Presentation on theme: "ERT 319/3 INDUSTRIAL WASTE TREATMENT SEM 1 (2012/2013 )"— Presentation transcript:
ERT 319/3 INDUSTRIAL WASTE TREATMENT SEM 1 (2012/2013 )
Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal, article 2 WASTE ? (Nemerow and Agardy, 1998) "Wastes" are substances or objects which are disposed of or are intended to be disposed of or are required to be disposed of by the provisions of national law. The goal of effective industrial waste treatment is directed towards the removal of all contaminants that adversely impact the water as well as air and land environments.
History of waste treatment & disposal Population moved away from disperse geographical areas to congregate together communities need proper waste handling 500 BC ( Athens) - law for banning the throwing of rubbish into the streets, apply open dump Industrial revolution increased industrial & domestic waste legislation was introduced. (more info on history: refer “Waste Treatment and Disposal, 2 nd Edition, Paul T. Williams”) In Malaysia; National Environmental Policy (2002), run by Department of Environment Malaysia (DOE)
Covers the mechanisms and processes used to treat waters that have been contaminated in some way by anthropogenic industrial or commercial activities prior to its release into the environment or its re-use. Most industries produce some wet waste although recent trends in the developed world have been to minimize such production or recycle such waste within the production process. However, many industries remain dependent on processes that produce wastewaters.
Impurities in ww are mainly due to the presence of solids in the water. The solids may be organic or inorganics in nature and may be present in suspended, colloidal, dissolved or in the various forms of their combinations. The prescribed limit or acceptable level of concentration of impurities or pollutants is laid down by the local authoroties such as Jabatan Alam Sekitar. The final discharge of ww will normally be either into the body of water or onto the land. The receiving bodies of water may be streams, lakes, ponds, canals, rivers, seas etc. Fundamentals of Wastewater Any liquid that contains impurities or pollutants in the form of solids or gasses or their combinations in such a concentration that is harmful if disposed into the environment WASTEWATER
CONCEPT OF TREATMENT The partial complete removal of excessive impurities present in wastewater. WASTEWATER TREATMENT The excessive impurities imply to the constituent (s) concentration(s) that is more than the acceptable level(s) for final or suitable reuse of treated wastewater. If the objective is to simply dispose of the final effluent into the body of water (receiving streams) or onto the land, the conc of specific constituents is reduced only up to acceptable limits prescribed by the local authorities Depends on the intended level of treatment
TYPES OF WASTEWATER Domestic Wastewater Industrial Wastewater Used water which has been discharged from the residential. The composition of WW depends on the source of its generation WW Generated by large & medium scale industries. Vary in quantity & quality from industry to industry and process to process for the same industry Contains organics & inorganics solids & microorganism (bacteria) Also known as municipal WW. Contains organics & inorganics solids & microorganism (bacteria)
Waste treatment & disposal In general, the first step in minimizing the effects of industrial wastes on receiving streams may be accomplished by: STEP 1 : VOLUME REDUCTION In general, the first step in minimizing the effects of industrial wastes on receiving streams and treatment plants is to reduce the volume of such wastes. This may be accomplished by: Reusing both industrial and municipal effluents as raw water supplies Changing production to decrease waster Conserving wastewater Classifying wastes
If wastes are classified so that manufacturing-process waters are separated from cooling waters, the volume of water requiring intensive treatment may be reduced considerably. Waste from manufacturing processes: Example: Water discharged from dyeing and washing of textile fabrics. Water used as cooling agents in industrial processes: Example: Cooling waters (CW) have been found to be contaminated by small leaks, corrosion products or the effect of heat. However, CW for power plant may contain hazardous contaminants. Sometimes it is possible to classify and separate the process waters themselves so that only the most polluted ones are treated and the relatively uncontaminated ones are discharged without treatment. Classification of Wastes
Water conservation is waste saved. Example: 1)Steel mills reuse CW to quench ingots 2)Coal processes reuse water to remove dirt and other noncombustible materials from coal. Concentrated recycled wastewaters are often treated at the end of their period of usefulness, because usually it is impractical and uneconomical to treat the wastewaters as they complete each cycle. The savings are twofold: Water costs and waste-treatment costs are lower. Conservation of Wastewater
Changing production to decrease wastes is an effective method of controlling the volume of wastes but is difficult to put into practice. It is hard to persuade plant managers to change their operations just to eliminate wastes. Normally, the operational phase of engineering is planned by the chemical, mechanical, or industrial engineer whose primary objective is cost savings. The main considerations of the environmental engineer, on the other hand, include the protection of public health and the conservation Changing Production to Decrease Wastes
Practiced mainly in areas where water is scarce or expensive, reusing industrial and municipal effluents for raw water supplies is proving a popular and economical method of conservation. Although there are many problems involved in reusing effluents for raw water supply, it must be remembered that any water supply poses problems to cities and industries. Because the problems of reusing sewage effluents are similar to those of reusing industrial effluents. Reusing Both Industrial and Municipal Effluents for Raw Water Supplies
Waste strength reduction is the second major objective for an industrial plant concerned with waste treatment. Any effort to find means of reducing the total pounds of polluting matter in industrial wastes will be well rewarded by the savings earned by reduced requirements for waste treatment. The strength of wastes may be reduced by few methods such as: (1) process changes (2) equipment modifications (3) segregation of wastes (4) by-product recovery STEP 2: Contaminant Concentration Reduction
Example: In Malaysia, – Environmental Quality (Industrial Effluent) Regulations 2009 – Environmental Quality (Clean Air) Regulations 1978 – Environmental Quality (Control of pollution from solid waste transfer and landfill) Regulations 2009 – Environmental Quality (Refrigerant Management) Regulations 1999 – etc. FOR MORE INFO, Legislation
Example: treatment of waste (sludge) through landfilling – comply with Environmental Quality (Control of pollution from solid waste transfer and landfill) Regulations Treatment of scheduled waste – comply with Environmental Quality (Scheduled waste treatment and disposal facilities ) Regulations 1989
The economics of waste treatment process In some countries (mostly EU) – taxes for landfill and incineration. Encourage the development of cleaner, lower waste producing process; go for recycle Each treatment process posed different economic effect e.g. landfilling’s operating cost is cheaper than incineration. However, incineration produces heat, power or steam (energy). But it also produce hazardous residue, requires expensive special landfill. Need to consider environmental and economics.