微量元素Fe2+、Co2+、Ni2+对麦秸与鸡粪混合厌氧发酵的影响

以麦秸与鸡粪为原料,采用批次式中温厌氧发酵方式,探究微量元素Fe²⁺、Co²⁺、Ni²⁺对混合厌氧发酵的影响。实验结果表明:Fe²⁺、Co²⁺、Ni²⁺最佳浓度分别为210、32、32 mg/L,当Fe²⁺、Co²⁺、Ni²⁺的添加浓度在适宜范围内时,可显著(p<0.05)提高发酵系统产CH₄潜力及CODs去除率;当Fe²⁺浓度为210 mg/L、Co²⁺浓度为32 mg/L、Ni²⁺浓度为32 mg/L时,其CH₄累积产量分别为322.21、331.19、357.10 mL/(g VS),相比于对照组为245.35 mL/(g VS)显著(p<0.05)提高31.33%、34.99%、45.54%,CODs去除率依次为61.83%、57.01%、63.63%,提高CH<...     

微量元素对蔬菜废弃物厌氧消化的促进效果

以蔬菜废弃物为原料的厌氧消化系统,由于原料的易酸化特性,在高负荷条件下易失稳,而低负荷的运行会导致较低的池容产气率。本研究采用自行设计的70-L厌氧发酵罐,在中温35℃条件下进行蔬菜废弃物厌氧消化的连续冲击负荷试验,根据气体成分（CH₄）的变化规律,添加微量元素（Fe, Co, Ni）以调控消化过程,使其由失稳状态恢复至稳定状态,旨在提高高负荷厌氧发酵的稳定性。研究结果表明,蔬菜废弃物中温厌氧消化系统的有机负荷率增大至2.0 g VS/(L•d)时,CH₄含量由50%降至40%,从第103天开始连续添加5天微量元素（Fe, Co, Ni）后,CH₄含量迅速恢复至50% ~ 55%的稳定状态,池容产甲烷率由0.38 L/(L•d) 增大至0.6 L/(L•d)左右并保持稳定。停止添加微量元素后,继续增大有机负荷率,厌氧消化系统稳定运行83天。当运行至第195天时（3.0 g VS/(L•d)）,CH₄含量再次出现下降趋势,由58.9%降至53.4%,添加3天微量元素后,CH₄含量再次恢复到55%以上的稳定状态。微量元素的添加可有效提高蔬菜废弃物厌氧消化的稳定性,能够快速恢复失稳的系统。     

生物质气化工艺废水特征及预处理实验研究

对生物质气化中试现场产生的废水进行了水质及水量特征分析,针对生物质气化工艺废水固体颗粒含量高、有机物浓度高、难生化降解、废水增量少的特点,采取减压蒸馏及芬顿氧化对生物质气化废水进行预处理。实验结果表明,在85 ~ 90℃、真空度 -0.07 ~ -0.095 MPa减压蒸馏条件下,废水COD、NH₄-N脱除率分别为74.38%、94.46%;在Fe²⁺-H₂O₂体系中,考察了H₂O₂与废水质量比、H₂O₂与Fe²⁺摩尔比、反应时间、H₂O₂浓度对COD、NH₄-N、TOC、TN等的影响,当H₂O₂与废水质量比为8.40%时,可将减压蒸馏蒸出液COD从2.05 × 10⁴ mg/L降至4.11 × 10³ mg/L,NH₄⁺-N从143 mg/L降至11.1 mg/L。     

铜离子对猪粪厌氧消化性能的影响研究

在实验室条件下,研究了铜离子浓度为100⁶00μg/g时对猪粪厌氧消化性能的影响。结果表明:铜离子浓度为100～300μg/g时可提高甲烷产量,浓度为400～600μg/g时,则明显抑制甲烷产量;整个过程中,系统的pH值一直维持在6.5600μg/g时对猪粪厌氧消化性能的影响。结果表明:铜离子浓度为100～300μg/g时可提高甲烷产量,浓度为400～600μg/g时,则明显抑制甲烷产量;整个过程中,系统的pH值一直维持在6.5⁷.2,无明显酸化;当铜离子浓度为300μg/g时,COD去除率最大,达到68.23%。铜离子浓度对TS,VS去除率影响不明显,TS去除率为30%7.2,无明显酸化;当铜离子浓度为300μg/g时,COD去除率最大,达到68.23%。铜离子浓度对TS,VS去除率影响不明显,TS去除率为30%³5%,VS去除率为55%35%,VS去除率为55%⁶0%。不同重金属浓度的COD在前15 d内均达到较高值,这有利于反应高效进行,而氨氮(NH4+-N)一直处于升高状态,对反应中的产甲烷微生物造成抑制作用,最终导致消化系统氨中毒,使Cu400,Cu500,Cu600 3个处理的发酵罐产气提前结束。     

柠檬酸对牛粪厌氧发酵产沼气的影响研究

文章研究了柠檬酸添加量对牛粪中温(35±1℃)厌氧发酵产沼气的日产气量、累积产气量、p H值以及COD降解率等的影响。结果表明:添加适量的柠檬酸对牛粪厌氧发酵产沼气具有显著的促进作用,0.6%的柠檬酸添加量取得了最高日产气量38.46 m L/g(VS);0.7%的柠檬酸添加量取得了最高累积产气量545.48 m L/g(VS);0.3%的柠檬酸添加量可以大幅提高COD去除率,达到了34.5%;随着柠檬酸添加量的增加,第二次产气高峰依次推迟,p H值从6.76逐渐降低到5.41,当柠檬酸添加量为0.9%时,p H值达到5.57。该研究结果为牛粪厌氧发酵规模化沼气工程的高效运行提供了技术参考。     

温度和pH值对餐厨垃圾和牛粪混合厌氧发酵的影响

通过序批式厌氧发酵,以产气量、产甲烷量、厌氧发酵过程中pH值以及有机物降解程度为指标,研究了不同温度、不同初始pH值对餐厨垃圾和牛粪混合厌氧发酵的影响。试验结果表明,温度为50℃时,厌氧发酵效果最佳,其单位产气量(以VS计)为722.98 mL/g,甲烷体积分数最高达62.73%.,有机物去除率为67.5%;初始pH值为7时,厌氧发酵效果最佳,其单位产气量(以VS计)为618.23 mL/g,甲烷体积分数最高达62.4%,有机物去除率为66%。     

不同固体含量下牛粪和秸秆厌氧发酵中微氧法原位脱硫效果研究

以牛粪和秸秆为原料进行厌氧发酵试验,研究固体含量(TS)为10%,15%和20%的3种发酵底物,采用微氧法原位脱硫对厌氧发酵的产气量、H_2S去除率、甲烷体积分数和O_2残留量等的影响。研究结果显示:采用微氧法原位脱硫后的3组发酵试验的日产气量都有所提高;尤其是TS20%组,通入空气后,日产气量(VS)提高了2 mL/g,说明微氧法原位脱硫对干发酵具有很好的促进作用;TS15%和TS 20%两组试验的脱硫效果显著,H_2S的去除率均大于90%;各试验组与对照组的甲烷体积分数相差不大;试验组通入空气后,O_2的残留量一般在0.5%左右,满足《车用天然气标准》的要求,表明微氧法原位脱硫不会影响沼气的厌氧发酵系统,是一种切实可行的沼气脱硫方法。     

Fe3+交联的预包覆Fe3O4纳米粒子改性rGO自支撑膜的储锂性能

本工作采用Fe³⁺对含有氧化石墨烯(graphene oxide,GO)预包覆Fe₃O₄的GO自支撑膜进行改性处理制备Fe³⁺诱导交联的预包覆Fe₃O₄纳米粒子复合热还原型氧化石墨烯自支撑膜(Fe³⁺@Fe₃O₄/r GO)。采用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)等测试手段表征材料组成、结构与形貌,并研究Fe³⁺@Fe₃O₄/r GO自支撑膜作为锂离子电池负极的储锂性能。结果表明球状Fe₃O₄纳米颗粒被GO片层紧密包裹,且经过Fe³⁺诱导交联的Fe³⁺@Fe₃O₄/r GO自支撑膜稳定性显著提高;电化学结果表明,在电流密度为100 m A/g恒...     

微生物燃料电池耦合处理重金属-有机废水性能研究

以双室微生物燃料电池(MFC)为研究对象,构建阳极为糖蜜废水、阴极为不同金属离子废水的微生物燃料电池,对其产电性能和去污能力进行测定。结果表明:微生物燃料电池可同时处理有机废水和金属离子废水,其中,Ag~+为阴极液时,其MFC稳定性最好,最高输出电压为198 m V、最大功率密度为23.1 m W/m~2、内阻为500Ω,Cu~(2+)为阴极液时分别为149 m V、13.9 m W/m~2、600Ω,Zn~(2+)为阴极液时分别为16 m V、1.9×10~(-6)m W/m~2、900Ω。阳极化学需氧量(COD)去除率以Ag~+为阴极液时最高,可达72%,Cu~(2+)和Zn~(2+)分别为54%和19.2%。阴极金属离子去除率Ag~+为72%、Cu~(2+)42%、Zn~(2+)19.8%。     

黑曲霉AS0006预处理玉米秸秆产沼气研究

为了提高玉米秸秆与牛粪混合发酵的产气效率,文章对黑曲霉AS0006预处理后的玉米秸秆进行了研究,考察了不同预处理时间的玉米秸秆在混合厌氧发酵过程中的日产气量、累积产气量、TS和VS去除率以及木质纤维素去除率等发酵特性的变化情况。研究结果表明:黑曲霉AS0006对木质纤维素有较强的降解能力,玉米秸秆经黑曲霉AS0006预处理28 d后,纤维素、半纤维素和木质素的降解率分别为26.86%,11.93%和25.09%;经过黑曲霉AS0006预处理的玉米秸秆与牛粪混合发酵可以提高日产气量并缩短厌氧发酵周期,其中,预处理21 d后的玉米秸秆的产气高峰最大,为523.4 mL/d;经过黑曲霉AS0006预处理的玉米秸秆与牛粪混合发酵后, TS和VS去除率以及木质纤维素去除率均比未经预处理的玉米秸秆高。     

分散原料沼气集中供气运行分析

我国规模化沼气工程存在原料单一、产气率低、装备落后等技术瓶颈,西南地区沼气原料来源分散、成分复杂,因此需要开发新的多种原料混合发酵的新模式来提高沼气工程厌氧消化效率。本工程通过全混式厌氧发酵两级工艺共同厌氧消化如秸秆和畜禽粪便等分散原料,形成新的沼气和发酵剩余物利用模式。结果表明,在30 d稳定运行期间,600 m³厌氧发酵罐每天可消纳猪粪7.9 t、浓污水8.2 t及农作物秸秆0.2 t,日产气量为900 m³,混合原料发酵的容积产气率达1.5 m³/(m³∙d)。     

厌氧膜生物反应器处理垃圾渗滤液在高负荷下的连续运行性能研究

为解决常规厌氧工艺在处理垃圾渗滤液的运行过程中存在微生物流失和出水水质较差等问题,考察了浸没式平板厌氧膜生物反应器处理垃圾渗滤液的运行性能。以垃圾填埋场新鲜渗滤液为研究对象,在中温(37±1)℃条件下进行连续厌氧消化试验,容积负荷为9.5 kg_COD/(m³·d),反应器运行67 d。实验表明,在水力停留时间为10 d的条件下,甲烷产率为217 mL/g_COD,化学需氧量(COD)平均去除率达88.7%,出水总挥发性脂肪酸为230 mg/L,pH稳定在7.83～8.19,系统具有良好的稳定性。膜通量设定为5 L/(m²·h)时,实验结束时未发生明显的膜污染,跨膜压差由2.6 kPa增长至4.1 kPa,系统运行良好。实验结果表明在处理垃圾渗滤液时,厌氧膜生物反应器可以在高负荷条件下稳定运行,膜在连续运行下的抗污染能力较好。     

Evaluation of marine algae as a source of biogas in a two-stage anaerobic reactor system

The marine algae are considered an important biomass source; however, their utilization as energy source is still low around the world. The technical feasibility of marine algae utilization as a source of renewable energy was studied to laboratory scale. The anaerobic digestion of Macrocystis pyrifera, Durvillea antarctica and their blend 1:1 (w/w) was evaluated in a two-phase anaerobic digestion system, which consisted of an anaerobic sequencing batch reactor (ASBR) and an upflow anaerobic filter (UAF). The results show that 70% of the total biogas produced in the system was generated in the UAF, and both algae species have similar biogas productions of 180.4(±1.5) mL g⁻¹ dry algae d⁻¹, with a methane concentration around 65%. The same methane content was observed in biogas yield of algae blend; however, a lower biogas yield was obtained. In conclusion, either algae species or their blend can be utilized to produce methane gas in a two-phase digestion system.     

The influence of thermal treatment on recirculating two phase anaerobic digestion system

Recirculated two-phase anaerobic digestion (RTAD) is a recent technique to improve biogas production. Recirculating the effluent of two-phase anaerobic system has a methanogens invasion risk to dark fermentation. Hot compressed water is possible to reduce the methanogens invasion. The objectives of this study are identifying the effect of hot compressed water pretreatment on RTAD and evaluating the fermentation system during the change of hydraulic retention time and effluent recirculation ratio. The RTAD system was built and operated with 4 different conditions, those are hydraulic retention time 2-day (HRT 2d), HRT 3d, Effluent Ratio 1:5 (R1:5) and R2:5. The result shows that the shorter HRT increase the biogas production. The pH in the reactor is more stable after the recirculation process. In bioreactor performance, the hot compressed water treatment increased the COD removal at all conditions. The highest COD removal achieved at condition of HRT 2-day with removal up to 94.5%. The system that using hot compressed water treatment has the higher energy potential at HRT 2-day, R 1:5 and R 2:5 compared with no hot compressed water treatment.     

Techniques for transformation of biogas to biomethane

Biogas from anaerobic digestion and landfills consists primarily of CH₄ and CO₂. Trace components that are often present in biogas are water vapor, hydrogen sulfide, siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide and nitrogen. In order to transfer biogas into biomethane, two major steps are performed: (1) a cleaning process to remove the trace components and (2) an upgrading process to adjust the calorific value. Upgrading is generally performed in order to meet the standards for use as vehicle fuel or for injection in the natural gas grid.Different methods for biogas cleaning and upgrading are used. They differ in functioning, the necessary quality conditions of the incoming gas, the efficiency and their operational bottlenecks. Condensation methods (demisters, cyclone separators or moisture traps) and drying methods (adsorption or absorption) are used to remove water in combination with foam and dust.A number of techniques have been developed to remove H₂S from biogas. Air dosing to the biogas and addition of iron chloride into the digester tank are two procedures that remove H₂S during digestion. Techniques such as adsorption on iron oxide pellets and absorption in liquids remove H₂S after digestion.Subsequently, trace components like siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide and nitrogen can require extra removal steps, if not sufficiently removed by other treatment steps.Finally, CH₄ must be separated from CO₂ using pressure swing adsorption, membrane separation, physical or chemical CO₂-absorption.     

Improvement of a grass-clover silage-fed biogas process by the addition of cobalt

Batch assays were performed with samples from a silage-fed mesophilic biogas process accumulating acetate to examine if the addition of single trace elements (iron, nickel, cobalt and molybdenum) or a mixture of trace elements could improve the process. The results from the batch assays led to the addition of cobalt to reach a concentration of 0.2 mg L⁻¹. This made it possible to increase the organic loading rate (OLR) above that in a parallel process not receiving any extra cobalt. Problems with low gas production and decreasing pH were overcome by the daily supply of this single element in small amounts. Acetate conversion to methane was improved, which was confirmed by increased specific methanogenic activity (SMA) with acetate as a substrate. As a consequence, an OLR of 7.0 g VS L⁻¹ day⁻¹ was achieved at a hydraulic retention time (HRT) of 20 days with an equivalent increase in methane production. Without cobalt addition, an OLR of 5.0 g VS L⁻¹ day⁻¹ with an HRT of 20 days was reached after 70 weeks operation.     

链霉素菌渣中温厌氧发酵产沼气性能研究

为实现链霉素菌渣的无害化、资源化利用,文章以链霉素菌渣为原料,在菌渣含固率为2%,温度为30±2℃的条件下进行60 d的厌氧发酵试验。试验结果表明:链霉素菌渣的累积产气量为18.20 L,中温产气能力为364.07 mL/g;在稳定产气阶段,发酵液的氨氮、VFAs含量均维持在较低水平,pH值大于7.0;厌氧发酵结束后,发酵液的VS去除率达64.32%;以金黄色葡萄球菌作为指示菌,在厌氧发酵后的沼液中未检测到链霉素残留。     

钙对生物质/塑料混合物共热解特性及动力学的影响

为了探究Ca2+对生物质/塑料混合物热解的影响,采用热重分析法研究了Ca2+浸渍酸洗玉米秸秆(ACS)/高密度聚乙烯(HDPE)混合物(AHM)的热解特性.结果表明,Ca2+的添加,使得AHM的初始分解温度以及第一失重峰对应温度均有所降低;此外,由于Ca2+的添加,AHM的第二失重峰对应温度基本不变,最大失重速率有所增...     

餐厨垃圾高温厌氧消化连续运行性能：有机物转化效率、发酵稳定性与代谢活性

在高温(50±1)℃条件下处理实际工程的餐厨垃圾,采用全混式厌氧反应器（CSTR）进行了80d的连续试验。试验以水力停留时间（HRT）20 d启动,HRT 15 d连续运行,研究了反应器启动和运行期间的发酵特性,解析了餐厨垃圾厌氧消化运行稳定性和代谢活性。试验结果表明,在HRT 15 d、有机负荷（OLR）为7.3 kgCOD/(m3·d)的条件下,容积产甲烷率为2.2L/(L·d),挥发性固体（VS）的甲烷产率达到480L/kgVS左右,有机物转化率约为95%。批次试验表明,高温产甲烷菌代谢乙酸能力较强,在适宜pH下可承受10000mg/L的乙酸浓度。餐厨垃圾的高温降解速率快,10 d达到90%的产气,有承受更高负荷的可能。系统pH稳定在7.6～7.7,总氨氮和自由氨浓度低于抑制水平。研究结果表明,餐厨垃圾的高温厌氧消化可实现较高的产气潜力和有机物去除率,系统稳定性好且有机物转化效率高,具有应用于工程高温餐厨垃圾厌氧处理的潜力。     

Fermentation properties of agro-residues, leaf biomass and urban market garbage in a solid phase biogas fermenter

The decomposition and gas production pattern of eight unprocessed biomass feedstocks representing annual weeds, leaf litter, agro residues and market wastes were monitored in this laboratory study. Solid phase fermentation was effected with a weekly fed biomass bed sprinkled twice daily with recycled fermentor liquid to initiate and sustain biogas production from the decomposing biomass bed. Fermentors were fed from the top with gradually increasing feed rates to determine maximum feed rates sustainable. Feed rates of 1 g total solids (TS) l⁻¹d⁻¹ was possible which lead to pseudo steady state gas production rates between 0.26–0.98 l l⁻¹ d⁻¹ at specific gas yields of 0.18–0.44 l g⁻¹ TS at 35–75% volatile solids (VS) destruction. Feedstocks such as paper mulberry (Broussenetia), Parthenium, Synedrella and urban garbage lost >50% VS in 30 d while paddy straw, bagasse and sugarcane trash exhibited lower VS loss (≥35%) in this period. During decomposition, bulky biomass feedstocks underwent compaction and obviated the need for a pretreatment step. Bulk densities rose manifold to reach between 150–350 g l⁻¹ within 20 d. A higher decomposition rate, process optimization and use of pre-compacted feedstocks have the potential to increase the feed rates (0.96–1.93 g TS l⁻¹d⁻¹), quantity of feedstock held in the reactor as well as gas production rates. The current gas production rates and space economy in these fermentors compare well with Indian cattle dung fermentors (0.3–0.5 l l⁻¹ d⁻¹) and is attractive.