Management of Leachate Generated from Long-Term Degradables of Municipal Solid Waste (MSW) in Open Dumps Using Effective Microorganisms (EM) Technology

Open dumping is the most common practice of final disposal of municipal solid waste (MSW) in most of the developing countries including Sri Lanka.Long-term degradables of MSW has been a precursor for leachate of high biological oxygen demand (BOD) and chemical oxygen demand (COD) to be generated due to organic compounds of higher molecular weights and treatment of such leachate seems to be a daunting task in many open dumps. Leachate generated from the Karadiana open dumpsite released to the Bolgoda lake results in many adverse effects on human health and aquatic ecosystem. Most of the organic compounds in the leachate are attributed to long term degradables, not readily biodegradable, and resist conventional treatment methods; hence, a reliable and efficient treatment system has been a long-felt need. In this study, the use of Effective Microorganisms (EM) technology for enhancing the biodegradability of long term degradables and subsequent treatment by advanced oxidation using Fenton oxidation is explored. A solution containing EMs (Lactic acid bacteria-9×107, photosynthetic bacteria-4×107, yeast-2×106 CFU/mL) (100 mL at day=1) was applied to the leachate with combinations of 0, 50, 75% dilutions having volumes of 1 L. At the time of application, COD levels of the said combinations were 20,030, 12,672 and 11,090 mg/L respectively. With the application of EMs (100 mL at day=1), COD levels were recorded to be 18,064, 3,951 and 3,002 mg/L respectively, after a retention time of 10 days. Further, Fenton oxidation was carried out subsequently for controls and for the ones added with EMs. The COD levels of controls were 2,400, 1,250 and 905 mg/L for 0, 50 and 75% dilutions respectively. The same treated with EMs were 1,009, 720 and 490 mg/L. Thus, it can be concluded that the application of EM technology is effective in reducing COD levels in the leachate generated from long term degradables.Keywords: Leachate, Municipal solid waste, Long term degradables, Effective microorganisms, Fenton oxidation, Chemical oxygen deman

Use of Reverse Osmosis Reject Water for Value Addition in Coco Substrate Industry

Previous studies corroborated that water enriched with various compounds is a major reasonfor Chronic Kidney Disease of Unknown Aetiology (CKDu) in Sri Lanka. Reverse osmosis(RO) units are being introduced in the CKDu prevalent areas for water purification.Generally, the RO reject water is disposed of directly to the ground and/or used for irrigationpurposes because it contains several minerals, which are favourable for the growth of plants.However, this practice may cause any negative environmental issues.Calcium nitrate is used as a value addition in coco substrate industry to wash out sodiumfrom the coir products because sodium competes with other cations which are essential forplant growth in the process of adsorption. However, discharging the spent calcium nitratesolution to land for irrigation purposes may lead to nitrate pollution. This study investigatesthe possibility of using RO reject water, which has considerably high amounts of calcium, asan alternative for the use of calcium nitrate, which may also lead to reduction of cost ofimporting calcium nitrate. Leachability tests were carried out using husk chips as the solidmedium with RO reject water and calcium nitrate as the treatment solution, respectively.When RO reject water was used as the washing solution, the results manifested (amount ofcalcium, magnesium adsorbed and sodium, potassium leached out) that the leachabilitypotential was well within the acceptable range as per the protocols. Based on the findings,RO reject water could be proposed as an alternative source to calcium nitrate.Keywords: Calcium nitrate, Coco substrate, Husk chips, Reverse osmosis, Water purificatio

Removal of Fluoride and Hardness in Dietary Intake (water) in Chronic Kidney Disease of unknown Etiology (CKDu) Prevalent Areas by Domestic Reverse Osmosis Units

The origin of Chronic Kidney Disease of unknown etiology (CKDu) that is rapidly invadingthe dry zone of Sri Lanka has not yet been identified. However, occurrence of the disease isthought to be linked with excess levels of fluoride and hardness in drinking water. Hence, thestudy herein focuses to evaluate the suitability of domestic Reverse Osmosis (RO) units;which introduced in CKDu affected areas to remove excess fluoride and hardness.Accordingly, the drinking water quality in CKDu prevalent areas in terms of fluoride andhardness was simulated in the laboratory and the removal of aforesaid constituents usingdomestic ROs was investigated.According to water quality analyses, domestic RO units effectively removed hardness even atextremely high initial concentrations, such as 1,730 mg/L (as CaCO3). Excessive removal ofCalcium and Magnesium by the RO units was observed, thus remineralization of thepermeate up to 80-100 mg/L as CaCO3 is required to ensure health benefits. Meanwhile,fluoride removal was observed to be highly dependent upon initial fluoride and hardnessconcentrations. It was not possible to suggest an „optimum removal level‟ for fluoride, wherepermeate fluoride concentration exceeded the maximum permissible WHO Drinking WaterGuideline value of 1.5 mg/L. However, it may arise at a point where fluoride and hardnessconcentrations in raw water fall within 1.7-3.5 mg/L and 570-1,130 mg/L as CaCO3,respectively.Plausible reasons for ineffective removal of fluoride could be the relatively small size andlow ionic charge of fluoride. Additionally, high concentration of heavy ions may interferewith fluoride adsorption of activated carbon filter in the domestic RO unit. Effective fluorideremoval could be achieved by adopting appropriate pre-treatment methods for hardnessremoval. Separate threshold levels for fluoride and hardness levels in drinking water shouldbe defined, especially for CKDu patients.Keywords: Chronic Kidney Disease, Domestic reverse osmosis units, Fluoride, Hardnes

Use of Reverse Osmosis Reject Water for Value Addition in Coco Substrate Industry

Previous studies corroborated that water enriched with various compounds is a major reasonfor Chronic Kidney Disease of Unknown Aetiology (CKDu) in Sri Lanka. Reverse osmosis(RO) units are being introduced in the CKDu prevalent areas for water purification.Generally, the RO reject water is disposed of directly to the ground and/or used for irrigationpurposes because it contains several minerals, which are favourable for the growth of plants.However, this practice may cause any negative environmental issues.Calcium nitrate is used as a value addition in coco substrate industry to wash out sodiumfrom the coir products because sodium competes with other cations which are essential forplant growth in the process of adsorption. However, discharging the spent calcium nitratesolution to land for irrigation purposes may lead to nitrate pollution. This study investigatesthe possibility of using RO reject water, which has considerably high amounts of calcium, asan alternative for the use of calcium nitrate, which may also lead to reduction of cost ofimporting calcium nitrate. Leachability tests were carried out using husk chips as the solidmedium with RO reject water and calcium nitrate as the treatment solution, respectively.When RO reject water was used as the washing solution, the results manifested (amount ofcalcium, magnesium adsorbed and sodium, potassium leached out) that the leachabilitypotential was well within the acceptable range as per the protocols. Based on the findings,RO reject water could be proposed as an alternative source to calcium nitrate.Keywords: Calcium nitrate, Coco substrate, Husk chips, Reverse osmosis, Water purificatio

Removal of Fluoride and Hardness in Dietary Intake (water) in Chronic Kidney Disease of unknown Etiology (CKDu) Prevalent Areas by Domestic Reverse Osmosis Units

The origin of Chronic Kidney Disease of unknown etiology (CKDu) that is rapidly invadingthe dry zone of Sri Lanka has not yet been identified. However, occurrence of the disease isthought to be linked with excess levels of fluoride and hardness in drinking water. Hence, thestudy herein focuses to evaluate the suitability of domestic Reverse Osmosis (RO) units;which introduced in CKDu affected areas to remove excess fluoride and hardness.Accordingly, the drinking water quality in CKDu prevalent areas in terms of fluoride andhardness was simulated in the laboratory and the removal of aforesaid constituents usingdomestic ROs was investigated.According to water quality analyses, domestic RO units effectively removed hardness even atextremely high initial concentrations, such as 1,730 mg/L (as CaCO3). Excessive removal ofCalcium and Magnesium by the RO units was observed, thus remineralization of thepermeate up to 80-100 mg/L as CaCO3 is required to ensure health benefits. Meanwhile,fluoride removal was observed to be highly dependent upon initial fluoride and hardnessconcentrations. It was not possible to suggest an „optimum removal level‟ for fluoride, wherepermeate fluoride concentration exceeded the maximum permissible WHO Drinking WaterGuideline value of 1.5 mg/L. However, it may arise at a point where fluoride and hardnessconcentrations in raw water fall within 1.7-3.5 mg/L and 570-1,130 mg/L as CaCO3,respectively.Plausible reasons for ineffective removal of fluoride could be the relatively small size andlow ionic charge of fluoride. Additionally, high concentration of heavy ions may interferewith fluoride adsorption of activated carbon filter in the domestic RO unit. Effective fluorideremoval could be achieved by adopting appropriate pre-treatment methods for hardnessremoval. Separate threshold levels for fluoride and hardness levels in drinking water shouldbe defined, especially for CKDu patients.Keywords: Chronic Kidney Disease, Domestic reverse osmosis units, Fluoride, Hardnes