Browsing by Author "Basnayake, BFA"

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item: Conference-Full-text
Development and Performance Evaluation of the Leachate Treatment System at Gohagoda Municipal Solid Waste Disposal Site
(2016-01-04) Priyashantha, KAS; Ariyawansha, RTK; Senevirathne, SADN; Basnayake, BFA; Chandrasena, ASH
A private company with technical support of University of Peradeniya has undertaken the task of rehabilitating the Gohagoda dumpsite. Not all of the leachate collection system (LTS) is completed yet and runoff water too gets mixed with the leachate on one side of the dumpsite. The LTS consisting of leachate collection tanks, a leachate treatment bioreactor(LTB) followed by an algae pond(AP), a floating wetland(FW), two sub-surface constructed wetlands(SCWs), two charcoal filter-beds(CFBs). LTSoutlet is being discharged into a natural stream (NS). In this research, the existing LTS was improved and the performances were evaluated. To determine the surface water quality of surrounding area and performance of the LTS, samples were obtained from 13 pre-defined points on weekly basis for two months, analysed for 14 quality parameters. Average pH, dissolved oxygen (DO), chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of inlet leachate to the LTS were 7.74±0.35, 0.46±0.5mg/L, 24,552±2,612mg/L and 4,125±965mg/L respectively. LTSoutlet of pH (7.16±0.23) was within the Central Environmental Authority water quality discharge standards. Average salinity, EC, DO, TDS, TSS, TS, VS, VSS, BOD, COD, PO4 -3, NO3 - and NH4 +of LTSoutlet were 0.84±0.25%0, 1.71±0.52mS, 0.63±0.6mg/L, 852±261mg/L, 1,058±199mg/L, 1,303±772mg/L, 406±220mg/L, 609±111mg/L, 217±177mg/L, 780±1,049mg/L, 2.33±3.29mg/L, 0.97±0.27mg/L, 4.38±1.59mg/L respectively. Average pH, TDS, BOD, PO4 -3 and NO3 - and NH4 + of NSoutlet were 7.69±0.39, 1,457±930mg/L, 1,382±784mg/L, 5.04±6.36mg/L, 1.58±1.26mg/L, 4.3±2.02mg/L respectively. The average removal efficiency of BOD was 95%. The lower values of the indicative parameters were when the LTS was stabilizing and attaining the required standards even without high growth in SCWs, until heavy rainfall occurred. Therefore, it is essential to install subsurface leachate interceptor drains and those connected to the leachate treatment system. It will require a proper dumpsite cover system to reduce infiltration and thus promote runoff. It is imperative to monitor and evaluate frequently the system and improve it with an aerated biological indicator pond.
item: Conference-Full-text
Development of a sustainable environmental preservation Centre (EPC) at Nawalapitiya for urban solid waste Management
(2013-11-14) Ariyawansha, RTK; Chandrasena, ASH; Senevirathne, SADN; Basnayake, BFA
An Environmental Preservation Centre (EPC) was established to resolve the solid waste management crisis of Nawalapitiya Urban Council. Material Recovery Facility (MRF), Inclined Step Grate (ISG) composting system of 5.5 tonnes/ day capacity, screening, storage and residual landfill, the total area covered by the fence including buffer zone are the major components of the EPC. After separating recyclables at the MRF, the remaining biodegradable is fed in to ISG system. Residual landfill is designed for inert materials that are remaining after the MRF and composting facility operations. MRF and ISG system are already constructed and currently initiated the operations. This is technically and financially feasible sustainable approach for protecting the environment and posterity.
item: Conference-Full-text
Optimization of rice straw hydrolysis to convert ligno-cellulose to simple sugars
(Division of Sustainable Resources Engineering, Hokkaido University, Japan, 2024) Madanayake, N; Basnayake, BFA; Jayakody, LN; Iresha, H; Elakneswaran, Y; Dassanayake, A; Jayawardena, C
Development and use of renewable energy is a key option towards poverty alleviation and to mitigate global warming. Annual rice straw yield of 2.7 million metric tons in Sri Lanka is the most abundant lingo-cellulosic crop residue for bioconversion into ethanol. This research focused on the hydrolysis phase in ethanol production to optimize the rice straw digestion in the saccharification process. In this study, four anaerobic leaching columns in which the base filled with gravel and sand were used. Except for the control, the other three contained an additional soil layer of 60 mm that was obtained beneath a pile of decomposing rice straw. Then, 500g of rice straw was added to each column. In one of the soil added columns, elute was re-circulated. Rice straw to water ratio was maintained at 1:20 by adding water and straw. Samples were taken at daily basis, except for non-recycled one with analysis of initial and final day for pH, conductivity, TDS, salinity, brix, TS, VS, VSS, TSS, VSS, and BOD. The non-recycled, soil added column gave increased values of conductivity, TDS, salinity, TSS, VSS, and well-grown white mycelia on straw. Highest values of measured parameters were reported in re-circulated column. The increment of cumulative conductivity, TDS, salinity, VS, TSS, and VSS, of non-recycled, soil added column was significant rather than the control. In applying Michaelis Menten kinetics, Vmax and Km for the column without soil are 0.33 and 26.7, with soil were 0.42 and 18.37 and with re-circulation were 7.22 and 0.15, respectively. The latter with higher rate of conversion with less inhibition, proved better affinity between substrate and enzyme. The elusions of TS for without and with soil were 58.0g and 71.5g. These converted to 40.1g and 50.8g of simple sugars and they were 8.0% and 10.1% of total straw weight, expressing in cellulose mass, varied between 22.9%-26.7% and 29%-33.8% of simple sugars. Thus, deduced energy contents are 1.03-1.40 MJ/kg and 1.30-1.77 MJ/kg. Hence hydrolysis of rice straw with soil, has a potential to recover 175 million liters of ethanol.