Characteristics of Leachate Infiltration through the Red Earth Profiles: A Laboratory Based Study

Municipal Solid Waste (MSW) management is a severe problem in Sri Lanka. As a remedy, a new sanitary landfill is planning to implement in Aruwakkalu, Puttalam district for dumping the Colombo MSW. Aruwakkalu area is covering Natural Red Earth (NRE), which considered as a strong adsorbent. However leachate released from possible MSW dump has significant threat on the environment. Therefore, this study is aim to identify possible leachate infiltration characteristics under different density profiles of NRE. The laboratory scale experimental design was conducted with five filter columns that filled with NRE, which was collected from Aruwakkalu area. The columns were filled up to 10 inches height under selected density range that occurred in NRE (1.4 gcm-3-1.6 gcm-3). Leachate from Karadiyana landfill site was diluted 50% and 200 ml of leachates were added to each column while maintaining standard flow, filtrate were collected from each column for chemical and physical analyses. Approximately two days interval was maintained between leachate each feeding events and sampling of the filtrate. Experiment was conducted few months until major physical and chemical changes that occurred in filtrate and NRE columns. NRE characteristics such as surface chemistry, particle size and shape were studied using Scanning Electron Microscope (SEM). X-ray Florescence analysis (XRF) was done to identify total chemistry. Elusion analyses were conducted under different pH to investigate soluble fractions of NRE. Further, Fourier-Transform infrared spectroscopy (FTIR) analyses were done to study adsorption sites. X-ray Diffraction analyses (XRD) were done to identify secondary minerals present in NRE. Cation Exchange Capacity (CEC) was studied for NRE samples using laboratory experimental setup. Atomic Absorption Spectroscopy (AAS), multiparameter electrodes and Spectrophotometer were used to study leachate and filtrate such as Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Dissolved Solid (TDS), conductivity, pH, salinity, Oxidation-Reduction Potential (ORP), phosphate, nitrate, and other selected elements (Fe, Zn, Pb, Cu, and Ni). Results indicate a significant reduction of conductivity and TDS from the filtered leachates in different soil columns. It has been noted, gradual incensement of TDS and conductivity with the time, however compare to raw leachate values are small in the filtrate. There were no considerable changes of pH with time. Selected anionic and cationic parameters reflect progressive and regressive changes during the period of experiment due to different process in the soil columns. Time taken for the percolation of leachate from each soil column was increased with the time due to compaction of soil with the continuous addition of leachate.Keywords: Red earth, Leachate, Landfill, Soil column

Development of Activated Iron Oxide Soil Pellets to Study the Filtering Efficiency of Fluoride Ions in Aqueous Fluoride Solutions

Fluoride in drinking water has become a severe problem especially in the dry zone of the Sri Lanka. The common methods available for removal of fluoride from aqueous solutions are not practical. Therefore there is a high demand for reliable fluoride removal techniques. Thus, natural red earth has been selected as the filter material. The main objective of this study is to investigate properties available in red earth to develop activated red earth pellets with the aim of removal of fluoride in prepared aqueous solutions. Red earth pellets were prepared using metal dies. Then the pellets were thermally activated. As control media raw red earth was used to compere the filtering efficiencies. Filtering process was conducted in three filters based on different influential fluoride concentrations of 1.5 ppm (filter A), 2.5 ppm (filter B) and 3.5 ppm (filter C). Each filter maintain with three filter columns which was filled by raw red earth, activated red earth and activated red earth pellets. The filtering process was conducted for 20 days until basic physical changes occur in the system. Results revealed that physical conditions of the red earth such as very low levels of trace metals, organic matter (OM), inorganic carbon and total organic carbon (TOC) are useful for the better filtering process and very fine unconsolidated nature provide passage for better infiltration. In general, raw red earth and activated red earth pellets have shown good filtering performances for the fluoride. According to the statistical analysis, filtering of low fluoride levels (1.5 ppm), red earth pellets are successful. Filtering of moderate level of fluoride (2.5 ppm) there was no difference among raw red earth and activated red earth pellets. However, activated red earth pellets can be recommended due to less turbidity in filtrate, durability, and easy handling. Conversely, to filter the higher fluoride values (3.5 ppm) raw red earth is the suitable media. In contrast, Fourier Transfer Infra–Red (FTIR) analysis for the filter materials shows possible vacant adsorption sites even after the completion of the experiment. Those vacant sites revealed additional capacity in the filter media. Also, the available adsorption sites have been diminished during the filtering, which can be concluded as the absorbance of fluoride on to them.Keywords: Red earth, Pellets, Filtering, Efficiency, Fluoride, Activatio

Groundwater Contamination in Jaffna Red Beds Mainly Focused on Nitrate and Trace Elements

The Jaffna peninsula is dependent on groundwater for all its water requirements andpredominantly for agricultural activities. Studies on effect of fertilisation and groundwaterpollution in such an area are of prime importance. Especially, nitrate rich drinking water ispotentially harmful to human health, particularly to infants. It is recommended that pregnantwomen and lactating mothers should limit nitrate consumption. According to the Jaffnahospital sources, people living in red bed area mostly affected by water bone diseases.Therefore, this study mainly focused on behaviours of nitrate and associated trace elements(Li, Cs, Cu, Sr, Zn, Mn, Fe, K, Mg and Na) in the wells around the red bed in order toinvestigate source and mobility.Physical parameters of water also can be determined the quality of water. The pH wasanalysed by using pH meter. The results were along the study area in WHO and SLS limit.Electric Conductivity is considered as an important water quality parameter in assessingdrinking and surface water. According to the SLS Standards, most of the sources had it abovethe permissible level. The source for the Salinity may be sea water intrusion in thisagricultural land area. Therefore, the water not suitable for the drinking purpose.Seventy randomly collected groundwater samples were analysed using atomic absorptionspectrometer (AAS, Varian 240). Results indicated that most of the wells were highlycontaminated with nitrate in red bed area than in the other regions. It was noted that, overdosage of fertiliser and agrochemicals cause for higher nitrate contamination. It is furtherobserved that the red bed in the area is unconsolidated and mainly formed by iron courtedsands with lower level of organic matter. This further concluded that nature of the red bedprovides favourable conditions for leaching nitrate to groundwater rather than retaining in thesoil. The trace elements such as K, Mg, Ca, Na, Sr, Li and Cu exceeded the permissible levelfor drinking water for all the wells. This may be due to sea water mixing with groundwaterthrough the groundwater flow or by wind spray. Especially, element Ca and Sr may haveaccumulated by weathering of shell fragments in the calcareous deposits in the area.Conversely element Cu may have leached from agrochemicals. However, Zn, Fe, and Bawere in lower concentrations. In general, there were significant correlations between theelements which clearly concluded that the sources for the contaminations are diverse andanthropogenic.Keywords: Fertilisation, Nitrate, Red bed, Groundwate

Development of a Laboratory Scale Filter Using Laterite to Treat Landfill Leachate

Municipal Solid waste (MSW) is a severe problem in Sri Lanka due to lack of proper solid waste management system, and leachate is one of the major issue associated with MSW. Around 95% of MSW is disposing into poorly managed open dump sites, where do not have methods to treat the leachate. Therefore, proper low-cost leachate treatment method is highly demanded in Sri Lanka.This study was carried out to develop a laboratory scale filter using laterite based earth materials in order to remove the pollutants from leachate. Study the durability of the filtering media and possible composition are the other aims. Six laterite soil samples were collected from six different locations in western province were geochemically tested prior to use as a filtering media.The experiment setup was designed with five filter columns. Four columns were made using laterite soil by mixing with 10%, 20%, 30%, and 40% compost ratios by weight. Remaining column was made from pure laterite as a control. Each column consists of 2 kg of filtering medium. Leachate from Karadiyana landfill site was used for the experiment after 50% dilution. Leachate feeding was done, with total volume of 750 ml per day by keeping two days of recovering time between each feeding session. The removal efficiencies of BOD, COD, TSS, TDS, conductivity, pH, Oxidation-Reduction Potential, phosphate, nitrate, and selected heavy metals such as Cu, Mn, Zn, Cd, Ni, Pb, and Fe were analyzed in fifty days of time period.Results indicate that, there are different filtering efficiencies for different parameters. In each column, pH level of the filtrate was within 6.3-8.0 and all were contributed to oxidize in the influent leachate. Filtering efficiencies for the important pollutants of leachate such as BOD, COD, phosphate, nitrate, and all the heavy metals were stable in considerable level even after fifty days of experiment except TSS, TDS, and conductivity. This indicates higher level of durability of the filtering materials. In general, life time of the filtering media has been enhanced by the batch wise feeding method. Therefore, further feeding of leachate is needed to select the suitable filtering media.Keywords: Laterite, Leachate, Removal efficienc

Myco-Remediation of Textile Wastewater and its Re-Usability in Irrigation

Environmental pollution by synthetic dye contained textile wastewater effluents disturb the human health and ecological equilibrium. Therefore, present study was focused on myco-remediation of textile wastewater effluents that generated from local textile dyeing industries. Three fungal strains; Aspergillus niger, A. aculeatus and A. nomius which previously isolated and identified as potential dye decolorising agents, were screened for its potential applicability on decolorisation of textile wastewater effluents. Four cylinders of each fungal isolates were introduced into 100 mL of three textile wastewater effluents obtained from Biyagama (BW), Pugoda (PW) and Negambo (NW) in Sri Lanka, without addition of further nutrients. All the experiments were carried out in triplicates and controls were maintained without addition of fungi. Samples were incubated at 28o C under shaking conditions (100 rpm). Percentage color removal was calculated by measuring the changes of the absorbance at maximum wavelength for each effluent. A. niger showed complete decolorisation of BW, PW and NW effluents within 48h of incubation while A. aculeatus and A. nomius taking 72 h for the same. Controls showed no decolorisation after 72 h. The treated effluents by A .niger, which showed rapid decolorisation of wastewater samples compared to the other two species, was used for the assessment of phytotoxicity for evaluation of the potential applicability on two commercially important edible plants (Oryza sativa and Vigna radiata) in Sri Lanka. The germination percentages of both O. sativa and V. radiata were less than 10% for all three wastewater effluents. Remarkably, 100% germination performance was observed for both O. sativa and V. radiata for the biologically treated effluents confirming the re-usability of selected wastewater effluents for the irrigation purposes. Though the biologically treated textile wastewater effluents cannot used for the drinking purposes directly without further purifications, present study confirmed the potential usability of biologically treated textile wastewater effluents on irrigation purposes.Keyword: Decolorisation, Myco-remediation, Fungi, Aspergillu

Chemical Characteristics of Buffer Zone Sediments And Implications on Adjoining Water in Diyawanna Lake

Diyawanna Lake is one of the major fresh water body located in the middle of SriJayewardenapura Kotte. Most of surrounding area of the lake consists of marshlands. Duringthe recent past several reclamation and development activities going on around the lake. Inaddition, sediments from surface runoff are finally accumulating in the lake margin (bufferzone). However, there is no any study done on sediment quality and impacts of them onadjoining water, especially in the buffer zone of such a fresh water body. Therefore, main aimof this study is to investigate quality of the sediment accumulated in the buffer zone of thelake and also to study the possible impacts on lake water from the sediments due tobiogeochemical reactions in the zone. Thirty three water samples were collected during dryperiod and samples were analysed for pH, electrical conductivity (EC), oxidation reductionpotential (ORP), salinity, total dissolved solid (TDS), NO3-, PO43-, SO42-, Cl-, alkalinity,hardness, Na, K, Ca, Mg, Cd, Cr, Cu, Fe, Pb, Mn, Zn and Ni. In addition, black organicsediment samples were collected from selected locations and tested for pH, ORP, EC, organiccarbon, total organic matter, NO-3, PO4-3, Na, K, Ca, Mg, Cd, Cr, Cu, Fe, Pb, Mn, Zn and Ni.Average values of pH, EC, ORP, TDS, NO3-, PO43-, SO42-, Cl-, alkalinity, hardness, Na, K,Ca, Mg, Cu, Zn and Fe for the lake water are 7.4, 222 μS/cm, -37 mV, 222 mg/l, 0.11 ppm,15.00 ppm, 1.43 ppm, 20.00 ppm, 0.0002 ppm, 772 ppm, 16 ppm, 10 ppm, 36 ppm, 21 ppm,0.001 ppm, 0.009 ppm and 0.14 ppm respectively. However, element Cd, Pb, Mn and Niwere not detected. Piper classification for the lake water indicate CaSO4 type, which reflecttypical gypsum type of waters with impact of mine drainage due to mineral pyrite in soil.Also, sulfur emitted by the vehicles may react with water to form sulfuric acid. In addition,gypsum type of water may also due to accumulation of building materials such as cement.Therefore reason for the CaSO4 type of water may be due to several sources in the area. Inaddition, compared to WHO guidelines only Cr (0.58 ppm) present in the water isconsiderably high, this may be due to direct discharge of urban dust into the lake.Average values of pH (6.1), ORP (54 mV), EC (122 μS/cm), organic carbon (3.1%), totalorganic matter (18%), nitrate (0.93 ppm), phosphate (12 ppm), Na (3.5 g/kg), K (11 g/kg), Ca(73 mg/kg), Mg (84 mg/kg), Cd (40 mg/kg), Cr (391 mg/kg), Cu (134 mg/kg), Fe (44 g/kg),Pb (833 mg/kg), Mn (157 mg/kg), Ni (196 mg/kg) and Zn (33 g/kg) in the sediments areconsiderably different value than the water. Compare with Canadian Environment Qualityguidelines average values of Cd, Cr, Pb and Zn are higher in the sediments. This is mainlydue to accumulation of those elements from runoff water. In general, it can be concluded thatprevailing physical conditions of the lake water is controlling leaching of heavy metals fromsediments to water. Conversely, anthropogenic sources seem to be increase accumulation ofheavy metals in the buffer zone sediments.Keywords: Diyawanna Lake, Water quality, Sediment qualit

Performance of Landfill Leachate Treatment from Laterite Based Soil-Layering System: A Laboratory Scale Investigation

leachate is a major issue throughout the world. In the Sri Lankan scenario there are not enough methods to treat or control generated leachate. Therefore the ultimate aim of this research is to evaluate the performances of laterite soil and compost to treat landfill leachate using a cost effective and reliable technique. Several standard procedures available in literature were incorporated with this study. Five different soil-layering systems (filters) were prepared by mixing laterite soil with compost (0%, 10%, 20%, 30% and 40% by weight). Leachate from the Karadiyana control dumpsite was fed for each filter over 100 days to evaluate the filtering performances of selected parameters such as BOD, COD, TSS, EC, ORP, pH, Phosphates, Nitrates and selected heavy metals including Zn, Ni, Pb, Mn, Cu, Fe and Cd. For each parameter, filtering efficiencies were calculated and concentrations of each parameter were compared with the selected water quality standards. In addition, Kruskal-Wallis and Mann-Whitney non-parametric tests were used for studying filtering efficiencies of those parameters. During the experiment, pH of all filtering systems was within 6.0-8.5 which complies with the water quality standards. Even after 100 days of operation, filtering efficiencies of BOD (>90%), COD (>85%), Nitrates (75-95%) and Phosphates (>90%) were at higher levels. Removal efficiencies of both TSS (40-90%) and EC (0-80%) illustrated wide range of fluctuations. Greater filtering efficiencies were obtained for Fe (90-100%). Highly diverse efficiencies were found for Mn, Cu, Ni, Cd, Zn and Pb. Within the operational period, phosphate and nitrate concentrations were fitted to water quality standards. However, COD and BOD concentrations were fixed to those standards especially after 25 days. Abundances of Cd, Cu, Fe, Zn and Ni were reached or very close to the maximum permissible levels of water quality standards. Conversely, TSS, Mn and Pb in the filtrates ignore the standard recommended levels. According to the statistical analysis, it can be ultimately concluded that using 20% of compost with 80% of laterite by dry weight gives the optimum conditions for the greater filtering performances.Keywords: Leachate, Laterite, Filte

Fourier Transform Infrared (FTIR) Spectroscopic Analysis of Soil Organic Matter in an Alluvial Type Gem Deposit in Pelmadulla, Sri Lanka

Organic matter is one of the most important and fundamental constituent in soil, which usually present in transported sediments. Therefore a wide spectrum of physically and chemically different organic matter can be expected in alluvial type sedimentary gem deposits. Composition of soil organic matter is very important, because it is tightly link with environmental issues such as mine gas poisoning, carbon budget and bioavailability of toxic elements in the soils.This study was conducted to identify the composition, distribution and impacts of the soil organic matter in the sedimentary profile of an alluvial gem deposit in Pelmadulla, Sri Lanka. Seventy seven soil samples were collected along the sedimentary profile in three different locations using auger drilling method. Chemical bonding structure of the each soil sample was analyzed in the mid IR region of FTIR spectroscopy. Total organic matter (TOM) and the total organic carbon (TOC) contents of the of each soil sample were measured using loss on ignition and the Walkley-Black wet oxidation methods respectively. In addition, selected basic physical and chemical parameters of the soil such as pH, oxidation-reduction potential, moisture content, and elution conductivity were also tested.Results indicate pH is in slightly acidic in nature and soil elution conductivity is higher in the peat layer of the bottom alluvial deposit. FTIR spectroscopic analysis proved the presence of several organic functional groups/bonds such as saturated aliphatic (2950-2970 cm-1, 2860-2880 cm-1), unsaturated aliphatic (2915-2935 cm-1, 2845-2865 cm-1), alcoholic (3200-3645 cm-1), carbonyl (1680-1820 cm-1), aryl (1450-1615 cm-1), disulfides (570-705 cm-1) and ether (2815-2850 cm-1). Some of those functional groups such as carbonyl and disulfide in organic matter may cause for the poisonous gas emissions. The ratio of TOC/TOM is slightly higher in the top and the bottom of the alluvial deposit. This indicates the high-carbon organic matters are present in the top and the bottom most layers. Conversely, carbon content of the middle layers in the deposit is less due to the intermediate level of organic matter degradation. In addition, middle region of the alluvial deposit is consisting of sandy nature, which reflects the dry climatic formation in the past thus the organic matter content is low. High soil elution conductivity in the bottom of the deposit indicates that the soluble ions were leached to the bottom and accumulate in the peat layer.Keywords: FTIR spectroscopy, Soil organic matter, Alluvial gem deposits, Geochemistr

Effectiveness of Aspergillus aculeatus on Decolorisation of Mixture of Two Different Textile Dye Classes

Textile dye effluents are one of the major type of water pollutants that release to the environment in huge loads. Textile dyes are resistant to natural degradation process and persist in the environment for a long time. Use of conventional chemical and physical treatment methods to textile dye effluents are highly expensive with having several drawbacks, thus not employed frequently. Therefore, the present study was aimed to evaluate the effectiveness of the isolated fungus; Aspergillus aculeatus for decolorisation of mixture of CI Direct Blue 201 (direct dye) and Cibacron Blue FR (reactive dye) dye classes. Four discs (5 mm diameter) of pre grown A. aculeatus fungal mycelia, which cut from the edges were inoculated into 250 mL of dye mixture at final concentration of 50 ppm (1:1 w/w), following enrichment with Potato Dextrose Broth (PDB) incubated in 100 rpm at 280° C for 7 days. Decolorisation of the dye mixture was evaluated by measuring the changes of the absorbance using UV-Visible spectrophotometer. Toxicity of the decolorized dye solutions was evaluated using the seed germination assay for Oryza sativa and Vigna radiata seeds. A. aculeatus showed 98%±2 decolorisation within 72h of incubation and decolorisation was highly suppressed at static conditions (46%±1 at 72h of incubation). Decolorisation was well effective up to five cycles at repeated addition of textile dyes to same initial fungal biomass. It was found that dead fungal biomass absorbed only 12%±2 of dye mixture at the same incubation period, suggesting that decolorisation take place with having live biomass of A. aculeatus confirming biotransformation of the dyes by the organism rather than adsorption. Seed germination assay shown that decolorised dye mixture was not toxic (100% germination for both seed species) compared to the original dye mixture (16.2±2.08 germination in O. sativa and 10.0±3.3% germination in V. radiata). Thus, the present study revealed that the fungus A. aculeatus is a potential candidate to use as a biological agent to remove textile dyes mentioned as a green approach to treat textile dye contained effluent. Further studies for other dyes are being evaluated.Keywords: Decolorisation, Aspergillus aculeatus, Textile dye, CI Direct Blue 201, Cibacron Blue F

Qualitative mineralogical analysis of Barracuda exploration well in the offshore Mannar Basin (the Indian Ocean) using FTIR and XRD techniques

The Mannar Basin plays a vital role in petroleum exploration in Sri Lanka, and its Barracuda exploration well was drilled up to 4206 m in depth. The objective of the current study is to identify mineralogy using Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) analyses. The FTIR and XRD analyses confirm the presence of quartz, feldspar, clay minerals (e.g., kaolinite, montmorillonite), calcite, and hematite in all marlstone and mudstone samples. These sedimentary rocks can be identified as potential petroleum source rocks in the Mannar Basin. Quartz, carbonate, and hematite cementations are directly reduced porosity and permeability, and thus primary migration of hydrocarbons from potential source rocks. Clay minerals act as a seal for hydrocarbon migrations in the Mannar Basin. A variety of dominant clay mineral assemblages allows the reconstruction of several paleoclimatic chronozones in warm/wet and arid climates. In contrast, feldspar dissolution promotes the primary migration of hydrocarbon from potential petroleum source rocks. Consequently, this study concluded that common minerals such as quartz, carbonate, and hematite are associated with the trapping and binding processes of hydrocarbons