SOLID WASTE DISPOSAL AND

HOSPITAL WASTE

MANAGEMENTDr. Sakshi kaur Chhabra2nd year post graduateDepartment of Public health dentistry

SOLID WASTE DISPOSAL1. Introduction2. Sources of refuse3. Methods of disposal4. Public education and international cooperation HOSPITAL WASTE MANAGEMENT1. Introduction2. Definition3. Classification of health care waste4. Sources of health care waste5. Health hazards of health care waste6. Treatment and disposal technologies7. Biomedical waste in india

SOLID WASTE DISPOSAL

Disposal of wastes is now largely the domain of sanitarians and public health engineers. However, health professionals need to have a basic knowledge of the subject since improper disposal of wastes constitutes a health hazard.

The term "solid wastes" includes garbage (food wastes) rubbish (paper, plastics, wood, metal, throw-away containers, glass), demolition products (bricks, masonry, pipes), sewage treatment residue (sludge and solids from the coarse screening of domestic sewage), dead animals, manure and other discarded material. Strictly speaking it should not contain nightsoil.

The per capita daily solid waste produced ranges between 0.25 to 2.5 kg in different countries.

Solid waste, if allowed to accumulate, is a health hazard because:-

a. it decomposes and favours fly breeding.

b. it attracts rodents and vermin.

c. the pathogens which may be present in the solid waste may be conveyed back to man's

food through flies and dust.

d. there is a possibility of water and soil pollution.

There is a correlation between improper disposal of solid wastes and incidence of vector-borne diseases. Therefore, in all civilized countries, there is an efficient system for its periodic collection, removal and final disposal without risk to health.

Sources of refuse

1. Street refuse

2. Market refuse

3. Stable utter refuse

4. Industrial refuse

5. Domestic refuse

The principal methods of refuse disposal are :-

(a) Dumping

(b) Controlled tipping or sanitary land-fill

(c) Incineration

(d) Composting

(e) Manure pits

(f) Burial

METHODS OF DISPOSAL

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. Kolkata disposes of its refuse by dumping and the reclaimed land is leased out for cultivation.

[a] DUMPING

The drawbacks of open dumping are :

(1) The refuse is exposed to flies and rodents.

(2) It is a source of nuisance from the smell and unsightly appearance.

(3) The loose refuse is dispersed by the action of the wind.

(4) Drainage from dumps contributes to the pollution of surface and ground water.

A WHO Expert Committee (1967) condemned dumping as "a most insanitary method that creates public health hazards, a nuisance, and severe pollution of the environment". Dumping should be outlawed and replaced by sound procedures

Controlled tipping or sanitary landfill is the most satisfactory method of refuse disposal where suitable land is available. It differs from ordinary dumping in that the material is placed in a trench or other prepared area, adequately compacted, and covered with earth at the end of the working day. The term "modified sanitary landfill"' has been applied to those operations where compaction and covering are accomplished once or twice a week.

Three methods are used in this operation :

1. The trench method

2. The ramp method

3. The area method

[b] CONTROLLED TIPPING AND SANITARY LANDFILL

[1] TRENCH METHOD -

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. Where compacted refuse is placed in the fill to a depth of 2 m (6 ft.), it is estimated that one acre of land per year will be required for 10,000 population.

[2] RAMP METHOD -

This method is well suited where the terrain is moderately sloping. Some excavation is done to secure the covering material.

[3] AREA METHOD -

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.

Refuse can be disposed of hygienically by burning or incineration. It is the method of choice where suitable land is not available. Hospital refuse which is particularly dangerous is best disposed of by incineration. Incineration is practised in several of the industrialized countries, particularly in large cities due to lack of suitable land. Incineration is not a popular method in India because the refuse contains a fair proportion of fine ash which makes the burning difficult.

A preliminary separation of dust or ash is needed. All this involves heavy outlay and expenditure, besides manipulative difficulties in the incinerator. Further, disposal of refuse by burning is a loss to the community in terms of the much needed manure. Burning, therefore, has a limited application in refuse disposal in India.

[C] INCINERATION

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.

The principal by-products are carbon dioxide, water and heat. The heat produced during composting – 60 degree C or higher, over a period of several days- destroys eggs and larvae of flies, weed seeds and pathogenic agents. The end-product -compost - contains few or no disease producing organisms, and is a good soil builder containing small amounts of the major plant nutrients such as nitrates and phosphates.

[D] COMPOSTING

The following methods of composting are now used :

(1) Bangalore method (Anaerobic method)

(2) Mechanical composting (Aerobic method)

[1] Bangalore method or hot fermentation process - As a result of investigations carried out under the auspices of the Indian Council of Agricultural Research at the Indian Institute of Science, Bangalore, a system of anaerobic composting, known as Bangalore method (hot fermentation process) has been developed. It has been recommended as a satisfactory method of disposal of town wastes and nightsoil.

Trenches are dug 90 cm (3 ft.) deep, 1.5 to 2.5 m (5-8 ft.) broad and 4.5 to 10 m (15-30 ft.) long, depending upon the amount of refuse and nightsoil to be disposed of. Depths greater than 90 cm (3 ft.) are not recommended because of slow decomposition. The pits should be located not less than 800 m (1/2 mile) from city limits

The composting procedure is as follows :

1. First a layer of refuse about 15 cm (6 in) thick is spread at the bottom of the trench. Over this, nightsoil is added corresponding to a thickness of 5 cm (2 in).

2. Then alternate layers of refuse and nightsoil are added in the proportion of 15 cm (6 in) and 5 cm (2 in) respectively, till the heap rises to 30 cm (1 ft.) above the ground level. The top layer should be of refuse, at least 25 cm (9 in) thickness. Then the heap is covered with excavated earth. If properly laid, a man's legs will not sink when walking over the compost mass .

Within 7 days as a result of bacterial action considerable heat (over 60 deg.C) is generated in the compost mass. This intense heat which persists over 2 or 3 weeks, serves to decompose the refuse and nightsoil and to destroy all pathogenic and parasitic organisms. At the end of 4 to 6 months, decomposition is complete and the resulting manure is a well decomposed, odourless, innocuous material of high manurial value ready for application to the land.

[2] MECHANICAL COMPOSTING – Another method of composting known as 'Mechanical composting' is becoming popular. In this, compost is literally manufactured on a large scale by processing raw materials and

Turning out a finished product. The refuse is first cleared of salvageable materials such as rags, bones, metal, glass and items which are likely to interfere with the grinding operation.

It is then pulverised in a pulverising equipment in order to reduce the size of particles to less than 2 inches. The pulverised refuse is then mixed with sewage, sludge or nightsoil in a rotating machine and incubated. The factors which are controlled in the operation are a certain carbon-nitrogen ratio, temperature, moisture. pH and aeration.

The entire process of composting is complete in 4 to 6 weeks. This method of composting is in vogue in some of the developed countries, e.g., Holland, Germany, Switzerland, Israel. The Government of India is considering the installation of mechanical composting plants in selected cities. Cities such as Delhi, Nagpur, Mumbai, Chennai, Pune, Allahabad, Hyderabad, Lucknow and Kanpur have offered to join the Government for setting up pilot plants for mechanical composting.

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 problem of refuse disposal in rural areas can be solved by digging 'manure pits' by the individual householders. 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.

[E] MANURE PITS

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

[F] BURIAL

Refuse disposal cannot be solved without public education. People have very little interest in cleanliness outside their homes.

Many municipalities and corporations usually look for the cheapest solution, especially in regard to refuse disposal. What is needed is public education on these matters, by all known methods of health education, viz., pamphlets, newspapers, broadcasting, films etc. Police enforcement of the laws may also be needed at times.

PUBLIC EDUCATION

An organization was formed - the International Solid Wastes and Public Cleansing Association (ISWA) in 1970. to assist countries in the general endeavour to improve sanitary services. A WHO International Reference Centre has also been set up in Switzerland to collect, evaluate and disseminate information z n wastes-disposal practices and to foster research

INTERNATIONAL COOPERATION

HOSPITAL WASTE MANAGEMENT INTRODUCTIONThe waste produced in the course of health-care activities carries a higher potential for infection and injury than any other type of waste. Therefore, it is essential to have safe and reliable method for its handling. Inadequate and inappropriate handling of health-care waste may have serious public health consequences and a significant impact on the environment. Appropriate management of health-care waste is thus a crucial component of environmental health protection, and it should become an integral feature of health-care services.

DEFINITION According to Bio-Medical Waste (Management and Handling) Rules, 1998 of India, "Bio-

medical waste" means any waste, which is generated during the diagnosis, treatment or immunization of human beings or animals or in research activities pertaining thereto or in the production or testing of biologicals.

SOURCES OF HEALTH CARE WASTE The institutions involved in generation of bio-medical waste are : - Government hospitals - Laboratories - Private hospitals - Research organizations - Nursing homes - Vaccinating centres - Physician's office/clinics - Biotechnologies institutions - Dentist's office/clinics - Blood banks - Dispensaries - Primary health centres - Medical research and training establishments - Animal houses - Slaughter houses

All these health-care establishments generate waste and are therefore covered under Bio-Medical Waste (BMW) Rules.

HEALTH HAZARDS OF HEALTH CARE WASTE Exposure to hazardous health-care waste can result in disease or injury due to one or more of

the following characteristics :

(a) it contains infectious agents

(b) it contains toxic or hazardous chemicals

(c) it contains sharps

(d) it is genotoxic

(e) it is radio-active. All individuals exposed to such hazardous health-care waste are potentially at risk, including

those who generate the waste or those who either handle such waste or are exposed to it as a consequence of careless management.

The main groups at risk are : medical doctors, nurses, health-care auxiliaries, and hospital maintenance personnel etc.

[1] HAZARDS FROM INFECTIOUS WASTE AND SHARPS Pathogens in infectious waste may enter the human body through a puncture, abrasion or cut

in the skin, through mucous membranes by Inhalation or by Ingestion. There is particular concern about infection with HIV and hepatitis virus B and C, for which there is a strong evidence of transmission via health-care waste. Bacterias resistant to antibiotics and chemical disinfectants, may also contribute to the hazards created by poorly managed waste.

[2] HAZARDS FROM CHEMICAL AND PHARMACEUTICAL WASTE Many of the chemicals and pharmaceuticals used in health-care establishments are toxic,

genotoxic, corrosive, flammable, reactive, explosive or shock-sensitive. Although present in small quantity they may cause intoxication, either by acute or chronic exposure, and injuries, including burns. Disinfectants are particularly important members of this group. They are used in large quantities and are often corrosive, reactive chemicals may form highly toxic secondary compounds.

[3] HAZARD FROM GENOTOXIC WASTE The severity of the hazards for health-care worker responsible for handling or disposal of

genotoxic waste is governed by a combination of the substance toxicity itself and the extent and duration of exposure. Exposure may also occur during the preparation of or treatment with particular drug or chemical. The main pathway of exposure is inhalation of dust or aerosols, absorption through the skin, ingestion of food accidentally contaminated with cytotoxic drugs, chemicals or wastes etc.

[4] HAZARD FROM RADIOACTIVE WASTE The type of disease caused by radioactive waste is determined by the type and extent of

exposure. It can range from headache, dizziness and vomiting to much more serious problems. Because it is genotoxic, it may also affect genetic material.

[5] PUBLIC SENSITIVITY Apart from health hazards, the general public is very sensitive to visual impact of health-care

waste particularly anatomical waste.

TREATMENT AND DISPOSAL TECHNOLOGIES FOR HEALTH CARE WASTE

Incineration, used to be the method of choice for most hazardous health-care wastes, and is

still widely used. However, recently developed alternative treatment methods are becoming

increasingly popular.

1. INCINERATION

2. CHEMICAL DISINFECTION

3. WET AND DRY THERMAL TREATMENT

4. MICROWAVE IRRADIATION

5. LAND DISPOSAL

6. INERTIZATION

[1] INCINERATION Incineration is a high temperature dry oxidation process, that reduces organic and

combustible waste to inorganic incombustible matter and results in a very significant

reduction of waste-volume and weight. The process is usually selected to treat wastes that

cannot be recycled, reused or disposed off in a land fill site.

Characteristics of the waste suitable for incineration are :

(a) low heating volume - above 2000 kcal/kg for single - chamber incinerators, and above 3500

kcal/kg for pryolytic double-chamber incinerators.

(b) content of combustible matter above 60 per cent.

(c) content of noncombustible solids below 5 per cent.

TYPES OF INCINERATORS

Incinerators can range from very basic combustion unit that operates at much lower temperature

to extremely sophisticated, high temperature operating plants. It should be carefully chosen on the

basis of the available resources, the local situation, and the risk- benefit consideration.

Three basic kinds of incineration technology are of interest for treating health-care waste :

(a) Double-chamber pyrolytic incinerators which may be especially designed to burn infectious

health-care waste;

(b) Single-chamber furnaces with static grate, which should be used only if pyrolytic

incinerators are not affordable; and

(c) Rotary kilns operating at high temperatures, capable of causing decomposition of genotoxic

substances and heat-resistant chemicals.

[2] CHEMICAL DISINFECTION Chemicals are added to waste to kill or inactivate the pathogens it contains, this treatment

usually results in disinfection rather than sterilization. Chemical disinfection is most suitable

for treating liquid waste such as blood, urine, stools or hospital sewage. However, solid

wastes including microbiological cultures, sharps etc. may also be disinfected chemically

with certain limitations.

[3] WET AND DRY THERMAL TREATMENT

WET THERMAL TREATMENT Wet thermal treatment or steam disinfection is based on exposure of shredded infectious waste to high temperature, high pressure steam, and is similar to the autoclave sterilization process. The process is inappropriate for the treatment of anatomical waste and animal carcassess, and will not efficiently treat chemical and pharmaceutical waste.

SCREW-FEED TECHNOLOGY Screw-feed technology is the basis of a non-burn, dry thermal disinfection process in which waste is shredded and heated in a rotating auger. The waste is reduced by 80 per cent in volume and by 20-35 per cent in weight. This process is suitable for treating infectious waste and sharps, but it should not be used to process pathological, cytotoxic or radioactive waste.

[4]MICROWAVE IRRADIATION Most microorganisms are destroyed by the action of microwave of a frequency of about

2450 MHz and a wave length of 12.24 nm. The water contained within the waste is rapidly heated by the microwaves and the infectious components are destroyed by heat conduction. The efficiency of the microwave disinfection should be checked routinely through bacteriological and virological tests.

[5] LAND DISPOSAL

MUNICIPAL DISPOSAL SITES

If a municipality or medical authority genuinely lacks the means to treat waste b-efore disposal, the use of a land fill has to be regarded as an acceptable disposal route. There are two types of disposal land-open dumps and sanitary landfills. Health-care waste should not be deposited on or around open dumps. The risk of either people or animals coming into contact with infectious pathogens is obvious.

Sanitary landfills are designed to have at least four advantages over open dumps : geological isolation of waste from the environment, appropriate engineering preparation before the site is ready to accept waste, staff present on site to control operations, and organized deposit and daily coverage of waste.

[6] INERTIZATION

The process of "inertization" involves mixing waste with cement and other substances before disposal, in order to minimize the risk of toxic substances contained in the wastes migrating into the surface water or ground water. A typical proportion of the mixture is: 65 per cent pharmaceutical waste, 15 per cent lime, 15 per cent cement and 5 per cent water. A homogeneous mass is formed and cubes or pellets are produced on site and then transported to suitable storage sites.

The United Nations Conference on the Environment and Development (UNCED) in 1992 recommended the following measures :

(a) Prevent and minimize waste production

(b) Reuse or recycle the waste to the extent possible

(c) Treat waste by safe and environmentally sound methods, and

(d) Dispose off the final residue by landfill in confined and carefully designed sites.

TREATMENT/DISPOSAL METHOD

ADVANTAGES DISADVANTAGES

[1] ROTARY KILN Adequate for all infectious waste, most chemical waste and pharmaceutical waste.

High investment and operating costs.

[2] PYROLYTIC INCINERATION

Very high disinfection efficiency. Adequate for all infectious ' waste and most pharmaceutical and chemical waste.

Incomplete destruction of cytotoxics. Relatively high investment and operating costs.

[3] SINGLE CHAMBER INCINERATION

Good disinfection efficiency. Drastic reduction of weight and volume of waste. The residues may be disposed off in landfills. No need for highly trained operators. Relatively low investment and operating costs.

Inefficiency in destroying thermally resistant chemicals and drugs such as cytotoxics.

[4] DRUM OR BRICK INCINERATION

Drastic reduction of weight and volume of the waste. Very low investment and operating costs.

Destroys only 99% of microorganisms.

[5] CHEMICAL DISINFECTION

1. Highly efficient disinfection under good operating conditions.

2. Some chemical disinfectants are relatively inexpensive.

1. Requires highly qualified technicians for operation of the process.

2. Uses hazardous substances that require comprehensive safety measures.

3. Inadequate for pharmaceutical, chemical and some types of infectious waste.

[6] WET THERMAL TREATMENT

1. Environmentally sound. 2. Relatively low investment and operating

costs.

1. Shredders are subject to frequent breakdowns and poor functioning.

2. Operation requires qualified technicians. 3. Inadequate for anatomical,

pharmaceutical, chemical waste and waste that is not readily steam-permeable.

[7] MICROWAVE IRRADIATION

Good disinfection efficiency under appropriate operating conditions.

Relatively high investment and operating costs

[8]INERTIZATION Relatively inexpensive. Not applicable to infectious waste.

BIO – MEDICAL WASTE IN INDIA Bio-Medical Waste (Management and Handling) Rule 1998, prescribed by the Ministry of

Environment and Forests, Government of India, came into force on 28th July 1998. This rule

applies to those who generate, collect, receive, store, dispose, treat or handle bio-medical

waste in any manner. Table 4 shows the categories of bio-medical waste, types of waste and

treatment and disposal options under Rule 1998. The bio-medical waste should be segregated

into containers/bags at the point of generation of the waste.

CATEGORIES OF BIO – MEDICAL WASTE IN INDIA [SCHEDULE-1] OPTION WASTE CATE]GORY TREATMENT AND

DISPOSAL

CATEGORY NO. 1

Human anatomical waste (human tissues, organs, body parts).

incineration / deep burial.

CATEGORY NO. 2

Animal waste (animal tissues, organs, body parts carcasses, bleeding parts, fluids, blood and experimental animals used in research, waste generated by veterinary hospitals colleges, discharge from hospital, animal house).

incineration / deep burial.

CATEGORY NO. 3

Microbiology and biotechnology waste (waste from laboratory cultures, stocks or specimens of micro-organisms, live or attenuated vaccines, human and animal cell culture used in research and infectious agents from research and industrial laboratories, waste from production of biologicals, toxins, dishes and devices and for transfer of cultures).

local autoclaving / microwaving / incineration.

CATEGORY NO. 4

Waste sharps (needles, syringes, scalpels, blades, glass, etc. that may cause puncture and cuts. This includes both used and unused sharps).

disinfection (chemical treatment®/ autoclaving/

microwaving and mutilation shredding).

CATEGORY NO. 5

Discarded medicines and cytotoxic drugs (wastes comprising of outdated, contaminated and discarded medicines).

incineration® destruction and drugs disposal in secured

landfills CATEGORY

NO. 6

CATEGORY NO. 7

Solid waste (Items contaminated with blood, and fluids including cotton, dressings, soiled plaster casts, linen, beddings, other material contaminated with blood).

Solid waste (wastes generated from disposable items other than the waste sharps such as tubings, catheters, intravenous sets etc.).

incineration® autoclaving / microwaving.

disinfection by chemical treatment®® autoclaving/

microwaving and mutilation / shredding ##.

CATEGORY NO. 8

Liquid waste (waste generated from laboratory and washing, cleaning, housekeeping and disinfecting activities).

disinfection by chemical treatment @@ and discharge

into drains.

CATEGORY NO. 9

Incineration ash (ash from incineration of any bio-medical waste).

disposal in municipal landfill.

CATEGORY NO. 10

Chemicals used in production of biologicals, chemicals used in disinfection, as insecticides,

etc.

chemical treatment®® and discharge into drains for liquids and secured landfill for solids.

COLOUR CODING

TYPE OF CONTAINER WASTE CATEGORY TREATMENT OPTIONS AS PER SCHEDULE 1

YELLOW PLASTIC BAG CAT.1, CAT.2 AND CAT.3, CAT.6

Incineration/deep burial

RED DISINFECTED CONTAINER/PLASTIC

BAG

CAT.3, CAT.6, CAT.7 Autoclaving/Microwaving/Chemical treatment

BLUE/WHITE

TRANSLUCENT

PLASTIC BAG/PUNCTURE PROOF CONTAINER

CAT.4, CAT.7 Autoclaving/Microwaving/Chemical treatment and Destruction/Shredding

BLACK PLASTIC BAG CAT.5 AND CAT 9 AND CAT.10

(SOLID)

Disposal in secured landfill

COLOUR CODING AND TYPE OF CONTAINER FOR DISPOSAL OF BIOMEDICAL WASTE [SCHEDULE – 2]

REFERENCES Park K. Textbook of Preventive & Social Medicine, 22nd Edition. Jabalpur: Banarasidas Bhanot

Publishers; 2013.

C.M. Marya, A Textbook of Public Health Dentistry, Jaypee Brothers Medical Pub; 1 edition, 30 March 2011.

S.S. Hiremath, Textbook of preventive and community dentistry, Elsevier; Second edition, 1 January 2011

www.googleimages.com

WWW. WHO. HEALTH CARE WASTE.