1. Dr. Muhammad Razzaq malik In the Name of Allah Most Beneficent and Most Merciful

2. Dr. Muhammad Razzaq malik SOLID WASTES & ITS DISPOSAL Solid waste or refuse, if allowed to accumulate, is a health hazard Health Hazards: It decomposes and favours fly breeding It attracts rodents and worms The pathogens which may be present in the solid waste may be conveyed back to man’s food through flies and dust. There is a possibility of water and soil pollution, and Heaps of refuse present an unsightly appearance and nuisance form bad odours.

3. Dr. Muhammad Razzaq malik SORUCES OF REFUSE 1.Domestic refuse 2.Market refuse 3.Stable refuse 4.Industrial refuse Rubbish comprises paper, clothing, bits of wood, metal, glass, dust and dirt. Garbage is consumption of food. It consists of waste food, vegetable peelings and other organic matter. Garbage needs quick removal and disposal because it ferments on storage. Garbage is consumption of food. It consists of waste food, vegetable peelings and other organic matter. Garbage needs quick removal and disposal because it ferments on storage.

4. Dr. Muhammad Razzaq malik Methods of disposal  There is no single method of refuse disposal which is equally suitable in all circumstances. The choice of a particular method is governed by local factors such as cost and availability of land and labour. The principal method of refuse disposals are:-  Dumping  Controlled Tipping or Sanitary Land –fill  Incineration  Composting  Manure Pits  Burial.

5. Dr. Muhammad Razzaq malik 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. It is a most insanitary method that creates public health hazards, a nuisance, and severe pollution of the environment.

6. Dr. Muhammad Razzaq malik Controlled tipping  The material is placed in trench or other prepared area, adequately compacted, and covered with earth at the end of the working day.  Chemical, bacteriological and physical changes occur in buried refuse. The temperature rises to over 60 deg. C within 7 days and kills all the pathogens and hastens the decomposition process.

7. Dr. Muhammad Razzaq malik Incineration 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.

8. Dr. Muhammad Razzaq malik Composting  Composting is a method of combined disposal of refuse and night soil 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 manorial value for the soil.  The principal by-products are carbon dioxide, water and heat.

9. Dr. Muhammad Razzaq malik How disease is carried from excreta

10. Dr. Muhammad Razzaq malik Method of excreta disposal 1. Unsewered areas  SERVICE TYPE (CONSERVANCY SYSTEM)  Nightsoil is collected from pail or bucket type of latrines by human agency, and later disposed of by burying or composting.

11. Dr. Muhammad Razzaq malik NON-SERVICE TYYPE (SANITARY LATRINES)  TYPES:  Bore hole latrine  Well or pit latrine  Water-seal type of latrines –Squatting Plate latrine –Commode latrine

12. Dr. Muhammad Razzaq malik SANITARY LATRINE  A sanitary latrine is one which fulfils the following criteria:  (1) Excreta should not contaminate the ground or surface water  (2) Excreta should not polluted the soil  (3) Excreta should not be accessible to flies, rodents, animals (pigs, dogs, cattle, etc.) and other vehicles of transmission.  (4) Excreta should not create a nuisance due to odour or unsightly appearance.

13. Dr. Muhammad Razzaq malik LATRINES SUITABLE FOR CAMPS AND TEMPORATRY USE  Shallow trench latrine  Deep trench latrine  Pit latrine  Bore hole latrine

14. Dr. Muhammad Razzaq malik COMPONANTS OF WATER SEAL TYPE OF LATRINE  SQUATTING PLATE  TRAP  CONNECTING PIPE  SEPTIC TANK

15. Dr. Muhammad Razzaq malik Septic tank  The main design features of a septic tank are as follows:  i. A capacity of 20-30 gallons or 2/12 -5 c.ft. per person recommended for household septic tanks. The minimum capacity of septic tank should be at least 500 gallons.

16. Dr. Muhammad Razzaq malik CHEMICAL CLOSET The closet consists of a metal tank containing a disinfectant fluid. The active ingredients of the fluid are formaldehyde and quaternary ammonium compounds. In addition, a harmless water dye and a deodorizing substance are usually incorporated. A seat with a cover is placed directly over the tank. Nothing except the toilet paper should be thrown into the chemical closet. The closet consists of a metal tank containing a disinfectant fluid. The active ingredients of the fluid are formaldehyde and quaternary ammonium compounds. In addition, a harmless water dye and a deodorizing substance are usually incorporated. A seat with a cover is placed directly over the tank. Nothing except the toilet paper should be thrown into the chemical closet.

17. Dr. Muhammad Razzaq malik Sewage  Sewage is waste water from a community, containing solid and liquid excreta, derived from houses, street and yard washings, factories and industries. It resembles dirty water with an unpleasant smell.

18. Dr. Muhammad Razzaq malik  Sullage:  The term “sullage” is applied to waste water which does not contain human excreta, e.g., waste water from kitchens and bathrooms  Sludge:  The organic matter which settles down is called sludge and is removed by mechanically operated devices, without disturbing the operation in the tank.

19. Dr. Muhammad Razzaq malik Modern Sewage treatment  Water-Carriage system and sewage treatment a. Primary treatment Screening Removal of grit Plain Sedimentation b. Secondary treatment Trickling filters Activated sludge process

20. Dr. Muhammad Razzaq malik Modern Sewage treatment

21. Dr. Muhammad Razzaq malik Other methods of waste disposal  Sea outfall  River outfall  Sewage Farming  Oxidation Ponds

22. Dr. Muhammad Razzaq malik Aim of Sewage Purification Health Aspects:  Unless prompt measures are taken to provide proper means of sewage disposal, the following environmental problems may be created:  Creation of nuisance, unsightliness and unpleasant odours.  Breeding of flies and mosquitoes  Pollution of soil and water supplies  Contamination of food  Increase in the incidence of disease, especially enteric and helminthes diseases.

23. Dr. Muhammad Razzaq malik Environmental aspects  The oxygen in the sewage water is used by the numerous aerobic bacteria fount in sewage. Depletion of oxygen may lead to the death of the plants and animal life in water. Furthermore, the water may yield an offensive smell because of the release of hydrogen sulphide.

24. Dr. Muhammad Razzaq malik Biochemical Oxygen Demand (BOD) It is most important test done on sewage. It is defined as the amount of oxygen absorbed by a sample of sewage during a specified period, generally 5 days, at a specified temperature, generally 20 deg. C for the aerobic destruction or use of organic matter by living organisms. It is most important test done on sewage. It is defined as the amount of oxygen absorbed by a sample of sewage during a specified period, generally 5 days, at a specified temperature, generally 20 deg. C for the aerobic destruction or use of organic matter by living organisms.  If the BOD is 300 mg /l and above, sewage is said to be strong, if it is 100 mg/l, it is said to be weak.