In many developing countries, dumpsites remain as the main disposal method for Municipal Solid Waste (MSW) and the quantity of MSW has exponentially increased due to the rapid urbanization, industrialization, economic growth, and change in lifestyles. The per capita waste generation estimated in the year 2050 would grow from the current level of generation by 19% in high-income countries and by 40% in low & middle-income countries. Although the concept of open dumpsite is obsolete in many developed countries, it is still considered a common disposal mechanism in developing countries mainly due to economic constraints. Bioreactor Landfill technology has been widely accepted as an effective method for the treatment of Solid Waste. However, the optimal operational conditions and long-term performance of the bioreactors for disposal of MSW remains a grey area of research. Long-term operation of four pilot bioreactors configurations, simulating Aerobic Bioreactor, Anaerobic Bioreactor, Hybrid Bioreactor and Control reactor (Open Dump), was experimentally simulated for 550 days. Fresh MSW in bioreactor landfills undergoes a physical-chemical-biological process (any order) and contributes to higher treatment efficacy. COD removal efficiencies at the closure of the experiment were 94.3%, 84.5%, 90.2% and 47.5% in aerobic, anaerobic, hybrid and control reactors. At the end of 550 days, the NH4+-N reduced to 80 mg/L (94%), 1440 mg/L (35%), 680 mg/L (44%) and & 40 mg/L (92.8%) in aerobic, anaerobic, hybrid bioreactors and control reactor respectively. The total gas production in aerobic, anaerobic and hybrid bioreactors are 20,683 L, 7,383 L and 12,071 L respectively, and the heavy metal removal efficiencies for all the bioreactors for Cu, Cr, Zn, Ni, Pb, and Mn were 55 - 75%, 25 – 50%, 60 – 90%, 68 – 80%, 72 – 85%, and 59 – 70% respectively. The total settlement was higher in the Hybrid reactor (22.86%), followed by the Aerobic reactor (21.43%), Anaerobic reactor (17.14%), and Control reactor (12.14%). From the carbon balance analysis, it was found that the carbon reduction in aerobic, anaerobic, hybrid, and control reactors was 53.5%, 44.8%, 58.1%, and 25.5%, respectively. The results of the experimental studies contemplate the various options in bioreactor landfill technology contributing to having a lesser land footprint with respect to time and efficiency. A modelling study was also carried out using MIKE SHE to assess and predict both spatial and temporal variation of groundwater (GW) contamination around the municipal solid waste open dumpsite through an integrated model considering both unsaturated and saturated zones. The prevailing situation of the contamination has been well understood with this modelling study and also as a separate integrated model was developed to assess the effect of strategies for control of leachate generation in contamination across the open dumpsite if the bioreactor landfill technology is adopted.
The efficacy of High-density polyethylene (HDPE) liners used in the Bioreactor Landfills was also studied in adverse conditions like a corrosive and hazardous textile salt. From the pilot-scale studies, accelerated test for understanding tensile strength at break, carbon black test and Scanning Electron Microscopy (SEM) analysis, the non-corrosive/non-deteriorating property of the HDPE liners has been well proved. The results of the carbon black test show that the carbon black content of all the samples was between 2–3%, which is similar to the initial content. The 100% textile salt solution caused a creeping phenomenon, resulting in the extension of crystallites on the HDPE material. However, the mean roughness (Sa) of the HDPE lining sheets was unaffected indicating the structure, physical and chemical properties, and strength of the HDPE material remained unaffected by the application of the highly corrosive hazardous salt waste from the textile common effluent treatment plant.