度有机废水和纤维素等,底物的种类不同,电池的产电能力也会存在差异.因此,有必要对这一系统中底物对电池产电性能及其他方面的影响进...     

我国餐饮废水处理技术研究进展

综合论述了我国餐饮废水的特点及处理现状,介绍了SBR法、生物接触氧化法、厌氧-好氧联合工艺法、膜生物反应器法、混凝法、电化学法处理餐饮废水的技术及适用条件.比较了各种处理技术的优势和不足,预测了我国餐饮废水处理的发展趋势.并认为,集除油、降解有机悬浮物于一体的餐饮废水一体化处理设备将会得到广泛应用,而针对餐饮废水特点培养出高效生物菌种的复合生物技术将是治理餐饮废水的最有效方法.     

堆肥反应器中2种微生物接种剂的堆肥效果研究

在严格控制堆肥条件的情况下,以鸡粪为堆肥基本原料,选用单一微生物巨大芽孢杆菌和复合微生物VT菌为接种剂,通过研究堆肥过程中的温度、氧气浓度、C/N、WSC(水溶性碳)、发芽指数(GI)以及脱氢酶和纤维素酶的活性动态变化来反映这2种微生物接种剂对堆肥效果的影响.结果表明,接种复合微生物菌剂VT的处理在堆肥升温和保持高温效果明显,接种微生物菌剂的2个处理的堆体内氧气浓度都较CK低,其中最低的为接种复合微生物菌剂VT的处理.接种微生物菌剂,C/N下降速度快,WSC浓度相对高,GI值上升速度明显加快,有利于加快堆肥腐熟进程,其中接种复合微生物菌剂VT的效果较单一微生物菌剂巨大芽孢杆菌好.接种微生物菌剂有利于堆肥升温期脱氢酶和纤维素酶活性增加,促进堆肥的氧化还原反应和纤维素的分解,且接种复合微生物VT的效果明显.     

Optimizing food waste hydrothermal parameters to reduce Maillard reaction and increase volatile fatty acid production

The occurrence of the Maillard reaction and melanoidins formation during the hydrothermal treatment of food waste can reduce the yield of volatile fatty acids (VFA); however, few studies have investigated the adverse effects of the Maillard reaction. This study identified the impact of hydrothermal treatment parameters on hydrolysis and melanoidins formation and optimized the hydrothermal treatment conditions to enhance VFA production by minimizing the impact of the Maillard reaction. A response surface methodology was employed to optimize the hydrothermal treatment parameters and VFA production was evaluated. Results showed that temperature, reaction time, and pH were significant interacting factors with respect to hydrolysis and melanoidins formation while the C/N ratio and moisture content of food waste had little impact. The optimal conditions for hydrothermal treatment (temperature of 132 °C, reaction time of 27 min, and a pH of 5.6) enhanced VFA production by 22.1%. Under optimal hydrothermal treatment conditions, a higher initial C/N ratio further increased VFA production.     

我国餐饮废水处理技术研究进展

综合论述了我国餐饮废水的特点及处理现状。介绍了SBR法、生物接触氧化法、厌氧-好氧联合工艺法、膜生物反应器法、混凝法、电化学法处理餐饮废水的技术及适用条件。比较了各种处理技术的优势和不足，预测了我国餐饮废水处理的发展趋势。并认为，集除油、降解有机悬浮物于一体的餐饮废水一体化处理设备将会得到广泛应用，而针对餐饮废水特点培养出高效生物茵种的复合生物技术将是治理餐饮废水的最有效方法。     

Adaptation of microbial communities to multiple stressors associated with litter decomposition of Pterocarya stenoptera

To understand the further impacts of multiple stressors in freshwater, we investigated the effects of heavy metal(HM, Cu and Zn) and nutrient enrichments(nitrogen and phosphorus, NP) on microbial decomposition of Pterocarya stenoptera litter and the associated extracellular enzyme activities and microbial biomass with microcosms. Results showed that the decomposition rates were slower in the polluted stream waters than those in the unpolluted ones, which corresponded to lower microbial biomass and integrated enzyme activities of cellulose and β-glucosidase. The decomposition rates were accelerated at low HM level, which was associated with the stimulated enzyme activities of hydrolytic enzymes or was stimulated by both NP levels in polluted stream waters. In particular, the hydrolase enzyme activities of microbial communities in polluted stream waters were stimulated by low HM level, suggesting that low HM level-stimulated litter decomposition may be due to the increased enzymatic activities. When microbial communities were exposed to HM and NP simultaneously, the inhibitory effect(in unpolluted stream waters) or the stimulated effect(in polluted stream waters) of low HM concentration was enhanced and attenuated, respectively, which suggests that the NP antagonistic effect against HM toxicity on litter decomposition may contribute to the litterassociated extracellular enzyme activities. These results suggest that the co-occurrence of HM and NP may have antagonistic effects on stream ecosystem functioning.