Treatment Of Sanitary Landfill Leachate Research Articles

Continuous Flow Electrochemical Process for Sanitary Landfill Leachate Treatment: Role of Inlet Flow Rate and Current Density

Continuous Flow Electrochemical Process for Sanitary Landfill Leachate Treatment: Role of Inlet Flow Rate and Current Density

Development of Hybrid Systems by Integrating an Adsorption Process with Natural Zeolite and/or Palygorskite into the Electrocoagulation Treatment of Sanitary Landfill Leachate

The effectiveness of a hybrid approach comprising electrocoagulation (EC) and adsorption (AD) (using natural zeolite and/or palygorskite) processes to treat raw sanitary landfill leachate (SLL) was investigated in terms of color, dissolved chemical oxygen demand (d-COD), nitrate nitrogen (NO3−-N) and ammonium nitrogen (NH4+-N) removal. Optimal EC conditions were found with a current density of 30 mA cm−2, Fe electrode material and pH 8. Implementation of the AD process using zeolite (ADzeo) as pre- or post-treatment for EC significantly increased the NH4+-N removal efficiency. The ADzeo-EC sequential treatment showed considerably higher color removal compared to the EC-ADzeo sequential treatment and was therefore determined to be the optimal sequential treatment. Integration of the AD process using palygorskite (ADpal) into the first or middle stage of the ADzeo-EC treatment system enhanced the overall NO3−-N removal efficiency. The hybrid ADzeo-ADpal-EC treatment system exhibited the highest simultaneous removal efficiencies of color, d-COD, NO3−-N and NH4+-N, corresponding to 95.06 ± 0.19%, 48.89 ± 0.89%, 68.38 ± 0.93% and 78.25 ± 0.61%, respectively. The results of this study indicate that the ADzeo-ADpal-EC hybrid system is a promising and efficient approach for treating raw landfill leachate.

Sanitary landfill leachate treatment by aerated electrochemical Fenton process

The aerated electrochemical Fenton procedure was investigated as a viable treatment approach for electrolytic degradation and decolourization of sanitary landfill leachate. The optimization effects of initial pH, applied voltage, H2O2 concentration and combination of iron electrodes on detoxification were demonstrated by COD and colour removal from stabilized leachate, respectively. The study illustrates that, under the optimum experimental parameters voltage of 4.5 V, electrolysis time of 90 min, H2O2 dosage of 5 g/L, pH 3, 99% of chemical oxygen demand (COD) and 100% colour are removed from stabilized leachate, and the biodegradability ratio of the five-day biochemical oxygen demand (BOD5) to COD increases from 0.1 to 0.72. In addition, the pure catalytic metallic iron anode and cathode electrode used in the electrochemical Fenton process was first electro-oxidized to Fe2+ for use during the Fenton reaction, then with Fe3+ that was reverted back to Fe2+ under the applied electrochemical-magnetic field, resulting in the iron dissolution and regeneration circuit (Fe2+/Fe3+/Fe2+). Additionally, Fe2+/Fe3+ served as bridges for agglomerates to coalesce into big, closely packed particles for better filterability and sedimentation action. As a preparatory step for the biochemical treatment, this technology has been effectively used to treat stabilized landfill leachate containing toxic refractory recalcitrant organics on a large scale. Additionally, by estimating the scientific experiment with a regression model approach for the outcomes, RSM software was employed in order to standardize the ECF treatment process, significantly reducing the number of test cases and trials.

Process parameters study of sanitary landfill leachate treatment using photo-Fenton-like systems

In this study, the effects of the combination of classical Fenton (CFP) and modified Fenton (MFP) processes with UV light on the treatment of sanitary landfill leachate have been investigated. Iron (Fe2+ and Fe0) dosage, hydrogen peroxide dosage, reaction time, pH and different UV lamps have been optimized to achieve high COD removal. In addition, zeroth, first and second order kinetic models are applied for all processes under optimum conditions. For CFP and MFP; optimum pH 3, reaction time 30 min, 4 g/kg TS Fe2+ and Fe0 and 5 g/kg TS H2O2 have been determined. The COD removal efficiency is determined as 48.86% for CFP and 59.27% for MFP under optimum conditions. COD removal efficiencies increased in photo Fenton application under UV light. The efficiency is found to increase under UVA light source from 48.86% to 49.17% and from 59.27% to 70.72% in in CFP and MFP, respectively. In the kinetic study, the highest R2 values are obtained in the CFP/UV process, while CFP and MFP are found to fit the 0th order kinetic model. In this study, it has been concluded that Fenton and photo Fenton applications are effective in reducing the COD values of landfill leachate.

Correction to: Characterization and Efficiency Evaluation of Cold Active Bacterial Isolates for Treatment of Sanitary Landfill Leachate

Correction to: Characterization and Efficiency Evaluation of Cold Active Bacterial Isolates for Treatment of Sanitary Landfill Leachate

Adsorption studies using natural palygorskite for the treatment of real sanitary landfill leachate

The efficiency of a naturally occurring palygorskite as an adsorbent for the simultaneous removal of color, dissolved chemical oxygen demand (d‐COD) and ammonium nitrogen (NH4+-N) from real, untreated sanitary landfill leachate (SLL) was investigated. Saturation and desorption studies of palygorskite were also performed for all three pollutants simultaneously. Optimal adsorption conditions were attained at palygorskite dosage of 133 g L−1 and suspension pH 8. In these conditions, color removal efficiency reached 85.4 ± 1.4% within just 2.5 min of contact time with the natural palygorskite, while d-COD and NH4+-N removal was 54.7 ± 0.6% and 41.9 ± 0.5%, respectively, for 180 min residence time. Limited reuse of palygorskite for color uptake was possible. NH4+-N uptake on palygorskite was irreversible, while d-COD and color uptake were reversible. The combination of natural palygorskite with natural zeolite in series, in any order, doubled the overall removal efficiency of NH4+-N from raw SLL. Solid characterization of palygorskite confirmed the adsorption of NH4+-N, aromatic and aliphatic organic compounds. BET specific surface area (SSA) analysis showed significant changes of the solid upon saturation. Zeta potential measurements of the suspended particles after SLL treatment in combination with FTIR and XPS analyses suggested that SLL decolorization was due to the adsorption of anionic aliphatic and aromatic compounds. The results of this study indicate that adsorption on natural palygorskite is a viable option for the pre-treatment of untreated landfill leachate.

Characterization and Efficiency Evaluation of Cold Active Bacterial Isolates for Treatment of Sanitary Landfill Leachate

Characterization and Efficiency Evaluation of Cold Active Bacterial Isolates for Treatment of Sanitary Landfill Leachate

Optimization of the adsorption process in the treatment of sanitary landfill leachate by Fenton-adsorption

Landfill leachate treatment is of utmost importance for pollution prevention. For this reason, in this study the performance of different types of activated carbons was monitored for applying in the Fenton-adsorption treatment of landfill leachate. Six carbon of different mesh and nature were studied, all of granular type. Only with the Fenton treatment a COD removal of >75% was achieved. Batch experiments were done to conduct adsorption isotherm studies and an adsorption column test was subsequently performed for Fenton-treated leachate. Granular coconut activated carbon revealed a better performance in removal of chemical oxygen demand (COD) and color during batch experiments. However, the activated carbon Gama L 8 × 30 (mesoporous) achieved removals >99% of COD and color in the adsorption column, removing 19.26 kg COD/kg carbon. Finally, it was found that the adsorption is carried out in multilayers with both carbons, having an adjustment with the models Temkin (80%) and Freunlich (96%) for granular coconut 12 × 40 and the Gama L 8 × 30, respectively.

A review on the application of nanoporous zeolite for sanitary landfill leachate treatment.

This review deals with low-cost nanoporous zeolites for the treatment of sanitary landfill leachate. Organic contaminants and ammoniacal nitrogen are significant parameters in landfill leachate treatment. Adsorption processes are regarded as promising alternative treatment options in this respect. Zeolites are aluminosilicate materials that are widely used in separation, filtration, adsorption and catalysis. Natural zeolite is a low-cost and readily available form of zeolite and is a promising candidate to be used as an ion-exchange material for ammonia and other inorganic pollutant removal from landfill leachate. In this review, adsorption isotherms and kinetic models in batch systems are evaluated and adsorption design parameters of the fixed-bed system are presented. Studies on ammonia removal from landfill leachate via zeolites have been thoroughly investigated. Leachate treatment systems combined with zeolites are presented. Cost of zeolites are also reported in comparison with other adsorbents. The investigated studies demonstrate that activated zeolite can improve the removal of chemical oxygen demand, NH3-N and colour significantly compared to the case where raw zeolite is used. Moreover, the composite of activated carbon and zeolite is also favorable for ammonia removal according to reported findings, where best adsorptive removal is attained on the composite media (24.39 mg/g).

Remediation of ammonia-stripped sanitary landfill leachate by integrated heterogeneous Fenton process and aerobic biological methods

ABSTRACT The use of heterogeneous Fenton process combined with biological and physical treatment of sanitary landfill leachate has been evaluated. Leachate used in this study was collected from the drainage system of a landfill in Borg El-Arab city – Egypt. As a pre-treatment step, the collected leachate was subjected to ammonia stripping at pH 10.0 for 6 h to reduce the ammonia toxicity for the subsequent biological treatment steps. In this step, over 80% of the ammonia content of the leachate could be removed. Then, the ammonia-stripped leachate was subjected to heterogeneous Fenton process or to aerobic biological treatment. At its optimum operating conditions namely; 37.18 g/L H2O2, 5 g/L catalyst and a reaction time of 4 h, the use of heterogeneous Fenton process achieved COD removal up to 73%. Corresponding COD removal obtained after biological treatment was 68%. To select the best sequence of the treatment steps, the ammonia-stripped sanitary landfill leachate was subjected to two treatment trains. The first one was biological treatment followed by heterogeneous Fenton process; while, the second was heterogeneous Fenton process followed by biological treatment. The highest reductions of the organic compounds and ammonia were achieved after using biological treatment followed by the heterogeneous Fenton process. The use of this treatment configuration achieved total COD, BOD and NH4-N removals of 88%, 84% and 96% respectively. Accordingly, the proposed treatment train can be considered effective in the treatment of landfill leachate and environmental protection.

Full Scale Sanitary Landfill Leachate Treatment by MBR: Flat Sheet vs. Hollow Fiber Membrane

The aim of this study was to find a cost-efficient leachate treatment system by comparing two MBR systems, flat sheet and hollow fiber. Data collected through continuous monitoring and laboratory analysis over the last two years has been evaluated in terms of treatment performance and economic analysis. MBR systems were found to be as effective and economical in terms of color, SS removal, and total treatment efficiency. It has been observed that the flat sheet membranes were clogged up in six weeks, while the hollow fiber membranes took 12–16 weeks to clog. Moreover, the hollow fiber module was less clogged and needed shorter washing times, resulting in lower amounts of chemical consumption. Hollow fiber membrane systems, compared to flat sheet membrane systems, have higher operational availability and lower maintenance costs. For the first time, the advantage of using submerged hollow fiber for the treatment of high-strength landfill leachate has been clearly demonstrated.

Electrocoagulation Treatment of Sanitary Landfill Leachate in Malaysia

The tropical climate condition and high moisture of solid waste characteristic in Malaysia led to the increase of leachate generation from landfill. Current leachate treatment showed less efficient to treat leachate due to various refractory pollutants in the leachate. This study employed electrocoagulation (EC) to investigate the effects of electrode material, current density and initial pH condition in reducing total suspended solid (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD5), ammonia-nitrogen and colour from the leachate. The result showed that aluminium electrode was able to remove all the parameters more effectively as compared to iron electrode. The optimum current density and pH condition were found to be 100 mA/cm2 and at pH 7, respectively. The COD in the leachate was predominantly exist as particulate matter and it was removed in the form of suspended solids. Although all the pollutant parameters still exceeded the standard discharge limit after the treatment, the electrocoagulation is proposed to act as pretreatment prior to biological treatment in sanitary landfill. The electrocoagulation also can treat leachate from open dumping landfill sites in order to reduce the leachate contamination into the environment.

Characterization and toxicological evaluation of leachate from Bacolod city sanitary landfill using tilapia (Oreochromis niloticus): a preliminary study

This study was carried out to characterize and assess the toxicity of Bacolod City Landfill leachate using Tilapia as bio-indicator species. Acclimatized Oreochromis niloticus fishes (length of 14 cm ± 2.0 cm and weight of 11.8 g ± 0.9 g) were introduced into each treatment tank containing three different concentrations of leachate in duplicates (10 ppm, 50 ppm and 100 ppm) and a control group. Physical reactions were observed such as erratic swimming, loss of reflex, hyperactivities, and surfacing. Reactions and mortality rate increased with increasing concentration and duration of exposure. Mortality rate using One-way Analysis of Variance (ANOVA) and Duncan’s Multiple Range Test (DMRT) revealed a significant difference between treatment groups and exhibited 100 ppm as the most potent concentration. Heavy metal analysis of Cu and Pb as well as physicochemical analysis of color, Chimecal Oxygen Demande (COD) and Total dissolved Solids (TDS) exceeded the country’s environmental standard set by DENR. The 96 h bioassay stemmed the median lethal concentration (LC50) at 57.688 ppm. The study provides a biomarker database in taking action for the responsible enactment and enforcement of laws to upgrade, enhance and install framework for proper treatment of sanitary landfill leachate in cities and municipalities in the country.

Sanitary Landfill Leachate Treatment with Double Chamber Anaerobic Reactor in Series with Constructed Wetland

A treatment system composed of a double-chamber anaerobic (DCA) reactor in conjunction with a constructed wetland (CW) of horizontal sub-surface flow, for the treatment of leachates generated in the municipal sanitary landfill of a typical mid-sized city was investigated. The aim of this work was to assess the capability of the system to remove pollutants such as organic load, nutrients and solids. The system was evaluated at hydraulic retention times (HRT) of 7.97, 5.31 and 2.88 days. The highest removal efficiencies for the system were obtained at HRT of 7.97 days and were 89% and 91% for TCOD and BOD, respectively. In the case of NO3−, NO2−, NH4+ and Total Kjeldahl Nitrogen (TKN), their removal rates were estimated at 88%, 93%, 93% and 85%, respectively; whilst for TS, TVS and TTSS they were 88%, 86% and 90%, respectively, again at HRT of 7.97 d. Efficiencies of 78%, 83% and 77% were obtained respectively for TCOD, BOD and TKN in DCA reactor at HRT of 1.5 d. Typha domingensis was identified as a species capable of adapting to the physicochemical conditions of the leachate, exhibiting an average growth of 196 cm. In leachate there were found low concentrations of heavy metals, being aluminum the metal with the highest concentrations (between 3.31–10.09 mg/L). Results show that it is feasible to implement the DCA reactor in series with a constructed wetland for the treatment of sanitary landfill leachates. Therefore, this system can be replicated for the treatment of leachates with similar conditions.

Two-stage integrated system photo-electro-Fenton and biological oxidation process assessment of sanitary landfill leachate treatment: An intermediate products study

Optimum experimental conditions for the photo-electro-Fenton (PEF) process using a lab-scale photo-reactor to treat a sanitary landfill leachate (SLL) were determined. The PEF process operational conditions were analyzed with a response surface methodology (RSM) that presented a high total carbon (TC) removal at the central point: current intensity of 2.3 A, H2O2 concentration of 9000 mg·L−1, Fe2+ concentration of 60 mg·L−1, an electrolysis time of 45 min and solution pH controlled at the range 3.5–4.5, reaching a minimum TC residual concentration of 344 mg·L−1 in the SLL, as well as 89 mg Pt-Co·L−1 of color, 254 nm = 0.18 a.u., 315 mg·L−1 5th day biochemical oxygen demand (BOD5), 782 mg·L−1 chemical oxygen demand (COD), improving the BOD5/COD = 0.4 ratio. The reaction byproducts were analyzed with gas chromatography-mass spectrometry (GC–MS). The generated byproducts were less toxic than the parent compounds found in the raw SLL. As the SLL toxicity was reduced, integration treatment strategies containing PEF processes and biological oxidation (BO) were studied. The best treatment strategy enabled the lethal concentration LC50% = 33% and reduced the residual TC concentration to 181 mg·L−1 through application of the PEF process. This possibly transformed recalcitrant compounds from raw SLL into more biodegradable substances (BOD5/COD = 0.53) facilitating the microbial activity in the posterior BO. This treatment strategy also produced a smaller number of identified byproducts, which confirms the good performance of the PEF process followed by BO.

Fenton treatment of sanitary landfill leachate: optimization of operational parameters, characterization of sludge and toxicology

ABSTRACT This investigation aimed to refine the operational parameters of the Fenton process, to compare Fenton-treated and non-treated leachate with respect to physicochemical variables and toxicity towards Daphnia magna, and to characterize the sludge. The optimal conditions for the Fenton treatment involved the use of a reagent containing 12 g Fe2+ L−1, H2O2/Fe2+ molar ratio of 9 and pH 2.0, with oxidation, flocculation and sedimentation times of 30, 10 and 15 min, respectively. Under these conditions, the values of the majority of parameters, including chemical oxygen demand (COD), biochemical oxygen demand, dissolved organic carbon, true color (TC), carbohydrates, proteins, phosphorus, total solids, total volatile solids, dissolved volatile solids, Kjeldahl nitrogen, N-NH3 and iron, were reduced significantly after treatment. However, sludge production rate remained somewhat high (98 kg m−3 of treated leachate), although the specific resistance to filtration of the sludge was moderate (12 × 109 cm g−1). While the Fenton process achieved a satisfactory removal of COD (87%) and TC (91%), the treated leachate contained organic compounds that were resistant to oxidation and remained toxic towards D. magna. Hence we conclude that the Fenton process alone is not appropriate for treatment of leachate, because it could negatively affect the ecosystem in receiving water bodies, but it could represent a viable alternative for the pretreatment of landfill leachate.

Treatment of sanitary landfill leachate by the combination of photo-Fenton and biological processes

In this work, the pollutant reduction performance in landfill leachate by combining both photo-Fenton and biological processes was investigated. First, conventional biological treatment was performed, consisting of a decantation process, with centrifugation at 5000 rpm for 15 min, followed by the biological process conducted at 2.36 ± 0.1 mg mg−1 (BOD5/MLSS) and 0.571 ± 0.04 vvm (L L−1 min−1) for 40 h. At the same time, in the application of the photo-Fenton process, a central composite rotatable design (CCRD) was applied to evaluate the effect of main process variables. The quadratic models of chemical oxygen demand (COD) and 5 days biological oxygen demand (BOD5) removal were proposed and validated, being separately used as objective functions during the search for optimal operating conditions. After the application of the conventional biological process, removals of 87 ± 2% and 84 ± 2% were obtained for COD and BOD5, respectively. For the photo-Fenton process under optimum conditions (3400 mg H2O2 L−1, 80 mg Fe2+ L−1, pH = 2.40 and 120 min), removals of 89 ± 3% COD and 75 ± 1% BOD5 were obtained. However, both processes did not meet effluent discharge standards. So, the optimized photo-Fenton process was then combined with the biological process, performed for 150 h with 1.571 ± 0.06 vvm and 4.41 ± 0.3 mg mg−1 (BOD5/MLSS). With the combined process, it was possible to treat an effluent with high organic load, achieving a removal of 98% COD and BOD5 and meeting the restrictive standards of release in recipient water bodies.

Ecotoxicological evaluation of electrochemical oxidation for the treatment of sanitary landfill leachates.

In this study, the efficiency of electrochemical oxidation to treat a sanitary landfill leachate was evaluated by the reduction in physico-chemical parameters and in ecotoxicity. The acute toxicity of the sanitary landfill leachates, before and after treatment, was assessed with the model organism Daphnia magna. Electrochemical oxidation treatment was effective in the removal of organic load and ammonium nitrogen and in the reduction of metal ions concentrations. Furthermore, a reduction of 2.5-fold in the acute toxicity towards D. magna after 36h of treatment was noticed. Nevertheless, the toxicity of the treated leachate is still very high, and further treatments are necessary in order to obtain a non-toxic effluent to this aquatic organism. Toxicity results were also compared with others described in the literature for different leachate treatments and test organisms.

Integration of membrane separation and Fenton processes for sanitary landfill leachate treatment

ABSTRACTThe appropriate treatment of sanitary landfill leachate is one of the greatest challenges nowadays due to the large volumes of solid waste generated. Thus, the aim of this study is to evaluate the performance of different routes involving the integration of advanced oxidation processes based on Fenton’s reagents (AOP-Fenton) and microfiltration (MF) and nanofiltration (NF) membrane processes for the treatment of landfill leachate. MF module configuration (submerged or sidestream) and MF and NF recovery rate were evaluated. The combination of AOP-Fenton, MF and NF proved to be an effective treatment for landfill leachate. High removal efficiencies of chemical oxidation demand (94–96%) and colour (96–99%) were obtained. The configuration named route 3, composed of MF of raw landfill leachate (MF1), POA-Fenton-MF2 of the MF1 concentrate and NF of both MF1 and MF2 permeates, showed a higher global water recovery and was responsible for lower waste generation. It was considered the best one in terms of environmental, technical and economical aspects.

Enhanced degradation of 1-naphthol in landfill leachate using Arthrobacter sp.

ABSTRACTArthrobacter sp. named as JY5-1 isolated from contaminated soil of a coking plant can degrade 1-naphthol as the sole carbon source. Through identification of species, analysis of the optimal degradation condition and kinetic equation, the degradation characteristic of Arthrobacter sp. JY5-1 was obtained. Later, the acclimated strain was added into the bio-reactor to observe treatment performance of landfill leachate. The results showed that the optimal conditions for strain JY5-1 biodegradation in the study were pH 7.0 and 30oC. The bio-reactor operation experiment declared that Arthrobacter sp. JY5-1 had a strengthened effect on COD removal of landfill leachate. Moreover, the efficiency of COD removal could be high and stable when JY5-1 was accumulated as a biofilm together with active sludge. These results demonstrate that adding 1-naphthol-degrading strain JY5-1 is a feasible technique for the enhanced treatment of sanitary landfill leachate, providing theoretical support for engineering utilization.