城市生活垃圾和污水厂剩余污泥联合厌氧消化产气性能研究

以城市生活垃圾和污水厂剩余污泥为消化原料,在中温(35℃)条件下,采用序批式厌氧消化方式,研究了生活垃圾和剩余污泥不同混合比例下的厌氧消化产气性能,以及不同原料配比对厌氧消化过程及消化效率的影响。按照生活垃圾和剩余污泥VS比分别为1∶0(R1),2∶1(R2),1∶1(R3),1∶2(R4)和0∶1(R5),试验设置了5个试验组。研究结果表明:两种物料混合后有助于提高消化效果和产气性能,其中,当城市生活垃圾和剩余污泥VS比为2∶1时,系统厌氧消化效果最好,VS去除率为35.98%,单位VS产气量为348.84 m L/g,产气中甲烷含量为53.8%,消化时间较单纯生活垃圾厌氧消化缩短了9 d。说明一定比例的生活垃圾和剩余污泥联合厌氧消化是提高厌氧消化效率的有效途径。     

剩余污泥与生活有机垃圾联合厌氧消化产沼气研究

以污水处理厂剩余污泥和生活垃圾为发酵原料,研究了不同原料配比对厌氧消化过程及消化效率的影响。结果表明,剩余污泥和生活垃圾联合厌氧发酵可以提高垃圾的消化效率,当剩余污泥和生活垃圾TS比为1∶4时厌氧消化效果最好,经过66 d消化后,COD去除率为59.79%,TS去除率为56.92%,VS去除率为66.87%。     

果蔬废弃物与剩余污泥协同厌氧消化特性研究

为了提升污泥的厌氧消化效率,文章从改善原料碳氮比入手,在温度为35℃,挥发性固体(VS)浓度为4%条件下,将果蔬废弃物与污泥按不同VS比例复配,并进行协同厌氧消化产甲烷潜力实验。实验结果表明:在厌氧消化过程中,不同配比实验组的pH值、氨氮浓度和挥发性脂肪酸浓度均在适宜的范围内;不同配比实验组的累积产甲烷量由高到低依次为6∶4,5∶5,4∶6,3∶7,8∶2,7∶3,2∶8,1∶9和9∶1,其分别比纯污泥组提高了516%,485%,430%,360%,335%,330%,290%,144%和-64%。通过Gomperzt修正方程拟合发现,果蔬废弃物与污泥协同厌氧消化的最佳VS配比为6∶4,此时体系的单位VS理论甲烷产率和单位VS最大甲烷日产量分别为114.05mL/g和14.61 mL/(g·d),分别比纯污泥组提高了422%和353%。     

剩余污泥与酒精糟液高温共厌氧消化能量平衡及动力学研究

利用酒精糟液易降解及其具有的热能资源优势,在实验室条件下考察了剩余污泥与酒精糟液高温共厌氧消化运行情况。结果表明,当剩余污泥和酒精糟液以体积比3∶1混合、有机负荷率为1.73 g/(L·d)、污泥停留时间为12.5 d的条件下稳定运行时,污泥挥发性固体(VS)去除率为49.4%,日产气率为0.54 L/g,能量平衡值为39.73 k J/d,突破了剩余污泥厌氧消化能量平衡为负值的瓶颈,充分利用了酒精糟液的热能资源。采用ChenHashimoto一级动力学模型方程评价厌氧消化过程,剩余污泥高温厌氧消化和剩余污泥与酒精糟液混合高温共厌氧消化的动力学常数K和最大比生长速率μmax分别为0.640 0,0.084 9 d-1和1.914 1,0.261 9 d-1,表明剩余污泥与酒精糟液混合高温共厌氧消化体系明显优于剩余污泥高温厌氧消化体系。     

稻草与猪粪连续混合厌氧消化制备生物燃气研究

以挥发性固体(VS)比1∶1的稻草与猪粪为混合原料,采用40 L有机玻璃反应器进行连续厌氧消化,考察不同有机负荷率(OLR)(3~12 kg VS/(m3·d))及温度(55℃、35℃)对厌氧消化性能及稳定性的影响。结果表明:高温消化在整个OLR范围内,池容产气逐渐增大,最大达到4.98 m3/(m3·d),平均原料产气率为439 L/(kg VS);中温消化在OLR为12 kg VS/(m3·d)时出现严重的挥发性脂肪酸(VFAs)抑制,在稳定运行的OLR范围(3~8 kg VS/(m3·d))内,池容产气率逐渐增大,最大达到3.45 m3/(m3·d),平均原料产气率为413 L/(kg VS);用p H值判断厌氧消化系统的稳定性可能不够灵敏或具有滞后性,VFAs、碱度以及p H连续变化的监测对于诊断消化系统可能存在的不稳定因素较为有效;在高有机负荷条件下易出现污泥膨胀,中温消化系统更易形成。     

水分选有机垃圾三种总固体厌氧消化产甲烷

以水分选城市生活有机垃圾(WS-OFMSW)为原料,采用35L厌氧反应器进行中温(30±2℃)批式厌氧消化,研究3种TSr分别为16.0%、13.5%和11.0%的样品对厌氧消化稳定性及性能的影响。结果表明,3种TSr均能实现稳定的产甲烷过程,pH自我恢复调节能力较强,在整个过程中没有产生挥发性脂肪酸抑制。较低的TSr有助于快速启动并缩短发酵周期,3种TSr厌氧消化分别于32、25和12d达到产气高峰。累积产甲烷量分别为273.1、283.0和313.7L·kgVS~(-1),平均甲烷浓度为64.6%、66.3%和65.7%。3种TSr厌氧消化的VS去除率分别为26.08%、35.76%和41.78%。通过该实验,获得相关的WS-OFMSW厌氧消化原始数据,为城市生活垃圾水分选技术的完善以及有机垃圾厌氧消化性能的提高指出了参考方向。     

含固率与接种比对分类厨余垃圾高固厌氧消化性能的影响

文章通过分类厨余垃圾中温高固批式厌氧消化试验,研究了含固率（15%,20%,25%）和接种比（1∶1,1∶2,1∶3）对分类厨余垃圾厌氧消化性能的影响。研究结果表明：含固率越高,接种比越低,产甲烷迟滞期就越长;在含固率为25%,接种比为1∶2的条件下,产甲烷迟滞期最长,但日最大产甲烷速率、单位挥发性固体（VS）产甲烷率和单位总固体（TS）产甲烷率均最高,分别为9.8 mL/（g·d）,217.7 mL/g和135.3 mL/g,TS和VS去除率也最高,分别为28.28%和49.47%;当接种比为1∶1时,3组厌氧消化体系均发生严重酸化导致系统崩溃;厌氧消化前期的主要发酵类型为乙酸型发酵和丁酸型发酵,后期主要为丙酸型发酵;在含固率为25%,接种比为1∶2的条件下,丙酸型发酵持续时间最长,对应的甲烷产率最高。     

猪粪中温单级与高温-中温两级厌氧消化效率比较分析

为探究畜禽粪便两级厌氧消化的产气性能及厌氧消化效率,以总固体含量为10.0%的猪粪作为原料,研究猪粪高温（55℃）-中温（37℃）两级厌氧消化工艺的长期连续运行性能,并与中温（37℃）单级厌氧工艺进行比较。结果表明,在近600天长期试验的前期（1～100 d）,高温反应器酸化反应占主导地位,甲烷含量仅为36.3%,两相工艺挥发性固体（VS）的甲烷产率达0.314 L/g,VS去除率达到60.2%,比单相工艺提高了16%。在长期试验的后期（215～575 d）,高温反应器甲烷化效果增强,甲烷含量达到55.9%,pH也升高到7.51,挥发性脂肪酸浓度相较前期下降了220%。该阶段两级工艺的甲烷产率为0.294 L/g,比同时期的单级厌氧提升了19%,对应的VS去除率提高了41%。猪粪在长期的两级工艺运行中,第一级的高温罐并不能维持长期的酸化状态,反而长时间呈现出较为明显的产甲烷效果,但第二级的中温罐长期处于相对稳定的产甲烷状态。总体而言,高固体猪粪两级厌氧消化工艺比单级厌氧工艺具有更高的甲烷产率及更好的有机物去除效果。     

餐厨垃圾厌氧消化工艺研究

为了提高餐厨垃圾的厌氧消化效率,对餐厨垃圾序批式厌氧消化(BT)、半连续厌氧消化(SCT)、固液两相厌氧消化(SLT)进行了比选研究。研究结果表明,SLT生产系统有效提高了厌氧消化效率,单位沼气产量与甲烷含量也都显著提高,SLT,SCT及BT的单位VS最大沼气日产量分别为430,270 m L和150 m L,最高甲烷含量分别为68%,57%和50%;SLT的产酸效率及有机酸利用率均显著提高,有机负荷率较SCT提高50%,能够达到9 g/(L·d)。餐厨垃圾的SLT工艺有机负荷及消化效率较SCT及BT工艺均有大幅提高。     

混合比对市政污泥与餐厨垃圾二级高温共消化的影响

研究不同混合比下市政污泥与餐厨垃圾二级高温共消化的情况。实验分别采用污泥与餐厨TS之比为3∶1,4∶1,5∶1的3种混合比,主要考查了混合比对二级反应罐的影响。研究表明,不同的混合比对各反应罐达到稳定时出料的COD浓度、VS的含量及其去除率、日产气量以及产气中甲烷含量等都有一定的影响,混合比为3∶1,4∶1,5∶1的反应罐稳定时出料的COD浓度分别为13 500,10 000,23 000mg/L,混合比为4∶1时,出料COD浓度最低。稳定时VS的含量随着混合比的增加而升高,分别为0.034 7,0.039 6,0.045 6g/g物料,VS的去除率分别为42.8%,26.7%,5.2%;稳定时各反应罐的日产气量随着混合比的升高而降低,分别为12 000,5 500,4 500mL,产气中甲烷含量分别为92.49%,91.55%,88.69%。     

鸡粪与NaOH预处理麦秸联合厌氧发酵产气性能与协同效果研究

试验研究了不同负荷下不同混合比例的鸡粪与NaOH预处理麦秸的厌氧发酵产气性能和协同作用效果。以鸡粪和2%NaOH预处理后的麦秸作为发酵原料,研究了混合物料在3种负荷和9种混合比例条件下的厌氧发酵产气情况。结果表明:在3种负荷(50,65,80 g/L)中,均是鸡粪和麦秸比例为1∶2时产气效果最佳,其累计产气量分别达到32 000,43 030 mL和50 370 mL;其TS产气率分别达到328.2,356.9,352.8 mL/g,比纯鸡粪相应负荷分别提高了27%,29%,23%。不同比例下,3种负荷中,均是65 g/L时产气效果最好,鸡粪与麦秸的协同作用使累计产气量提高了7%～17.7%。     

CSTR反应器鸡粪厌氧消化中试启动研究

在中温(37℃)条件下,利用全混式厌氧(CSTR)反应器进行鸡粪废水厌氧消化启动的实验室模拟,将试验分为4个阶段(Ⅰ,Ⅱ,Ⅲ,Ⅳ),逐级增加进料负荷量,研究分析各阶段影响因素。结果表明:CSTR反应器能够正常启动鸡粪废水厌氧消化,当试验各阶段(Ⅰ∶Ⅱ∶Ⅲ∶Ⅳ)进料比为1∶2∶2.67∶3.33时,相应的最高产气速率之比约为1∶1.76∶2.04∶2.46;在进料COD为25 496 mg/L,HRT为31 d时,氨氮最高浓度为2 122 mg/L左右,COD去除率为(57.5±1.93)%,每日甲烷产量(单位质量VS)为(301±6)mL/g。试验4 d后,CSTR反应器产生的沼气中CH4含量稳定在61.8%～70.1%。     

Evaluation of biogas production from different biomass wastes with/without hydrothermal pretreatment

Municipal biomass waste is regarded as new available energy source, although it could cause serious environmental pollution. Generally, biogas recovery by anaerobic digestion was seen as an ideal way to treat biomass waste. Different types of biomass waste have different biogas production potential. In this paper, cow manure, pig manure, municipal sewage sludge, fruit/vegetable waste, and food waste were chosen as typical municipal biomass waste. In addition, hydrothermal pretreatment was used to accelerate digestion and increase biogas production. Biochemical methane potential (BMP) test was used to evaluate biogas production for raw biomass and hydrothermal treated waste. Raw materials of fruit/vegetable and food waste show higher methane production than that of cow manure, pig manure, and municipal sewage sludge. After hydrothermal pretreatment at typical condition (170 °C at 1 h), the biogas production of pig manure, cow manure, fruit/vegetable waste, and municipal sewage sludge increased by 7.8, 13.3, 18.5, and 67.8% respectively. While, for treated food waste, the biogas decrease by 3.4%. The methane yield of pig manure, fruit/vegetable waste, and municipal sewage sludge increased by 14.6, 16.1, and 65.8%, respectively. While, for treated cow manure and food waste, the methane decrease by 6.9% and 7.5%.     

餐厨垃圾SBMR-ASBR两相厌氧消化产气性能研究

以学校食堂餐厨垃圾为原料,考察餐厨垃圾在SBMR-ASBR反应器中产酸和产甲烷性能。结果表明:高负荷下启动酸化相有利于系统快速形成稳定的乙醇型发酵,且可以避开丙酸型发酵,在10 g/(L.d)负荷(以VS计)下,稳定状态产酸率平均达到55 000 mg/L,VFA中乙醇和乙酸分别平均稳定在27 000 mg/L和23 000mg/L,两者共占总VFA的91%;甲烷相可以稳定运行的最高负荷为5 g/(L.d)(以VS计),此时,系统整体处理能力为3.3 g/(L.d),单位容积产气率达到2.3 L/(L.d),甲烷含量在65%～70%,TS,VS去除率分别达到77%,83%。在实际工程中可以高负荷启动酸化相,有利于系统形成稳定的乙醇型发酵和高负荷运行的甲烷相。     

Biogas production from municipal sewage sludge (MSS)

Biogas is produced by anaerobic (oxygen free) digestion of organic materials such as sewage sludge, animal waste, and municipal solid wastes (MSW). As sustainable clean energy carrier biogas is an important source of energy in heat and electricity generation, it is one of the most promising renewable energy sources in the world. Biogas is produced from the anaerobic digestion (AD) of organic matter, such as manure, MSW, sewage sludge, biodegradable wastes, and agricultural slurry, under anaerobic conditions with the help of microorganism. Biogas is composed of methane (55–75%), carbon dioxide (25–45%), nitrogen (0–5%), hydrogen (0–1%), hydrogen sulfide (0–1%), and oxygen (0–2%). The sewage sludge contains mainly proteins, sugars, detergents, phenols, and lipids. Sewage sludge also includes toxic and hazardous organic and inorganic pollutants sources. The digestion of municipal sewage sludge (MSS) occurs in three basic steps: acidogen, methanogens, and methanogens. During a 30-day digestion period, 80–85% of the biogas is produced in the first 15–18 days. Higher yields were observed within the temperature range of 30–60°C and pH range of 5.5–8.5. The MSS contains low nitrogen and has carbon-to-nitrogen (C/N) ratios of around 40–70. The optimal C/N ratio for the AD should be between 25 and 35. C/N ratio of sludge in small-scale sewage plants is often low, so nitrogen can be added in an inorganic form (ammonia or in organic form) such as livestock manure, urea, or food wastes. Potential production capacity of a biogas plant with a digestion chamber size of 500 m³ was estimated as 20–36 × 10³ Nm³ biogas production per year.     

Enhancing biomethanation of municipal waste sludge with grease trap waste as a co-substrate

Grease trap waste (GTW) presents a challenge to wastewater treatment processes due to its slow biodegradation kinetics, high oxygen demand, and risks of pipeline blockage. The objective of this work was to evaluate the feasibility of GTW as an organic-rich co-substrate to improve biomethane production in the anaerobic digestion of municipal waste sludge (MWS) from sewage treatment, one of the most abundant feed materials to municipal anaerobic digesters. Waste characterization confirmed the high organic content of GTW at 138 gVS/L, which was 626% higher than that of MWS (19 gVS/L). The methane potential of GTW approximated 145 L_Methane/L_GTW, which was more than 15 times higher than that of MWS (8.9 L_Methane/L_MWS). When GTW was added as a co-substrate in addition to MWS, the high methane potential and organic content of GTW resulted in significant improvement in methane production during the anaerobic co-digestion of MWS, e.g. a 65% increase at the GTW loading of 5.5 gVS/L, representing a less than 4% (vol/vol) addition of GTW. Thus, the operational feasibility of anaerobic co-digestion using GTW as the co-substrate is enhanced by the insignificant volumetric GTW loading required for significant improvements in methane production. Process inhibition and reduction in biogas production, however, occurred with higher GTW loadings, suggesting the importance of proper GTW loading rates for the implementation of anaerobic co-digestion processes effective in improving biomethanation of municipal waste sludge.     

Biohydrogen production from waste glycerol and sludge by anaerobic mixed cultures

Key factors affecting biohydrogen production from waste glycerol and sludge by anaerobic mixed cultures were optimized using response surface methodology (RSM) with central composite design (CCD). Investigated parameters were waste glycerol concentration, sludge concentration, and the amount of Endo–nutrient addition. Concentrations of waste glycerol and sludge had a significant individual effect on hydrogen production rate (HPR) (p ≤ 0.05). The interactive effect on HPR (p ≤ 0.05) was found between waste glycerol concentration and sludge concentration. The optimal conditions for the maximum HPR were: waste glycerol concentration 22.19 g/L, sludge concentration 7.16 g-total solid (TS/L), and the amount of Endo–nutrient addition 2.89 mL/L in which the maximum HPR of 1.37 mmol H₂/L h was achieved. Using the optimal conditions, HPR from a co-digestion of waste glycerol and sludge (1.37 mmol H₂/L h) was two times greater than the control (waste glycerol without addition of sludge) (0.76 mmol H₂/L h), indicating a significant enhancement of HPR by sludge. Major metabolites of the fermentation process were ethanol, 1,3-propanediol (1,3-PD), lactate, and formate.     

微量金属元素对厌氧污泥颗粒化的影响

以牛粪为原料的厌氧发酵过程中,向厌氧生物反应器中加入1.0 mg/(L·d)的Fe2 ,0.15mg/(L·d)的Co2 和0.4 mg/(L·d)的Ni2 ,研究微量金属元素对牛粪厌氧发酵液产气特性和厌氧污泥颗粒化的影响.实验结果表明:添加适量的微量金属元素,能够加快牛粪厌氧发酵液的产气速度,增加产气量.同时,添加微量金属元素Fe2 ,Co2 ,Ni2 ,能够改善产甲烷菌的生长速度和生物活性,促进厌氧污泥的颗粒化.     

Biochemical assays of potential methane to test biogas production from dark fermentation of sewage sludge and agricultural residues

This study aims to study the methane generation potential (BMP tests) of different samples from the dark acid fermentation of sewage sludge:wine vinasse, and sewage sludge:wine vinasse:poultry manure. Specifically, mixtures of sewage sludge (S) and wine vinasse (V) were used in a 50:50 ratio and mixtures of sewage sludge and wine vinasse with 10 g/L of poultry manure (PM) (50:50 + 10 g/L) (S:V + PM). The goal was to determine the effect of the high ammonia concentrations in poultry manure when was used as co-substrate in the anaerobic methanogenic degradation of sewage sludge and vinasse. Results obtained show that the addition of 10 g/L of poultry manure to the SV mixture improves the production of methane generation, reaching values of 166 mL of accumulated methane. The SVPM mixture shows the highest purification percentages, with 63.90% TCOD removal, 79.51% SCOD removal and a yield of 52.05 mLCH₄/gSV_added. The SVPM test showed a higher concentration of microorganisms during the BMP test, although the population of microorganisms for the SV test was doubled and presented greater activity with values of 2.27 versus 1.73E-11 LCH₄/Cells.     

Use of organic waste for biohydrogen production and volatile fatty acids via dark fermentation and further processing to methane

Despite the suitability of organic waste for dark fermentation (DF), anaerobic digestion (AD) counteracts its large-scale use for biohydrogen production. Therefore, 12 types of organic waste obtained from sugar, textile, food, and milk industries are investigated in batch single-stage AD and compared energetically to batch two-stage DF with subsequent AD. From the viewpoint of DF, a parametric study of mesophilic and thermophilic conditions, different substrate concentrations, and mixed cultures, i.e., granular and digested sludge, is conducted. Hydrogen yields of 90–160 L_N/kg_oDM (mean) and maximum yields of 199–291 L_N/kg_oDM are achieved with starchy and sugary wastes. Concentrations of volatile fatty acids of 9.7–14.5 g/L (mean) show the possible material uses. Thermophilic conditions are more suitable than mesophilic ones. Furthermore granular sludge is applicable for DF. The energetic comparison of the procedures demonstrates a method for assessing the applicability of waste and allows preliminary economic estimations.