Landfill Leachate Wastewater Research Articles

Electrocatalytic mechanism of titanium-based anodes and research progress of chemical saline wastewater treatment: A short review

Electrocatalytic treatment of chemical saline wastewater showed great technical advantages due to its characteristics of simple operation, high catalytic efficiency and little secondary pollution. The review takes the classification and composition of titanium-based anodes as the starting point. Typical studies of wastewater treatment by electrocatalytic technology based on free radicals and non-free radicals were also discussed. Combined with the previous researches about electrocatalytic mechanisms in recent years, the mechanisms of titanium-based anodes were analyzed in terms of ·OH, active chlorine and others. The studies on titanium-based anodes in chemical wastewater containing different salt concentrations, such as dye wastewater, coal chemical wastewater, landfill leachate wastewater, fertilizer and pesticide production wastewater, etc., were thoroughly examined. According to the amount of electricity required for the removal of organic matter per unit, the energy consumption of titanium-based anodes for wastewater treatment by electrochemistry was described. The review would provide theoretical basis and technical support for electrocatalytic treatment of chemical saline wastewater.

Enhancing biological dissolved organic nitrogen removal in landfill leachate wastewater: The role of sodium acetate co-metabolism

Dissolved organic nitrogen (DON) comprises approximately 25% of dissolved nitrogen in landfill leachate wastewater (LLW), posing potential risks such as stimulating algal growth and forming disinfection by-products if not treated properly. While DON characterization and removal by physicochemical methods in wastewater treatment systems have been examined, biological strategies for effective DON removal remain less developed. This study explores the influence of sodium acetate addition during denitrification process on LLW DON removal. With sodium acetate addition (Stage I), we achieved 99% ammonia removal, 94% total inorganic nitrogen (TIN) removal, and 45% DON removal. Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS) results suggested the majority of sulfur-containing DON molecules were eliminated in Stage I. Conversely, in the absence of sodium acetate (Stage II), while 99% ammonia removal was maintained, TIN removal dropped to around 10%, and DON concentrations (largely sulfur-containing DON) increased by approximately 22%. Cycle tests revealed similar DON reductions in the aerobic phase across both stages, whereas in the anoxic phase, DON concentrations decreased in Stage I but increased in Stage II. Functional gene prediction indicated higher expression of decarboxylase and deaminase genes in Stage I compared to Stage II. Consequently, this study posits that sodium acetate addition enhances DON removal, potentially via co-metabolism.

Electrochemical oxidation of perfluorooctanesulfonate (PFOS) from simulated soil leachate and landfill leachate concentrate

The near-widespread presence of poly- and perfluoroalkyl substances (PFASs) in humans has generated concerns regarding the potential negative impact of these chemicals on human health, as some PFASs are exceedingly persistent and bioaccumulative. Among the perfluorinated PFASs, which exhibit high polarity and strong carbon–fluorine bonds, perfluorooctanesulfonate (PFOS) is one of the frequently encountered species. In this study, the efficiency of electrooxidation (EO) and its application in groundwater simulation were first evaluated as a realistic approach to PFOS removal. After optimizing EO parameters including the solution pH, current density, and the effects of inlet concentration and the anode material, 83 % total organic carbon (TOC) removal was obtained. In groundwater experiments, in which the infiltration of PFOS from soil layers into groundwater was simulated, 79 % TOC removal efficiency was achieved in the more complex groundwater; moreover, an F− ion concentration of 8.78 mg/L was obtained from the decomposition of PFOS. To increase the realism of the simulation, the leachate process was repeated four times, and the EO process was applied to each sequential leachate. In addition, the process efficiency was studied in real landfill leachate wastewater to which PFOS had been added. Despite the challenging wastewater composition, 84 % TOC removal efficiency was achieved. Together, these results indicate that BDD-anodic oxidation may be a practical method to treat PFOS-contaminated groundwater and wastewater.

Kappa carrageenan-vanillin composite hydrogel for landfill leachate wastewater treatment

Removing heavy metals from landfill leachate wastewater treatment is an environmental challenge because of its complicated characteristics and composition. Although several chemical and physical processes were developed for landfill wastewater treatment, membrane technologies are still common. Nevertheless, membrane fouling, energy requirements and brine management are drawbacks of membrane technologies. This study proposed a biodegradable, gravity-driven kappa-Carrageenan-vanillin hydrogel for biologically treated leachate wastewater treatment to reduce the treatment cost and brine management problem. The composite hydrogel was synthesized using a facile method, with an average pore size of 2.58 ± 0.5 nm and acts as a water filter with super high flux and excellent rejection for heavy metal ions, divalent ions and other contaminants in the landfill leachate wastewater. The hydrogel filter achieved high rejection for divalent ions from salt feed solutions such as sodium chloride, magnesium sulphate, and copper sulphate. An average rejection of 42 ± 5 % was achieved for sodium chloride, 78 % ± 5 % for copper, 72 % ± 5 % for divalent magnesium ion, and 17 % ± 5 % for sulphate rejection. The hydrogel filter achieved a flux of 27 ± 5 LMH for landfill leachate wastewater with high rejection efficiency for total organic carbon, turbidity, and heavy metal separation. The filtration of the landfill leachate with the hydrogel resulted in a high rejection of total organic carbon (77 ± 3 %), 95 ± 3 % turbidity removal, 73 ± 5 % TDS removal, and 95–97 % colour removal. Heavy metal ions were rejected in the following order: Al (80 ± 3 %) > Ba (88 ± 2 %) > Pb (79 ± 3 %) > Cd (72 ± 3 %). The composite hydrogel filter is inexpensive, reliable, and highly efficient in removing contaminants under gravity filtration, requiring no external energy or high hydraulic pressures and ease of scalability for commercial applications.

Fabrication of carbon-based hydrogel membrane for landfill leachate wastewater treatment

The challenge of effectively managing the discharge of metal ions into aquatic environments, which poses a significant risk to both human health and ecosystems, persists despite the availability of various analytical tools and techniques. There are limitations of existing separation technologies and the inefficacy of hydrogel materials in removing low molecular weight contaminants, such as metal ions, in aqueous solutions. This study added carbon powder to the hydrogel membrane to reduce the low-mechanical strength and drying problems and increase its capacity for adsorbing ionic and non-ionic substances. The study introduced a novel carbon-based aluminium hydroxide hydrogel for wastewater filtration. CG was characterized using various analytical techniques, including examining surface morphology, elemental analysis, surface functional groups, and surface charge. These analytical tools provided a comprehensive understanding of the properties and performance of the CG. The effects of different carbon-based hydrogel (CG) concentrations on water flux and ion rejection were evaluated in a gravity filtration setup. Experiments investigated the influence of different ion concentrations, activated carbon (AC) concentration, centrifugation, water flux, and rejection on removing heavy metals from synthetic and natural wastewater. The pure water flux of the hydrogel membrane was 120 LMH. The results indicated that an AC concentration of 4 g/L in the aqueous solution is optimal for heavy metals removal, with 99.9 % removal for Pb2+ and Cu2+, 84 % rejection for Ca2+, and 85 % rejection for Mg2+ in 10 mg/L of synthetic water. Besides, the 4 g/L AC hydrogel membrane removed 90 % of Ni, Zn, Pb, As, and Cu ions and 53 % of the total organic carbon from leachate wastewater.

Novel Approach to Landfill Wastewater Treatment Fouling Mitigation: Air Gap Membrane Distillation with Tin Sulfide-Coated PTFE Membrane.

This study addressed the fouling issue in membrane distillation (M.D.) technology, a promising method for water purification and wastewater reclamation. To enhance the anti-fouling properties of the M.D. membrane, a tin sulfide (TS) coating onto polytetrafluoroethylene (PTFE) was proposed and evaluated with air gap membrane distillation (AGMD) using landfill leachate wastewater at high recovery rates (80% and 90%). The presence of TS on the membrane surface was confirmed using various techniques, such as Field Emission Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Energy Dispersive Spectroscopy (EDS), contact angle measurement, and porosity analysis. The results indicated the TS-PTFE membrane exhibited better anti-fouling properties than the pristine PTFE membrane, and its fouling factors (FFs) were 10.4-13.1% compared to 14.4-16.5% for the PTFE membrane. The fouling was attributed to pore blockage and cake formation of carbonous and nitrogenous compounds. The study also found that physical cleaning with deionized (DI) water effectively restored the water flux, with more than 97% recovered for the TS-PTFE membrane. Additionally, the TS-PTFE membrane showed better water flux and product quality at 55 °C and excellent stability in maintaining the contact angle over time compared to the PTFE membrane.

Simultaneous landfill leachate treatment and electricity production by sediment microbial fuel cell

The sediment microbial fuel cell (SMFC) is a new technology that uses exoelectrogenic bacteria and organic compounds to transform chemical energy into electrical energy. The application of SMFC technology is gaining popularity since it can simultaneously reduce contaminants in wastewater and generate electricity. An SMFC performance is mainly governed by the kinetics of the electrodes within the fuel cell, of which the materials that make up the electrodes significantly impact their performance. The objective of the ongoing investigation was to study the performance of three types of electrodes for minimizing pollutants from landfill leachate wastewater while also generating electrical energy. Sediment and leachate samples were taken from the Regional Landfill wastewater treatment facility in Blang Bintang, Aceh Besar, the Province of Aceh. Three transparent acrylic reactors with a length, width, and height of 45 cm, 20 cm, and 12 cm, respectively, were employed in this experiment. The electrode materials utilized in this study were zinc (Zn), copper (Cu), and iron (Fe), with each electrode having a surface area of 124 cm2. Temperature, pH, voltage, and carbonaceous compound removal measured as COD were used to assess the SMFC performance. The study results showed that the temperature and pH of the three reactors have a similar trend, and the values are not much different at 24.36±0.25°C and 9±0.03, respectively. The reactor installed with Cu electrode produced the maximum electrical voltage of 470 mV, whereas those with Fe and Zn had the highest voltages of 107 mV and 23 mV, respectively. The percentage of COD removal for reactors equipped with Zn, Cu, and Fe electrodes was 40.70%, 41.09%, and 41.23%, respectively. Although the COD removal by each reactor of different electrode materials did not show a significant difference, the reactor with Cu electrode gave better performance when viewed from the electrical voltage.

Perfluorooctanoic acid (PFOA) removal from real landfill leachate wastewater and simulated soil leachate by electrochemical oxidation process

Poly and perfluoroalkyl compounds (PFASs) are a group of chemicals that are widely used and are difficult to purify. Within this group, perfluorooctanoic acid (PFOA), known for its highly polar and strong carbon–fluorine bonds, is a frequently encountered species in surface water, drinking water, and groundwater. In this study, we investigated the efficiency of electrooxidation (EO) in PFOA removal, optimization of EO parameters, and groundwater simulation in a realistic scenario. The EO optimization experiments were performed with a boron-doped diamond (BDD) anode for different values of pH, current density, and inlet concentration, and the effects of different anode materials were investigated for comparison. Under optimum conditions, total organic carbon (TOC) removal of up to 90% was achieved. In the groundwater simulation, we applied optimized EO parameters after obtaining leachates from the soil. A TOC removal of up to 86% was obtained in the EO of simulated groundwater contaminated with PFOA. In the case of realistic leachate simulation, four different leachate treatments were applied to PFOA-contaminated soil, and high TOC removal was achieved in all matrices. Additionally, the EO with BDD was applied to landfill leachate wastewater supplemented with PFOA to monitor the effectiveness of the process. A TOC removal of 85% was achieved, and it was observed that the number of free F-ions increased. The results showed that the BDD EO has a high potential for the treatment of PFOA-contaminated groundwater. • A realistic simulation was designed to obtain PFOA-contaminated groundwater. • Parameter optimization for BDD EO was performed. • The effects of different anodes (DSA) in the EO was investigated. • TOC removal efficiencies for water and wastewater were 90% and 78%, respectively. • TOC removal of 85% was achieved for PFOA contaminated groundwater.

Fouling and Performance Investigation of Membrane Distillation at Elevated Recoveries for Seawater Desalination and Wastewater Reclamation.

This study reports on the impact of elevated recovery (i.e., 80%, 85%, and 90%) on the fouling and performance of air gap membrane distillation (AGMD) with real seawater and landfill leachate wastewater samples using polytetrafluoroethylene (PTFE) polymer membranes. Increasing the feed temperature from 55 °C to 65 °C improved the water flux of seawater and wastewater and shortened the operating time by 42.8% for all recoveries. The average water flux in the 80%, 85%, and 90% recovery experiments at the 65 °C feed temperature was 32%, 37.32%, and 36.7% higher than the case of 55 °C for the same recoveries. The water flux decline was more severe at a higher temperature and recovery. The highest flux decline was observed with a 90% recovery at 65 °C feed temperature, followed by an 85% recovery at 65 °C. Close examination of the foulants layer revealed that seawater formed a cake fouling layer made predominantly of metal oxides. In contrast, the landfill leachate fouling was a combination of pore blocking and cake formation, consisting mainly of carbonous and nitrogenous compounds. Physical cleaning with deionized (DI) water at 55 °C and 65 °C and chemical cleaning with hydrogen peroxide (H2O2) were investigated for their efficiency in removing membrane foulants. Analytical results revealed that seawater fouling caused membrane pore blockage while wastewater fouling formed a porous layer on the membrane surface. The results showed that membrane cleaning with hydrogen peroxide restored >97% of the water flux. Interestingly, the fouling factor in seawater tests was 10%, while it was 16% for the wastewater tests.

Microalgae-bacteria consortium for wastewater treatment and biomass production.

The diversity of microalgae and bacteria allows them to form a complementary consortium for efficient wastewater treatment and nutrient recovery. This review highlights the potential of wastewater-derived microalgal biomass as a renewable feedstock for producing animal feed, biofertilisers, biofuel, and many valuable biochemicals. Data corroborated from this review shows that microalgae and bacteria can thrive in many environments. Microalgae are especially effective at utilising nutrients from the water as they grow. This review also consolidates the current understanding of microalgae characteristics and their interactions with bacteria in a consortium system. Recent studies on the performance of only microalgae and microalgae-bacteria wastewater treatment are compared and discussed to establish a research roadmap for practical implementation of the consortium systems for various wastewaters (domestic, industrial, agro-industrial, and landfill leachate wastewater). In comparison to the pure microalgae system, the consortium system has a higher removal efficiency of up to 15% and shorter treatment time. Additionally, this review addresses a variety of possibilities for biomass application after wastewater treatment.

Sodium docusate as a cleaning agent for forward osmosis membranes fouled by landfill leachate wastewater

Membrane cleaning is critical for economic and scientific reasons in wastewater treatment systems. Sodium docusate is a laxative agent and removes cerumen (ear wax). Docusate penetrates the hard ear wax, making it softer and easier to remove. The same concept could be applied to soften and remove fouling layers on the membrane surface. Once softened, the foulants can be easily flushed with water. This innovative approach can address the challenge of developing superior methods to mitigate membrane fouling and material degradation. In this study, we evaluated the efficiency of sodium docusate for cleaning fouled forward osmosis membranes with real landfill leachate wastewater. Experiments were conducted to examine the impact of dose rate, contact time, flow or static conditions, and process configuration (forward osmosis (FO) or pressure retarded osmosis (PRO) upon fouling created by landfill leachate dewatering. A remarkable (99%) flux recovery was achieved using docusate at a small concentration of only 0.1% for 30 min. Furthermore, docusate can also effectively restore flux with static cleaning without using pumps to circulate the cleaning solution. Furthermore, cleaning efficiency can be achieved at neutral pH compatible with most membrane materials. From an economic and energy-saving perspective, static cleaning can almost achieve the same cleaning efficiency as kinetic cleaning for fouled forward osmosis membranes without the expense of additional pumping energy compared to kinetic cleaning. Since pumping energy is a major contributor to the overall energy of the forward osmosis system, it can be minimized to a certain degree by using a static cleaning approach and can bring good energy savings when using larger membrane areas. Studies of the contact angle on the membrane surface indicated that the contact angle was decreased compared to the fouled membrane after cleaning (e.g. 70.3° to 63.2° or FO mode and static cleaning). Scanning Electron Microscopy revealed that the cleaning strategy was successful. Infrared Spectroscopy showed that a small amount of sodium docusate remained on the membrane surface. Docusate is more environmentally friendly than acid or alkaline solutions from an environmental perspective. Furthermore, the cleaning solution can be reused for several cycles without discarding it due to the surfactant properties of docusate.

Engineering of heterojunction TiO2/CaIn2S4@rGO novel nanocomposite for rapid photodegradation of toxic contaminants

The in-situ reduction of GO to rGO and simultaneous deposition of TiO2 and varying concentrations CaIn2S410 % (rGO-C1), 20 % (rGO-C2), and 40 % (rGO-C3) resulted in the formation of robust photocatalysts for the degradation of aqueous (azo and thiazine) dyes methylene blue (MB), congo red (CR) and real wastewater. Batch experiments were performed to analyse the effect of pH, catalyst dose, initial dye concentration and time. Compared to other synthesised composites, rGO-C2 demonstrated enhanced photodegradation activity, with a degradation efficiency of almost 100 % within 25–30 min. A possible mechanism for the photodegradation of dyes was also proposed, and post-degradation products were analysed using the LC–MS technique. The kinetic studies show that the degradation efficiency of rGO-C2 followed pseudo-first-order reaction kinetics (k = 0.027 min−1. The rGO-C2 photocatalysts demonstrated excellent photocatalytic degradation in real textile industry wastewater and landfill leachate wastewater. It displayed excellent recyclability and stability up to the four-cycle.

Mature landfill leachate treatment using granular sludge-based reactor (GSR) via nitritation/denitritation: Process startup and optimization

Mature landfill leachate wastewater (LLW) was characterized by high ammonia, refractory chemical oxygen demand (COD) and heavy metal contents, which limits the nitrogen removal in conventional activated sludge systems. Granular sludge is known to be more resistant to toxic compounds because of its dense structure and diverse microbial community. Here, granular sludge-based reactor (GSR) was applied with nitritation/denitritation (Nit/DNit) process for effective ammonia-rich mature LLW treatment at 20 °C. After a short startup period, the efficiencies of ammonia removal and total inorganic nitrogen removal stabilized at 99 % and 93 %, respectively, under a hydraulic retention time (HRT) of 6 h. High ammonia oxidation rate (~ 0.64 g N/g VSS/d) was achieved, with ~93 % ammonia conversing to nitrite before being reduced to nitrogen gas. Microbial analysis results revealed that Nitrosomonas (ammonia oxidizing bacteria) and Thauera (denitrifiers) were the dominant bacteria with key functional genes involved in the Nit/DNit. With an increase in the LLW loading, increased ammonia oxidation rates and biomass retention were also observed. This study demonstrated that granular sludge-based technology is feasible for mature LLW treatment.

Surface modification of nanofiltration membrane with kappa-carrageenan/graphene oxide for leachate wastewater treatment

In this study, the top layer of commercial UA-60 loose nanofiltration (NF) membranes is coated with cross-linked kappa-carrageenan (κ-CGN) and graphene oxide (GO) solution. Various GO concentrations are investigated to improve salt rejection and antifouling properties. The surface functional groups, surface morphology, elemental analysis, hydrophilicity, and surface charge of all membranes were investigated using a range of analytical tools. Coated membranes are tested for 2000 ppm NaCl (sodium chloride) and MgSO4 (magnesium sulfate) for salt rejection studies. Landfill leachate wastewater was used for antifouling studies. The κ-CGN-GO coating increased the wettability and negative surface charge, increasing salt rejection. The GO concentration of (0.075; wt/v %) with 1.2 wt% κ-CGN aqueous solution is optimal for coating solution. The optimal UA-60-κ-CGN-GO3 membrane showed the highest FRR (flux recovery ratio) of 95.73% and the lowest total fouling percentage of 18.9%, with a slightly low water flux compared to the pristine UA-60 membrane. The κ-CGN-GO coating has the potential to overcome membrane fouling and low selectivity for wastewater treatment owing to the increased selectivity and antifouling properties of the coated membranes.

A hybrid process for leachate wastewater treatment: Evaporation and reverse osmosis/sequencing batch reactor.

In this study, a hybrid process for leachate wastewater treatment including evaporation and reverse osmosis (RO) membrane or biological treatment systems was suggested. Experiments were performed on a real landfill leachate wastewater. The leachate was subjected to evaporation; as a result, a distillate was obtained containing less organic matter and less substantial amounts of other pollutants, as ammonium salts and total phenols were removed. Tests were carried out at different evaporation temperatures and times. The initial leachate pH was adjusted and optimized. For optimum conditions, each of chemical oxygen demand (COD), total phenol, and ammonium salt concentrations were reduced to 99.99%, 95.00%, and 83.00%, respectively. The distillate of the first stage of the proposed process was then exposed to RO membrane system, as a first study, under different transmembrane pressure of 20, 30, and 40 bar and at different pH values of 7, 8, and 9. As a second suggested treatment system, the distillate was subjected to a biological treatment process for 30 days as a retention time, pH = 6, and room temperature 25°C ± 1°C. At the end of the research study, a comparison was conducted between results obtained with RO membrane separation and biological treatment system as two distinct treatment systems proposed for leachate landfill wastewater treatment. Although both systems were effective for landfill leachate wastewater treatment, however, with the RO membrane separation system, COD removal efficiency reached 99.99%. In the other hand, with biological treatment process, COD elimination was as much as 90.00%. Certainly, evaporation and RO are not novel ways of landfill leachate treatment; however, few studies have attempted to use similar combined system for landfill leachate wastewater treatment and attained effective results of treated water. PRACTITIONER POINTS: A hybrid process of evaporation and RO membrane or biological treatment systems was suggested for leachate wastewater treatment. For optimum conditions, COD, total phenols, and ammonium salt reductions were achieved to 99.99%, 95%, and 83%, respectively, after the first evaporation stage. The distillate of the first stage of the proposed process was then exposed to RO membrane system and biological treatment system. Different transmembrane pressure and different pH values were optimized for RO.

Preparation of fouling resistant and highly perm-selective novel PSf/GO-vanillin nanofiltration membrane for efficient water purification

To meet the rising global demand for water, it is necessary to develop membranes capable of efficiently purifying contaminated water sources. Herein, we report a series of novel polysulfone (PSf)/GO-vanillin nanofiltration membranes highly permeable, selective, and fouling resistant. The membranes are composed of two-dimensional (2D) graphite oxide (GO) layers embedded with vanillin as porogen and PSf as the base polymer. There is a growing interest in addressing the synergistic effect of GO and vanillin on improving the permeability and antifouling characteristics of membranes. Various spectroscopic and microscopic techniques were used to perform detailed physicochemical and morphological analyses. The optimized PSf16/GO0.15-vanillin0.8 membrane demonstrated 92.5% and 25.4% rejection rate for 2000 ppm magnesium sulphate (MgSO4) and sodium chloride (NaCl) solutions respectively. Antifouling results showed over 99% rejection for BSA and 93.57% flux recovery ratio (FRR). Experimental work evaluated the antifouling characteristics of prepared membranes to treat landfill leachate wastewater. The results showed 84–90% rejection for magnesium (Mg+2) and calcium (Ca+2) with 90.32 FRR. The study experimentally demonstrated that adding GO and vanillin to the polymeric matrix significantly improves fouling resistance and membrane performance. Future research will focus on molecular sieving for industrial separations and other niche applications using mixed matrix membranes.

Effect of Feammox on Landfill Leachate Treatment and Its Influence on pH

Feammox is a new biological nitrogen removal process which can synchronously achieve NH4 +-N oxidation and Fe3+ reduction under the action of microorganisms. In order to investigate the starting of Feammox and the influence of different pH on the denitrification effect of simulated landfill leachate wastewater, the Feammox reaction was carried out by inoculating Anammox sludge under anaerobic conditions, and the N/Fe conversion pathway in the reaction was observed. On the 43rd day, the influent Fe3+ concentrations in the reactor was increased, and it was found that it promoted Feammox. Taking Feammox sludge in good operation as inoculation sludge, pH was set at 3.5-7.5, respectively. The results showed that the landfill leachate had the best denitrification effect when pH =4.5, and the Feammox reaction almost did not exist in the reactor when pH =3.5

Energy efficient removal of COD from landfill leachate wastewater using electrocoagulation: parametric optimization using RSM

In the present work, electrocoagulation method was employed using iron/aluminium electrodes for COD removal in the treatment of landfill leachate. The process was optimized with variables such as initial pH, applied current, initial COD and electrolysis time experimentally varied as per CCD design to know their influence on chosen response variables viz. COD removal efficiency and electrical energy consumption. The optimum conditions found were pH 5, applied current 0.5 A, initial COD concentration 5450 ppm and application time 9 min to achieve 64.25% efficiency with 0.59 W hour per gram removal of COD. The results prove that electrocoagulation process could be suitably used as an effective method for treatment of leachate. Operating cost of optimized condition was figured out as Indian rupee 0.211 (equivalent to 0.0028 US $) per gram of COD removed.

Hybrid Sono-Electrocoagulation Process for the Treatment of Landfill Leachate Wastewater: Optimization through a Central Composite Design Approach

The effectiveness of the process of ultrasonication (US), electrocoagulation (EC) and hybrid sono-electrocoagulation (US+EC) on landfill leachate wastewater treatment was evaluated based on the removal efficiency of % color and % Chemical Oxygen Demand (COD) along with power consumption. The experimental results showed that the hybrid US+EC had a high color (100%) and COD (94%) removal efficiency with a lower power consumption of 4.50 kWh/m3 compared to the individual EC and US processes. In this hybrid US+EC process, the effects of various operating parameters were investigated and optimized using Design-Expert (12) based on the central composite design approach. The optimization results indicated a maximum COD removal efficiency of 71.05% with a minimum power consumption of 2.33 kWh/m3 at the following optimal experimental conditions: electrolyte concentration (X1) = 0.76 g/L, current density (X2) = 2.75 A/dm2, COD concentration (X3) = 3919.50 mg/L, sonication power (X4) = 100 W and treatment time (X5) = 36.05 min. The synergistic effect was calculated using the US, EC and US+EC process based on the % COD removal efficiency and has a positive effect of 20.51%. The % COD and % color removal efficiency were analyzed using a closed reflux method and UV-VIS spectrophotometer. Thus, the hybrid US+EC process, significantly enhances the efficiency of pollutants removal from landfill leachate wastewater.

Physicochemical Characteristics of Landfill Leachate from Simpang Renggam Landfill Site, Johor, Malaysia

The worldwide increasing amount of municipal solid waste causes a major problem in managing waste as well as requires an effective solution to manage the waste generation. In Malaysia, landfilling is the main alternative technique for managing solid waste. In the same way, the main advantage of having a landfill is that it is easy to operate and comparatively lower in cost. Thus, in Malaysia, total 296 municipal solid waste landfills are open to overcome this issue. Drawbacks of landfilling can includes; i) generation of noxious gases, ii) leachate wastewater contamination of both ground and surface water, iii) problems such as odor, noise, and dust, iv) attraction of disease vectors and, v) the requirement for considerable land area. This present research study focuses on the characterization of Simpang Renggam Landfill (SRLS) Site such as its organic constitutes (mg/L), Ammoniacal Nitrogen (mg/L), SS (mg/L), BOD5/COD, BOD5 (mg/L), and pH. All the analyzed results were compared with the past researchers’ researches and also were compared with Malaysian Environmental Quality Act 1974. From the results, it is concluded that the Simpang Renggam Landfill Site was characterized old (stabilized) landfill leachate wastewater with BOD5/COD > 0.1. For the SRL site, it is recommended that physical-chemical method is better fitted for the leachate wastewater treatment and the aerated lagoon technique does not support the treatment of aging leachate.