A comparison of the toxicity of landfill leachate exposure at the seed soaking and germination stages on Zea mays L. (maize)

To compare the toxicity of landfill leachate exposure at the early stages of seed soaking and germination on maize, a field experiment was conducted to evaluate the physiological aspects of growth, yield and potential clastogenicity of root-tip cells. The maizes were treated with leachate at levels of 2%, 10%, 20%, 30% or 50% (V/V). First, the change of physiological indexes, including chlorophyll (Chl), Malondialdehyde (MDA) and Reactive oxygen species (ROS) levels, combined with yield all showed that soaking with leachate, but not germination, generated a greater ecological risk on maize. After a soaking treatment of maize with 50% leachate, the Chl, MDA and ROS levels during a vigorous growth period were 47.3%, 149.8% and 309.7%, respectively, of the control, whereas the yield decreased to 68.6% of the control. In addition, our results demonstrated that the leachate at lower levels could promote growth. This is mainly embodied in that the yield of maize treated with 10% leachate at the soaking stage increased to 116.0% of the control. Moreover, the cytological analysis experiment also demonstrated that the ecological risk of leachate still exists in both cases. Furthermore, the gray relational analysis showed that the ear row number and tassel branch number were the major factors affecting the yield of maize treated with 50% leachate at the stages of soaking and germination, respectively. In general, these results are helpful in understanding the phytotoxicity of leachate, which provides additional reference data for risk assessment and management of leachate.     

生活垃圾填埋场渗滤液处理工程实例分析

本文通过实例阐述了“混凝沉淀+两级A/O(缺氧/好氧)-MBR系统(膜生物反应器)+SWRO(海水淡化反渗透)”组合工艺在生活垃圾渗滤液处理中的应用。实际运行结果表明,当进水平均COD浓度为2668.7 mg/L、NH₃-N质量浓度为2910 mg/L时,出水平均COD浓度为7.6 mg/L、NH₃-N质量浓度为1.9 mg/L,水质可满足《生活垃圾填埋场污染控制标准》(GB16889-2008)要求,运行成本合计约为60元/m³.本工程实例将为我国生活垃圾填埋场渗滤液处理提供技术支持与经验参考。     

Effect of loading rate on shear strength parameters of mechanically and biologically treated waste

● Mechanical behavior of MBT waste affected by loading rate was investigated. ● Shear strength ratio of MBT waste increases with an increase in loading rate. ● Cohesion is inversely related to loading rate. ● Internal friction angles are positively related to loading rate. ● MBT waste from China shows smaller range of φ. Mechanical biological treatment (MBT) technology has attracted increasing attention because it can reduce the volume of waste produced. To deal with the current trend of increasing waste, MBT practices are being adopted to address waste generated in developing urban societies. In this study, a total of 20 specimens of consolidated undrained triaxial tests were conducted on waste obtained from the Hangzhou Tianziling landfill, China, to evaluate the effect of loading rate on the shear strength parameters of MBT waste. The MBT waste samples exhibited an evident strain-hardening behavior, and no peak was observed even when the axial strain exceeded 25%. Further, the shear strength increased with an increase in the loading rate; the effect of loading rate on shear strength under a low confining pressure was greater than that under a high confining pressure. Furthermore, the shear strength parameters of MBT waste were related to the loading rate. The relationship between the cohesion, internal friction angle, and logarithm of the loading rate could be fitted to a linear relationship, which was established in this study. Finally, the ranges of shear strength parameters cohesion c and effective cohesion c ´ were determined as 1.0–8.2 kPa and 2.1–14.9 kPa, respectively; the ranges of the internal friction angle φ and effective internal friction angle φ ´ were determined as 16.2°–29° and 19.8°–43.9°, respectively. These results could be used as a valuable reference for conducting stability analyses of MBT landfills.     

某生活垃圾卫生填埋场填埋作业区覆膜抽气除臭试验研究

本文采用三种不同的覆膜抽气模式对填埋场作业面进行除臭试验研究,结果表明:覆膜1.0mm+3台负压车、2条负压管比单层覆膜0.3mm+1台负压抽气车、2条临负压管或覆膜0.3mm+3台负压车对氨气、硫化氢和臭气浓度的去除效果都要更好;但覆膜抽气法对总挥发性有机物(Total Volatile Organic Compounds,TVOC)的去除效果较之前更差,这主要是由于TVOC主要为分子量较大的有机物,扩散较慢,且垃圾堆体在厌氧条件下产生的TVOC浓度更高。     

翠屏山垃圾填埋场存在的问题及处理

分析了徐州市翠屏山垃圾填埋场存在的问题，提出了相应的解决方法。     

Effects of introducing energy recovery processes to the municipal solid waste management system in Ulaanbaatar, Mongolia

Currently, most developing countries have not set up municipal solid waste management systemswith a viewof recovering energy fromwaste or reducing greenhouse gasemissions. In this article, we have studied the possible effects of introducing three energy recovery processes either as a single or combination approach, refuse derived fuel production, incineration and waste power generation, and methane gas recovery from landfill and power generation in Ulaanbaatar, Mongolia, as a case study. We concluded that incineration process is the most suitable as first introduction of energy recovery. To operate it efficiently, 3Rs strategies need to be promoted. And then, RDF production which is made of waste papers and plastics in high level of sortingmay be considered as the second step of energy recovery. However, safety control and marketability of RDF will be required at that moment.     

Estimation of Biogas Generation from a Uasb Reactor via Multiple Regression Model

In this study, regression analysis based an estimation model for biogas generated from an up-flow anaerobic sludge blanket (UASB) reactor treating landfill leachate is developed using several leachate parameters, such as pH, conductivity, total dissolved solids, chemical oxygen demand, alkalinity, chloride, total Kjeldahl nitrogen, ammonia, total phosphorus. These landfill leachate parameters are monitorized over a period of 1000 days at 35 ± 1°C in the UASB reactor. In order to develop the best model giving highest estimation performance, eight model equations including different input parameter combinations are analyzed. Based on the results of regression analysis, the best coefficients of the model equation are determined. As a conclusion, the developed model in this study can give accurate biogas amount prediction for the USAB reactor-based leachate treatment system.     

Anaerobic oxidation of methane coupled to sulfate reduction: Consortium characteristics and application in co-removal of H2S and methane

Anaerobic sludge from a sewage treatment plant was used to acclimatize microbial colonies capable of anaerobic oxidation of methane (AOM) coupled to sulfate reduction. Clone libraries and fluorescence in situ hybridization were used to investigate the microbial population. Sulfate-reducing bacteria (SRB) (e.g., Desulfotomaculum arcticum and Desulfobulbus propionicus) and anaerobic methanotrophic archaea (ANME) (e.g., Methanosaeta sp. and Methanolinea sp.) coexisted in the enrichment. The archaeal and bacterial cells were randomly or evenly distributed throughout the consortia. Accompanied by sulfate reduction, methane was oxidized anaerobically by the consortia of methane-oxidizing archaea and SRB. Moreover, CH₄ and SO₄^2 ? were consumed by methanotrophs and sulfate reducers with CO₂ and H₂S as products. The H₃CSH produced by methanotrophy was an intermediate product during the process. The methanotrophic enrichment was inoculated in a down-flow biofilter for the treatment of methane and H₂S from a landfill site. On average, 93.33% of H₂S and 10.71% of methane was successfully reduced in the biofilter. This study tries to provide effective method for the synergistic treatment of waste gas containing sulfur compounds and CH₄.     

Microbial aerosol particles in four seasons of sanitary landfill site: Molecular approaches, traceability and risk assessment

Landfill sites are regarded as prominent sources of bioaerosols for the surrounding atmosphere. The present study focused on the emission of airborne bacteria and fungi in four seasons of a sanitary landfill site. The main species found in bioaerosols were assayed using high-throughput sequencing. The SourceTracker method was utilized to identify the sources of the bioaerosols present at the boundary of the landfill site. Furthermore, the health consequences of the exposure to bioaerosols were evaluated based on the average daily dose rates. Results showed that the concentrations of airborne bacteria in the operation area (OPA) and the leakage treatment area (LTA) were in the range of (4684 ± 477)–(10883 ± 1395) CFU/m³ and (3179 ± 453)–(9051 ± 738) CFU/m³, respectively. The average emission levels of fungal aerosols were 4026 CFU/m³ for OPA and 1295 CFU/m³ for LTA. The landfill site received the maximum bioaerosol load during summer and the minimum during winter. Approximately 41.39%– 86.24% of the airborne bacteria had a particle size of 1.1 to 4.7 µm, whereas 48.27%– 66.45% of the airborne fungi had a particle size of more than 4.7 µm. Bacillus sp., Brevibacillus sp., and Paenibacillus sp. were abundant in the bacterial population, whereas Penicillium sp. and Aspergillus sp. dominated the fungal population. Bioaerosols released from the working area and treatment of leachate were the two main sources that emerged in the surrounding air of the landfill site boundary. The exposure risks during summer and autumn were higher than those in spring and winter.     

高级氧化技术在垃圾渗滤液处理中的应用

垃圾渗滤液是一种成分非常复杂的高浓度有机废水.本文介绍了高级氧化技术在垃圾渗滤液处理中的应用现状.主要包括Fenton氧化法、光化学催化氧化法、湿式氧化法、臭氧氧化法、超声氧化法、电化学氧化法、超临界水氧化法及等离子体技术在垃圾渗滤液处理中的应用,分析了高级氧化技术处理垃圾渗滤液的原理,探讨了它们的优缺点,并对高级氧化技术处理垃圾渗滤液应用的未来发展进行了展望.