Treatment Of Stabilized Landfill Leachate Research Articles

Microalgae cultivation in stabilized landfill leachate for simultaneous treatment and biomass production

BackgroundThe high toxicity of landfill leachate has motivated to an investigation of economical and ecological treatment prior releasing into environment. Recently, microalgae have emerged as an alternative method due to its ability to recover nutrient and potential for bio-fuel production. However, the high concentrations of inhibitory compounds and ammoniacal nitrogen in young landfill leachates require high dilutions for microalgae to thrive. Hence, this study aims to evaluate the performance of microalgae by using stabilized landfill leachate with lower to no dilutions in nutrient removal, biomass and lipid production. MethodsLeachate concentrations of 33, 44, 66, 89 and 100 v/v% were initially treated with the microalgae C. vulgaris. Parameters of chemical oxygen demand (COD), ammoniacal nitrogen (NH3–N), orthophosphate (PO43−), total phosphorus (TP) and colour removal were evaluated. Cost analysis was conducted to evaluate the economical appropriateness. Significant findingsThe highest removals were achieved at 43.67% of COD, >97% of NH3–N, 79.26% of PO43−, 77.64% of TP and 44.04% of colour. Highest biomass yield obtained was 220 mg/L by 89 v/v% of leachate concentration with 8.14% of lipid yield. Cost of treatment was calculated to be ∼$0.02 per m3 leachate. The feasibility of stabilized landfill leachate treatment without any dilutions using microalgae was attained as they can survive amidst this condition, perform nutrient removals, and produce biomass simultaneously.

Performance of Ozone/SnCl4 Oxidation in Stabilized Landfill Leachate Treatment

Landfill leachate is well known as contains a high concentration of pollutants and threatens our environment as well as human life. Therefore, this study investigates the potential of ozonation (O3) and tin tetrachloride (SnCl4) in remedying stabilised landfill leachate (SAL). The performance of this treatment is evaluated by measuring the percentage removal of chemical oxygen demand (COD) and colour at different dosages, pH, and reaction times. The optimum percentage removals recorded for colour and COD were 98% and 83.2%, respectively, at an optimum dosage ratio (COD: SnCl4) 1:1.25, reaction time of 60 min and pH 8.5. Moreover, the biodegradability ratio of the sample also shows an improvement from 0.03 to 0.28, using this treatment. Thus, these data show that the oxidation process has a great potential to remediate recalcitrant pollutants like leachate

Multi-response optimization of coagulation-flocculation process for stabilized landfill leachate treatment using a coagulant based on an industrial effluent

Multi-response optimization of coagulation-flocculation process for stabilized landfill leachate treatment using a coagulant based on an industrial effluent

Development of a novel polyvinylidene fluoride membrane integrated with palm oil fuel ash for stabilized landfill leachate treatment

Stabilized landfill leachate is a complex wastewater containing high concentration of non-biodegradable organic compounds and Ammoniacal nitrogen. Thus, an advanced treatment such as membrane technology is required to treat leachate effectively. In this study, membrane filtration process was employed to treat stabilized leachate. A new type of membrane was fabricated by incorporating palm oil fuel ash (POFA) into hydrophobic polyvinylidene fluoride (PVDF) polymer to produce flat sheet membrane via phase inversion technique. Response Surface Methodology (RSM) was applied to optimize the membrane fabrication. The filtration process was carried out using cross-flow ring (CFR) test. The best removal efficiencies of COD, colour and NH3–N was found using a membrane with the following composition: 13.9 wt% PVDF and 1.2 wt% POFA. To improve the permeability and anti-fouling ability, the best performing membrane was further modified using polyvinyl alcohol (PVA). The performance and characterization of unmodified and modified membranes were systematically analyzed. The results showed that filtration properties of modified membrane were efficiently developed by 0.5 wt% of PVA. Pure water flux value was enhanced from 40.16 to 81.08L/m2.h and transmembrane pressure was reduced from 0.60 to 0.55 bar as a result of the surface and pore size improvements. Moreover, the modified membranes significantly enhanced the removal of COD (57.06%), colour (58.27%) and NH3–N (55.44%) due to the newly developed microstructure. This study offers the best way to develop PVDF- POFA membrane improved by PVA for stabilized landfill leachate treatment. The produced PVDF membrane was also economical compared to the commercially available PVDF membrane.

Comparison study of COD and ammoniacal nitrogen adsorption on activated coconut shell carbon, green mussel (Perna viridis), zeolite and composite material in stabilized landfill leachate treatment

Comparison study of COD and ammoniacal nitrogen adsorption on activated coconut shell carbon, green mussel (Perna viridis), zeolite and composite material in stabilized landfill leachate treatment

Sequential treatment for stabilized landfill leachate by ozonation–adsorption and adsorption–ozonation methods

This paper investigates the potential use of sequential treatment using ozonation–adsorption and adsorption–ozonation processes for stabilized landfill leachate treatment. Zeolite was used as adsorbent due to its novel composition of naturally hydrated aluminosilicate minerals. Preliminary tests were conducted to determine the optimum conditions of ozone and zeolite. Results demonstrated that the usage of ozonation as a post-treatment for adsorption could effectively remove 92%, 82%, and 75% of colour, COD, and NH4–N, respectively. In addition, the application of ozonation as a pre-treatment showed a good removal for colour, COD, and NH4–N with a removal efficiency of 93%, 80%, and 71%, respectively. Also, an improvement in biodegradability of the leachate was achieved after ozonation/adsorption and adsorption/ozonation which increases the BOD5/COD ratio from 0.016 to 0.195 and 0.194, respectively, where the maximum BOD5/COD in the raw leachate was 0.02. This is attributed to the oxidation of high molecular weight organics in the sample. A combined treatment leads to a removal of inorganic and small non-biodegradable organic molecules, which decreases the COD and further improve the BOD5/COD ratio. This study demonstrates that the application of ozonation as a pre- and post-treatment with zeolite is an effective treatment method that can improve the treatment of stabilized landfill leachate .

Stabilized landfill leachate treatment by zero valent aluminium-acid system combined with hydrogen peroxide and persulfate based advanced oxidation process

The toxic leachate generated from landfills is becoming a major nuisance to the environment and has vital role in groundwater contamination. This study evaluated the potential of zero valent aluminium (ZVAl) based advanced oxidation processes (AOPs) for stabilized landfill leachate treatment. Hydrogen peroxide (HP) and persulfate (PS) were used to generate additional radicals in aerated ZVAl acid process. ZVAl-acid system achieved 83% COD removal efficiency under optimized conditions such as acid washing time of 20 min, ZVAl dose of 10 g L−1 at initial pH 1.5. The highest exclusion efficiencies in terms of TOC, COD as well as color were 83.52%, 96% and 63.71% respectively in treatment systems showing the following order: ZVAl/H+/Air/HP/PS > ZVAl/H+/Air/PS > ZVAl/H+/Air/HP > ZVAl/H+/Air > ZVAl/H+. The involvement of other metals such as Fe and Cu in the process has been found. The reusability study revealed that ZVAl powder can be effectively used up to three cycles. The 28.48 mg/l of Al3+ residue was observed in this process which has to be removed before discharge of effluent. The study indicated that the ZVAl based AOPs is stable and active for the degradation of organic pollutants present in landfill leachate and a promising solution except for the aluminium discharge which has to be given special care.

Stabilized landfill leachate treatment using heterogeneous Fenton and electro-Fenton processes

In the present study, stabilized landfill leachate treatment by heterogeneous Fenton and electro-Fenton (EF) was carried out. Iron-manganese binary oxide loaded zeolite (IMZ) was used as a catalyst for generating hydroxyl radicals in the acidic medium. Heterogeneous Fenton process was capable of removing 88.6% COD from landfill leachate at the optimal conditions, while 87.5% COD removal was observed at optimal EF treatment conditions. Biodegradability of landfill leachate was increased significantly from 0.03 to 0.52 after Fenton treatment. The prepared heterogeneous catalyst was found reusable with a reduction in COD removal rate. Even though, both the processes are efficient for leachate treatment, the low catalyst dosage requirement in case of EF process justifies that it is more feasible than Fenton process.

Stabilized landfill leachate treatment by coagulation-flocculation coupled with UV-based sulfate radical oxidation process

In this work, the feasibility of coagulation-flocculation coupled with UV-based sulfate radical oxidation process (UV/SRAOP) in the removal of chemical oxygen demand (COD) of stabilized landfill leachate (SLL) was evaluated. For coagulation-flocculation, ferric chloride (FeCl3) was used as the coagulant. The effect of initial pH of SLL and COD:FeCl3 ratio on the COD removal was evaluated. The result revealed that COD:FeCl3 ratio of 1:1.3 effectively removed 76.9% of COD at pH 6. The pre-treated SLL was then subjected to UV/SRAOP treatment. For UV/SRAOP, the sulfate radical (SR) was generated using UV-activated persulfate (UV/PS) and peroxymonosulfate (UV/PMS). The dosage of oxidant and reaction time were found to be the main parameters that influence the efficiency of COD removal. On the other hand, the effect of initial pH (3–7) and the type of oxidant (PS and PMS) was found to have no significant influence on COD removal efficiency. At optimum conditions, approximately 90.9 and 91.5% of COD was successfully removed by coagulation-flocculation coupled with UV/PS and UV/PMS system, respectively. Ecotoxicity study using zebrafish showed a reduction in toxicity of SLL from 10.1 to 1.74 toxicity unit (TU) after coagulation-flocculation. The TU remained unchanged after UV/PS treatment but slightly increased to 1.80 after UV/PMS treatment due to the presence of residual sulfate ion in the treated effluent. In general, it can be concluded that coagulation-flocculation coupled with UV/SRAOP could be a potential water treatment method for SLL treatment.

Stabilized landfill leachate treatment using Guadua amplexifolia bamboo as a source of activated carbon: kinetics study

ABSTRACTIn the present study, the characteristics of leachate generated from dumpsite called ‘Zapote’ located in southern region of Tamaulipas, Mexico were evaluated. The adsorption of non-biodegradable organic matter measured as chemical oxygen demand (COD), color and heavy metals from leachate on activated carbon (AC) prepared in acid media from Guadua amplexifolia bamboo has been studied. In addition, the computation of kinetic parameters during the adsorption process as well as the most probable mechanisms was determined. The ACs were analyzed by using scanning electron microscopy and Fourier transform infrared spectroscopy. The experimental data showed that the ACs removed up to 81.4% of color and reduced COD up to 91.6% after 9 h of reaction at 60°C. For heavy metals, the maximum adsorption uptake was achieved at pH = 8.0 within 20 min with removal percentages of 87.0% (Pb(II)), 43.0% (Cu(II)) and 30.5% (Ni(II)). A pseudo-second-order model explained the adsorption kinetics most effectively for Pb, Ni and Cu, while a pseudo-first order was found for Zn. The AC synthesized from the G. amplexifolia species could be potentially used as an effective adsorbent in the reduction of COD, and removal of color and heavy metals.

Removal of organic matter from stabilized landfill leachate using Coagulation-Flocculation-Fenton coupled with activated charcoal adsorption.

The treatment of stabilized landfill leachate (SLL) by conventional biological treatment is often inefficient due to the presence of bio-recalcitrant substances. In this study, the feasibility of coagulation-flocculation coupled with the Fenton reaction in the treatment of SLL was evaluated. The efficiency of the selected treatment methods was evaluated through total organic carbon (TOC) removal from SLL. With ferric chloride as the coagulant, coagulation-flocculation was found to achieve the highest TOC removal of 71% at pH 6. Then, the pretreated SLL was subjected to the Fenton reaction. Nearly 50% of TOC removal was achieved when the reaction was carried out at pH 3, H2O2:Fe2+ ratio of 20:1, H2O2 dosage of 240 mM and 1 h of reaction time. By coupling the coagulation-flocculation with the Fenton reaction, the removal of TOC, COD (chemical oxygen demand) and turbidity of SLL were 85%, 84% and 100%, respectively. The ecotoxicity study performed using zebrafish revealed that 96 h LC50 for raw SLL was 1.40% (v/v). After coagulation-flocculation, the LC50 of the pretreated SLL was increased to 25.44%. However, after the Fenton reaction, the LC50 of the treated SLL was found to decrease to 10.96% due to the presence of H2O2 residue. In this study, H2O2 residue was removed using powdered activated charcoal. This method increased the LC50 of treated effluent to 34.48% and the removal of TOC and COD was further increased to 90%. This finding demonstrated that the combination of the selected treatment methods can be an efficient treatment method for SLL.

Performance of combined ozone and zirconium tetrachloride in stabilized landfill leachate treatment

The current study investigated the performance of combined ozonation and zirconium tetrachloride (ZrCl4) for an anaerobic stabilized landfill leachate treatment. The effectiveness of ZrCl4 dosage [COD0/ZrCl4 ratio (g/g)], pH variation, and reaction time during ozonation were evaluated to obtain the optimal operational conditions of ozone (O3)/ZrCl4 oxidation process. The maximum removal efficiencies for chemical oxygen demand (COD) and color were 88 and 100 %, respectively, at 1/2 g zirconium tetrachloride dosage (COD0/ZrCl4), pH 6, and 90 min reaction time, whereas 79 % removal for ammonia (NH3–N) was obtained at pH 11. Biodegradability (BOD5/COD) was improved from 0.07 to 0.09 and 0.34 after treatment with O3 alone and O3/ZrCl4, respectively. Treatments using ozonation alone and zirconium alone were performed and compared with the results obtained from the treatment with the new catalytic ozone method (O3/ZrCl4). The new oxidation method (i.e., O3/ZrCl4) obtained better removal efficiencies for organic substances and ammonia and this method reported better biodegradability ratio compared with other related processes. The O3/ZrCl4 process is also more efficient than O3/Fenton and O3/persulfate for stabilizing leachate treatment.

Performance of combined sodium persulfate/H2O2 based advanced oxidation process in stabilized landfill leachate treatment

A combination of persulfate and hydrogen peroxide (S2O82−/H2O2) was used to oxidizelandfill leachate. The reaction was performed under varying S2O82−/H2O2 ratio (g/g), S2O82−/H2O2 dosages (g/g), pH, and reaction time (minutes), so as to determine the optimum operational conditions. Results indicated that under optimum operational conditions (i.e. 120 min of oxidation using a S2O82−/H2O2 ratio of 1 g/1.47 g at a persulfate and hydrogen peroxide dosage of 5.88 g/50 ml and8.63 g/50 ml respectively, at pH 11) removal of 81% COD and 83% NH3–N was achieved. In addition, the biodegradability (BOD5/COD ratio) of the leachate was improved from 0.09 to 0.17. The results obtained from the combined use of (S2O82−/H2O2) were compared with those obtained with sodium persulfate only, hydrogen peroxide only and sodium persulfate followed by hydrogen peroxide. The combined method (S2O82−/H2O2) achieved higher removal efficiencies for COD and NH3–N compared with the other methods using a single oxidizing agent. Additionally, the study has proved that the combination of S2O82−/H2O2 is more efficient than the sequential use of sodium persulfate followed by hydrogen peroxide in advanced oxidation processes aiming at treatingstabilizedlandfill leachate.

Semi-aerobic stabilized landfill leachate treatment by ion exchange resin: isotherm and kinetic study

This study was carried out to investigate the treatability of ion exchange resin (Indion MB 6 SR) for the removal of chromium (VI), aluminium (III), zinc (II), copper (II), iron (II), and phosphate (PO4)3−, chemical oxygen demand (COD), ammonia nitrogen (NH3-N) and colour from semi-aerobic stabilized leachate by batch test. A range of ion exchange resin dosage was tested towards the removal efficiency of leachate parameters. It was observed that equilibrium data were best represented by the Langmuir model for metal ions and Freundlich was ideally fit for COD, NH3-N and colour. Intra particle diffusion model, pseudo first-order and pseudo second-order isotherm models were found ideally fit with correlation of the experimental data. The findings revealed that the models could describe the ion exchange kinetic behaviour efficiently, which further suggests comprehensive outlook for the future research in this field.

Stabilized landfill leachate treatment by sugarcane bagasse derived activated carbon for removal of color, COD and NH3-N – Optimization of preparation conditions by RSM

The present work demonstrated preparation of sugarcane bagasse derived activated carbon (SCAC) by physico-chemical activation method for adsorptive removal of color, COD and NH3-N from an anaerobic landfill located at Sahom, Perak, Malaysia. The effect of variable parameters in SCAC preparation includes activation time, activation temperature and KOH impregnation were studied. Based on the central composite design (CCD), the quadratic model was employed in order to correlate the effect of variable parameters in SCAC preparation on adsorptive removal of pollutant and the carbon yield. From the analysis of variance (ANOVA), the optimum conditions for preparation of SCAC was at 687°C of activation temperature, 2h of activation time and 2.59 of impregnation ratios with higher adsorptive removal of color (87.3%), COD (77.8%), and NH3-N (41.05%), respectively. The experiment results showed the capability of SCAC for adsorptive removal of pollutants from stabilized landfill leachate treatment.

Anaerobic stabilized landfill leachate treatment using chemically activated sugarcane bagasse activated carbon: kinetic and equilibrium study

Adsorption via activated carbon (AC) is one of the best methods to treat stabilized landfill leachate. However, this technique has been justified due to expensive and limited resource of AC precursor. Thus, in this study, sugarcane bagasse, a cheap and abundant biomass from agricultural waste, was used to prepare AC. The prepared sugarcane bagasse activated carbon (SCAC) was tested for color, chemical oxygen demand (COD), and ammoniacal nitrogen (NH3-N) removals from anaerobic stabilized landfill leachate. SCAC was prepared using physical and chemical activation. SCAC was characterized for its surface area, surface morphology, and functional groups. The performance of the adsorbent was examined in a batch mode study by varying the shaking speed, contact time, adsorbent dosage, and pH. The experimental results indicated that SCAC could adsorb and remove the pollutants from anaerobic municipal stabilized landfill. Removal of color, COD, and NH3-N were favorably described by Langmuir isotherm model, with a maximum monolayer adsorption capacity of 555.56 Pt/Co, 126.58 and 14.62 mg/g, respectively. Pseudo-second-order model fits well with the experimental results and indicates that the adsorption was controlled by chemisorptions. The experimental results revealed that the optimum experimental conditions (e.g. 200 rpm shaking speed, 180 min contact time, 7 g AC dosage, and pH 7) resulted in 94.74, 83.61, and 46.65% removal of color, COD, and NH3-N, respectively.

PRETREATMENT OF LANDFILL LEACHATE USING IRON(III) CHLORIDE AND HYDROGEN PEROXIDE

In this paper, the application of Iron(III) chloride and hydrogen peroxide oxidation processes for stabilized landfill leachate treatment was investigated. The leachate came from a municipal sanitary landfill and the average values of its main parameters were: pH 8,03; COD 605 gO2/m 3; BOD 65 gO2/m 3; NH4 + 92 gN/m3; conductivity 6,47 mS/cm; UV254 absorbance 0,300 and turbidity 1,6 NTU. It is demonstrated that the application of Iron(III) chloride and hydrogen peroxide can effectively remove leachate pollutants such as color, COD and UV254 absorbance. A combination process, accomplished at different weight ratios of reagents H2O2/ Fe was 1,7 to 32. The best conditions for process were found at a ratio Fe/COD equal to 0,9 and H2O2/Fe equal to 4,2. Leachates were significantly oxidized under these conditions in terms of COD removal 72%, color removal 93% and UV254 absorbance removal 82,2%.

An overview of electro-oxidation processes performance in stabilized landfill leachate treatment

Abstract Among numerous techniques, electro-oxidation occupies a noticeable place in landfill leachate treatment. In recent years, electro-oxidation processes have been shown to be effective alternative for the removal of refractory organic compounds from stabilized landfill leachate. This paper aims to provide an overview about the effectiveness and mechanism of electro-oxidation processes employed for stabilized landfill leachate treatment. A review of the recent literature published on the electro-oxidation processes (i.e. electrochemical, electro-Fenton, photoelectro-Fenton, photoelectrochemical, and electrochemical peroxidation) performance and efficiency in stabilized leachate treatment are summarized and presented in this study. This study concluded that, although the high treatment cost caused by the energy consumption may limit electro-oxidation techniques, electro-oxidation processes are still a promising and effectual technology for the reduction of pollutants in stabilized landfill leachate.

Evaluation of coagulation (FeCl3) and anion exchange (MIEX) for stabilized landfill leachate treatment and high-pressure membrane pretreatment

Laboratory-scale experiments were conducted to assess the effectiveness of coagulation (ferric chloride – FeCl3) and magnetic ion exchange (MIEX) as a pretreatment option for treating stabilized landfill leachate using reverse osmosis (RO) and nanofiltration (NF) membranes. Leachate from three different landfills was collected and characterized as stabilized leachate with a ratio of biochemical oxygen demand to chemical oxygen demand in the range of 0.02–0.11. Batch jar-tests were conducted to determine the effectiveness of FeCl3 and MIEX. A maximum reduction of 71% and 34% dissolved organic carbon (DOC) and 94% and 48% UV-254 absorbing organic matter (OM) was observed using FeCl3 and MIEX, respectively. Effective doses of FeCl3 (22mmolL−1) and MIEX (5mLL−1) were selected for leachate pretreatment before membrane operation. Batch RO and NF membrane experiments were conducted with raw and pretreated leachates to study the change in permeate flux for each type of membrane and leachate. Even though the pretreated leachate contained over 45% less UV-254 absorbing OM than raw leachate, leachate pretreatment did not increase the permeate flux as compared to raw leachate during RO and NF membrane treatment. The potential cause of the decrease in permeate flux in pretreated leachate as compared to raw leachate was hypothesized as the change in characteristics of pretreated leachate and membrane surfaces caused by the continuous increase in pH of pretreated leachate.

The Effectiveness of Silica Sand in Semi-Aerobic Stabilized Landfill Leachate Treatment

This study examines the suitability of natural silica sand as a low-cost adsorbent for the removal of ammoniacal nitrogen and heavy metals, particularly iron and zinc, from semi-aerobic stabilized landfill leachate. Leachate samples were collected from the Pulau Burung landfill site (PBLS) in Penang, Malaysia. The above-mentioned contaminants are highlighted in this study because of their unsafe concentrations at PBLS. The effects of shaking time, settling time, and silica sand dosage on the study parameter removal efficiencies were investigated to predict the performance of the process. The adsorptions of ammoniacal nitrogen, iron, and zinc were judiciously described by Langmuir and Freundlich isotherm models. The optimum removal efficiencies of ammoniacal nitrogen, iron, and zinc obtained were 51%, 44.4%, and 39.2%, respectively, with a shaking time of 90 min, a settling time of 60 min, and with a dosage of 60 g (0.5 kg/L) of silica sand. Based on the coefficient of determination (R2) values obtained from Langmuir and Freundlich isotherm models, ammoniacal nitrogen, iron, and zinc adsorption were better fitted to the Freundlich model.