Modeling water quality changes o f urban canalsin Colombo cit y against rainfall an d land use patterns

Modeling the relationships between surface water quality with rainfall and land-use patterns is of prime importance in exploring effective method s for mitigating the water pollution in areas like Colombo city. These models are important for land-use planning and resource management to plan for best environmental management practices and it is possible to compile detailed inventories and to monitor water quality in surface water bodies. This study focuses on modeling the surface water quality change s of urban canals in Colombo from 2003 to 2009 in relation to rainfall of different climatic seasons, land use types, and population density using a G IS based approach together with statistical modeling. The data on land use, monthly rainfall, population density and water quality from 200 3 to 200 9 was collected from the Department of Survey, Department of Meteorology, Department of Census & Statistics and Sri Lanka Land Reclamation & Development Company respectively. Results revealed that there is a strong significant difference within the mea n values of Conductivity, Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD) and Salinity percentage according to the climatic seasons. The water quality attributes; Conductivity, Phosphate , BO D and Salinity percentage were significantly correlated to land-use types (Built-up/Homesteads, Barren, Marsh/Paddy, Park/Playground, Plantation, Scrub and Water bodies). A significant regression model could be drawn to predict the surface water quality in Colombo city using one water quality indicator (BOD) which ma y suggest that point-sources contribute more pollutants than non-point sources. Recommendation s were mad e to consider more important water quality parameters such as biological parameters within an extended study area for future studies because they will be providing complex models of water quality with other factors

Critical factors affecting the integration of biomass gasification and syngas fermentation technology

Gasification-fermentation is a thermochemical-biological platform for the production of fuels and chemicals. Biomass is gasified at high temperatures to make syngas, a gas composed of CO, CO2, H2, N2 and other minor components. Syngas is then fed to anaerobic microorganisms that convert CO, CO2 and H2 to alcohols by fermentation. This platform offers numerous advantages such as flexibility of feedstock and syngas composition and lower operating temperature and pressure compared to other catalytic syngas conversion processes. In comparison to hydrolysis-fermentation, gasification-fermentation has a major advantage of utilizing all organic components of biomass, including lignin, to yield higher fuel production. Furthermore, syngas fermentation microorganisms do not require strict CO:H2:CO2 ratios, hence gas reforming is not required. However, several issues must be addressed for successful deployment of gasification-fermentation, particularly those that involve the integration of gasification and fermentation. Most previous reviews have focused only on either biomass gasification or syngas fermentation. In this review, the critical factors that affect the integration of biomass gasification with syngas fermentation, such as carbon conversion efficiency, effect of trace gaseous species, H2 to CO ratio requirements, and microbial preference of carbon substrate, are thoroughly discussed