Assessment of factors affecting household solid waste generation and its composition in Gulberg Town,Lahore, Pakistan

This paper analyzes and compares the findings of the characterization study of collected solid waste from households of three different socioeconomic groups in Lahore, Pakistan, over the four seasons, i.e. Spring (March–April, 2008), Summer (May–June, 2008), Monsoon (August–September, 2008) and Winter (December 2008 and January 2009). The generation rate of waste was 0.96 kg/cap/day for high-income, 0.73 kg/cap/day for middle and 0.67 kg/cap/day for low-income group. The average of total household solid waste (HSW) generation is 0.79 kg/cap/day (including 0.75 kg/cap/day for spring, 0.77 kg/cap/day for summer, 0.86 kg/cap/day for monsoon and 0.76 kg/cap/day. The breakdown for the major physical components of the waste shows that organic waste accounts for the largest proportion (67.46 %). The relations between waste generation rates by physical category and subcategory, in addition to factors such as socioeconomic groups (population density levels, household income and household size), seasonal variation, and daily variation (difference of HSW generation among days of a week) were also analyzed. Statistical analysis shows that there was no significant difference in overall waste generation among days of a week. A significant difference between the seasons for food waste, cardboard, PET, HDPE, other hazardous waste, battery cells, and dust and stone (p < 0.001) was found. The generation rates were found to be higher when compared to other developing countries.     

Monitoring trace metals in different tissues of Cyprinus carpio from the Indus River in Pakistan

This replicated 4×2 factorial study investigated the bioaccumulation of selected metals (Mn, Pb, Zn, Hg and Cr) in four tissues (gills, liver, muscle and skin) of common carp (Cyprinus carpio) domiciled in two sites (upstream and downstream) of Indus River in Mianwali district of Pakistan. The data were statistically compared for the main effects of the site and fish organs and their interaction on the bioaccumulation pattern of these metals in fish organs at P?P?相似文献   

Enhanced catalytic complete oxidation of 1,2-dichloroethane over mesoporous transition metal-doped γ-Al2O3

High-surface-area mesoprous powders of γ-Al₂O₃ doped with Cu^2 +, Cr^3 +, and V^3 + ions were prepared via a modified sol–gel method and were investigated as catalysts for the oxidation of chlorinated organic compounds. The composites retained high surface areas and pore volumes comparable with those of undoped γ-Al₂O₃ and the presence of the transition metal ions enhanced their surface acidic properties. The catalytic activity of the prepared catalysts in the oxidation of 1,2-dichloroethane (DCE) was studied in the temperature range of 250–400°C. The catalytic activity and product selectivity were strongly dependent on the presence and the type of dopant ion. While Cu^2 +- and Cr^3 +-containing catalysts showed 100% conversion at 300°C and 350°C, V^3 +-containing catalyst showed considerably lower conversion. Furthermore, while the major products of the reactions over γ-alumina were vinyl chloride (C₂H₃Cl) and hydrogen chloride (HCl) at all temperatures, Cu- and Cr-doped catalysts showed significantly stronger capability for deep oxidation to CO₂.     

Property-performance relationship of core-shell structured black TiO2 photocatalyst for environmental remediation

● Properties and performance relationship of CSBT photocatalyst were investigated. ● Properties of CSBT were controlled by simply manipulating glycerol content. ● Performance was linked to semiconducting and physicochemical properties. ● CSBT (W:G ratio 9:1) had better performance with lower energy consumption. ● Phenols were reduced by 48.30% at a cost of $2.4127 per unit volume of effluent. Understanding the relationship between the properties and performance of black titanium dioxide with core-shell structure (CSBT) for environmental remediation is crucial for improving its prospects in practical applications. In this study, CSBT was synthesized using a glycerol-assisted sol-gel approach. The effect of different water-to-glycerol ratios (W:G = 1:0, 9:1, 2:1, and 1:1) on the semiconducting and physicochemical properties of CSBT was investigated. The effectiveness of CSBT in removing phenolic compounds (PHCs) from real agro-industrial wastewater was studied. The CSBT synthesized with a W:G ratio of 9:1 has optimized properties for enhanced removal of PHCs. It has a distinct core-shell structure and an appropriate amount of Ti³⁺ cations (11.18%), which play a crucial role in enhancing the performance of CSBT. When exposed to visible light, the CSBT performed better: 48.30% of PHCs were removed after 180 min, compared to only 21.95% for TiO₂ without core-shell structure. The CSBT consumed only 45.5235 kWh/m³ of electrical energy per order of magnitude and cost $2.4127 per unit volume of treated agro-industrial wastewater. Under the conditions tested, the CSBT demonstrated exceptional stability and reusability. The CSBT showed promising results in the treatment of phenols-containing agro-industrial wastewater.     

Elements of fishing community resilience to climate change in the coastal zone of Bangladesh

Resilience has been conceptualized in various ways by anthropologists, ecologists, systems scientists and engineers; the boundaries of resilience are subjective and context dependent. Consequently, choosing the standards and metrics for assessing resilience remains key challenges for policy makers. In this study, using multicriteria evaluation of 40 basic criteria of human, physical, financial, natural and social assets, we have identified several elements, such as experienced fishermen, natural abundance of hilsa (Tenualosa ilisha), ability to assert decision on fish selling, nets and boats ownership, social harmony and capacity of buying food as essential livelihood assets for the fishermen at Hatiya Island, Bangladesh. These assets may enhance the relative resilience of the fishing community of the island to climate change by as much as 20–40%. The results of this study will improve our understanding of the elements that lead to resilience at the community level.     

Municipal solid waste management in Lahore City District,Pakistan

This study deals with generation, composition, collection, transportation, and disposal, as well as the present cost of the waste management on the basis of 60% collection of the total waste and the cost of proposed improved system of management on the basis of 100% waste collection using the IWM-2 LCI model. A GIS map of Data Ganj Bakhsh Town (DGBT) of Lahore City District showing communal storage facilities is also provided. DGBT has a population of 1,624,169 living in 232,024 dwellings. The total waste generated per year is 500,000 tons, or 0.84/kg/cap/day. Presently 60% of the MSW is collected and disposed in open dumps, while 40% is not collected and lies along roadsides, streets railway lines, depressions, vacant plots, drains, storm drains and open sewers. In DGBT, 129 containers of 5-m³ capacity, 120 containers of 10-m³ capacity and 380 skips of 2.5-m³ capacity are placed for waste collection. The overall collection and disposal cost of the MSW of DGBT is $3,177,900/yr, which is $10.29/ton. Modeling was conducted using the IWM-2 model for improved collection and disposal on the basis of 100% service, compared to the current 60% service. The modelled cost is $8.3/per ton, which is 20% less than the present cost, but the overall cost of 100% collection and disposal increases to $4,155,737/yr.     

Heterogeneous Traffic Induced Effects on Vertical Dispersion Parameter in the Near Field of Roadways - a Wind Tunnel Study

The varying traffic parameters such as traffic volume, speed, shape and size, and terrain roughness conditions play a vital role on dispersion of pollutants in the near field of roadways. Simulation experiments were carried out in the Environmental Wind Tunnel (EWT) to evaluate the traffic induced effects on vertical dispersion parameter (σ _z ) for heterogeneous traffic conditions in the near field of roadways for evaluating the effect of variations in traffic volume, terrain roughness condition and approaching wind direction. The model vehicle movement system was fabricated and made operational in the EWT, which allowed the variation in traffic volume, speed and wind road inclination. Sixty-six hydrocarbon tracer experiments were performed to evaluate σ _z in the near field of roadways for variable traffic volume, three terrain roughness conditions and two approaching wind directions (i.e., 90° and 60°). The values of σ _z for heterogeneous traffic conditions were found to be higher for low roughness conditions in comparison to other two higher roughness conditions for various traffic volumes and approaching wind directions. This revised version was published online in July 2006 with corrections to the Cover Date.     

High reduction of 4-nitrophenol using reduced graphene oxide/Ag synthesized with tyrosine

There is a demand for the development of environmental friendly methods for the synthesis of graphene composites. Reduced graphene oxide/silver (RGO/Ag) nanocomposites are very good catalysts. Here, we propose a simple, green method for the synthesis of RGO/Ag nanocomposite using the amino acid tyrosine as bioreductant and stabilizing agent. RGO/Ag nanocomposite was characterized by using various analytical techniques and studied for its catalytic degradation of 4-nitrophenol. Results of attenuated total reflectance Fourier transform infrared spectroscopy and Zeta potential at ?55 mV reveal the surface capping of tyrosine onto the reduced graphene oxide nanosheets. RGO/Ag nanocomposites show excellent catalytic reduction of 4-nitrophenol with NaBH₄, when compared to actual individual silver nanoparticles.     

Cash transfers and residential demand for electricity: insights from BISP,Pakistan

Environmental Science and Pollution Research - We examine the causal impacts of the cash transfer program, namely the Benazir Income Support Program (BISP), on residential demand for electricity...