Solid waste disposal and control

various types of solid waste and their disposal and control measures

1. DEVIPRIYA P V M PHARM ENVIRONMENT AND HEALTH SOLID WASTE DISPOSAL AND CONTROL

2. Solid waste disposal and control Waste: unwanted solid and liquid material from household, streets, commercial establishments and industries. Scavanging : collection and disposal of refuse which is not carried by the sewers but done by natural labour . Conservancy system: the collection and disposal of human excreta by manual labour . Water carriage system: the removal of sewage through sewers and drains. Refuse : solid waste material/ discarded waste matter.

3. The refuse is the discarded material from houses, streets, commercial, industrial and agricultural activities. Refuse generally contains ash, paper, metal, wood, glass, rags, dust, peelings of fruits, vegetables & left over foods etc. Refuse from rotton vegetables, fruits, waste food is called garbage. Industrial waste mainly contain burnt fuel, metal ,wood, glass pieces, paper, dust, chemicals & harmful liquid waste. The accumulation of refuse is a health hazard because it can result in development of diseases, pollution of water, air and soil. The refuse should be collected, transported and disposed in a sanitary manner.

4. Storage and collection of Refuse Household waste should be stored in sanitary dust bins covered with a lid. Street and road side refuse should be stored in large size public bins . Wheel barrow or street refuse cart can be used for the collection of refuse. The collected should be carried in covered vehicles to the site of disposal site. Collection of refuse in paper sacks or polythene sacks is also becoming popular

5. Methods used for refuse disposal: Dumping Controlled tipping Burial Composting Burning.

6. Dumping: Simplest and easy method of disposing dry refuse. Low lying areas from habitation is selected. When the area is filled with refuse, it is leveled and covered with earth. But, causes public nuisance as it emits offensive gases, and it acts as breeding places for files, attract rodents, pigs, stray cattles etc. Also leads to air and ground water pollution. Controlled tipping: Pits of 3 feet depth are dug away from the habitation. The refuse is put in the pit and covered with earth daily. When the pit is full, it is completely covered with earth and allow to remain for 6 months

7. During this period the refuse gets converted to manure. After the end of 6 months, the pit is dug open and the manure is taken which can be used in agricultural fields. Burial: For disposal of dry refuse. A pit is dug and refuse is dumped in it & covered with earth daily. When the pit is full it is completely covered with earth and another one is dug for further use. Compositing: The process of converting the organic matter into manure with the help of bacterial action. Pits of 3 feet depth are made &refuse and human excreta are placed in alternate layers.

8. When the pit is full it is covered with earth and left as such for 6 months for composting. As a result of chemical and bacterial action intense heat is produced(60°C) which kills the pathogenic microbes. After 4-6 months the decomposition is complete and the manure formed is used for agricultural purposes. The pits are reused This method of disposal of refuse and human excreta is also known as Hot fermentation process. Mechanical compositing: Advanced method of refuse disposal. The water insoluble or large sized substances such as metal, rags, glass, stones etc are sorted from refuse and it is grinded in machine

9. This refuse is then mixed mechanically with sewage containing human excreta and incubated. The decomposition completes in 4-6 weeks and the so formed compost is used as manure. Burning (Incineration): Equipment used is incinerator. Suitable for disposal of hospital refuse because it may contain various types of discharges, blood and dead issues of patients. If refuse contain pieces of glass, metal ,sand etc it must be sorted out before burning. Drawbacks of burning: Expensive, direct loss of manure, an incinerator is required, not effective in rainy seasons

10. Excreta disposal Human excreta should be disposed in sanitary manner for protecting the public from diseases. Human excreta is a major source of infection as it contain pathogenic microorganisms, viruses, protozoa, helminthic parasites and their eggs. The faeces of patients contain various disease producing agents which are transmitted through air, food, flies, soil etc. It directly pollutes the water and food . The diseases associated with its improper disposal include typhoid, diarrhoea , dysentry , cholera, fever etc

11. Methods for disposal of human excreta ( 1)Rural and unsewered areas Service type Non service type (2) Sewered areas Water carriage system and sewage treatment

12. Service type latrines: Human excreta is collected from privies(a toilet located in a small shed outside a house) and latrines by manual labour in buckets and transferred into night soil carts for transportation to distant places for final disposal. This system is called service type or conservancy system and such latrines are called service type latrines. Drawbacks of service type latrines: Human excreta is exposed to flies even in carts. Soil and water pollution Some quantity of excreta remains sticking to the buckets. Highly objectionable smell Large number of manual labourers are required. It is against human dignity.

13. Non service type latrines It includes: Bore hole latrine Dug well latrine Water seal latrine Shallow trench latrine Deep trench latrine RCA latrine(Research Cum Action project, Govt of India)

14. Water carriage system (sewage system) Human excreta is collected and removed along with waste water through underground pipes known as sewers to a distinct place for final disposal. Sewage include excreta, urine, waste water from houses, commercial establishments, factories, stables & rain water. Requires lot of money to lay down the underground system of pipes and to maintain them. Advantages of sewage system: No manual labour for excreta removal Latrines always remain clean No nuisance of smell or flies Disease spreading by insects, rodents or animals is checked Overall improvement of community health.

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