Advanced Treatment Of Leachate Research Articles

Electrochemical treatment for leachate membrane retentate: Performance comparison of electrochemical oxidation and electro-coagulation technology.

With the widespread use of membrane in advanced treatment of leachate, China produces a large amount of leachate membrane retentate (LMR) (≈23.4 million tons) annually, which is usually treated by incineration or recirculation in engineering, but these technologies have many drawbacks. LMR is suitable for electrochemical treatment due to its high electrical conductivity. This study compared the performances of electrochemical oxidation (EO) and electro-coagulation (EC) technology on LMR treatment under different experimental conditions, including anode material, current density, initial pH and reaction time. We found that EO optimal conditions achieved 70.1%, 83.1%, 78.7%, 98.7%, and 69.7% removal of total organic carbon (TOC), UV absorption (at 254nm), chromaticity, ammonia nitrogen (NH3-N), and total nitrogen (TN), respectively. Compared with EO, EC exhibited a similar removal ability for orgainics and better removals of chroma, but much less performance for removing nitrogen pollutants in the same reaction time, that is, removals of NH3-N and TN were only 31.5% and 36.2%, respectively. Meanwhile, EC showed much higher instantaneous current efficiency of COD than EO under its optimal reaction time (120min). In addition, the UV-Vis spectra and 3D fluorescence spectra indicated that EO exhibited relatively outstanding performance in decomposing dissolved organic matter (DOM) with rather complicated structures than EC. Also, the flow field-flow fractionation technique demonstrated that EO preferentially destroy humic-like, large molecular weight DOM, and converting them to smaller molecules, which resulted in more volatile organic compounds in EO samples than EC samples. While EC had little selectivity in the removal of organics, except humic-like DOM with relative small molecular. These findings can provide a theoretical basis for the electrochemical treatment of LMR.

Decision-making for the selection of different leachate treatment/management methods: the ANP and PROMETHEE approaches.

Municipal solid waste (MSW) landfill leachate is a highly contaminated liquid effluent. Leachate has a complex nature that needs to be appropriately treated before being discharged into the environment. There are various options for leachate treatment. Deciding which option should be applied is a complex process, since it depends on many factors that need to provide a balance between the technical, economic, and environmental aspects of sustainability. Multi-criteria decision-making (MCDM) methods are useful techniques to solve complex problems that cannot be easily solved. In this study, MCDM techniques are used for an evaluation of four different leachate treatment options: recirculation of leachate to a landfill site (A1), combined treatment with municipal wastewater (A2), anaerobic and aerobic sequential treatment (A3), and advanced leachate treatment based on membrane processes (A4). The selection of the most appropriate one, based on the criteria, analytic network process (ANP), and preference ranking organization method for enrichment evaluations (PROMETHEE) methods, was applied as MCDM techniques using the Super Decisions software and D-Sight software, respectively. Both the ANP and the PROMETHEE analysis results demonstrate that option A2 is the most appropriate for all of the decision-makers.

A review on the advanced leachate treatment technologies and their performance comparison: an opportunity to keep the environment safe.

Landfill application is the most common approach for biowaste treatment via leachate treatment system. When municipal solid waste deposited in the landfills, microbial decomposition breaks down the wastes generating the end products, such as carbon dioxide, methane, volatile organic compounds, and liquid leachate. However, due to the landfill age, the fluctuation in the characteristics of landfill leachate is foreseen in the leachate treatment plant. The focuses of the researchers are keeping leachate from contaminating groundwater besides keeping potent methane emissions from reaching the atmosphere. To address the above issues, scientists are required to adopt green biological methods to keep the environment safe. This review focuses on the assorting of research papers on organic content and nitrogen removal from the leachate via recent effective biological technologies instead of conventional nitrification and denitrification process. The published researches on the characteristics of various Malaysian landfill sites were also discussed. The understanding of the mechanism behind the nitrification and denitrification process will help to select an optimized and effective biological treatment option in treating the leachate waste. Recently, widely studied technologies for the biological treatment process are aerobic methane oxidation coupled to denitrification (AME-D) and partial nitritation-anammox (PN/A) process, and both were discussed in this review article. This paper gives the idea of the modification of the conventional treatment technologies, such as combining the present processes to make the treatment process more effective. With the integration of biological process in the leachate treatment, the effluent discharge could be treated in shortcut and novel pathways, and it can lead to achieving "3Rs" of reduce, reuse, and recycle approach.

Present Conditions and Problems regarding Advanced Leachate Treatment Technologies

Present Conditions and Problems regarding Advanced Leachate Treatment Technologies

Evaluation and remediation of organics, nutrients and heavy metals in landfill leachate – a case study in Beijing

Leachate pollution in landfill sites is a major source of environmental concern. This study evaluates organics, nutrients and heavy metals in a landfill site in Beijing, and introduces a method combining coagulation–flocculation with filtration for the advanced treatment of leachate. The results confirm that CODCr, TN, NH4+ − N, TP, Mn and As in leachate treated by an anaeobic–oxic biological method are unable to meet discharge or surface water quality standards. When treated with coagulation–flocculation combined with filtration under optimal conditions (cationic polyacrylamide dosage of 8.0 mg/L; polyaluminium chloride dosage of 350 mg/L; 0.4–0.6 mm ceramsite media in the filtration process), the residual NH4+− N, TN, Mn and As in the leachate meet the maximum allowed values for landfill leachate discharge or surface water quality standards in China; the exceptions are chemical oxygen demand and total phosphorus. Leachate treatment processes could be further strengthened or improved.

Advanced treatment of leachate by using aerobic/anoxic MBR system followed by a nanofiltration process. A case study in Istanbul Komurcuoda Leachate Treatment Plant

Advanced treatment of leachate by using aerobic/anoxic MBR system followed by a nanofiltration process. A case study in Istanbul Komurcuoda Leachate Treatment Plant

Advanced Treatment of Stabilized Leachate by Sodium Hypochlorite Composite Chemicals

In this work, advanced treatment of leachate after biological treatment was performed using sodium hypochlorite solution (NaClO) + ferric chloride (FeCl3) + polyacrylamide (PAM) and NaClO + aluminum poly-chloride (PAC) + PAM, respectively, to determine the optimal condition for removal of COD and color. It was found that the optimal condition was: PAM 5 mg/L, FeCl3 420 mg/L, NaClO 6 mL/L, reaction time 15 min for treatment using FeCl3 + NaClO + PAM, and PAM 5 mg/L, PAC 800 mg/L, NaClO 6 mL/L, reaction time 15 min for PAC + NaClO + PAM. After being treated at the optimal conditions, the effluent quality met requirements of the tertiary grade described in “Integrated wastewater discharge standard”.

Advanced treatment of landfill leachate from a sequencing batch reactor (SBR) by electrochemical oxidation process

Biologically stabilized landfill leachate usually requires further removal of organic substances and ammonia nitrogen (NH3-N) before final discharge. In this paper, the advanced treatment of landfill leachate pretreated by sequencing batch reactor (SBR) via electrochemical oxidation was carried out in an electrochemical compartment reactor with oxide-coated titanium anode (Ti/TiO2-IrO2). The effect of voltage, chlorine content, initial pH value, and ferrous sulfate (FeSO4) on the removal efficiency of contaminants was investigated systematically. The removal efficiency of organic pollutants and ammonia nitrogen (NH3-N) increased with the increase of voltage, chlorine content and the addition of ferrous iron. The initial pH value has a different effect on the removal of COD and NH3-N. Compared with the traditional electrochemical oxidation, the process with Fe(II/III) is more efficient with low power consumption, and the removal efficiency of organic pollutant is slightly lower when Fe(II) is used. A lower power consumption of 16.6 kWh·(kg COD)–1 indicated the electrochemical oxidation with Fe(II) was a promising alternative for the advanced treatment of leachate.

Advanced leachate treatment at Buckden landfill, Huntingdon, U.K.

During April 1994, Aspinwall and Company was appointed to design and commission a treatment plant to treat leachate from the Buckden South Landfill Site, located about 1 km SW of Huntingdon in Cambridgeshire, U.K. The landfill is located in the flood plain of the River Great Ouse, which flows within 400 m of the site. Leachate characterization and flow studies took place during early 1994, after an extensive fin drain collection and interception system had been installed. Aspinwall then undertook leachate treatment trials, as part of the detailed design of the on-site treatment plant that needed to be capable of treating 200 m3/d of leachate to very high standards. The treatment trials were carried out to investigate and design an aerobic biological process that would provide primary treatment, before secondary effluent polishing stages that would involve reed beds and ozonation. The latter specialized stage was intended to provide treatment of a range of pesticides, including the herbicides mecoprop and isoproturon, which were found in leachate and might not be removed fully by biological treatment stages. The leachate also contained contaminants typical of methanogenic conditions, including ammoniacal-N at values in excess of 400 mg/L, with a required effluent discharge consent standard of 10 mg/L. Key words: leachate, mecoprop, isoproturon, biological treatment, ozonation, reed bed, toxicity-based consent.