characteristicsofsewagewastewatercollection-pptx

Characteristics of sewage; waste water collection

1. PRINCETON INSTITUTE OF ENGINEERING AND TECHNOLOGY FOR WOMEN-HYDERABAD. DEPARTMENT OF CIVIL ENGINEERING CHARACTERISTICS OF SEWAGE& WASTE WATER COLLECTION Presented by: MOOD NARESH ASST.PROF PETW

2. INTRODUCTION Sewage consists of various residential, public and industrial mixtures of wastewater, which contain organic and inorganic materials in dissolved or suspended or colloidal form as well as various microorganisms useful and harmful to human life. We need the characteristics and examination of sewage before designing any sewage treatment system to work efficiently.

3. Basic Terms Sewage: It is the Liquid Waste or Wastewater produced as a result of water use. Sewer: It is a pipe or conduit for carrying sewage. It is generally closed and flow takes place under gravity .

4. Sewerage: Sewerage is the system of collection of wastewater and conveying it to the point of disposal with or without treatment. waste water collection Dometic : It is wastewater from houses offices, other buildings, hotels and institutions Industrial : It is the liquid waste from industrial process Storm-water: It includes surface run-off generated by rainfall and the street wash

5. Components of Wastewater Engineering Collection System  Network of Sewer pipes Disposal  Sewage Pumping Stations and Outfalls Treatment Works  Wastewater treatment Plants

6. Fig: Components of Wastewater Engineering

7. Types of Sewers Sanitary Sewer- It carries sanitary sewage like waste from municipalities including domestic and industrial waste-water Storm Sewer-It carries storm sewage including surface run-off and street wash Combined Sewer- It carries domestic, industrial and storm Sewage House Sewer-It is the sewer conveying sewage from plumbing system of a building to common municipal system Lateral Sewer- This sewer carries discharge from houses sewer

8. Types of Sewers Sub-main-This sewer receives discharge from two or more laterals Main/Trunk Sewer- Receives discharge from two or more sub-mains Outfall Sewer- It receives discharge from all collecting system and conveys it to the point of final disposal

9. L a t e r al Main/ T runk Sewer Su b -main sewer Outfall sewer H ou se Sewer Fig: Types of Sewers

10. Types of Sewer Systems 1. Separate System If storm water is carried separately from domestic and industrial wastewater the system is called as separate system. Separate systems are favored when There is an immediate need for collection of the sanitary sewage but not for storm water. When sanitary sewage needs treatment but the storm water does not.

11. Types of Sewer Systems 2. Combined System It is the system in which the sewers carry both sanitary and storm water, combined system is favored when; Combined sewage can be disposed off without treatment Both sanitary and storm water need treatment Streets are narrow and two separate sewer cannot be laid

12. Types of Sewer Systems 3. Partially Combined System If some portion of storm or surface run-off is allowed to be carried along with sanitary sewage the system is known as partially combined system. (In Urban area of developing countries, mostly partially combined system is employed as it is economical) In Pakistan we use this system

13. Characteristics OF SEWAGE / Waste water The Characteristics of sewage arc classified as follows: Physical characteristics Chemical characteristics and Biological characteristics

14. 1. Physical characteristics

15. A . Color : Color is due to the suspended and other matters found in wastewater. If sewage is fresh it has a soap solution color i.e grey-brown and decomposed sewage has dark grey color . B. Odour: Fresh sewage is of soapy or oily odour but stale sewage has offensive odour due to H 2 S, CH 4

16. C. Temperature: Generally sewage has slightly higher temperature than the water which increases the biological activities. 40 degree C. D . Turbidity : It is very turbid than water due to the presence of high suspended and other

17. E. Solids : 350-1200 mg/L Though sewerage typically contains lower than zero to 0.5 % solids, the remainder being water, still the nuisance caused by the solids cannot be unnoted, as these solids are extremely degradable and so want correct disposal. The sewerage solids could also be classified into dissolved solids, suspended solids and volatile suspended solids.

18. Data of the volatile or organic fraction of solid, that decomposes, becomes necessary, as this constitutes the load on biological treatment units or resources of a stream once sewerage is disposed off by dilution. The estimation of suspended solids, each organic and inorganic, provides a general image of the load on deposit and grit removal system throughout sewerage treatment. Dissolved inorganic fraction is to be thought-about once sewerage is employed for land irrigation or the other utilize is planned.

19. 2. Chemical Characteristics Sewage contains complex compounds derived from urine, faces, inorganic chemicals etc. a. pH b. DO (Dissolved Oxygen) c. BOD (Biochemical Oxygen Demand) d . COD (Chemical Oxygen Demand)

20. a. pH The hydrogen ion concentration expressed as pH scale, could be a valuable parameter within the operation of biological units. The pH scale of the contemporary sewerage is slightly quite the water provided to the community. However, decomposition of organic matter might lower the pH scale, whereas the presence of business waste material might manufacture extreme fluctuations typically the pH scale of raw sewerage is within the vary 5 to 8.0 .

21. DO (Dissolved Oxygen): It i s the a m o u nt o f oxy g e n d i s so l v e d i n waste wate r . Pre s e n ce i t i n dicates th e sewage i s f resh o r oxi d a tion h as be e n oc c urred a f ter tre a tme n t . It i s ne c essary to ensure at least 4 ppm of DO in stream in which treated wastewater is disposed otherwise fish are likely to be killed. BOD (Biochemical Oxygen Demand) BOD i s de f i n ed as the a m o u nt o f o x ygen re q uired f or the bacteria to oxidize the organic matter present in the sewage. BOD – 80 mg/L

22. COD (Chemical Oxygen Demand) It is defined as the amount of oxygen required for chemical oxidation of organic matters readily oxidizable carbonaceous and other matter. COD – 150 mg/L

23. 3. Biological characteristics Domestic sewage consists of various types of plant or animal microorganism and the biological characteristic of sewage is related to the presence of these microorganisms. This microorganism whose presence is 22 — 25 millions numbers in a liter of sewage may be pathogenic, indicator organisms etc. The main source of pathogenic microorganism is excreta from sick people and these organisms require living tissues to grow and reproduce and harmful to man.

24. The microorganism can be broadly classified into: (a) Aquatic plants ( b ) A q u a tic a n im a ls (c) Aquatic mold (fungi), bacteria and virus.

25. Aquatic Plants consists of waterweeds algae etc. Aquatic animals consist of fish, snails, amphibians insects, earth Worms, hydra etc. Aquatic mold (fungi), bacteria and virus are also aquatic plant but categorized separately. These are responsible for disease.

26. The bac t erium whi c h n e eds f r ee oxygen to sur v i ve i s called aer o bic bacter i a and w h i ch survives a n aero b i c without bacteria f r ee oxygen i s c a l led and which s urvives in presence or absence of free oxygen is called facultative bacteria . The dec o mposit i on o f sewage i s p o ssible due to these bacteria .

27. THANKS!