Pollution may be defined as any condition in which certain substances are present in such concentrations that they can produce undesirable effects or changes in physical, chemical, biological, radiological properties of air, water, soil. Such substances are called pollutants. The primary air pollutants are those that are emitted directly from the source, which include particulate matter like ash, smoke, dust, fumes, mist, spray and inorg. Gases like SO2, H2S, NO, NH3, CO, HF and olefins, aromatic hydrocarbons, radioactive compound. The secondary air pollutants are those that are formed by the interactions of primary pollutants and normal atm. constituents. These include SO3, NO2, PAN, ozone, aldehydes, ketones, sulphates and nitrate salts. The problem of water pollution due to discharge of domestic and industrial wastes into aquatic systems has already become a serious problem in the country. The water pollutants are classified into oxygen demanding wastes, disease causing agents, synthetic org. compounds, plant nutrients, inorg. chemicals & minerals, sediments, radioactive substances, thermal discharges, oils.
[...] The gas close to the negative electrode is, thus, ionized upon passing through the discharge. As the negative ions and electrons migrate towards the grounded surface, they in turn charge the passing particles. The electrostatic field then draws the particles to the collector surface where they are deposited. For industrial applications, vertical plates exposed to horizontal gas flow are normally used. Advantages Disadvantages 1. Press. Drop & power Relatively high initial cost and requirements is large space small compared to other devices; requirement. [...]
[...] It involves the transfer of the pollutant from gas phase to the liquid phase across the interface in response to a concentration gradient, with the concentration decreasing in the direction of mass transfer. Selection of scrubbing medium mainly depends on: high gas solubility and high selectivity between solute species, low vapor pressure, non corrosiveness, easy regeneration and recovery, low costs, low viscosity at absorption temperature, non toxicity, non flammability, and chemical stability, it should not cause the water pollution or waste disposal problems. [...]
[...] The quality standards usually depend on whether water will be reused or discharged into receiving stream the effluents treatment methods depends on the composition, concentration, condition and specifications of the effluent. LITURATUR REVIEW: Anaerobic treatment of dairy wastewaters, Burak Demirel, Orhan Yenigun and Turgut T. Onay Thermophilic aerobic biological wastewater treatment, Timothy M. LaPara and James E. Alleman. The advantages of this technology include rapid biodegradation rates, low sludge yields, and excellent process stability. Use of Absorbers Based on Starch for the Effluent Treatment of Dyeing Liquors, Axel Nechwatal , Monika Nicolai, Klaus-Peter Mieck Commercial supercritical water oxidation sludge processing, James W. [...]
[...] The principle requirements of a biological waste treatment process are an adequate amount of bacteria, oxygen, and some means of achieving contact between the bacteria and the organics. Two methods commonly used are activated sludge process and biological film system. Activated sludge process: the essential features of the process are: an aeration stage, solids-liquid separation following aeration, and a sludge recycle system. Wastewater after primary treatment enters an aeration tank where the organic matter is brought into intimae contact with sludge from the secondary clarifier. [...]
[...] Secondary treatment (biological), commonly used systems for treatment are activated sludge process, trickling filters. Advanced waste treatment: Removal of suspended Removal of dissolved solid: solids: Micro straining Adsorption on activated C Coagulation & filtration Solvent extraction Ion exchange Reverse osmosis Eletrodialysis THEORY: GASEOUS EFFLUENT TREATMENT: The cleaning techniques are applied to those cases where emissions of pollutants cannot be prevented and pollution control equipment is necessary to remove them from the main gas stream. Particulate matter emitted in gaseous streams consists of discrete and minute suspended particles. [...]
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