Comparative toxicity of an effluent from a chlor-alkali industry and HgCl2
Release of waste waters from industries severely affect aquatic flora and fauna. Effluents from industries involved in the production of pesticides, or from industries utilizing toxic substances in their production processes are of particular concern. One such industry, the chlor-alkali industry, utilizes mercury as a cathode in an electrolytic process. The present study reports the toxicity assessment of the effluent from a chlor-alkali factor, Jayshree Chemicals Ltd., Ganjam, Orissa. The reported production capacity of the plant is 50 tons of NaOH per day. The effluent discharged, 50,000 1 per day, contains mercury ranging up to 1.5 mg/l, much more than the permissible limit of 0.01 mg/l set by the Central Board for the Prevention and Control of Water Pollution, India. The effluent enters the Rushikulya River Estuary and finally the Bay of Bengal. This paper was also designed to determine whether the mercury present in the effluent was toxic or whether the toxicity involved some other parameters of the effluent as well.
The ABC's of Pollutant Bioassay Using Fish
This is a recommended method for tests of acute toxicity of pollutants to fish. Improved procedures are recommended: chiefly, more frequent observations of mortality and simple statistical treatment. The four-day lethal concentration or the lethal threshold concentration should be used as the final expression of the test result. Toxicity curves should be constructed as the experiment progresses, for the information of the investigator. Tests should provide at least two liters, and preferably three liters of test water per gram of fish per day, whether the test is static or continuous-flow. Tests should not be aerated. Standard species such as rainbow trout are recommended. Effects of mixtures should be assessed by adding toxicant concentrations which have been expressed as fractions of the lethal concentration. Some suggestions are made for using the standard bioassay technique in experiments on sublethal and chronic effects.
Techno-economic analysis of chemical looping combustion with humid air turbine power cycle
Abstract Power generation from fossil fuel-fired power plant is the largest single source of CO2 emission. CO2 emission contributes to climate change. On the other hand, renewable energy is hindered by complex constraints in dealing with large scale application and high price. Power generation from fossil fuels with CO2 capture is therefore necessary to meet the increasing energy demand, and reduce the emission of CO2. This paper presents a process simulation and economic analysis of the chemical looping combustion (CLC) integrated with humid air turbine (HAT) cycle for natural gas-fired power plant with CO2 capture. The study shows that the CLC–HAT including CO2 capture has a thermal efficiency of 57% at oxidizing temperature of 1200 °C and reducer inlet temperature of 530 °C. The economic evaluation shows that the 50 MWth plant with a projected lifetime of 30 years will have a payback period of 7 years and 6 years for conventional HAT and CLC–HAT cycles respectively. The analysis indicates that CLC–HAT process has a high potential to be commercialised.