Kinetics of Solid Waste Biodegradation in Laboratory Lysimeters

Solid waste biodegradation kinetics determine the time it takes to achieve stabilization of solid waste in landfills. This paper reports the results of a laboratory scale investigation aimed at evaluating the effect of different enhancement techniques on solid waste biodegradation kinetics. The experiments were carried out in a group of five lysimeters. The effect of temperature and leachate recirculation was investigated. Total Volatile Solids (TVS) and fiber content under controlled conditions of temperature and moisture were monitored for a period of nine months. The experiments were carried out under both mesophilic and thermophilic conditions. The moisture of solid waste was controlled through the process of leachate recirculation. The results of kinetic analysis showed that solid waste degradation follows first order kinetics. The optimal conditions for solid waste biodegradation were found to be mesophilic temperature of about 38oC and moisture content of about 65%. It was concluded that leachate recirculation enhanced the biodegradation process over the whole studied range of moisture content, while the temperature influence was the maximum during mesophilic stage. The biodegradation under thermophilic conditions was decelerated as compared to control lysimiter. The results obtained by this study may be applied to a real scale bioreactor landfill

The Impact of Climate Change on Water Availability and Recharge of Aquifers in the Jordan River Basin

Climate change can seriously affect the Middle East region by reduced and erratic rainfall. Formulating appropriate coping policies should account for local effects and changing flows interconnecting spatial units. We apply statistical downscaling techniques of coarse global circulation models to predict future rainfall patterns in the Yarmouk Basin, using a linear regression to extrapolate these results to the entire Jordan River Basin (JRB). Using a detailed water economy model for the JRB we predict rainfall patterns to evaluate the impact of climate change on agriculture and groundwater recharge. For the JRB, rainfall in 2050 will be around 10% lower than present precipitation, but with substantial spatial spreading. An overall reduction of net revenue from crop cultivation is estimated at 150 million USD, with major losses in Israel, Jordan, and the West Bank; Syrian revenues will slightly increase. The recharge of groundwater is affected negatively, and outflow to the Dead Sea is substantially lower, leading to further increases in salinization

Effect of soundscape dimensions on acoustic comfort in urban open public spaces

Soundscapes in public squares play important roles in urban open spaces. This study aimed to discover the effect of four soundscape dimensions, namely relaxation, communication, spatiality and dynamics, on acoustic comfort in urban open public spaces. A typical city square in China was selected as a case site. Sound environment measurements and questionnaire surveys were carried out for 8 survey positions. The results showed that the perceived dominance of sound sources had a significant effect on relaxation, communication, spatiality and dynamics. Relaxation was greater when the natural sound was perceived dominantly, while it was lower when mechanical sounds or anthropogenic sounds were perceived dominantly. Acoustic comfort had a significant correlation with the soundscape dimensions and LAeq, with spearman's correlation coefficients of 0.495 (relaxation), 0.210 (sound pressure level) and 0.288 (spatiality). In terms of the differences in perceived sound types, acoustic comfort was positively correlated with relaxation when natural sound or anthropogenic sound was perceived dominantly. As spatiality increased, acoustic comfort first decreased and later increased when relaxation was higher, while there were positive correlations between acoustic comfort and relaxation under the other situations. Moreover, when spatiality or communication was higher, there were significant correlations between acoustic comfort and dynamics. According to these results, acoustic comfort can be increased as soundscape dimensions change in an urban open public space

Selecting renewable energy options: an application of multi-criteria decision making for Jordan

Renewable energy sources are environmentally friendly and sustainable resources. However, there is no unique renewable energy resource that suits all countries. As such, nations must select the right option ‒ or combination of options ‒ that aligns with their local economic, technical, and environmental circumstances. Such a selection process is usually performed using a decision-making tool based on multi-criteria analysis. This study aims to find the most effective renewable energy option for Jordan by soliciting experts’ opinions under several criteria and sub-criteria. The collected responses of experts from the energy field were analyzed using the analytical hierarchy process (AHP). The AHP model used in the study consisted of four criteria, eleven sub-criteria, and four renewable energy alternatives. The results indicate that the technical criterion had the highest weight of 53.6% as compared to the environmental criterion which came second with a weight of 29.0% followed by geographical and socioeconomic criteria which have the lowest weights of 11.3% and 6.0%, respectively. The results reveal that under the technical criterion a high rank has given to maturity of the technology followed by availability of know-how with a weight of 0.875 and 0.125, respectively. The sequence of the preferable options based on the study results was: wind energy with 51.9%, followed by the solar energy option with 31.3%, and finally biomass and hydropower with 10.5% and 7.1%, respectively. Sensitivity analysis was performed and showed that the renewable energy options are not sensitive to the technical or environmental criteria, while they were slightly sensitive to the geographical and socioeconomic criteria

Assessment of Greenhouse Gas Emissions and Energetic Potential from Solid Waste Landfills in Jordan: A Comparative Modelling Analysis

Landfilling of solid waste has been and continues to be among the most common practices of solid waste disposal. This is particularly true for Jordan, where approximately 3.3 million tons of municipal solid waste (MSW) is annually generated, with 90% of the generated amount disposed into landfills. The main objective of this study is to estimate the quantities of landfill gas (LFG) generated from the solid waste disposal and its potential as a source of clean energy in Jordan using four different models, namely, GasSim 2.5, LandGEM, Afvalzorg, and Mexico Landfill Gas Model V2 (MLFGM V2). Furthermore, the greenhouse gas (GHG) mitigation potential of LFG projects was estimated. Currently, there are 18 active landfills that are distributed across the country. Based on screening criteria, the landfills were grouped into three categories: five landfills were considered for energy production, four were strong candidates for LFG collection and flaring, while the remaining nine landfills do not receive enough waste to be considered for either energy recovery or flaring. The total amount of LFG emissions was found to be 1.6 billion M3 of LFG, while the landfill energetic potential of the recovered LFG was estimated to be 34.8 MW. On the other hand, GHG mitigation potential was assessed between the years 2020 and 2030, which was found to be 18 million ton CO2 eq. The proposed LFG energy recovery projects will lead to increased biogas contribution to Jordan’s local renewable energy mix from a current level of 1% to 6%