Temporal Variation in Leachate Composition of A Newly Constructed Landfill Site in Lahore in Context To Human and Environmental Risks

The present study was aimed to explore the seasonal and temporal variation in the extent and sources of physiochemical and trace elements in the Lakhodair solid waste Landfill site in Lahore, Pakistan. For the seasonal and temporal study of leachates, systematic composite samples were collected monthly (for one year) and analyzed for physiochemical and trace elements. The concentration of TDS, TSS, COD, NH3-N, BOD5, sulfate, sulfides, phenolic compounds, oil and grease were higher than the National Environmental Quality standard (NEQs). The trace elements, namely Mn (1.7 mg/L), and Cd (0.05 mg/L), while in a few samples Fe (14 mg/L), Ni (1.6 mg/L), and Zn (6.7 mg/L) were higher than the NEQs. In Lakhodair leachates, TDS, COD, NH3-N, BOD5, sulfides, and Cl have a high concentration coefficient (i.e., CC 3 to > 6), which may cause considerable to high contamination, while remaining parameters may cause low to moderate contamination (CC 1 to ≤ 3). The lower BOD5/COD ratio (< 0.1) in the Spring and Autumn seasons, represents the active methanogenesis and anaerobic activities in the Lakhodair landfill site. The anaerobic and methanogenesis enhance the redox reaction as a result CO2 is emitted and alternatively increases pH, TDS, COD, Cl, BOD5, NH3-N, sulfides, phenolic compounds in leachates. However, the lower concentration of some trace elements may be because of an anaerobic process that may immobilize the trace elements. It is presumed that the trace elements in the Lakhodair landfill may be in a metastable state, which is not easy to leach out. It’s hereby recommended that Leachate produced in the Lakhodair landfill site need to handle carefully so as to limit the environmental and health implication.

Impacts of litter decay on organic leachate composition and reactivity

Litter decomposition produces labile and recalcitrant forms of dissolved organic matter (DOM) that significantly affect soil carbon (C) sequestration. Chemical analysis of this DOM can provide important knowledge for understanding soil DOM dynamics, but detailed molecular analyses on litter derived DOM are scarce. Here we use ultrahigh resolution mass spectrometry (FT-ICR MS) to characterize the molecular composition of DOM from fresh and progressively decomposed litter samples. We compared high reactive (HR) and low reactive (LR) litter sources with regard to changes in the chemistry and bioavailability of leachates throughout the early phase of litter decay. We show that litter reactivity is a driver of chemical changes in the leached DOM of litter species. Birch, alder and Vaccinium (i.e. HR) litter initially produced more DOM with a higher lability than that of spruce, pine and wood (i.e. LR) litter. Labile oxidized phenolic compounds were abundant in leachates produced during the initial HR litter decay stages, indicating litter lignin degradation. However, the similarity in chemistry between HR and LR leachates increased during the litter decay process as highly leachable structures in HR litter were depleted. In contrast, chemistry of leachates from LR litter changed little during the litter decay process. The oxygenated phenolic compounds from HR litter were driving the lability of HR leachates and the changes in relative abundance of molecules during DOM incubation. This appeared to result in the creation of stable aliphatic secondary microbial compounds. In LR leachates, lability was driven by labile aliphatic compounds, while more resistant phenolic compounds were associated with recalcitrance. These results show how DOM dynamics follow different paths depending on litter reactivity, which has important implications for soil biogeochemistry and C sequestration.

Leachates From Landfill Sites In Thessaloniki, Greece: Effect Of Aging

Sanitary landfilling still is one of the most common management systems of solid urban wastes. The persistent environmental impact of landfills depends on leachate characteristics. The present study aimed at the characterisation of leachate from two landfill sites in the prefecture of Thessaloniki, Greece. Mavrorachi landfill stands in our study as a representative Greek active landfill site, that started operating in 2008. Tagarades landfill has stopped receiving waste from 2008 after 27 years of full operation. In this investigation, leachate samples were physico-chemically characterised so as to assess their pollution potential and their concentration in regard to the type and age of landfill. Elevated concentrations of inorganic and organic constituents were observed in the leachate composition. COD ranged from 2,490 mg/L to 19,700 mg/L, while the respective range for BOD was 390-14,850 mg/L during a 35-year period. The pH values of the leachate samples presented more moderate fluctuations between 7.3 and 8.5. In addition, the ammoniacal nitrogen content increased as landfill age increased, whereas heavy metals concentrations showed significant variations with a slight decreasing trend. The results presented in this paper proved that as time passed, the values of most parameters decreased as the biodegradable compounds are broken down while the refractory compounds resist to biodegradation. Thus, the age has a pronounced influence on the composition of leachate. This study also focused on quantifying the level of contamination that leachates can be potentially cause on a comparative basis by Leachate Pollution Index (LPI). LPI values showed that pollution load was declining but is still not negligible after 33 years.

USE OF GEOSYNTHETIC CLAY LINER AS A WATERPROOFING BARRIER IN SANITARY LANDFILLS

One of the main sources of soil and water (superficial and subterranean) contamination is the inadequate solid waste disposal. In this sense, sanitary landfills have great importance for environmental protection, and in these systems, the geosynthetics materials, such as the Geosynthetic Clay Liner (GCL), are widely employed. However, for landfills with leachate recirculation, the application of GCL is vetoed by many government agencies. In view of this, this study sought to provide an analysis of recent advances in application of GCL in landfill sites. For this reason, the main configurations of landfills and characteristics of its leachate were presented, as well as of the GCL by means of case studies applied to the context. The results indicated that the most important parameter to be evaluated in GCL performance is its hydraulic conductivity, which can be influenced directly by leachate composition (conventional and recirculated) as to the presence of cations and anions. Thus, it is concluded that the evaluation of these characteristics is essential to ensure the proper performance of GCL in landfills.

Leachate composition and environmental risks from waste wood dumps.

High concentrations of phenols can be found in leachate and stormwater of woodprocessing, storage and disposal sites. Although timber is a natural product, mishandlingof wood waste may harm the environment.As a common practice, wood residues were dumped in landfills in Estonia. As a nationalstrategy, it has been decided to close all of the dumping sites. In many cases, woodresidues have been used for capping of municipal dump sites. It has been suspected, thatenvironmentally hazardous phenolic compounds may be leaching out from such landfills.Pathways for generation of natural phenolic compounds, as well as the ecologic impact ofthem have not been studied in Estonia.In this paper, leachate composition from dumpsites of waste wood is studied and thehazards of phenols to the environment are discussed. In the wood waste, phenol can befound mainly in tannins, resin and lignin. Phenols in tannins are water-soluble, butphenols in resins are more soluble in organic solvents, such as ether, what is producedduring decomposition of lignin. Chipping and storage of wood in the water-richenvironment speeds up the leaching of phenols.The leachate from wood waste dumps is quickly purified by natural processes in the soil.It is assumed that in most cases the natural phenols do not migrate far from the dump siteor storage area. The problem may arise in case where such waste is stored near to thewater body or the leach-water is repeatedly re-circulated into the deposit of waste wood.

Seasonal Changes and Toxic Potency of Landfill Leachate for White Mustard (Sinapis alba L.)

Landfills are the most broadly used methods for the disposal of municipal solid waste (MSW). Leachate can be contaminated with pollutants that may pose a threat to the landfill surrounding namely soil, groundwater and surface waters.. Examination of leachate composition is determinative in long-term impact of landfills on the environment and human health. Moreover, it is essential to assess such prior knowledge for prevention of negative outcomes. The evaluation of the seasonal changes of landfill leachate and rainwater composition is presented in this paper. Research samples of leachate and rainwater were collected from February till June of 2017 (still ongoing) and analyzed for pH, electrical conductivity, dissolved oxygen, series of trace elements, Subsequently the test of leachate toxicity for higher plants (Sinapis alba L.) was carried out. Up to now, the results do not indicate significant seasonal difference in landfill leachate composition, however the toxicity tests provided on Sinapis alba L. demonstrate that landfill leachates can present a significant source of contamination. This research can serve practical tools for evaluating quality and risk assessment for landfill leachate.