Introduction • What Are Waste ? “ 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 the law” • Disposal means “Any operation which may lead to resource recovery, recycling, reclamation, direct re-use or alternative uses.”
Waste management • Waste management is the collection, transport, processing, recycling or disposal and monitoring of waste materials. • Waste management is also carried out to recover resources from it. • It involve solid, liquid, gaseous or radioactive substances with different methods and fields.
Kinds of Wastes • Solid wastes: wastes in solid forms, domestic, commercial and industrial wastes Examples: plastics , bottles, cans, papers, scrap iron, and other trash • Liquid Wastes: wastes in liquid form Examples: domestic washings, chemicals, oils, waste water from ponds, manufacturing industries and other sources. • Bio-degradable :can be degraded (paper, wood, fruits and others) • Non-biodegradable : cannot be degraded (plastics, bottles, old machines, cans, Styrofoam containers and others)
Conti … • Hazardous wastes: Substances unsafe to use commercially, industrially, agriculturally, or economically and have any of the following properties- ignitability, corrosivity, reactivity & toxicity. Eg. battery ,alcohol ,poisonous substances . • Non-hazardous : Substances safe to use commercially, industrially, agriculturally, or economically and do not have any of those properties mentioned above. These substances usually create disposal problems.
CLASSIFICATION OF WASTES • Domestic wastes - Eg) paper, plastic ,glass, ceramics, vegetable wastes • Commercial wastes - Eg) printer paper, meat remnants • Ashes - Eg) coal, wood and coke - Open burning of wastes also generates ashes • Animal Wastes -Eg)dung of animals - rejected feed
Biomedical Wastes - E.g) expired drugs, plastic syringes, surgical dressings Construction Wastes - E.g)metal rods, bricks, cement, concrete, roofing materials- digging activities E.g) telephone, electricity, drainage Industrial Solid Wastes -E.g)garment factory would dump textiles of various kinds Sewer -removed from sewerage -left on the roadside
Hazardous wastes - potentially dangerous- react explosively with air or water- Change in the genetic structure of individuals E-Waste- electronics disposed (E.g.) Secondary computers, electronics, mobile phones, television sets & refrigerator Nuclear waste - containing radioactive material- product of a nuclear fission
Effects of waste If not managed • Affects our health • Affects our socio-economic conditions • Affects our coastal and marine environment • Affects our climate • Rise in global temperatures ‘ • Rise in sea levels
WASTE MANAGEMENT Wastemanagementisthe • Storage • Collection • Transportandhandling • Recycling • Disposalandmonitoringofwastematerials.
Storage: • Galvanizedsteeldustbin with close fitting cover is a suitable receptacle for storing refuse. • In recent innovation western countries using Papersack. refuse stored in the paper sack, and the sack itself is removed with the contents of disposal. • Publicbins: • They are usually uncovered in India. • They are kept on a concrete platform raised 2 to 3 inches above ground level
Wastehandlingandseparationinvolvesactivitiesassociatedwithwastemanagementuntilthewasteisplacedinstoragecontainersforcollection.Handlingalsoencompassesthemovementofloadedcontainerstothepointofcollection.Wastehandlingandseparationinvolvesactivitiesassociatedwithwastemanagementuntilthewasteisplacedinstoragecontainersforcollection.Handlingalsoencompassesthemovementofloadedcontainerstothepointofcollection. • wasteistransferredfromasmallercollectionvehicletolargertransportequipment
Recyclingreferstothecollectionandrefuseofwastematerialssuchasemptybeveragecontainer.Recyclingreferstothecollectionandrefuseofwastematerialssuchasemptybeveragecontainer. • Thematerialsfromwhichtheitemsaremadecanbeprocessedintonewproducts. • Materialsforrecyclingmaybecollected • separatelyfromgeneralwasteusingdedicatedbins.
Method of disposal • Dumping • ControlledTippingorSanitaryLandfill • Burial • Incineration • Composting • Vermi composting • Biogas • Manurepits
DUMPING Refuse is dumped in low lying areas partly as a method of reclamation of land but mainly as an easy method of disposal of dry refuse. As a result of bacterial action, refuse decreases considerably in volume and is converted gradually into humus.
Drawbacks of open dumping • The refuse is exposed to flies and rodents • It is a source of nuisance from the smell and rodents • It is a source of nuisance from the smell and unsightly appearance. • The loose refuse is dispersed by the action of the wind
CONTROLLEDTIPPINGANDSANITARYLANDFILL • It is the most traditional method of waste disposal. • Waste is directly dumped into disused quarries, mining voids or borrow pits. • Disposed waste is compacted and covered with soil • Gases generated by the decomposing waste materials are often burnt to generate power. • It is generally used for domestic waste..
Three methods are used in this operation : • The trench method • The ramp method • The area method
TRENCHMETHOD • Where level ground is available, the trench method is usually chosen. A long trench is dug out • - 2 to 3 m (6-10 ft.) deep and 4 to 12 m, (12-36 ft.) wide, depending upon local conditions. The refuse is compacted and covered with excavated earth, it is estimated that one acre of land per year will be required for 10,000 population.
AREAMETHOD • This method is used for filling land depressions, disused quarries and clay pits. The refuse is deposited, packed and consolidated in uniform layers up to 2 to 2.5 m (6-8 ft.) deep. Each layer is sealed on its exposed surface with a mud cover at least 30 cm (12 inches) thick. Such sealing prevents infestation by flies and rodents and suppresses the nuisance of smell and dust. This method often has the disadvantage of requiring supplemental earth from outside sources.
BURIAL • This method is suitable for small camps. • A trench 1.5 m wide and 2 m deep is excavated, and at the end of each day the refuse is covered with 20 to 30 cm of earth. When the level in the trench is 40 cm from ground level, the trench is filled with earth and compacted, and a new trench is dug out. The contents may be taken out after 4 to 6 months and used on the fields. If the trench is 1 m in length for every 200 persons, it will be filled in about one week
INCINERATION • Incineration is a waste treatment process that involves the combustion of solid waste at 1000C. • Waste materials are converted into ash, flue gas, and heat. • The ash is mostly formed by the inorganic constituents of the waste and gases due to organic waste. • The heat generated by incineration is used to generate electric power.
COMPOSTING • Composting is a method of combined disposal of refuse and nightsoil or sludge. It is a process of nature whereby organic matter breaks down under bacterial action resulting in the formation of relatively stable humus-like material, called the compost which has considerable manurial value for the soil.
MANUREPITS • In rural areas in India, there is no system for collection and disposal of refuse. • Refuse is thrown around the houses indiscriminately resulting in gross pollution of the soil. The garbage, cattle dung, straw, and leaves should be dumped into the manure pits and covered with earth after each day's dumping. Two such pits will be needed, when one is closed, the other will be in use. In 5 to 6 month's time, the refuse is converted into manure which can be returned to the field. This method of refuse disposal is effective and relatively simple in rural communities.
Conclusion • Waste disposal takes many forms including direct discharge to land or water, and sludge disposal. • Such wastes need to be managed in such a way that the adverse effects are minimized to protect the environment and human health.
Evaluation • Which are the kinds of waste ? • What are the diiferent methods of disposal of community waste?