Leachate Quality Research Articles

Phytoplankton Population as Phytoremediation Agents in Jatibarang Landfill Leachate Pond of Central Java, Indonesia

Remediation of microalgae from leachate is less explored because of its very high level of pollutants such as ammonia-nitrogen, heavy metals, inorganic salts, and organic chlorinated. Moreover, leachate poisons many organisms. This study aimed to determine the phytoplankton species in the leachate pond Jatibarang landfill, Central Java, Indonesia, and as an effort in phycoremediation. Sample was obtained from 4 stations; Inlet pond (J1), aerobic pool (aeration pool) (J2), sedimentation pond (J3), and pond outlet (J4). The results showed two phytoplankton species, Chlorella sp. and Chlamydomonas sp. Based on the abundance of Chlorella sp., the highest number was found at sedimentation pond with an average of 54,904 cells L-1, followed by pond outlet with an average of 17,449 cells L-1, aerobic pool with an average of 8,869 cells L-1, and pond Inlet with an average of 3,424 cells L-1. Chlamydomonas sp. was only found at pond Inlet with an average of 12,375 cells L-1. Further, the BOD decreased from station 2, 3, and 4 with percentages 12%, 29%, and 32%, respectively; COD gained 28%, 33%, 33%, respectively; and TSS, respectively, gained 22%, 35%, and 30%. To sum up, the pond’s water quality as producing leachate in Jatibarang landfill concerning pH, DO, and Cd are still below the leachate quality standard. Whereas the BOD, COD, and TSS exceed leachate quality standards.

Assessment of Contamination Potential in Okhla Landfill, New Delhi by using Leachate Pollution Index

Landfill leachate generation from a landfill site is one of the main problems for both developed and developing countries around the world. Leachates liberated from the site contain various organic, inorganic, heavy metals, and sometimes hazardous chemical and organic pollutants, which are the origin of the deterioration of air and water quality in its vicinity. The present attempt was performed to assess seasonal variation of the leachate quality, and also determine three sub-indices of leachate which are LPIorg, LPIin, and LPIhm, and the overall LPI of operational, uncontrolled landfills in South Delhi by using leachate pollution index (LPI). Around twenty-five (25) parameters were analyzed during pre-monsoon, monsoon, and post-monsoon seasons from the collected leachate samples. Out of twenty-five pollutants, COD, BOD, NH4-N, EC, and TDS were found beyond the set standard limit in all seasons. Other pollutants like TKN, TSS, TCB, and Cl were also found in high concentrations. Arsenic (As) concentration was found beyond permissible during post-monsoon. The concentration of lead (Pd) in the pre and post-monsoon season was observed beyond the standard limit. Sub-LPI indices in the pre-monsoon season were observed as LPIorg 82.0, LPIin 40.8, and LPIhm 6.9, and likewise, Sub-LPI in monsoon season were LPIorg 81.4, LPIin 25.5, and LPIhm 5.2 and Sub-LPI post-monsoon season was calculated as LPIorg 90.5, LPIin 30.2 and LPI hm 6.2. Almost in all the seasons, LPIorg i.e. organic pollutants was dominated then followed by LPIin, and LPIhm. The overall LPI value of the study area during the pre-monsoon, monsoon and post-monsoon was 32.5, 28.2 and 32.0, respectively. It was observed that overall LPI (calculated) was maximum during pre-monsoon followed by post-monsoon and monsoon. LPI value was beyond the standard limit, except for LPI hm, which was below the standards. It was recommended that more waste-to-energy plants and decentralized waste segregation units need to be set up, to avoid direct dumping of all mixed waste in the landfill sites.

Performance of Selected Plants Based Growth on Landfill Leachate Treatment Using Wetland Application

Introduction: This research was conducted to process untreated leachate using plants in artificial wetlands. The aim was to obtain plant selection criteria based on the relative growth rate (RGR) and removal efficiency (Re) of biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Methods: The methodology used leachate containing about 1,000 mg/L and 5,000 mg/L BOD and COD, respectively. Three plants, Typha angustifolia, Cyperus papyrus, and Canna indica, were tested. The research stages included a range finding test for 14 days and definitive leachate experiments for the three plants for 36 days. Results: The results revealed that three types of plants could process leachate without treatment for 36 days after acclimatization (DAA). The determining period was 0-12 DAA with a decrease in BOD and COD concentrations in the range of 40-60% and an increase in the ratio of BOD/COD, which expresses increased leachate biodegradability. The following 24 days showed a decrease in the BOD/COD ratio and a constant decrease in the concentration of both parameters as an indicator of the stability of leachate quality. This pattern was followed by plant growth performance and showed the order of priority for C. papyrus, C. indica, and T. angustifolia. Conclusions: There was an adequate leachate detention time when BOD and COD decreased to a maximum. The response time of plants in reducing the concentration of substances was a new approach to plant selection.

Enhancing bauxite residue properties for plant growth: Gypsum and organic amendment effects on chemical properties of soil and leachate

Here, we assess the effects of gypsum and local organic waste as amendments to non-weathered, filter-pressed bauxite residue (BR) to improve its properties and support plant growth. In addition, we monitored the leachate quality of the amended BR under progressive leaching that simulated precipitation conditions in Northern Brazil. Free-draining column tests consisting of BR amended with gypsum and organic waste, at 5% and 10% w/w, respectively, were leached for 8 weeks to assess the effects on the chemical composition of BR and the leachates. Adding gypsum to BR reduced the exchangeable sodium (Na) percentage (ESP) from approximately 79%–48%, whereas adding only organic waste had smaller effects on ESP (from ∼79% to ∼ 70%). The mean leachate pH ranged from 8.7 to 9.4 for the gypsum, and organic waste amended BR, while this was 10.3 in the leachate of the unamended BR. The treatments had similar trends of electrical conductivity throughout the experiments and were below 2 dS/cm after 8 weeks, when ∼1.700 mm simulated precipitation had leached. Aluminium (Al), Arsenic (As), and Vanadium (V) concentrations in leachates of BR with gypsum, either alone or in combination with organic waste, were significantly lowered than in leachate of non-amended BR. By contrast, metal concentrations increased if organic waste was added to BR. We conclude that amending BR with gypsum, in combination with organic waste, significantly improves the chemical properties of the solid phase and achieved rehabilitation goals for SAR and EC of the leachates after 8 weeks of leaching. However, despite high leaching rates, rehabilitation goals for pH and ESP were not achieved with gypsum either alone or combined with organic waste.

Leaching Behaviour of Synthetic Leachate through a Sewage Sludge and Red Gypsum Composite as Intermediate Landfill Cover

This paper examines the environmental impact of the use of compacted sewage sludge:red gypsum (SS:RG) mixture as intermediate landfill cover in terms of yield and quality of leachate as characterised by hydraulic conductivity and leaching behaviour. A series of column tests using the constant head method is carried out by percolating the synthetic leachate through samples that have been compacted at various degrees (60, 70, 75, 80 and 85%). The leachate quality is monitored at pre-determined days for pH, COD, Cu, Fe and Zn. In general, hydraulic conductivity decreases in three stages, in which the first stage is mainly attributed to the particle rearrangement and hydration of calcium silicate hydrate (CSH). The hydration of CSH increases the pH, which causes the heavy metal to precipitate and be entrapped within the matrices of CSH gel, thereby further reducing the porosity and hydraulic conductivity. A minimum of 75% compaction has shown favourable final porosity, hydraulic conductivity, and leachate quality, although a minimum of 80% compaction is recommended in order to achieve a satisfactory compressive strength of greater than 345 kPa for a landfill operation.

Landfill leachate pretreatment effects on nanofiltration and reverse osmosis membrane performance

The present study investigates the effects of landfill leachate pretreatment by coagulation-flocculation (C/F) on the performance of nanofiltration (NF) and reverse osmosis (RO) membranes by comparing permeate flux, fouling resistance, and leachate quality. Pretreated leachates were produced by applying the C/F with ferric chloride (FeCl3) and alum sulfate (Al2(SO4)3), named P1 and P2 leachates. Raw leachate (RL), P1, and P2 samples were treated using five different polymeric membranes termed NP030, NP010, XN45, BW30, and X201. The C/F pretreatment with FeCl3 or Al2(SO4)3 increased XN45's permeate flux by more than 80%. In this case, fouling median resistance values were 2.13e+ 08, 0.96e+ 08, and 1.02e+ 08 m−1 for RL, P1, and P2, respectively. Kruskal-Wallis test showed a significant difference between RL and pretreated leachate groups (p-value < 0.05). No significant difference between P1 and P2 was identified by the Dwass-Steel-Critchlow-Fligner test run for pairwise comparisons. These results indicate that the leachate pretreatment reduced membrane fouling by more than 50%, independently of the coagulant employed. Although higher removals of organic contaminants were, on average, obtained by membrane treatment for RL than for P1 and P2 samples, membranes that operated for RL treatment presented the worst performance in terms of permeate flux and fouling resistance. Therefore, NF and RO processes are not advisable as a single step in a landfill leachate treatment train, and a pretreatment step is recommended. This research makes a major contribution to the field by providing quantitative data for the conceptual premise that leachate pretreatments mitigate membrane fouling. Our findings help elucidate pretreatment effects on membrane performance and determine the preferable leachate treatment layout.

Effect of increased temperature and leachate recirculation on biogas production and settlement of municipal solid waste.

This study evaluated the effects of increased temperature and leachate recirculation on volatile solids (VS), biogas, hydrogen sulphide (H2S) leachate quality (pH and chemical oxygen demand) and the settlement of municipal solid waste (MSW). Three large-scale tests were conducted with no leachate recirculation at 21°C, weekly leachate recirculation at 20°C and weekly leachate recirculation at 50°C. Leachate recirculation and increased temperature accelerated biodegradation and pushed forward the onset time (from 27 to 8 days). The increase of biodegradation activity was reflected in the change of biogas production, VS and settlement. Compressibility index , increased from 0.71 and 0.77 at 21°C to 0.83 when the temperature was 50°C. In addition, leachate recirculation and high temperature reduced H2S concentration levels by inhibiting the growth of sulphate-reducing bacteria and leachate recirculation lowered H2S production by dissolving the high H2S presence. The results showed that MSW can have significantly changed mechanical and biochemical behaviour under different temperatures and saturations. The results help understand the processes in landfills for more effective short-term and long-term design and management.

Physicochemical Characterization and Evaluation of Seasonal Variations of Landfill Leachate and Groundwater Quality around Tanjaro Open Dump Area of Sulaymaniyah City, Kurdistan, Iraq

The current study is concerned with the primary environmental assessment of the physicochemical characterization of seasonal fluctuations in the leachate of Tanjaro open dump site in Sulaymaniyah City, and its impact on the quality of the groundwater. The primary characteristics of the leachates were their high levels of organic and inorganic components and their toxicity because of the presence of heavy metal concentrations. For almost all physicochemical parameters, the leachate from the Tanjaro area dumping has incredibly high values. All heavy metals were present in leachate, with the exception of cadmium and mercury, albeit at levels below their respective permitted limits. The characterization revealed that Leachate 1 (L1) may be referred to as young leachate, whereas Leachate 2 (L2) and Leachate 3 (L3) can be referred to as old leachate due to their pH values. It was indicated that the Tanjaro dumping is operating and in the early stages of stabilization. BOD5/COD was around 0.63, and the leachate was highly biodegradable in the anaerobic phase. Groundwater, which contains little to no organic matter, was not found to be severely affected by monitoring wells located close to the dumpsites. The conductivity, total dissolved solids, total hardness, Mn, and Fe were some of the values that went above the WHO guidelines. Correlation analysis was used as a preliminary descriptive technique to establish the strength of the association between the relevant variables. Some parameters were discovered to be statistically significantly correlated with one another, pointing to a close connection between these parameters.

Monitoring of experimental landfill cells with membrane concentrate infiltration: A systematic assessment of leachate quality and treatment performance

The present study investigates the impacts of reverse osmosis concentrate (ROC) infiltration on the leachate quality and treatment performance. Simulated landfill cells were constructed and monitored for 254 days. Integrated leachate samples were treated using a reverse osmosis (RO) system to assess changes in leachate quality on membrane fouling and effluent ecotoxicity. Our findings showed that concentrate infiltration increased the leachate's organic content and recalcitrance. The pollution parameters' median values were higher in leachates drained from cells that operated with ROC recirculation (i.e., 6729 vs 1367 mg L−1 [chemical oxygen demand, COD], 33.39 vs 17.39 cm−1 [absorbance at 254 nm, UV254]; p-value < 0.05). Membrane fouling resistance was 6-fold higher when the RO system was used to treat the methanogenic leachates generated by cells operating at ROC infiltration mode. The ecotoxicological assessment using Vibrio fischeri bacteria indicated that membrane concentrate recirculation increases leachate ecotoxicity and decreases its removal efficiency by RO treatment. The current research provides information to re-examine the recirculation practice of leachate concentrate streams. Recommendations and research prospects are drawn in this context.

Municipal Solid Waste and Leachate Characterization in the Cairo Metropolitan Area

The composition of municipal solid waste (MSW) in the Cairo metropolitan area is investigated. The outputs of MSW sorting analysis at various locations in Cairo with different waste management schemes are presented. Organics (58–75%) and plastic waste (19–28%) are the main components of MSW in Cairo with a higher percentage of organics in landfills compared to dumpsites. The leachate quality is analyzed, and the analysis results indicate that the concentration of macro inorganic pollutants (NH4+, Na+, Ca2+, and Cl−) and heavy metals (e.g., Cd2+ and Zn2+) are exceeding the majority of values reported in the literature in various cities all over the world. There was no evidence of an effect of the recycling process on chloride concentration in leachate, while the concentration of iron was reduced. The variation of leachate quality with time for two samples collected from the same municipal solid waste landfill is presented. The first leachate sample is a two-year-old, and the second sample is a sixteen-year-old. There was a significant increase in the concentration of chloride, sodium, chromium, calcium, and magnesium. The implications of the leachate quality in Cairo on the longevity of barrier systems in an MSW landfill are discussed.

Bench scale percolation tests on radioactive Cs-contaminated soil in Fukushima and soil modified with water-absorbing polymer agent

The reuse of removed soil generated from decontamination projects in Fukushima as a recycled material for the construction of embankments has been under consideration for the sake of reducing the volume of this soil for its final disposal. Agents containing water-absorbing polymers are used in Fukushima to modify the removed soil in order to increase the separation efficiency of foreign materials and to improve the easiness of handling. As the reuse of modified soil containing organic water-absorbing materials, such as a superabsorbent polymer, is rather rare in the geotechnical field, it necessitates an investigation into the impact of the modifying agent on the leachate quality to ensure the environmental safety of the recycling project. In this study, therefore, bench scale percolation tests were conducted to examine the changes in the leachate quality of the removed soil with and without modification by an agent containing a superabsorbent polymer. The tests lasted for more than 950 days (liquid/solid ratio of over 10). The peak 137Cs concentration in the leachate from the removed soil was 8.6 Bq/L and the accumulated leaching ratio was 0.243 %. The leaching of 137Cs from the modified soil decreased by 60 % after mixing the removed soil with a 3 % water-absorbing polymer agent. The leaching of K+ and ammonia nitrogen (NH4+-N) was 40 % and 60 % lower, respectively, after the soil modification, while the accumulated amount of leaching of the dissolved organic carbon in the initial stage was 60 % higher. The total leachate amount collected from the modified soil was 4 % lower than that collected from the removed soil.

Determination of risk of spontaneous waste ignition and leachate quality for open municipal solid waste dumpsite

The waste receiving capacity of most municipal solid waste (MSW) landfill sites in India is exhausted, resulting in the formation of larger waste heaps. In the majority of Indian cities, these old waste heaps are prone to frequent smoldering and ignition resulting into fires. In this study, the potential risk of spontaneous ignition of landfilled waste at landfill surface was analyzed based on the physico-chemical characteristics of waste, carbon monoxide (CO) levels, landfill surface temperature (LST). The leachate pollution index was also determined to analyze the leachate quality for three different seasons (monsoon, pre-monsoon and post-monsoon). The regression analysis was carried out to understand the thermal properties (smoldering temperature, smoldering time, ignition temperature etc.) of MSW. The results showed that old waste has a higher tendency to undergo ignition compared to fresh waste. It has also been observed that the lower MC of old waste samples in the range of 3.4% and 18.2% is the most likely cause of early smoldering (106.6–109.5 °C) and ignition (198.6–208.4 °C) of old waste. In pre-monsoon season, CO concentrations for sub-surface (10–30 cm depth) smoldering events (SSE) were observed to be between ∼ 150 to 200 ppm. This CO level substantially dropped to 10 ± 1 ppm in the post-monsoon season. The estimation of the leachate pollution index (LPI) showed an index score of 27.35, 30.47 and 10.71 for pre-monsoon, monsoon and post-monsoon seasons, respectively. The determination of CO levels, increased LST and physico-chemical properties of landfilled waste will greatly assist in the abatement of environmental pollution arising from landfill fires.

Sustainable green roofs: a comprehensive review of influential factors.

Green roofs have gained much attention as a modern roofing surface due to their potential to deliver many environmental and social benefits. Studies have indicated that different GR designs deliver different ecosystem services, and there are important factors that affect GR performance. This article reviewed significant factors that influence GR performance and sustainability. Substrate and drainage layer material choice significantly affects stormwater retention potential, leachate quality, plant survival, and determines GR environmental footprints. Subsequently, type of plants, their form, and kinds used on GRs impact GR ecosystem function. Leaf area is the most studied trait due to its influence on the cooling potential and energy performance. In order to achieve a sustainable GR, it is essential to select the type of plants that have a high survival rate. Perennial herbs, particularly forbs and grass as dominant groups, are heat and drought tolerant, which make them suitable in GR experiment. Furthermore, selecting a suitable irrigation system is as important as two other factors for having a sustainable GR. Irrigation is essential for plant survival, and due to the current pressure on valuable water sources, it is important to select a sustainable irrigation system. This review presents three sustainable irrigation methods: (i) employing alternative water sources such as rainwater, greywater, and atmospheric water; (ii) smart irrigation and monitoring; and (iii) using adaptive materials and additives that improve GR water use. This review sheds new insights on the design of high-performance, sustainable GRs and provides guidance for the legislation of sustainable GR.

Comparison of macro and micro-pollutants abatement from biotreated landfill leachate by single ozonation, O3/H2O2, and catalytic ozonation processes

Micropollutants (MPs) in landfill leachate have attracted increasing attention because they pose a potential threat to the aquatic environment and ecosystems once discharged into nearby aquifers without proper treatment. Although ozone-based oxidative techniques perform well for the removal of MPs in low-strength water streams, their role in leachate containing high dissolved organic matter (DOM) concentration requires further exploration. Moreover, it is unclear the mechanism of different ozone-based processes in advanced treatment for biotreated landfill leachate. This study compared the single ozonation and two ozone-based advanced oxidation processes (AOPs, heterogeneous catalytic ozonation and O3/H2O2 process) for polishing biotreated leachate. The mechanism of different ozone-based processes during leachate treatment was explored, which facilitates selecting of the appropriate process based on leachate quality and target treatment requirements. The removal efficiency and energy requirements of the macro and micro-pollutants were evaluated. The results revealed that the role of catalytic ozonation is mainly to enhance the direct ozone oxidation, whereas the O3/H2O2 process is to promote the indirect oxidation. The strengthening effect was most visible in the early stage (specific transferred ozone dose (STOD) < 2 gO3/gDOC) for catalytic ozonation, whereas it was more pronounced in the later stage for the O3/H2O2 process. The removal of UV-quenching substances correlated well with the elimination of MPs (R2 > 0.95), which provides a surrogate-based predictive model for the removal of MPs from high-strength leachate. Catalytic ozonation consumed the least amount of energy when the desired chemical oxygen demand (COD) removal was ≤ 35 %, otherwise, the O3/H2O2 process was the most energy-efficient. In any process, MPs with O3 or OH reactivity could achieve more than 90 % elimination when the COD removal exceeded 30 %.

Biochar granulation, particle size, and vegetation effects on leachate water quality from a green roof substrate.

Biochar, due to its favourable physiochemical properties, has been promoted as an ideal substrate additive on green roofs, with potential benefits to hydrological function. However, biochar is susceptible to water erosion, which may result in biochar loss and water pollution. The use of granulated biochars or biochars in large particle sizes could potentially alleviate biochar erosion loss, but effects on leachate quality have not been investigated. Also, biochar type and particle size influence plant performance, and effects on discharge quality may vary with vegetation. We assessed the effects of unprocessed and granulated biochars at five (0.25-0.5mm, 0.5-1mm, 1-2mm, 2-2.8mm, 2.8-4mm) and four (1-2mm, 2-2.8mm, 2.8-4mm, and 4-6.3mm) particle size ranges, respectively, on leachate quality on a typical green roof substrate, with presence and absence of vegetation (Agastache foeniculum - a drought-tolerant native forb). We evaluated integrated leachate quality using the CCME Water Quality Index (WQI). Unprocessed biochars reduced nutrient leaching due to increased water retention capacity (WRC) and total porosity. In contrast, granulated biochars, although showing less pronounced mitigation of nutrient leaching, reduced total suspended solids (TSS) and improved WQI in leachate due to enhanced plant performance. In addition, small biochar particles better reduced nutrient leaching and particle loss than large biochar particles, possibly due to increased WRC and formation of water-stable aggregates. The presence of vegetation generally reduced the leaching of nutrients and TSS, consistent with plant nutrient uptake and root substrate stabilization. However, plant biomass was correlated with increased total N leaching, likely due to litter inputs and rapid litter decomposition. We conclude that applications of granulated biochars may best improve discharge quality from green roofs through sorption effects and by enhancing plant performance.

Temporal study of physicochemical parameters of leachates and assessment of solid waste and ground water quality of Pirana dumping site, Ahmedabad, India.

The characterisation of solid waste (SW), leachate, is essential for developing an appropriate management strategy or treatment method. However, due to a range of contributing factors, such as waste type and dumping site locations, forecasting leachate quality is often challenging. This research article discusses leachate quality indicators and the temporal variations of leachate quality collected throughout various seasons and after 1-2years of storage. In addition to that, the article also provides the data of different physicochemical parameters of SW and ground water (GW) quality collected from of Pirana solid waste dumping area (Pirana SWD), Ahmedabad, India, and surrounding areas throughout various seasons. The parameters like pH, COD, TDS, sulphates, nitrates, ammonia nitrogen, hardness, and heavy metals were all monitored to see whether there any temporal variations. When leachates were obtained 'fresh,' all parameters evaluated showed significantly higher values. As time passed, the values of the parameters (COD, ammonia nitrogen) stabilised. Heavy metals such as Hg, As, Pb, and Cr were detected in both fresh and old samples. Similarly in SW, the presence of heavy metals Hg (0.39ppb), Pb (1.12ppb), and Cr (16.86ppb) were also detected. In case of GW, some samples also show the high TDS but the presence of metals like Cr, Ni, and Zn is less than permissible limit.

Treatment of mature landfill leachate in tropical climate using membrane bioreactors with different configurations

This study describes the collection of landfill leachate from seven sites in different climatic zones of Sri Lanka and characterizes the landfills through the analyses of leachate quality. Membrane bioreactors (MBRs) with different configurations were employed to treat some of those leachates. An aerobic MBR (AMBR) system was operated in three Phases. In the first Phase, an AMBR alone, in the second Phase an anaerobic reactor followed by an anoxic reactor and an AMBR and in the third Phase an anoxic reactor followed by an AMBR were operated. In Phases I and II, the sludge retention time (SRT) and the hydraulic retention time (HRT) were kept at infinite (as no intentional wasting of sludge was made) and 96 h; in Phase III, the SRT was varied from 60, 30, 20 to 10 days and under each SRT, the HRT was varied from 96, 48, 24 and 12 h. The optimum operating conditions for the configuration used in Phase III was established through extensive experiments which had a SRT. The three MBR configurations removed more than 93%, 64.8% and 59% of BOD5, COD and total nitrogen respectively. They also removed large amounts of slowly biodegradable substances and nitrogenous compounds other than NH4+, NO3− and NO2−. Relationships between SRT and MLSS as well as SRT and fouling rate of membrane have been found. The study illustrates the capabilities of MBR in treating landfill leachate.

AI-based ensemble modeling of landfill leakage employing a lysimeter, climatic data and transfer learning

Predicting leachate pollutants is of prime importance in detecting the amount of pollution in water resources adjacent to sources of leakage. In this study, Electrical Conductivity (EC) as a physicochemical water pollution parameter with the possibility of portable measurement was used as an indicator of leachate quality for the Tychy-Urbanowice operating and closed landfill complex. In order to simulate landfill conditions, two lysimeter experiments were conducted simultaneously. Using sensors mounted in the lysimeters, from the end of November 2018 to the end of December 2019, EC, waste temperature and waste moisture were measured for the open lysimeter and only waste moisture for the closed lysimeter. Additionally, meteorological data obtained from the nearest synoptic station and soil moisture and temperature acquired from the GLDAS satellite were employed as external data to analyze various conditions. Thereafter, Artificial Neural Network (ANN), Neuro-Fuzzy Inference System (ANFIS), and Emotional ANN (EANN) models were developed to determine the parameters affecting the EC value recorded for the open lysimeter and subsequently, predict the missing EC parameter of the closed lysimeter by employing the transfer learning method. Following that, in order to improve the precision of EC predictions, ensemble techniques were applied to the outputs of the models that were developed. The results showed that the moisture of the lysimeters made a significant contribution to the EC value prediction. It is worth mentioning that among ANN, ANFIS, and EANN, the EANN model yielded more precise results in EC estimation, with the average DC above 0.80 and 0.90 for individual and ensembled modeling in both the training and verification phases, respectively.

Microbial Treatment of Raw and Primary Treated Sanitary Landfill Leachate by Indigenous Strain Brevibacillus agri.

Landfill leachate is a potential environmental threat. Sanitary landfills are model sites which contains a leachate collection pool and a processing facility to treat it up to environmental standards before discharge. The present study is the very first endeavor to establish leachate treatment efficiency of indigenous microbial strain Brevibacillus agri. Leachate samples were inoculated with isolated strain and incubated for 41days in an orbital shaker. Percent reduction in major water quality parameters was assessed after 0, 7, 21, and 41days of incubation, for understanding the degradation kinetics. Results of the study demonstrate that Brevibacillus agri was effective in improving the wastewater quality of both raw and primary treated leachate. Overall reduction for different water quality parameters was found to be 50% higher for primary treated leachate than that for raw leachate within 21days of incubation. Microbial degradation followed first-order kinetics with rate constants in the range of 0.0047-0.03 and 0.0061-0.074day-1 for raw and primary treated leachate respectively. Calculated half-life of each pollutant parameter was significantly higher in the raw sample (23-147days) as compared to the primary treated one (27-112days). The leachate pollution index (LPI) value of the raw leachate was also found to be > 25% higher than primary treated leachate sample after microbial treatment. Hence, it can be concluded that on site application of primary treatment technology followed by secondary microbial degradation by indigenous microflora, viz., Brevibacillus sp., may prove effective to achieve desirable water quality for safe environmental discharge.

Assessment of Sewage Sludge and Coir Pith as Alternative Cover Materials to Red Soil in Bioreactor Landfills

This study assessed the performance of sewage sludge and coir pith as a potential alternative to virgin red soil as cover material in bioreactor landfills. Three field scale models of anaerobic bioreactor landfills were set up so as to study the performance of the cover materials on leachate generation time, quality and quantity. In one reactor (R1), red soil was used as the cover and was kept as control. In the other two reactors (R2 and R3), modified sewage sludge and coir pith were used as the cover materials, respectively. The leachate produced from each were analyzed based on its quality (Total Solids, pH, BOD, COD, Nitrate and Iron), quantity and generation time. Red soil provided respectively 41.08% and 25.5% reduction in BOD than modified sewage sludge and coir pith. However, coir pith showed better performance in reduction of leachate quantity, total solids, nitrate and iron, thus making it suitable for use as an alternate cover material.