Leachate Wastewater Research Articles

Zeolite and Activated Carbon as Catalysts on Leachate Clarification

Improper solid waste management worldwide has increased the negative impacts of landfills due to the production of methane, carbon dioxide, and leachate wastewater. In the present work, granular activated carbon (GAC), zeolite (Ze), and hydrogen peroxide were used for the purification of landfill leachate. Emphasis was given to decreasing operational costs for a big-scale advanced oxidation process. Thus, the aim was to evaluate the effect of oxidant and catalysts dosages, and different highly basic pHs. Up to 95% of dark brown colour and 100% of turbidity from landfill wastewater were removed. Based on the experimental findings, it is suggested that an application of activated carbon and hydrogen peroxide in a dosage ratio between 1.7 and 2.0 would be economically attractive in terms of reduced operation costs.

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.

A magnetic sludge carbon combined persulfate-based ISCO system for leachate-contaminated groundwater remediation

Activation of persulfate by a green magnetic Steel Converter Slag-Sludge Carbon composite (SCS@SC) and subsequent remediation of actual leachate wastewater was studied in an intermittent reactor and column system to assess the potential of the persulfate-based in situ chemical oxidation (SR-ISCO) system for combined oxidative-reductive removal of organic contaminants from groundwater. In the batch experiment, an iron leaching concentration of 6942 mg/L, was higher than 223.2 and 124.4 times that of steel converter slag (31.14 mg/L) and sole sludge carbon (55.80 mg/L). In the column experiments, the total organic carbon (TOC) removal was maintained at 41.7 %, the loading rate reached 48.86 % with 15 g SCS@SC and 0.15 M persulfate after 400 min. The persulfate consumption, sulfuric acid generation, free radical generation, and iron ions flow out under acidic conditions, which are consistent with TOC removal. The mechanism of persulfate activation and organic matter removal was discussed and proposed by electron paramagnetic resonance (EPR) and energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and gas chromatography-mass Spectrometry (GC–MS) to characterize the chemistry of solid and aqueous phases. A mechanism for contaminant removal was presented, which involves free radicals of persulfate activation by zero-valent iron (Fe0) and iron carbide (Fe3C) and precipitation removal by iron oxides. According to the findings, a viable alternative method for the inexpensive synthesis of catalysts from solid wastes such as sludge and steel converter slag was developed.

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.

Magnetic-activated carbon composites derived from sludge and steel converter slag for wastewater treatment

It is generally challenging to design efficient, low-cost, and environmentally friendly persulfate catalytic materials for wastewater purification. We report a simple strategy to synthesize a steel converter slag-sludge carbon catalyst with steel converter slag as a template, suspended sludge as a precursor, and one-step pyrolysis. A persulfate activator was used to remove phenol and organic matter from actual wastewater leachate. The catalyst had a shell structure, a large surface area, abundant adsorption groups, and polymetallic catalytic capacity. The catalytic capacity depended on zero-valent iron (Fe0), which effectively leached active Fe2+ composite to produce hydroxyl and persulfate radicals by activating persulfate. The maximum phenol degradation was 94.5% in 55 min with 2 mM persulfate, 100 mg/L catalyst, and 20 mg/L phenol, which was 6 and 44 times greater than that of pure sludge carbon and steel converter slag, respectively. For actual wastewater leachate, the maximum removal rate of total organic carbon was 77.75% with 0.15 M persulfate, 50 g/L catalyst, and 1125 mg/L total organic carbon; all the fluorescent substances were removed. This work provides a new approach for designing persulfate catalysts derived from green resources. Further, our approach is practical for the treatment of wastewater that has high concentrations of organic material.

Development of electrodes integrated hybrid constructed wetlands using organic, construction, and rejected materials as filter media: Landfill leachate treatment.

This study developed microbial fuel cell (MFC)-based hybrid constructed wetland systems using different filter media, i.e., organic (biochar), construction (sand), and rejected (iron particle, concrete particle, and stone dust) materials, and evaluated the performance of the developed systems for treating landfill leachate. The mean ammonium nitrogen (NH4-N), total nitrogen (TN), total phosphorus (TP), biochemical oxygen demand (BOD), chemical oxygen demand (COD) removal percentages within the hybrid systems ranged between 91 and 98%, 90 and 98%, 97 and 99%, 88 and 93%, 93 and 97%, respectively, despite higher pollutants concentration in leachate wastewater. The aerobic environment in the cathode compartment (due to intermittent load) and free-draining of wastewater (from cathode to anode compartment) supported electrochemically inactive, active pollutants removal in the electrodes integrated first stage vertical flow (VF) wetlands. The second stage electrodes integrated horizontal flow (HF) wetlands supported electrochemical-based organic removal and nitrification because of efficient organic removal in the previous VF wetland stages. Nitrogen, phosphorus accumulation percentages in plant tissues ranged between 0.3 and 7%, 0.4 and 14%, respectively. Nutrient removal was achieved through chemical and microbial routes. The biochar-packed VF wetland produced a maximum power density of 20.6mW/m2. The coexistence of unsaturated, saturated media in the partially saturated HF wetland maintained the required environmental gradient between the electrodes and improved operational performance.

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.

Photodegradation of Polycyclic Aromatic Hydrocarbons from Coal Tar into Mine Wastewaters and Sewage Wastewater on a Flat-Bed Photoreactor

Wastewater treatment has been widely focused on the undesirable pollutants derived from various activities such as coking, coal gasification, oil spills, and petroleum. These activities tend to release organic pollutants, however polycyclic aromatic hydrocarbons (PAHs) happen to be highlighted as the most carcinogenic pollutant that easily comes into contact with the environment and humans. It causes major challenges due to its lingering in the environment and chemical properties. Although various techniques such as ions exchange, advanced oxidation, and reverse osmosis have been conducted, some of them have been ignored due to their cost-effectiveness and ability to produce a by-product. Therefore, there is a need to develop and implement an effective technique that will alleviate the organic pollutants (PAHs) in various water sources. In this study, a self-made flat-bed photoreactor was introduced to degrade PAHs in various water sources such as acidic mine drainage, alkaline mine drainage, and sewage wastewater. A previous study was conducted, and only 7.074 mg/L, 0.3152 mg/L and 1.069 mg/L in 4 weeks and thereafter 19.255 mg/L, 1.615 mg/L and 1.813 mg/L in 8 weeks in acidic mine drainage, alkaline mined, drainage, and sewage wastewater leachate from a 2916.47 mg/L of PAHs in coal tar, was analysed. It was found that the flat-bed photoreactor was highly effective and able to obtain a removal efficiency of 64%, 55%, and 58%, respectively; without the flat-bed photoreactor, happened the removal efficiency was of 53%, 33%, and 39%, respectively, in 60 min in acidic mine drainage, alkaline mine drainage, and sewage wastewater. The photodegradation of PAHs was favoured in the acidic mine drainage, followed by sewage wastewater and alkaline mine drainage respective, showing time and solar irradiation dependence.

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.

Biotechnological potential of microorganisms from landfill leachate: isolation, antibiotic resistance and leachate discoloration.

Disposal of municipal solid waste (MSW) can be considered a risk to human health representing a great environmental problem in several countries. MSW landfills are a significant source of toxic elements in the environment. Microorganisms able to thriving in leachate wastewater may exhibit metabolic machinery to synthesize a wide range of enzymes able to degrade and/or discolor toxic compounds from leachate. The use of non-pathogenic microbial cells for human health, recovered from leachate for biotechnological application, can be considered a promising approach in bioremediation processes of toxic compounds found in these environments. The present work aimed to the isolation, antibiotic resistance evaluation and leachate discoloration by microorganisms isolated from landfill leachate of Foz do Iguaçu. Forty bacteria and fifteen filamentous fungi were isolated. From these, six bacterial showed resistance at least one tested antibiotic, while six fungal isolates showed resistance to the antimycotic nystatin. CCMIBA_4L (unidentified bacteria) and Paecilomyces sp. CCMIBA_5N, were able to discolor 19.15% and 25.26% of the leachate, respectively. The results of the present work encourage future studies to characterize the enzymes involved in the discoloration and degradation of the leachate. The findings demonstrated the potential for the use of microorganisms from landfill leachate as bioremediation tools.

Fertirrigation Wastewater Use for the Irrigation of Tomato and Eggplant Seedlings

ABSTRACT Wastewater reuse from fertirrigation has become a new strategy for sustainable crop production, especially because there is a need to save fresh water. It can also reduce fertilizer costs and environmental pollution. This work aimed to evaluate the production of tomato and eggplant seedlings irrigated with wastewater reuse from fertirrigation. The experiment was carried out in a completely randomized design in a 2 × 4 factorial scheme with four replicates, where each replicate was represented by 25 seedlings. Treatments were represented by two crops (tomato and eggplant) and four concentrations of fertirrigation wastewater leachate (Treatment 1 (T1): 25%; Treatment 2 (T2): 50%; Treatment 3 (T3): 75% and Treatment 4 (T4): 100%). Seedlings were evaluated for the following parameters: number of leaves, seedling height, basal stem diameter, leaf area, total dry mass, and relative water content. With the exception of the basal stem diameter, eggplant seedlings were affected by leachate concentrations for all the other parameters evaluated, while tomato seedlings presented significant responses for all variables. It was observed that the use of concentrations between 50 and 75% of fertirrigation wastewater leachate can be a possible alternative to reduce the use of chemical fertilizers in the production of tomato and eggplant seedlings.

The Effects of Wastewater on The Chemical and Physical Properties of Fine-grained Soils

The objective of this study was to evaluate the effects of different management and land use on soil chemical and physical properties as well as to validate the sensitivity of the soil to leachate. For this purpose, the effect of the wastewater discharged to the soil on the soil's properties taking advantage of the wastewater treatment capacity of the soil was investigated. In this study, different natural soils named SA, SG, SK, and SU were placed in plexiglass pipes with a length of 100 cm and a diameter of 20 cm and fed with wastewater for 21 days with an uninterrupted flow. Soil samples were collected from pipes after 21 days and some parameters were analyzed in order to evaluate the effect on soil structure. As a result, it was revealed that the existing chemical and physical properties of natural soils were affected by wastewater. The pH values of the soils showed a slight tendency to increase after wastewater leachate, except for the SG soil. The Na and K contents of soils increased up to approximately 283% and 390%, respectively. Additionally, it was calculated that the SAR of the soils increased by 118.18%-180.70%. The EC value decreased by 8.77% in SA soil after wastewater leakage, while it increased by 189% in SG soil. While the N and H contents of soils decreased after the wastewater leachate, the Mg, Ca, P, Al, Pb, Zn, and C contents varied according to the soil type. As the fine-grain percentage of the soils increased, their Na adsorption capacity increased (r2=0.96).

Environmental pollution size of the Bishkek Solid Waste Landfill and treatment of generated leachate wastewater

The disposal of municipal solid wastes (MSW) is one of the important issues today. The MSW is generally disposed of in a landfill. The disintegration of wastes in landfill generates the wastewater known as leachate and it became one of the budding environmental impacts. The landfill leachate seeps into natural ponds next to the Bishkek (Kyrgyzstan) landfill. The MSWs are dumped with an irregular landfill in Bishkek, and it has been observed that this situation creates many environmental pollution problems (air pollution due to the combustion of wastes and generated biogas, due to leakage of leachate from the landfill) around the landfill. The leachate in the ponds is not treated and leaks into the environment. In this study, the potential of the coagulation-flocculation(CF) and electrooxidation (EO) processes was investigated for the treatment of leachate from the sanitary landfill located in Bishkek-Kyrgyzstan. The initial COD (1400 ± 50 mg/L), TOC (540 ± 15 mg/L), and ammonia nitrogen (315 ± 10 mg/L) from landfill leachate were treated by the CF process as 33, 23, and 14% at pH 6.5 with alum dosage of 5 g/L, and 40, 29 and 10.1% at pH 8.5 with ferric chloride dosage of 5 g/L, respectively.Removal efficiencies at applied currents of 1.0, 3.0, and 5.0 A with an EO reactor using boron-doped diamond (BDD) plate anode and stainless steel (SS) plate cathode were 67.20, 88.30, and 97.90% for COD, 60.10, 85.38, and 95.53% for TOC, and 48.9, 94.6 and 99.8% for ammonia nitrogen, respectively. As a result, it was seen that Bishkek’s irregular solid waste landfilling leachate, which causes environmental pollution, was effectively treated with the EO process. By establishing a regular landfill, Bishkek municipal solid wastes must be disposed of in the landfill and treated of the leachate.

Microbial fuel cells constructed from the integration of anaerobic and aerobic sanitary landfill site systems

The world’s main source of energy now is fossil fuels but the demand for power is increasing. In addition, the burning of fossil fuels produces harmful greenhouse gases and has a significant impact on the environment. The fuel cell system in this study is based on the aerobic and anaerobic integration system are used in most waste disposal methods in Malaysia. It is a system of electrochemistry results from the oxidation of organic matter that transfers electrons to carbon graphite This research is to study the effectiveness of the method generating electricity from micro-fuel cells produced from leachate wastewater and it is also conducted to identify microbial activity using a double chamber system. The food waste obtain is divided into double chambers which is aerobic and anaerobic. Digital readings using a multimeter are performed for ten to thirteen days continuously to obtain the highest reading results for voltage and electric current. The measurement of the highest reading result on the 11th day recorded a reading as high as 146.8 mV at 2000 mV while the current reached 28 μA at 2000 μA. This study has proven that there is the production of electrical sources from the activity of organisms present in food waste using microbial fuel cell systems. The result show that food waste and cattle manure produce the highest voltage and current. This has provided an opportunity to explore alternative ways of generating electricity according to the environment and conditions of each region.

A New Process for the Recovery of Ammonia from Ammoniated High-Salinity Brine

This paper describes a new method for the recovery of high-concentration ammonia from water in the form of ammonium chloride, ammonium hydroxide and ammonium carbonate. The method was applied to the Solvay process, in which sodium bicarbonate is produced through the reaction of ammoniated brine and CO2 gas. The Solvay effluent contains ammonia in the form of soluble ammonium chloride. The proposed method is based on the recovery of ammonia using a high-alkalinity reactant, calcium oxide (CaO), in a closed electrocoagulation cell operating at a specific current density. The recovered ammonia is collected as a gas within a closed cell containing deionized (DI) water at room temperature. Afterwards, the collected solution (DI water–NH3 gas) is concentrated through a separate process, and is then reused in the Solvay process and other applications. The electrocoagulation process is applied to the treatment cell using aluminum electrodes and a current density of 5–15 mA/cm2. After 7 h of treatment using the electrocoagulation cell, a high reduction of the ammonia concentration—99%—was realized after ~9 h of the electrochemical treatment. The initial ammonia concentration in a Solvay effluent of 13,700 mg/L N was decreased to 190 mg/L N. Furthermore, an ammonia recovery of 77.1% in the form of ammonium hydroxide was achieved. Generally, this process, which starts at room temperature, can result in an energy reduction of 80%—from 7.8 to 2.3 kWh/kg NH3—compared to conventional processes, which entail heating the Solvay effluents to 160 °C. The proposed system and method were found to be suitable for the recovery of ammonia from ammoniated water, and can be utilized for the treatment of landfill leachate, and municipal and industrial wastewater.