添加垃圾渗滤液对厨余垃圾厌氧发酵产氢的影响

以厨余垃圾和垃圾渗滤液为原料,考察了垃圾渗滤液的不同添加量对厌氧消化稳定性及产氢气性能的影响。结果表明,在厨余垃圾中添加少量的垃圾渗滤液能缩短厌氧消化的延滞期而不影响其消化及产气性能,垃圾渗滤液浓度越高则越容易形成氨抑制,严重影响厌氧消化作用的进行。在40 g厨余原料中添加100 g垃圾渗滤液,其厌氧消化延滞期为6 h,氢气含量稳定在50%,最大产氢气速率为4.8 mL/(h.g),最终氢气产量为48.37 mL/g;添加200~500 g垃圾渗滤液均形成氨抑制,严重影响产气性能,产气速率均低于2.5 mL/(h.g),最终产气量为16~30 mL/g。     

垃圾渗滤液对地下水污染的PRB实验研究

应用原位修复地下水的新技术———渗透反应格栅(PRB),以被垃圾渗滤液污染的地下水为研究对象,分别以粉煤灰和膨润土为反应介质,设计了两种可渗透反应格栅。实验结果表明:两种反应介质主要利用吸附特性去除靶污染物,对COD的去除率分别达到60%和50%以上,对Cr6+、NH4+的去除率均为50%左右,说明PRB技术处理垃圾渗滤液对地下水的污染是可行的。还简要分析了PRB技术在实验过程中存在的问题,以及影响PRB反应介质的主要因素。     

填埋场覆盖层甲烷氧化机理及影响因素分析

我国城市生活垃圾中有机物含量,特别是食品垃圾含量高,垃圾在填埋后会产生大量填埋气(LandfillGas).甲烷是垃圾填埋场释气的主要成分之一,其温室效应作用是CO2的20倍以上.甲烷可以通过多种途径消耗,但通过土壤进行氧化仍是其最为主要和有效的消耗方式.目前国内对这方面的研究比较少.文章主要分析了氧化的机理和土壤温度、含水率、厚度以及含氮量对氧化过程的影响;介绍了国际上在氧化产物上的最新发现,从而为如何调控填埋场覆盖层条件以降低甲烷排放提供一种依据并为氧化产物的研究提供新思路.     

生物反应器填埋场处理渗滤液的效能及产能特性研究

选用新型生物反应器填埋场(由卫生填埋场和产甲烷反应器组成),进行了渗滤液处理效能及产能特性研究。结果表明:新型生物反应器填埋场有助于渗滤液中有机物进行分相降解,在渗滤液的净化和填埋场垃圾的稳定化上优于渗滤液直接循环的填埋场。产甲烷反应器处理垃圾渗滤液时,在进水的VFA浓度大于3000mg/L条件下,CODCr去除率76%～94%;容积CODCr去除率0 88～4 85g/(L·d);容积沼气产率0 5～2 85L/(L·d)。     

Electrohydrolysis of landfill leachate organics for hydrogen gas production and COD removal

Hydrogen gas production with simultaneous COD removal was realized by application of DC voltages (0.5-5.0 V) to landfill leachate. The rate and the yield of hydrogen gas production were investigated at different DC voltages by using aluminum electrodes and DC power supply. The highest cumulative hydrogen production (5000 mL), hydrogen yield (2400 mL H₂ g⁻¹ COD), daily hydrogen gas formation (1277 mL d⁻¹), and percent hydrogen (99%) in the gas phase were obtained with 4 V DC voltage. Energy conversion efficiency (H₂ energy/electrical energy) reached the highest level (80.6%) with 1 V DC voltage. Hydrogen gas production was mainly realized by electrohydrolysis of leachate organics due to negligible H₂ gas production in water and leachate control experiments. The highest COD removal (77%) was also obtained with 4 V DC voltage. Electrohydrolysis of landfill leachate was proven to be an effective method for hydrogen gas production with simultaneous COD removal.     

A comparative study on estimating the landfill gas potential: Modeling and analysis

The main objective of this study is to investigate the use of the landfill gas as potential energy and electricity obtained from the municipal solid waste (domestic, industrial, medical waste, and sewage sludge) stored regularly in the Harmandali solid waste landfill area, within the boundaries of the contiguous area of Izmir. The most important factor in making a decision about energy potential in the landfill is the amount of methane in the landfill gas. There are several approaches that have been used to determine the amount of the landfill gas. In this study, three different methods and one approach in the literature were used for this purpose. The methods used are the Multi-Phase, the LandGEM, and the IPCC 2006. The results of the landfill gas obtained using the three methods, namely the Multi-Phase, the LandGEM (k = 0.35, k = 0.1, and k = 0.05), and the IPCC 2006, were as follows, respectively: 291897215, 792073359, 769734749, 681685027, and 491752247 m³. It may be concluded that the Harmandali Landfill has high landfill gas potential based on the measurements and mathematical methods used in the Harmandali landfill.     

Gasification of landfill leachate in supercritical water: Effects on hydrogen yield and tar formation

Landfill leachate was gasified in supercritical water (SCW) in a batch reactor made of 316 SS. The effects of temperature, pressure, reaction time and oxidation coefficient (OC) on the pollutant removal efficiencies and gasification characteristics were investigated. To observe the formation of tar and char visually, a capillary quartz reactor was also used. Results indicated that CO₂, H₂ and CH₄ were the most abundant gaseous products. Temperature has an appreciable effect on the gasification process. Increasing temperature enhanced the H₂ yield (GY_H2) and TOC removal efficiency (TRE) significantly. Although the influence of reaction time on the fractions of gaseous products was negligible at time above 300 s, the yields of H₂, CH₄, and CO₂ increased with reaction time whereas the CO, C₂H₄ and C₂H₆ yields decreased. Tar and char formation was evident on the interior surface of capillary quartz reactor. Adding a little oxidant could increase H₂ and CH₄ yields and decrease tar and char formation. GY_H2 reached up to the maximum of 231.3 mmol L^?1 leachate at 500 °C, 25 MPa, 600 s and 0.2 OC, which was 2.4 times of that without oxidant.     

Hydrogen evolution in microbial electrolysis cells treating landfill leachate: Dynamics of anodic biofilm

This study investigates the potential opportunities of hydrogen evolution treating landfill leachate in a set of two microbial electrolysis cells (MEC-1 and 2) under 30 °C and 17 ± 3 °C temperatures, respectively. The system achieved a projected current density of 1000–1200 mA m^?2 (MEC-1) and 530–755 mA m^?2 (MEC-2) coupled with low cost hydrogen production rate of 0.148 L La^?1 d^?1 (MEC-1) and 0.04 L La^?1 d^?1 (MEC-2) at an applied voltage of 1.0 V. Current generation led to a maximum COD oxidation of 73 ± 8% (MEC-1) and 65 ± 7% (MEC-2) with ≥100% energy recovery. The system also exhibited a high hydrogen recovery (66–95%), pure hydrogen yield (98%) and tremendous working stability during two months of operation. Electroactive microbes such as Pseudomonadaceae, Geobacteraceae and Comamonadaceae were found in anodophilic biofim, along with Rhodospirillaceae and Rhodocyclaceae, which could be involved in hydrogen production. These results demonstrated an energy-efficient approach for hydrogen production coupled with pollutants removal.     

中国城市生活垃圾填埋气甲烷产量评估

研究了国内城市生活垃圾清运量、填埋量、构成特点及变化趋势,采用联合国政府间气候变化委员会(IPCC)推荐的用于估算填埋气甲烷产量的IPCC缺省法,对2005～2009年中国城市生活垃圾填埋气甲烷产量进行了初步评估;目前我国年垃圾填埋气甲烷产量已超过50亿m3,可转化为电能200亿kWh左右,人口密度越大、经济越发达地区其填埋气产量越高,在地域上呈现由东到西递减趋势。开发填埋气回收利用工程,不仅能有效地控制温室气体甲烷的排放,而且通过净化后还可获得资源量可观的清洁能源,实现能源与环保的双赢。     

垃圾渗滤液膜滤浓缩液处理技术的研究进展

随着人们生活水平的提高和综合素质的增强,大家对环境保护的意识也越来越强。垃圾渗滤液因为其成分复杂,浓度高,成为当今比较棘手且热门的污水处理问题。目前,较为常见的垃圾渗滤液处理工艺流程是膜生物反应器(MBR),纳滤(NF)与反渗透(RO)组合工艺。但是这种工艺会产生浓度极高且成分复杂的膜滤浓缩液,在污水处理过程中是难度很大的一部分。总结了现阶段国内外流行的几种处理垃圾渗滤液膜滤浓缩液的技术,并对其在经济、能耗、环保等方面进行了分析和总结。     

SMFC处理不同浓度垃圾渗滤液的效果及产电性能

构建沉积型微生物燃料电池(SMFC),并考察不同渗滤液浓度条件下SMFC的降解效果及产电性能。结果表明:高、低渗滤液浓度条件下SMFC对污染物质均有较好的去除能力,COD去除率分别为95%,79%,氨氮降解率分别为81%,72%;厌氧污泥中挥发性悬浮固体去除率分别为19.6%,16.4%;稳定运行时,SMFC产电均呈周期性变化,最高输出电压分别为0.261,0.078 V(外阻为1 000Ω),功率密度分别为10.35,0.204 m W/m2。因此,SMFC可实现对垃圾渗滤液的除污产电一体化,且高浓度渗滤液条件下SMFC具有更好的运行效果及产电性能。     

硫化亚铁自然氧化倾向性的研究

含硫油品储罐中，由于硫腐蚀形成的主要硫化产物硫化亚铁的氧化放热是引起油品自燃的主要原因，对硫化亚铁的自然氧化进行了跟踪实验，考查了硫化亚铁自然氧化的温度变化特征，绘制了不同条件下硫化亚铁的氧化升温曲线，分析了水分、油品及空气流量对氧化升温特征的影响，为实际生产提供了有利的理论依据。     

An integrated system for hydrogen and methane production during landfill leachate treatment

The patent-pending integrated waste-to-energy system comprises both a novel biohydrogen reactor with a gravity settler (Biohydrogenator), followed by a second stage conventional anaerobic digester for the production of methane gas. This chemical-free process has been tested with a synthetic wastewater/leachate solution, and was operated at 37 °C for 45 d. The biohydrogenator (system (A), stage 1) steadily produced hydrogen with no methane during the experimental period. The maximum hydrogen yield was 400 mL H₂/g glucose with an average of 345 mL H₂/g glucose, as compared to 141 and 118 mL H₂/g glucose for two consecutive runs done in parallel using a conventional continuously stirred tank reactor (CSTR, System (B)). Decoupling of the solids retention time (SRT) from the hydraulic retention time (HRT) using the gravity settler showed a marked improvement in performance, with the maximum and average hydrogen production rates in system (A) of 22 and 19 L H₂/d, as compared with 2–7 L H₂/d in the CSTR resulting in a maximum yield of 2.8 mol H₂/mol glucose much higher than the 1.1–1.3 mol H₂/mol glucose observed in the CSTR. Furthermore, while the CSTR collapsed in 10–15 d due to biomass washout, the biohydrogenator continued stable operation for the 45 d reported here and beyond. The methane yield for the second stage in system (A) approached a maximum value of 426 mL CH₄/gCOD removed, while an overall chemical oxygen demand (COD) removal efficiency of 94% was achieved in system (A).     

Landfill leachate treatment by solar-driven AOPs

Sanitary landfill leachate resulting from the rainwater percolation through the landfill layers and waste material decomposition is a complex mixture of high-strength organic and inorganic compounds which constitutes serious environmental problems. In this study, different heterogeneous (TiO₂/UV, TiO₂/H₂O₂/UV) and homogenous (H₂O₂/UV, Fe²⁺/H₂O₂/UV) photocatalytic processes were investigated as an alternative for the treatment of a mature landfill leachate. The addition of H₂O₂ to TiO₂/UV system increased the reduction of the aromatic compounds from 15% to 61%, although mineralization was almost the same. The DOC and aromatic content abatement is similar for the H₂O₂/UV and TiO₂/H₂O₂/UV processes, although the H₂O₂ consumption is three times higher in the H₂O₂/UV system. The low efficiency of TiO₂/H₂O₂/UV system is presumably due to the alkaline leachate solution, for which the H₂O₂ becomes highly unstable and self-decomposition of H₂O₂ occurs. The efficiency of the TiO₂/H₂O₂/UV system increased 10 times after a preliminary pH correction to 4. The photo-Fenton process is much more efficient than heterogeneous (TiO₂, TiO₂/H₂O₂/UV) or homogeneous (H₂O₂/UV) photocatalysis, showing an initial reaction rate more than 20 times higher, and leading to almost complete mineralization of the wastewater. However, when compared with TiO₂/H₂O₂/UV with acidification, the photo-Fenton reaction is only two times faster.The optimal initial iron dose for the photo-Fenton treatment of the leachate is 60 mg Fe²⁺ L⁻¹, which is in agreement with path length of 5 cm in the photoreactor. The kinetic behaviour of the process (60 mg Fe²⁺ L⁻¹) comprises a slow initial reaction, followed by a first-order kinetics (k = 0.020 , r₀ = 12.5 mg ), with H₂O₂ consumption rate of k_H2O2 = 3.0 mmol H₂O₂, and finally, the third reaction period, characterized by a lower DOC degradation and H₂O₂ consumption until the end of the experiment, presumably due to the formation of low-molecular-weight carboxylic groups. A total of 306 mM of H₂O₂ was consumed for achieving 86% mineralization (DOC_final = 134 mg L⁻¹) and 94% aromatic content reduction after 110 kJ_UV L⁻¹, using an initial iron concentration of 60 mg Fe²⁺ L⁻¹.     

垃圾填埋气在发电方面的应用--某13.8MW电厂的运行经验

根据欧盟能源政策有关促进可再生能源和热电联产的计划，距雅典市7km远的Ano Liosia垃圾填埋场兴建了一座热电厂。结合填埋场的具体情况，对热电厂的建设和运行进行了一系列调整。填埋场产生的填埋气用来进行热电联产。由竖井和水平管网组成的集气系统将填埋气引入热电厂，产生的电足够供应15000人的城镇。热电厂2001年投入运行，包括11个热电机组，总装机容量达13．8MW，年发电量约为110GWh，全部并入电网。烟气余热回收的热量用来生产蒸汽和热水。年产热约16．5MW。文章介绍了Ano Liosia热电厂的运行经验。     

宁波大岙垃圾卫生填埋场填埋气的综合利用

介绍了宁波大岙垃圾卫生填埋场在填埋气产生量估算的基础上,开发填埋气燃烧系统、填埋气砖厂利用项目、填埋气燃烧发电项目,实现了节能减排与综合利用。     

山西省新建垃圾填埋场的渗滤液零排放研究

对新建垃圾填埋场的渗滤液零排放进行了论述,通过对新建垃圾场的特点及场区面积的划分,回灌量、蒸发量、调节池容积的综合计算得出实现渗滤液零排放的相关结论。     

Hydrogen production via CaO sorption enhanced anaerobic gasification of sawdust in a bubbling fluidized bed

This paper presents the experimental results of CaO sorption enhanced anaerobic gasification of biomass in a self-design bubbling fluidized bed reactor, aiming to investigate the influences of operation variables such as CaO to carbon mole ratio (CaO/C), H₂O to carbon mole ratio (H₂O/C) and reaction temperature (T) on hydrogen (H₂) production. Results showed that, over the ranges examined in this study (CaO/C: 0-2; H₂O/C: 1.2-2.18, T: 489-740 °C), the increase of CaO/C, H₂O/C and T were all favorable for promoting the H₂ production. The investigated operation variables presented different influences on the H₂ production under fluidized bed conditions from those obtained in thermodynamic equilibrium analysis or fixed bed experiments. The comparison with previous studies on fluidized bed biomass gasification reveals that this method has the advantage of being capable to produce a syngas with high H₂ concentration and low CO₂ concentration.     

Characteristics of vegetation and its relationship with landfill gas in closed landfill

An investigation was carried out to elucidate landfill gas (LFG) and the vegetation characteristics in closed landfill. The results indicate that the stabilization process of the landfill is an important factor influencing the components of landfill gases. The coverage, height and species of vegetation increase with the closed time of landfill. Fourteen species were observed in the investigated cells, dominated by Phragmites australis, an invasive perennial plant. The concentrations of methane and carbon dioxide from vegetated cover soil were lower than those from non-vegetated cover soil.     

Effect of recirculation on bioelectricity generation using microbial fuel cell with food waste leachate as substrate

Recirculation is one of the effective techniques used to upsurge the output of anaerobic reactors. The present study investigates the effect of recirculation of anolyte on bioelectricity generation using food waste leachate in two chamber Microbial Fuel Cell (MFC) with carbon electrodes and Ultrex as proton exchange membrane (PEM). The MFCs are operated in fed-batch mode at varying COD concentrations of 500–1250 mg/L with the hydraulic retention time of 17 h for recirculation. Maximum current density, power density and columbic efficiencies of 100.34 mA/m², 14.42 mW/m² and 10.25% respectively for MFC without recirculation and 150.30 mA/m², 29.23 mW/m² and 14.22% respectively for MFC provided with recirculation are obtained at COD of 1250 mg/L. Comparative performance analysis of the cells indicates that recirculation enhances the bioelectricity production in MFC. Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) analyses are also done to find the changes in PEM.