Efficient Removal of Chromium and Lead from Tanneries Effluent of Korangi Industrial Area Karachi Using Rotating Disk Mesh as Anode Electrode Electrocoagulation

The aim of this study was to examine the best electrode design for the electrocoagulation process with the best removal performance, reduced passivation on the electrode surface, and lower energy consumption requirements for removing Chromium (Cr) and Lead (Pb) from leather tannery effluent. Three different electrodes were compared: non-rotating disk electrode (NRDE), rotating disk electrode (RDE) and rotating disk mesh electrode (RDME). All electrodes were used to observe a reduction in passivation on the electrode surface and its effects on the removal performance of Cr and Pb. The material used for the electrodes was iron. The maximum removal efficiency obtained was Cr = 87.9% and Pb = 97.5% under the following operating conditions: pH = 7, treatment time = 90 min, current density = 6.57 mA/cm², and RPM = 80. The results show that the electrical energy requirement for treating chromium and lead using RDME was 4.5 kWh/m³, which was found to be lower than the energy requirement observed in various other studies for treating tannery effluent. According to the results, RDME shows the highest removal performance with lower specific energy consumption compared to NRDE and RDE. RDME can be efficiently employed at a larger scale for treating leather tannery effluent

A review of chemical demineralization and desulphurization of high ash & high sulphur lignite coal

Globally, large reserves of low grade or lignite coal are available. Low-ranking coal contains high mineral content, moisture content, and low calorific value. The major problem in coal is sulphur and ash When used for combustion, this type of coal imposes harmful impacts on the environment. It results in the production of greenhouse gases and ash, which are hazardous for the environment and human health. Usually, the demineralization and desulphurization process is used to remove the minerals matters before its use in industrial processes such as combustion, carbonization, gasification and liquefication. Which are harmful to the environment if combusted untreated. Therefore, the number of upgrading technology is being used to reduce the mineral matters from coal and save the environment. The current paper reviews the potential of demineralization and desulphurization processes to enhance the usability of lignite coal. Moreover, it focuses on preserving the high-grade coal which is already depleted in abundance

Estimation of Power Production Potential from Natural Gas Pressure Reduction Stations in Pakistan Using ASPEN HYSYS

Pakistan is a gas rich but power poor country. It consumes approximately 1, 559 Billion cubic feet of natural gas annually. Gas is transported around the country in a system of pressurized transmission pipelines under a pressure range of 600-1000 psig exclusively operated by two state owned companies i.e. SNGPL (Sui Northern Gas Pipelines Limited) and SSGCL (Sui Southern Gas Company Limited). The gas is distributed by reducing from the transmission pressure into distribution pressure up to maximum level of 150 psig at the city gate stations normally called SMS (Sales Metering Station). As a normal practice gas pressure reduction at those SMSs is accomplished in pressure regulators (PCVs or in throttle valves) where isenthalpic expansion takes place without producing any energy. Pressure potential of natural gas is an untapped energy resource which is currently wasted by its throttling. This pressure reduction at SMS (pressure drop through SMS) may also be achieved by expansion of natural gas in TE, which converts its pressure into the mechanical energy, which can be transmitted any loading device for example electric generator. The aim of present paper is to explore the expected power production potential of various Sales Metering Stations of SSGCL company in Pakistan. The model of sales metering station was developed in a standard flow sheeting software Aspen HYSYS®7.1 to calculate power and study other parameters when an expansion turbine is used instead of throttling valves. It was observed from the simulation results that a significant power (more than 140 KW) can be produced at pressure reducing stations of SSGC network with gas flows more than 2.2 MMSCFD and pressure ration more than 1.3

Kinetic Study of Cotton Stalk and Rice Husk Samples under an Inert and Oxy Combustion Atmospheres

International audienceBiomass materials such as CS (Cotton Stalks) and RH (Rice Husk) are a renewable source of energy. As biomass resources have potential to offer a uninterpted supply of biofuels through thermal decomposition processes. Nevertheless, an appropriate understanding of reaction kinetics and thermal properties of biomasses play a vital role in designing of the commercial plants using biomass as a raw material for energy generation. The kinetic characteristics of the CS and RH samples under pure nitrogen 99.9% and pure oxygen 99.9% was performed. The temperature was raised from ambient to 900 o C maintaining the heating rate of 10 o C/min. CS and RH decomposition was noticed in three dissimilar regions. The kinetic characteristics such as (pre-exponential factor, the order of reaction and activation energy) were calculated for both selected materials. The activation energies calculated under nitrogen environment for CS and RH was 68.77 and 72.31 kJ/mole, whereas the regression coefficient (R 2) was 0.9877 and 0.9731 respectively. The activation energies under oxygen environment were higher, it was 106 and 118 kJ/mole. The regression coefficient (R 2) under oxygen environment was 0.9987 and 0.99883 for above sample sequence

Determination of Arsenic and Health Risk Assessment in the Ground Water of Sindh, Pakistan

As (Arsenic) is one of the lethal element present at the various locations of the world, putting human beings in danger by polluting the water. Arsenic Kit and atomic absorption spectrometer were used to determine As in ground water of Sindh province, Pakistan. Twenty-Four (24) districts both on the left and right bank of RI (River Indus) were analyzed. It was observed from the results that highest As concentration 200 ppb (parts per billion) i.e. above the WHO (World Health Organization) limit (10 ppb) was observed in Sakrand, district Shaheed Benazirabad followed by Hala, Matairi, TMK (Tando Mohammad Khan) and Nasarpur regions. It was further found that ground water of regions on the left bank of RIwas more contaminated than the right bank. Contour map was created using OriginPro and coordinate systems to highlight the elevated arsenic in the studied area. HRA (Health Risk Assessment) of these areas was carried out to calculate EDI (Estimated Daily Intake), TQH (Target Hazard Quotient) and CR (Cancer Risk). 45% of the total ground water samples analyzed were above the permissible limit for As in water and mostly these are located on the left bank of RI. The local wells in Sindh have never been tested for metal concentration former to use. These results provide baselines for researchers, NGO's (Non-Governmental Organizations) and government to apply arsenic treatment technologies in those area

Thermochemical Conversion of Biomass for Syngas Production: Current Status and Future Trends

The thermochemical conversion of different feedstocks is a technology capable of reducing the amount of biowaste materials produced. In addition, the gasification of feedstock using steam as a gasifying agent also produces hydrogen, which is a clean energy fuel. This article aimed to encapsulate the current status of biowaste gasification and to explain, in detail, the advantages and limitations of gasification technologies. In this review paper, different gasifying agents such as steam, air, and oxygen, as well as their effects on the quality of syngas production, are discussed. In addition, the effects of reactor configuration and different operating parameters, such as temperature, pressure, equivalence ratio, and incorporation of a catalyst, as well as their effects on the ratio of H2/CO, LHV, syngas yield, and tar production, were critically evaluated. Although gasification is a sustainable and ecologically sound biomass utilization technology, tar formation is the main problem in the biomass gasification process. Tar can condense in the reactor, and clog and contaminate equipment. It has been shown that an optimized gasifier and a high-activity catalyst can effectively reduce tar formation. However, key biowaste treatment technologies and concepts must first be improved and demonstrated at the market level to increase stakeholder confidence. Gasification can be the driving force of this integration, effectively replacing fossil fuels with produced gas. In addition, support policies are usually needed to make the integration of biomass gasification technology into the industry profitable with fully functional gasification plants. Therefore, to address such issues, this study focused on addressing these issues and an overview of gasification concepts

Plastic Waste Recycling, Applications, and Future Prospects for a Sustainable Environment

Plastic waste accumulation has been recognized as one of the most critical challenges of modern societies worldwide. Traditional waste management practices include open burning, landfilling, and incineration, resulting in greenhouse gas emissions and economic loss. In contrast, emerging techniques for plastic waste management include microwave-assisted conversion, plasma-assisted conversion, supercritical water conversion, and photo reforming to obtain high-value products. Problems with poorly managed plastic waste are particularly serious in developing countries. This review article examines the emerging strategies and production of various high-value-added products from plastic waste. Additionally, the uses of plastic waste in different sectors, such as construction, fuel production, wastewater treatment, electrode materials, carbonaceous nanomaterials, and other high-value-added products are reviewed. It has been observed that there is a pressing need to utilize plastic waste for a circular economy and recycling for different value-added products. More specifically, there is limited knowledge on emerging plastic waste conversion mechanisms and efficiency. Therefore, this review will help to highlight the negative environmental impacts of plastic waste accumulation and the importance of modern techniques for waste management

Biochemical treatment of poultry manure and buffalo dung to enhance methane generation using lab-scale an-aerobic digester: effect of mesophillic condition on methane generation

Poultry industry is one of the important growing poultry Industry of Pakistan, the pollution produced due to this causing serious environmental threats such as aquatic life disturbance, air, water and land pollution, pathogen contamination, bad odor, soil contamination and ammonia evaporation. This research study deals with utilization of poultry manure (PM) and buffalo dung (BD) for methane generation and enhance the generation through optimization of substrate mixing ratio and observe the effect of mesophillic condition on methane generation. The PM and BD were biochemically treated by anaerobic digestion. The mixing of P.M and B.D were carried out in ratio 3/1, 1/3 and 1/1 in 500 ml glass bottles acting as bio-reactor. The PM and BD alone were also used in different bioreactor. All the digesters have retention time of 65 days and operated at temperature of 37oC. Each digester distilled water and substrates were used in 1:1 ratio. All the digesters were operated by batch wise process. The generation of biogas from experimental work was maximum from 1:3 of P.M and B.D yield 561 Nml/gm.vs. The methane generation was also maximum in digester containing one part of P.M and three part of buffalo dung the methane generation was also maximum 66 %containing 32 % carbon dioxide. From this study we conclude that biochemical treatment of substrates mixed together in different ratios produces large quantity, quality, higher biodegradability and effective volatile solid removal from substrate