Fe/C微电解法提高垃圾渗滤液的可生化性

Fe/C微电解法是以金属腐蚀的原理处理垃圾渗滤液的一种高级氧化技术,通过铁屑在渗滤液中同Cu、C、N等物质发生发应,产生氧化还原反应,形成絮凝物质从渗滤液中分离。在厌氧出水经Fe/C微电解进一步提高垃圾渗滤液可生化性的研究中,控制反应在酸性条件下进行,pH调节在5.0左右,Fe/C比(质量比)为1:1,调节搅拌转数为150 r/min,反应时间为60 min,出水的BOD5/CODCr(B/C)可达到0.3~0.4。Fe/C微电解法处理垃圾渗滤液,其B/C平均提高到0.365,平均净提高0.292,可生化性大大增强,有利于后续生物处理的进行。

H_2S removal in landfill leachate treatment using UASB reactor

Leachate from a sanitary landfill site in Chengdu, China is treated using a hybrid-UASB reactor at pilot scale. H2S, resulting from the anaerobic bioconversion process of sulfate-reducing bacteria（SRB）, inhibits the growth and activity of methane-producing bacteria（MPB）and poses serious problems of pollution, so FeCl3is used for H2S removal. The results show that the system performs well in the treatment process. COD removal generally increases with the increase in the organic loading rate（OLR）, while the sulfate removal decreases slowly. As the OLR is higher than 7 kgCOD/（m3·d）, both COD and sulfate removal tend to be stable. When the reactor is operated at the design load of 9 kgCOD/（m3·d）, COD and sulfate removal remain about 79% and 91%, respectively. At the same time, the percentage of COD removed by SRB（CODSRB）also decreases from 8.9% to 4.0%. With FeCl3 addition, COD removal increases to 83%, while sulfate removal and CODSRBfurther decrease to 89% and 1.89%, respectively. According to the mass balance, nearly 82% of the sulfur is prevented from converting into H2S. Moreover, when the FeCl3 dosage is more than 1.6 g/L leachate, H2S can be removed totally from the biogas. Therefore, the application of FeCl3 for H2S removal in leachate treatment using the UASB reactor is very suitable and viable.

Nitrite Accumulation during the Denitrification Process in SBR for the Treatment of Pre-treated Landfill Leachate

The nitrite accumulation in the denitrification process is investigated with sequencing batch reactor （SBR） treating pre-treated landfill leachate in anoxic/anaerobic up-flow anaerobic sludge bed I（UASB）. Nitrite accumulates obviously at different initial nitrate concentrations （64.9,54.8,49.3 and 29.5 mg·L^-1 ） and low temperatures, and the two break points on the oxidation-reduction potential （ORP） profile indicate the completion of nitrate and nitrite reduction. Usually, the nitrate reduction rate is used as the sole parameter to characterize the denitrification rate, and nitrite is not even measured. For accuracy, the total oxidized nitrogen （nitrate ＋ nitrite） is used as a measure, though details characterizing the process may be overlooked. Additionally, batch tests are conducted to investigate the effects of C/N ratios and types of carbon sources on the nitrite accumulation during the denitrification. It is observed that carbon source is sufficient for the reduction of nitrate to nitrite, but for further reduction of nitrite to nitrogen gas, is deficient when C/N is below the theoretical critical level of 3.75 based on the stoichiometry of denitrification. Five carbon sources used in this work, except for glucose, may cause the nitrite accumulation. From experimental results and cited literature, it is concluded that Alcaligene species may be contained in the SBR activated-sludge system.

Molecular analysis of microbial community in a groundwater sample polluted by landfill leachate and seawater

Seashore landfill aquifers are environments of special physicochemical conditions (high organic load and high sa- linity), and microbes in leachate-polluted aquifers play a significant role for intrinsic bioremediation. In order to characterize microbial diversity and look for clues on the relationship between microbial community structure and hydrochemistry, a cul- ture-independent examination of a typical groundwater sample obtained from a seashore landfill was conducted by sequence analysis of 16S rDNA clone library. Two sets of universal 16S rDNA primers were used to amplify DNA extracted from the groundwater so that problems arising from primer efficiency and specificity could be reduced. Of 74 clones randomly selected from the libraries, 30 contained unique sequences whose analysis showed that the majority of them belonged to bacteria (95.9%), with Proteobacteria (63.5%) being the dominant division. One archaeal sequence and one eukaryotic sequence were found as well. Bacterial sequences belonging to the following phylogenic groups were identified: Bacteroidetes (20.3%), β, γ, δ and ε-subdivisions of Proteobacteria (47.3%, 9.5%, 5.4% and 1.3%, respectively), Firmicutes (1.4%), Actinobacteria (2.7%), Cyanobacteria (2.7%). The percentages of Proteobacteria and Bacteroides in seawater were greater than those in the groundwater from a non-seashore landfill, indicating a possible influence of seawater. Quite a few sequences had close relatives in marine or hypersaline environments. Many sequences showed affiliations with microbes involved in anaerobic fermentation. The remarkable abundance of sequences related to (per)chlorate-reducing bacteria (ClRB) in the groundwater was significant and worthy of further study.

Iron Reduction and Adsorption on Shewanella Putrefaciens nearby Landfills in Northwest Florida

In Northwest Florida, the soil is mainly covered by poorly drained sandy soil of Myakka, which is characterized by a subsurface accumulation of humus and AI and Fe oxides. When organic rich landfill leachate is leaked to the iron rich soils, ferrous iron is released with the oxidation of organic compounds in the leachate. In this research, we investigated the activities of S. putrefaciens in reducing iron oxide in the iron rich soil of Northwest Florida with landfill leachate serving as the carbon source. S. putrefaciens had similar maximum specific growth rate and half saturation coefficients for all the leachate and soil samples. The average maximum specific growth rate was 0.008 hr^-1 and the average half saturation coefficient was 243.8 mg/L. Averagely, 2.2 mg ferrous iron was generated per mg COD consumed. In addition, adsorption of reduced ferrous iron on S. putrefaciens was further characterized. Ferrous iron adsorption on S. putrefaciens was a kinetic process, which increased with the increase of the reaction time. Equilibrium ferrous iron adsorption on S. putrefaciens can be reached after three hours. Ferrous iron had linear adsorption isotherms on S. putrefaciens for the pH range of 5 to 9.

Analysis of pollutant components in landfill leachate from hinterland landfill in Three Gorge Water Reservoir

This paper mainly discusses the protection of water resource environment in Three Gorge Water Reservoir, a systematic investigation and analysis of the landfill leachate＇s polluting components, hazardous and changing rule in landfill leachate from hinterland landfill located in the surrounding area have been carried out, and proposed the countermeasures for disposition the leachate furtherly.

Influence of Calcination Temperature on TiO_2 Nanotubes’Catalysis for TiO_2/UV/O_3 in Landfill Leachate Solution

The influence of calcination temperature on TiO2 nanotubes＇ catalysis for TiO2/UV/03 was investigated. TiO2 nanotubes （TNTs） were prepared via the sol-gel method and calcined at 300--700 ℃, which were labeled as TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700, respectively. TNTs were characterized by transmission electron microscopy （TEM） and X-ray diffraction （XRD）. It is found that TNTs calcined at 400 ℃ showed the best thermal stability. When the calcination temperature increased from 400 ℃ to 700 ℃, the special structure of tubes was destroyed and gradually converted into nanorods and/or particles. The transformation from anatase to rutile occurred at 600 ℃, and the rutile phase was enhanced when the calcination temperature was increased to over 600 ℃. The calcina- tion temperature＇s influence on TNTs＇ adsorption activity for for TiO2/UV/O3 was investigated in landfill leachate solution chemical oxygen demand （COD） and catalytic activity In landfill leachate solution, the adsorption activity of COD decreased in the reduced order of TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700. In photocatalytic ozonation, TNTs-400 showed the best catalytic activity while TNTs-700 exhibited the worst. In other three processes, the COD removal of TNTs-300/UV/O3 was higher than those of TNTs-500/UV/O3 and TNTs-600/UV/O3 in the first 20 rain, and then became close to those of the latter two in the following 40 rain. Compared with TNTs-300 and TNTs- 400, TNTs-600 had the best anti-fouling activity, while TNTs-500 and TNTs-700 had lower anti-fouling activity than the former three. In photocatalytic ozonation, the calcination temperature of 400 ℃ was appropriate when TNTs were obtained at the synthesis temperature of 105 ℃.

Removal of Pb(Ⅱ) ions from aqueous solutions by litchi pericarp and its leachate

The adsorption capacity of Pb(Ⅱ) on litchi pericarps was investigated as a function of temperature,pH,and adsorbent dose using batch experiments.The experimental data obtained were evaluated using adsorption equilibrium isotherms and a kinetic model.Additionally,the removal of Pb(Ⅱ) in leachate of litchi pericarps was also evaluated.The results show that litchi pericarps exhibit a high adsorption capacity to Pb(Ⅱ),with the maximum removal efficiency occurring at a temperature of 25 ℃,a pH of 6.0-7.0 and an adsorbent dosage of 10 g/L.Langmuir and Freundlich isotherms and the pseudo-second-order kinetic model can all fit the equilibrium adsorption satisfactorily,with correlation coefficients(R^2) of 0.9935,0.9918 and 1.0,respectively.An average removal efficiency of 66.65% is found for Pb(Ⅱ) in leachate of litchi pericarps.

Characterization of Indigenous and Adapted Hydrocarbon Degrading Bacteria Isolated from Landfill Leachate from Ain Temouchent Engineered Landfill, Algeria

One of the most important issues regarding the design of engineered landfill is landfill leachate that is produced when water passes through the waste. Landfill Leachate comprises a mass of different organic and inorganic components which can be dissolved or suspended. Regardless of the nature of the components, it poses a potential pollution on local land and surface waters. The present work was undertaken to assess, isolate, identify and characterize the hydrocarbon degrading bacteria associated with environmental samples collected from discharge of Ain Temouchent, Algeria. The samples （landfill leachate） were chemically and microbiologically analyzed using standard techniques. These organisms were further studied to determine the level of biodegrading activities on hydrocarbons as the single carbon source using enrichment medium under different physical and chemical parameters （pH, temperature, NaCI and tolerance of crude oil...）, The identification of seven strains isolated named as Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudornonas sp., Staphylococcus aureus, Staphylococcus xylosus, Staphylococcus hominis and Staphylococcus warnerii. These strains growth on a neutral medium and temperature between 30 ℃ and 37 ℃, 5 at 6% of NaCI concentration, and can use a concentration of 5 at 10% of crude oil as sole source of carbon.

Tropical Leachate Properties as a Growing Media for Algae as a Source of Biodiesel Production

Algae can be found in ponds, rivers, lakes, abandoned ponds and also can grow abundantly in the aged pond of leachate landfill since there is the source of sunlight, CO2 （carbon dioxide） and nutrients. Like plants, algae make their own food by photosynthesis but differ from the plant; algae do not have roots, petals, stems or leaves. Leachate is the water that contains dissolved and suspended solids resulting from the percolation of water that drains through the waste in the landfill. The constituents of the leachate include organic matters and inorganic matters which depend on the age of landfill and type of the waste. The aim of this research study is to identify the characteristics of the leachate from aged landfill that cause the growth of the algae. Metals that act as the nutrients that exist in the leachate were measured using ICP-OES （inductively coupled plasma-optical emission spectroscopy）. BOD5 （biochemical oxygen demand that is measured in 5 days） and COD （chemical oxygen demand） were measured using DO （dissolved oxygen） meter and spectrophotometer, respectively. The pH of the leachate was measured using pH meter. The results showed that the highest metal that exists in the leachate was magnesium in quantity of 8.52 ppm. BOD5 and COD of the leachate gave the results of 5.24 mg/L and 99.67 mg/L, respectively. The pH of the leachate is considered as alkaline since the value of the pH is 8.38. This indicates that the characteristics of the leachate for algae growth was aged landfill with the alkaline condition and the nutrient needed by the algae for growing is magnesium.

Evapotranspiration and Removal Performance in the Treatment of High Salinity LandfilI-Leachate Using HSF

In this study, the water budget in the treatment of high salinity landfill-leachate was estimated and the influence of evapotranspiration （ET） on treatment performance was investigated. The salinity of the inside of horizontal subsurface flow constructed wetland （HSF） of the raw leachate inflow was 15.0± 3.4 g.Cl/L which was in the level of the salinity of the survival limit of reed, and that of the double diluted leachate inflow was 9.3 ± 1.9 g.CI7L. There were large differences in the vegetation between HSF of the raw leachate inflow and that of the double diluted leachate inflow. The dense vegetation bed of double diluted leachate inflow during the growing season （April-October） provided a high ET and a large water loss, which made great contributions to the reduction of the outflow load of COD and T-N. The HSF with die-back reeds in the non-growing season （November-March） provided a slight ET and a small water loss and made less of a contribution to pollutant removal compared to the HSF with dense vegetation bed during the growing season. However, the HSF with die-back reeds during the non-growing season exhibited higher removal performance than the unplanted HSF.

Prediction of Leachate Generation in a Landfill Using Artificial Neural Networks

One of the problems encountered in the operation of a leachate treatment in a landfill is the quantity of the fluctuating leachate. Therefore, information on the precise prediction about the quantity of leachate produced in a landfill is required. This information can be obtained by using an ANN （artificial neural networks） model. In this study, a prediction on a leachate generation for a period of 15 days was made. The input for the ANN model consists of data such as rainfall, temperature, humidity, duration of solar radiation, and the landfill characteristics, while the output is the leachate landfills production in Minamiashigara, Japan. The ANN algorithm uses a BP （back propagation） with LM （Levenberg-Marquadrt） training type. By using the input-output data pairs, the training of ANN model was conducted in order to obtain the values of the weights that describe the relationship between the input-output data. Furthermore, with the trained ANN model, the prediction of leachate generation for a period of 15 days was made. The study result shows that the prediction accuracy ofleachate generation of ANN-C model, with a correlation coefficient （r） of 0.924, is quite good. Thus, the prediction of leachate generation using artificial neural network model can be recommended for predicting leachate generation in the future. In this study, a prediction on a leachate generation for a period of 15 days was made. The quantity of leachate generation in a landfill can be obtained by using ANN for future periods. By entering data for future periods （t ＋1） in ANN models, the leachate generation for the period （t ＋1） can be predicted.

Determination of heavy metal ion in landfill leachate with solvent extracting ＆ fluorescence quenching method

Add the masking agent and biscyclohexanoneoxalyldihydraone into the diluted clarificd liquid of the landfill leachate which was treatmented by digestion and centrifugal filtration to complexate all heavy metal ion in the trcatmented liquid, and extracted using CHCl3 many time, then it were demasking and decomposing respectively, and adjusted different pH and formed Me^n＋-PAN coordination compound when these metal ion reaction with PAN. The Fluoresence quenching of Rh6G （λex/λem=543mn/558nm） when the metal ion coordination compound was add into the Rh6G solution step by step, the quenching intensity was directly proportional to the concentration of the metal ion in the certain range. So a new method of fast and simple for determination of trace metal ion in landfill lcachate was established to determine metal ion in sample of different landfill leachate in Three Gorge Water Reservoir, and comparison the classic assay method with satisfactory results.

Treatment of Landfill Leachate by Stripping and Catalytic Ozone Oxidation

In order to investigate the effect of stripping and catalytic ozone oxidation technology on COD and ammonia nitrogen removal after coagulation and sedimentation, the efficiency of ozone oxidation and catalytic ozone oxidation were compared. The experimental results showed that： stripping and catalytic ozone oxidation technology has a significant effect on landfill leachate treatment. The removal rate of the COD and NH3-N can reach 88.60% and 98.00% under the initial concentration of COD and NH3-N were 2053.35 mg/L and l 123. 76 mg/L separately.

Volume and Toxic Composition of Leachate from an Open Dump

In Mexico, hazardous and non-hazardous urban solid wastes are commonly disposed of in dumps. Inappropriate waste disposal makes solid waste disposal sites potential sources of pollution and health risks. The objective of the present study was to evaluate the impact of leachate from a dump on surface water systems. Physical, chemical, and bacteriological characteristics and the volume of leachate were measured. The site of study is located in Zinaprcuaro, Michoac^m, Mexico, and was chosen due to the water supplies were in line with the dump, thus conforming a system to test for movement of toxins. Leachate and water from three ponds located at different distances to the dump were sampled during three months of a year to measure physicochemical and bacteriological parameters, according to the standard methods of the American Public Health Association; the concentration of heavy metals was measured by atomic absorption spectrometry. Most characteristics exceed the maximum permissible limits established for the Mexican legislation regarding wastewater discharges and drinking water. Likewise, analysis of variance showed statistically significant differences between concentrations of pollutants in relation to the distance from the dump of sampled sites and with season of sampling, thus confirming the contamination of water by dump leachate.

Particle size distribution of the organic matters in the treated leachate using aged-refuse-bioreactor

Micro-filtration membrane （1.2 μm）, hyper-filtration membrane （0.45 μm） and nano-filtration membrane （1000 Dalton） were used to characterize the particle size distribution of the organic matters in effluent leachate treated by the aged-refuse-bioreactor（ARB） installed at Laogang Refuse Landfill, Shanghai. The results showed that the particle size distribution of the treated fresh and aged leachate using the ARB were quite consistent. The organic matter with particle size below 1000 Dalton accounted for about 90%, balanced with the suspended （〉1.2 μm） and colloidal （1000 Dalton-l.2μm） matters. Hence, it is proposed that coagulation, nano-filtration and electrically chemical oxidation may be not applicable for the advanced treatment for the effluents to reach the discharge standard limit value defined in Chinese national Standard for Pollution Control on the Landfill Site of Municipal Solid Wastes （GB16889-2008）, CODCr〈100 mg/L. Aged refuse bioreactor combined reverse osmosis was suggested as an economically and technically feasible technology to treat sanitary landfill leachate.

Effect of Leachate Recirculation on Characteristics of Leachate Generation of Municipal Solid Waste from Landfill Lysimeter

The objectives of this study are to determine the characteristics of leachates generated from landfill lysimeters of municipal solid waste. Two lysimeters with diameter and height of 0.70 and 2.40 m, respectively, were prepared. The lysimeters were operated with and without leachate recirculation. The leachate produced were quantified and characterised every day for the quantity, pH and ORP （oxidation reduction potential）. Meanwhile, the BOD and COD parameters were characterised every once week. Based on the data of experimental results that the lysimeter with a recirculation gave positive effects on the degradation of waste in landfills, that is the degradation process becomes faster. This is indicated by the quantity and quality of leachate generated. The lyisimeter conducted with recirculation of leachate shew the quantity of leachate generated larger than the lysimeter without recirculation. While the quality of the leachate includes pH, ORP, made it shown that the degradation process is faster. These results operations, especially for young waste. BOD and COD indicate that leachate recirculation on lysismeter suggest that leachate recirculation can be performed on landfills

Effects of Biochars and Other Organic Soil Amendments on Plant Nutrient Availability in an Ustoxic Quartzipsamment

A sandy soil, Nampong soil （classified as Ustoxic Quartzipsamment）, was incubated under controlled condition i） to compare the mineralization of major plant nutrients derived from different types of biochars and other organic soil amendments; ii） to examine their effects on soil properties and plant nutrient availability; and iii） to evaluate the plant nutrient losses in leachate from the rooting zone of soil incorporated with the different amendments. The experiment was arranged in a completely randomized design with 3 replications. Five treatments of soil amendments used were cassava stem base biochar （CSB）, rice husk biochar （RHB）, chicken manure （CM）, compost （CP）, and no amendment application （control）. The RHB treatment released the highest amounts of mineralized NO^-N, available P and K （2.30-17.26, 5.50-42.90 and 43.00-187.63 mg kg-1, respectively） while the CM treatment releasing the highest NH4＋-N in the range of 1.86-53.67 mg kg-1. The CSB and RHB treatments showed better continuity of mineralization of nutrients than the treatments of CM and CP, particularly in the case of the CSB treatment. In the soil column incubation experiment, the amounts of NH4＋-N and NO3-N in all treatments barely changed on Day 1 to Day 30 of incubation and then the amounts increased markedly on Day 60. On Day 601 the RHB treatment contained a very high amount of NO3--N （〉 250 mg kg-1）. This suggests that N would become more available 30 d after the incorporation. The CM treatment gave the highest amounts of organic matter and available P in the ranges of 4.64-8.94 g kg-1 and 14.41-36.33 mg kg-1, respectively, during the 60-d column incubation. The CSB treatment tended to have higher available K throughout the measuring period. The NO3--N was leached from the soil column quite quickly on Day 1 of incubation while the loss of NH^-N decreased slightly from Day 1 until the end of the measurement. The amounts of P and K losses varied with the type of soil amendments, and the pattern of the loss was irregular.