Treatment Of Municipal Landfill Leachate Research Articles

A novel integrated microbial and laccase-anchored carbon catalyst system for the effective treatment of toxic organic and recalcitrant-rich municipal landfill leachate

A novel integrated microbial and laccase-anchored carbon catalyst system for the effective treatment of toxic organic and recalcitrant-rich municipal landfill leachate

Evaluation of combined thermo-chemical processes for the treatment of landfill leachate using virgin and recovered FeCl3 coagulants

Sludge resulting from treatment of municipal waste landfill leachate contains suitable cationic substances such as Fe-based recovered coagulants which, if not recovered, can cause environmental problems. The present study aimed to maximise coagulant recoverability and investigate its potential reuse for the treatment of municipal waste landfill leachate. The study focused on establishing (i) the effect of mineral acids on leaching of Fe, (ii) the % of maximum recovery of Fe coagulant, (iii) the impact of ultrasound on recovery, and (iv) effectiveness of recovered coagulant when reused in coagulation-flocculation treatment of landfill leachate. Sulfuric acid outran hydrochloric acid in performance, with the acid leaching process leading to the recovery of 70.12% of Fe (acid concentration = 3.80 M, solid-to-liquid ratio = 8%, and heating time = 5 h). Subsequently, a developed acid leaching process was tested, which results showed that the highest rate of Fe recovery occurred without ultrasound treatment, meaning the use of it could reduce the recovery rate due to the increase in the iron (III) oxide-hydroxide [Fe(OH)3] sedimentation. Comparative experiments were undertaken with the recovered and virgin coagulants. These revealed that Fe-based recovered coagulant led to the 60.21% and 91.40% removal of COD and total suspended solid respectively, while the values of the COD and total suspended solid removal with the virgin FeCl3 were 7.66% and 6.42% lower than that of Fe under optimal conditions (dosage = 9.38 g/L, pH = 8.94, settling time = 52.9 min). The present study established that Fe recovered could be exploited as an eco-friendly coagulant to replace FeCl3 in the landfill leachate treatment.

The influence of combined treatment of municipal wastewater and landfill leachate on the spread of antibiotic resistance in the environment – A preliminary case study

Environmentally-friendly management of landfill leachate (LL) poses a challenge, and LL is usually co-treated with municipal wastewater in wastewater treatment plants (WWTPs). The extent to which the co-treatment of LL and municipal wastewater influences the spread of antibiotic resistance (AR) in the environment has not been examined to date. Two WWTPs with similar wastewater composition and technology were studied. Landfill leachate was co-treated with wastewater in one of the studied WWTPs. Landfill leachate, untreated and treated wastewater from both WWTPs, and river water sampled upstream and downstream from the wastewater discharge point were analyzed. Physicochemical parameters, microbial diversity, and antibiotic resistance genes (ARGs) abundance were investigated to determine the impact of LL co-treatment on chemical and microbiological contamination in the environment. Landfill leachate increased pollutant concentrations in untreated wastewater and river water. Cotreatment of LL and wastewater could affect the abundance and diversity of microbial communities and the interactions between microbial species. Co-treatment also decreased the stability of microbial co-occurrence networks in the examined samples. The mexF gene was identified as a potential marker of environmental pollution with LL. This is the first study to explore the impact of LL on the occurrence of AR determinants in wastewater and rivers receiving effluents.

Combination of electrochemically activated persulfate process and electro-coagulation for the treatment of municipal landfill leachate with low biodegradability

To handle complex wastewater with limited biodegradability, hybrid treatment systems are necessary. The current study represents the combined effectiveness of sulfate-radical associated electro-chemical advanced oxidation process (SR-EAOP) and electro-coagulation (EC) for the treatment of stabilized landfill leachate. For SR-EAOP, Pt/Ti was employed as the anode and an iron plate as the cathode; while EC treatment was performed by switching the polarity. Hence, both electrochemical treatment was carried out in single reactor. Initially, the effects of pH, applied voltage, persulfate and Fe2+ dosage, on the performance of SR-EAOP was examined. Sulfate radical was generated in the electrolytic system via cathodic reduction of persulfate (PS) and ferrous (Fe2+) ion activation. Auxiliary processes such as anodic oxidation via Pt/Ti anode and indirect electro-chemical oxidation were also contributed for pollutant degradation. Combined process SR-EAOP followed by EC (SR-EAOP + EC) has better leachate treatment efficacy in comparison with EC + SR-EAOPs. The SR-EAOP + EC based combined treatment mechanism achieved an efficient COD reduction of 88.67% than that of EC + SR – EAOP process (74.51% COD reduction). Characterization studies have been carried out for post-treated dried-sludge using Field Emission scanning electron microscope (FE-SEM) and X-ray powder diffraction (XRD) techniques. The combined process treatment (SR-EAOP + EC) can be applied as pre-treatment for leachate decontamination.

Municipal landfill leachate remediation coupling acidogenesis and bioelectrogenesis for biohydrogen and volatile fatty acids production

This study aimed at sustainable treatment of municipal landfill leachate (MLL) along with resource recovery by integrating acidogenesis and bioelectrogenesis. Initially, during acidogenic fermentation, more than 60 % of MLL COD was converted to biohydrogen (0.23 L/g CODload) and volatile fatty acids (VFAs; 56.15 g COD/L). Acetic (25.09 g COD/L), propionic (1.27 g COD/L), and butyric acid (29.77 g COD/L) made up the majority of VFAs. To increase MLL's further treatment, the left-over COD in the acidogenic effluent was introduced into bio-electrochemical treatment system. Three differently configured bio-electrochemical treatment systems (BET1, BET2, and BET3) were evaluated varying their anode composition. BET1 was operated with a capacitive designed PANi/CNT composite electrode, while BET2 was operated with PANi-SSM and BET3 with a graphite electrode. The modified composite electrode in BET1 played a significant role in leachate treatment (COD removal, 71.21 %) displaying a power density of 35 mW/m2. Apart from higher removal of ammoniacal nitrogen, sulfates and phosphates, the composite electrodes in the BET1 resulted in improved bioelectrogenic activity and capacity of electrons migration between electrode and biocatalyst. Additionally, the modified anode showed higher redox peak currents, lower charge transfer resistance, and ohmic losses.

Facile synthesis of SrWO4@MIL-88A(Fe) heterojunctions and their deep treatment of dye wastewater and municipal landfill leachate using photo-Fenton technology

Dye wastewater and municipal landfill leachate greatly threaten the ecological environment and human health. We prepared SrWO4@MIL-88A(Fe) composites in this work by room temperature synthesis. A systematic degradation study of methylene blue (MB) and landfill leachate was carried out using the photo-Fenton process. The results showed that SrWO4@MIL-88A(Fe) could degrade 93.75 % of MB within four min. Within 15 min of sunlight irradiation, SrWO4@MIL-88A(Fe) could degrade up to 95 % of MB. It could eliminate up to 87.19 % of COD, 90.23 % of BOD5, 99.50 % of TOP- P, 80.96 % of TOP-N, and 81.48 % of NH3-N in the leachate. The toxicity of the deep-purified leachate is significantly reduced, and alfalfa seeds can use the remaining organic matter in the leachate to germinate and grow, thus achieving self-purification of the detoxified leachate. In addition, the photo-Fenton technology can effectively kill the bacterial microorganisms in the leachate and reduce the epidemiological hazard to organisms. In conclusion, the photo-Fenton process of SrWO4@MIL-88A(Fe) provides a purification pathway for the dual-effect treatment of MB and municipal landfill leachate.

Application of integrated sequence of air stripping, coagulation flocculation, electrocoagulation and adsorption for sustainable treatment of municipal landfill leachate

Leachate generated from landfill is required to be treated by simple, fast, economic and environmentally sustainable methods before being discharged to the environment since it is considered as a highly pollutant wastewater. The aim of this research work is to check the potential treatability of integrated sequence of air stripping, coagulation flocculation, electrocoagulation and adsorption method for leachate generated from an uncontrolled municipal solid waste landfill site complying with legal discharge standard. At optimum retention period of 36 hours air stripping method exhibited a maximum removal of 96.87% of NH 4 -N, 74.5% of BOD 5 , 52.78% of COD, 8.7% of Hg and 18.43% of Pb from raw leachate at normal pH and air flow rate of 10 L/min. The application of optimized CF process using FeCl 3 as coagulant of dosage 3.09 mg/L resulted a maximum removal of 84.20% of BOD 5 , 57.67% of COD and 46.2% of Hg at pH 5.22. Following CF process EC process was adopted with Fe electrode and optimized by CCD of response surface methodology. At optimum pH 7.46, current density 3.13 mA/cm 2 and electrolysis time 24.83 min the maximum removal was recorded as 51.1% COD and 91.92% Hg. EDAX analysis confirmed the presence of Hg in the precipitates of ECP. Finally fixed bed column adsorption study using chitosan beads resulted in 98.11% of Hg removal. The integrated treatment sequence resulting an overall removal of 96.87% of NH 4 -N, 95.97% of BOD 5 , 90.23% of COD, and 99.93% of Hg which is sufficient enough to reduce pollutants of raw leachate below discharge standards at overall costs of USD 0.036/L. • Integrated sequence of multiple physicochemical treatment methods were used to reduce pollution load from raw municipal landfill leachate. • Process variables of electrocoagulation method were optimized by center composite design of response surface methodology. • EDAX confirmed the removal of Hg by electrocoagulation process using iron electrodes. • Low cost chitosan beads were used for adsorption. • The leachate discharge standard in inland surface water was achieved at nominal cost.

(Anti)estrogenic activity impacted by complex environmental matrices: A DOM and multiphase distribution approach

The presence of estrogenic endocrine disruptors in aquatic environments has been a concern and bioassays are recommended tools for their monitoring. However, the physicochemical properties of contaminants and the environmental matrix features may influence the resultant response. This study aimed to assess this influence on the Yeast Estrogen Screen (YES) assay. Mixtures of 17β-estradiol (E2) and humic acid (HA) were evaluated through the Schild approach aiming to investigate the interactions between estrogens and dissolved organic matter (DOM). Moreover, environmental samples from municipal landfill leachate and wastewater treatment plant (WWTP) influents and effluents were screened for (anti)estrogenic activity at both dissolved and particulate phases. Finally, results were statistically confronted with physicochemical parameters through principal component analysis (PCA). The HA test concentrations strongly reduced the E2 response, even at low levels. Humic substances may not only reduce estrogen bioavailability, but also interfere with the assay mechanism through enzymatic inhibition thus masking the sample estrogenic potential. Landfill leachate had total E2-Eq in the range 1282–2591 ng L−1, while WWTP influent and effluent were in the range 12.1–41.4 and <DL–2.3 ng L−1, so estrogenicity was reduced 92% in average. Particulate phase was responsible for 33–100% of measured E2-Eq between matrices, though cytotoxicity occurred in some extracts. Antiestrogenic activity was observed in both phases and might also have masked the estrogenicity of samples. PCA did not resulted in positive correlations supporting a multiphase distribution pattern of estrogenic compounds. Nevertheless, the solids and organic matter characteristics supported the data interpretation. In conclusion, the in vitro YES assay is subjected to factors intrinsic to the environmental sample that can influence on the measured estrogenic response. Therefore, results interpretation should be performed together with organic matter characterization parameters, cytotoxicity and antiestrogenic activity evaluation.

Bioremediation of Raw Landfill Leachate Using Galdieria sulphuraria: An Algal-Based System for Landfill Leachate Treatment

This study aims to evaluate the potential of using a thermophilic acidophilic red alga, Galdieria sulphuraria for effective on-site treatment of municipal landfill leachate (LL). This study focused on evaluating the effects of LL dilution, nitrogen loading, and initial algal biomass density on the overall treatment efficiency, and evaluated the long-term performance of the system using 5-day growth cycles. This study confirmed that optimal conditions for G. sulphuraria biomass production are 20% strength LL, a lower initial biomass concentration of 0.25 g L−1, and the addition of N at twice the level of initial media. Furthermore, the results indicated G. sulphuraria’s ability to grow in elevated NH4-N concentration (&gt;950 mg L−1) and provide nitrogen removal rates of up to 40 mg L−1 d−1. In addition, the long-term running experiment showed that the proposed algal-based system could be applied in semi-continuous mode to achieve bioremediation. Overall, the results obtained from this study can be used to develop the necessary process parameters to implement large-scale algal-based systems for landfill leachate treatment.

Advancement and Challenges in Municipal Landfill Leachate Treatment–The Path Forward!

Advancement and Challenges in Municipal Landfill Leachate Treatment–The Path Forward!

A critical review of the recently developed laboratory-scale municipal solid waste landfill leachate treatment technologies

Leachate contamination poses a serious risk to water resources. Therefore sustainable treatment techniques are essential to protect the environment and public health. The study provides a comprehensive review of leachate treatment technologies with a critical evaluation of the strengths and limitations. The choice of technology is highly dependent on the capital and operating cost, types of leachate, and regulatory standards. The study observed that aerobic biological treatment (e.g., lagoons, constructed wetlands) and physicochemical treatment (e.g., air stripping, coagulation, flocculation, etc.) are suitable to remove organic substances. While the above technologies have limitations in treating heavy metals and ammonia. On the other hand, adsorption and advanced oxidation are very effective in treating old leachate that contains heavy metals and NH3-N. But the process needs pretreatment and expensive chemicals supply, which is unsustainable. Advanced oxidation can efficiently remove COD, especially from matured leachates due to the complete degradation of recalcitrant organic pollutants. Still, it seems ineffective for young leachates with high organic pollutant loads. The review also identifies the cost for chemicals and energy needed to treat different leachates with each specific technology. Therefore, innovative techniques are required that will minimize energy consumption, sludge and toxin production, and recover organic, inorganic, xenobiotic compounds in a harmless phase and maximize their beneficial applications.

Treatment of municipal waste landfill leachate with low pressure reverse osmosis and nanofiltration membranes

Two different approaches to treat municipal landfill leachate with reverse osmosis membranes are evaluated and discussed. Possibilities are evaluated to radically reduce concentrate flow by a value that does not exceed 0,5-1 % of initial feed water flow to withdraw all rejected impurities together with dewatered sludge. Experimental procedure is developed and described to evaluate reduction of membrane flux and rejection during leachate treatment and recovery increase. Results of experimental investigations are presented that enable us to determine main characteristics of membrane process such as: membrane flux, ammonia rejection, membrane types, number of stages, and recovery. Experimental relationships are obtained to determine the required membrane recovery values that correspond to ammonia concentration in the feed water to meet required regulation values in the product water.

A combined treatment of municipal solid waste landfill leachate using Opuntia ficus-indica cactus as coagulant and titaniferous sand as filter material

In Morocco, the increasing production of municipal solid waste (MSW) and its by-products, in particular leachate, is a major concern. MSW leachate is a very complex effluent, loaded with organic and inorganic pollutants; it poses a serious threat to human health and the environment. In Agadir city, the leachate generated is stored in seven tanks in the Tamellast landfill. The daily flow of this effluent accelerates the saturation of the storage tanks. Overflowing leachate presents a potential environmental hazard, and proper treatment of the leachate has inevitably become a requirement. Therefore, this study aims to find a simple, inexpensive and efficient leachate treatment system. Two techniques using local natural materials have been combined to achieve significant results: coagulation and infiltration-percolation. Cactus powder and cactus mucilage have been selected to treat leachate by coagulation and titaniferous sand as a filter material for the infiltration-percolation process. Laboratory scale experiments show very interesting results. Due to its effectiveness at a dose of 20 mg / l at pH 11, the effluent treated with cactus mucilage was chosen to undergo secondary treatment (86.54% for turbidity and 14.60% for electrical conductivity). The elimination of turbidity and electrical conductivity achieved after infiltration-percolation is, respectively, 97% and 39%.

Efficiency assessment of municipal landfill leachate treatment during advanced oxidation process (AOP) with biochar adsorption (BC)

Leachate generated in landfills are characterized by high toxicity related to, high concentrations of organic and non-organic pollutants, therefore, it is advisable to use highly effective methods of their purification to prevent environmental contamination. The aim of this study was to determine the treatment efficiency of landfill leachate during the application of integrated processes: advanced oxidation (AOP) and biochar adsorption (BC). In the case of the AOP, the chemical process was the Fenton reaction in which the source of hydroxyl radicals was H2O2 (system I) and SPC - sodium percarbonate (system II). Leachate was derived from the regional municipal waste landfill in Silesian Province (Poland) which was characterized by the pH of 8.40, COD value was 3155 mg L−1 and BOD was under 165 mg L−1. The BOD/COD ratio was at a low level (0.053) that indicated low biodegradability. The applied systems allowed of the COD reduction index to the level of 549 mg L−1 (H2O2+BC) and 944 mg L−1 (SPC+BC) where the limit threshold is 125 mg L−1. In the same case of the TOC index, these values were respectively 119 and 186 mg L−1, where the limit value is 30 mg L−1.This study has been aimed to estimate the toxicity of leachate treatment in integrated systems: AOP processes + biochar adsorption. Toxicity of treated and untreated leachate has been analysed by Sinapis alba and Lepidium sativum plants-based tests. It was found that while conducting the Fenton process as system I (H2O2) at all reagent doses, the removal efficiency of COD and TOC was 17% and 12% higher, respectively, compared to system II. The most advantageous dose of regents was 2.5:1 and biochar - 2 g L−1. It was observed that in the SPC+BC system the roots of L. sativum and S. alba were on average 34% and 28% longer compared to the H2O2+BC system. Higher germination index (GI) of both tested plants, indicating lower wastewater toxicity, was recorded for the SPC+BC system.

Treatment of municipal solid waste landfill leachate by aeration assisted electrochemical peroxidation process using aluminium and iron electrodes

Treatment of municipal solid waste landfill leachate by aeration assisted electrochemical peroxidation process using aluminium and iron electrodes

Treatment of municipal landfill leachate: Optimization of organic loading rate in a two-stage CSTR followed by aerobic degradation

This study investigates the performance of a combined anaerobic-aerobic system in the treatment of leachate within 5 months. Experiments were carried out in a two-stage anaerobic completely stirred tank reactor followed by an aerobic reactor with effective volumes of 10, 30, and 14 L at a constant rate of 2 L/day. The reactors were placed in series so that the output from the first anaerobic reactor was the input for the second one, and the output from the second reactor was connected to the input of the aerobic phase. After an initiation phase, the organic loading rate (OLR) was increased from 0.55 to 2.65 kg COD/m3. day. The optimum OLR was found to be 2.05 kg COD/m3. day at which, the removal efficiency of chemical oxygen demand (COD) in the two-stage anaerobic phase, the aerobic phase, and the treatment system as a whole were 93%, 37.1%, and 95.6%, respectively. The BOD5 removal efficiency of the system was 96.8%. The coefficients of determination between the removed COD and produced biogas were 0.98 and 0.99. Although the two-stage anaerobic phase increased the levels of ammonia nitrogen, alkalinity and turbidity by 31.28%, 15.18%, and 18.7%, the aerobic phase reduced these parameters by 50.30%, 57.23%, and 72.1%, respectively.

Treatment of municipal landfill leachate at different stabilization stages in two-stage membrane bioreactor bioaugmented with Alcaligenes faecalis no. 4

Organic and nitrogen removals in two-stage membrane bioreactor (2-stage MBR) applied to the treatment of fresh, mixed, and partially stabilized leachate at different concentrations were investigated. A pilot-scale 2-stage MBR system was operated at a different hydraulic retention time of 2.5 and 1 days during which organic loading rates were varied between 1.5 and 20.2 kg BOD/m3 d. The effect of Alcaligenes faecalis no.4 bio-augmentation and its survival during the treatment was examined. High organic and nitrogen removals (>90%) was achieved when the system was applied to fresh and mixed leachate with BOD/COD of 0.5–0.76 but the removals of COD, TKN was reduced to 58–70% and A. faecalis no.4 population became extinct when partially stabilized leachate was pre-treated and reduced its BOD/COD to 0.11. This study demonstrates the applicability of 2-stage MBR to the treatment of leachate with varied characteristics provided that its treatment conditions were properly adjusted.

Methane and nitrous oxide emissions from a two-stage membrane bioreactor applied in municipal landfill leachate treatment

The emissions of two major greenhouse gases, i.e., CH4 and N2O, during the treatment of partially stabilized municipal solid waste leachate by a practical-scale two-stage membrane bioreactor (MBR) were investigated. The system consisted of anoxic and aerobic reactors that had a total hydraulic retention time (HRT) of 4 days and were operated with internal sludge recirculation at 100% of the influent flow rate. At steady operation, high organic and nitrogen removals of 99% for BOD, 97% for COD, 99% for TOC and 94% for TKN were achieved. During operation, high direct CH4 emissions from the anoxic reactor, accounting for 90% of the total emissions from the system and 16.2% of the total organic carbon mass removed, were observed. N2O was emitted to a much lower extent, and N2O emissions varied much less between the reactors. The presence of methane- and nitrous oxide-producing bacteria was confirmed by PCR-DGGE and real-time PCR analyses. The operation of the two-stage MBR with sludge recirculation enabled the co-existence of CH4- and N2O-producing microorganisms in the sludge from the anoxic and aerobic reactors, with an approximately 30% difference in their microbial communities.

Treatment of Municipal Landfill Leachate by Electrochemical Oxidation: Assessing Operating Variables and Oxidation Products

In this study, the electrochemical oxidation treatment of landfill leachate on a boron-doped diamond (BDD) electrode was examined. A factorial design method was applied to evaluate the experimental...

Treatment of urban municipal landfill leachate utilizing garbage enzyme

In the present study, an attempt has been made to extend the application of garbage enzyme (GE) (fermented mixture of jaggery, organic waste, and water in the ratio 1:3:10) from the domestic wastewater to the urban municipal landfill leachate of Ghazipur, Okhla and Bhalswa landfill sites of Delhi (India). The Leachate Pollution Index (LPI) has been found to be 27.6, 25.4 and 29.2, respectively. The competence of GE was assessed by comparing the initial and final LPIs. The GE was added to the leachate for the contact period of 7–28 days under different mix proportions of 5%, 10%, 15%, and 20%. The maximum final LPI reduction of 74.75% was observed in the Okhla landfill leachate for mixing the proportion of 20% GE after 28 days. However, the mixing ratio of 5% GE showed significant reduction of 60.61% and 55.12% in the final LPI of Ghazipur and Bhalswa landfill leachate, respectively.