solid waste disposal and management

1. - Neeraja A

2.  Solid wastes are the wastes arising from
human and animal activities, that are
normally solid and that are discarded as
useless or unwanted materials

3.  Solid wasted include crockery, bottles,
plastics, and other wastes thrown out as
garbage.
 Old Automobile spares, machines, etc,.
 Building material wastes, settled solid
components of sewage, dead animals,
chemicals, paints from industries and crop
residue from agriculture, pathogenic
materials from hospitals, etc,.

4. SOURCES QUANTITY [Mt/annum]
Municipal wastes 25-39
Agricultural residues 350
Cattle manure 210
Poultry manure 3.3
Out of 30 Mt/annum of municipal wastes, 8.5 Mt/annum comes
out from nine metropolitan cities only. About 60-80% of these
wastes are collectes on daily basis and rest is left to deacy.

6. SOLID WATES
SANITARY
LANDFILL
INCINERATION COMPOSTING RECYCLING

7.  A sanitary landfill is designed to reduce the
amount of waste that leaks out in the
environment.
 The landfill is lined with clay to prevent
leaching, methane produced by rotting of
garbage in the dump may need to be
vented to prevent possible fire or
explosion.
 The methane thus collected is used for
electricity production.
 The water leaching must be treated before
reaching ground water.

9.  Composting is a common practice of solid
waste disposal in rural areas for the
production of manure and biogas.
 Composting is a process biological degradation
or breakdown of organic matter under aerobic
conditions.
 The organic compost resulting from this
process makes a nutrient rich soil amendment
that aids water retention, slow soil erosion
and improves crop yeilds.

11.  The most quick & convenient method.
 It reduces the amount of wastes that goes to
the landfill,
 They can also generate electricity from the
heat generated by burning the garbage.
 They are designed to burn thousands of
tonnes of wastes per day.
 However, it causes pollution adding fly ash,
particulates and gases.
 Wastes do not completely burn even at high
temp (1,300°C). The residues are taken to
landfill or sea to dispose.

13.  Recycling of wastes helps in reducing
pollution.
 The materials that can be recycled collecte
from the wastes are paper, cloth, metals,
glass, rubber & plastics.
 Other recyclable materials are cars,
electronic goods such as computers, etc.

15.  Any discarded material containing substances
known to be toxic, carcinogenic, mutagenic
or teratogenic to humans or other life forms;
ignitable, explosive, or highly reactive is
called hazardous wastes.
 The wastes containing certain chemicals,
metals and pathogenic organismsare also
hazardous in nature.
 These can damage the environment as well
as endanger life at low cocentrations.

17.  Hazardous waste management costs heavily
therefore waste reduction should be
incorported.
1. Toxic substances should be replaced by
non-toxic substances.
2. Transferring the waste to some other
industry where they can be utilized in some
other ways.
3. Substituting the raw materials.
4. Recycling and reprocessing.

18. 1) Thermal treatment
2) Chemical treatment
3) Physical treatment
4) Biological treatment

19.  Wastes must be heated to about 1200ºC for a
sufficient period to complete destruction.
 The ash resulting is reduced in volume upto
90% and the rest is stored in a landfill.
 Plenty of oxygen is added for quick and
complete burn.
 Gaseous hydrocarbons are not consumed in
the incinerator.
 Scrubbers and precipitators remove minerals,
particulate and other pollutants from the
stack.

20.  Chemical treatment can transform toxic
substances to non-toxic substances.
 Neutralization, removal of metals/halogens
& oxidation are few chemical processes.
 Neutralization is followed in treating acidic
or alkaline wastes.
 Acidic wastes is neutralized by slaked lime
Ca(OH)2, caustic soda (NaOH) or soda ash
(Na2CO3).
 Alkaline wastes are neutralized by mineral
acid. eg. H2SO4 or HCl or with CO2.

21.  Removal of metals is done by ion exchange,
membrane technique, reverse osmosis,
electrodialysis, activated carbon absorption
& precipitation.

22.  Physical treatments tie up or isolate
substances.
 Charcoal or resins filters absorb toxins.
 Distillation separates hazardous components
from aqueous solutions.
 Precipitation and immobilization in ceramics,
glass, or cement isolate toxins from the
environment.

23.  Specific bacterial strains capable of
degrading the wastes breaking down into CO2
& water are used.
 By using recombinant DNA technology new
microorganisms could be developed to feed
on specific hazardous wastes.

25.  Finally after treatment the hazardous wastes
are disposed by the following methods.
1. Landfilling
2. Incineration
3. Deep well injection

26. Guidelines:
 The site must be located higher than 100
year flood plain.
 Impermeable lines be installed to collect the
leachates.
 Any leachate that is collected should be
pumped out and treated.
 Monitoring wells are required to check the
quality of ground waters in the area.

27. Common wastes which can be disposed are:
 Sludge from cyanide bearing wastes,
 Sludge from phenol treatment,
 Heavy metal containing wastes,
 Ash from various treatment categories of
wastes,
 Discarded containers.

28.  A high temperature thermal oxidation, which
converts wastes into gases and combustible
substances.
 This method is used to dispose combustible
liquids and solid hazardous wastes and
pesticides and petroleum refineries wastes.
 It destroys pathogens & decomposes organic
compounds into CO2, H2O, etc.,
 This process is adopted for wastes that
cannot be recycled or reused.

29.  Developed in late 1800’s.
 A specific kind of geological formation must
be needed for disposal.
 The formation must be deep, providing space
& sandwiched between impermeable layers
of rock.
 This method is very expensive and risky,
hence not followed in routine practice.

32.  Biomedical wastes are wastes which are
generated during diagnosis, treatment or
immunization or in the research and testing
biologicals.
 Hospital wastes are needles, syringes,
surgical gloves, bottles, blood and body
fluid, placenta and other body parts,
radioactive substances, cytotoxic drugs,
chemicals, etc.,

33.  AIDS,
 Hepatitis,
 Meningitis,
 Gastroenteric, respiratory, ocular, genital &
skin infections
 Anthrax, etc.,

34.  The wastes are disposed by burning it in
incinerator at 1200ºC .
 Other methods by using autoclave,
microwave, hydro wave, etc.,
 Wastes burnt below 1200ºC release toxic
pollutants like dioxins, furans which are
carcinogenic & suppress immune and
reproductive systems

35.  Launching mass awareness campaign through
electronic and print media to inform clinics
and dispensaries to undertake proper
management of biomedical wastes.
 Training of staffs towards proper segregation
of biomedical wastes is also necessary.