Waste water treatment processes
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The document summarizes various stages of wastewater treatment processes. It discusses preliminary treatment which removes solids, grit, and grease. Primary treatment uses sedimentation to remove 60% of suspended solids. Secondary treatment uses biological processes like activated sludge and oxidation ditches to remove organic matter. Tertiary treatment further removes nutrients and particles through processes like filtration and disinfection. The document provides details on the treatment units and processes involved at each stage of wastewater treatment.
Waste water treatment processes
- 1. Presented By Submitted to Ashish Agarwal Imran Ahmad Civil Engg. III yr. H.O.D. Civil Dept.
- 2. Preliminary Treatment Primary Treatment Secondary Treatment Tertiary Treatment
- 4. Preliminary Treatment Removal of waste water constituents such as rags, sticks, floatable grit, and grease that may cause maintenance or operational problem with the treatment operations, processes, and ancil1ary systems
- 5. Preliminary Treatment Preliminary treatment consists of following units • Screening For removal of floating matter. • Grit Chamber For removal of sand and grits. • Comminuters For grinding large size suspended solids • Floatation Units For removal of oil and grease • Skimming Tanks • Flow Measuring units such as partial flume • Pumps • Pre-aeration Units
- 6. Primary Treatment Removal of a portion of the suspended solids and organic matter from the wastewater.
- 7. Advanced Primary Treatment Enhanced removal of suspended solids and organic matter from the wastewater. Typically accomplished by chemical addition or filtration known as Coagulation and Flocculation.
- 8. Primary Treatment Primary treatment consists of following processes/units • Sedimentation Primary Settling Tanks • Coagulation Secondary Settling Tank • Flocculation
- 9. Secondary Treatment Removal of biodegradable organic matter [insoluble or suspension state} and suspended solids. Disinfection is also typically included in the definition of conventional secondary treatment
- 10. Secondary Treatment with Nutrient Removal Removal of biodegradable organics, suspended solids, and nutrients (nitrogen phosphorus, or both nitrogen and phosphorus)
- 11. Secondary Treatment Secondary Treatment Process for Wastewater Applications: • Aeration Systems • Biological Treatment Systems • Sludge and Bio solids Processing Systems Secondary treatment consists of following processes. • Activated Sludge Process • Oxidation Ponds and lagoons • Trickling Filter
- 12. Removal of residual suspended solids (after secondary treatment), usually by granular medium filtration or micro screens. Disinfection is also typically a part of tertiary treatment. Nutrient removal is often included in this definition
- 13. Tertiary Treatment Tertiary treatment consists of following processes and units. • Membrane Filtration and Separation • Dechlorination and Disinfection Systems • Reverse Osmosis (RO) Systems • Ion Exchange • Activated Carbon Adsorption • Physical/Chemical Treatment
- 14. Functions of Water Treatment Units Unit Treatment Function (Removal) Screening Floating matter Sedimentation Suspended matter Coagulation Suspended matter, a part of colloidal matter and bacteria Chemical methods Iron, Manganese, etc. Filtration Remaining colloidal dissolved matter, bacteria Disinfection Pathogenic bacteria, Organic matter and Reducing substances Softening Hardness Aeration, chemicals use Colour, Odour, Taste
- 15. Source of Domestic Wastewater 5% 10% Toilet Flushing 40% 15% Bathing Laundry 30% Kitchen Others
- 17. I E N F F F L L U U E E N N T T
- 18. Plan of a Typical Waste Water Treatment Plant
- 19. Primary Treatment Process Sedimentation is primary treatment Process. Sedimentation is a physical water treatment process used to settle out suspended solids in water under the influence of gravity.
- 20. Removal Efficiency of Primary Treatment Process : • Removal efficiency of Biological Oxygen Demand (B. O.D.) in primary treatment process is 30% • Removal efficiency of Total Suspended Solids (T.S.S.) in primary treatment process is 60%
- 21. Typical Primary Treatment Plant with preliminary treatment process
- 23. Secondary Treatment Process Stabilization ponds & Lagoons: • The stabilization ponds are open flow through basins specifically designed and constructed to treat sewage and biodegradable industrial wastes. • They provide long detention periods extending from a few to several days. • Pond systems, in which oxygen is provided through mechanical aeration rather than algal photosynthesis are called aerated lagoons. • Lightly loaded ponds used as tertiary step in waste treatment for polishing of secondary effluents and removal of bacteria are called maturation ponds.
- 24. Activate Sludge Process In activated sludge process wastewater containing organic matter is aerated in an aeration basin in which micro-organisms metabolize the suspended and soluble organic matter.
- 25. Activated sludge plant involves: • wastewater aeration in the presence of a microbial suspension • solid-liquid separation following aeration • discharge of clarified effluent • wasting of excess biomass, and • return of remaining biomass to the aeration tank.
- 26. Removal Efficiency of Activated Sludge Process : Metal Removal Efficiency Al <20% Mo <20% As <20% Pb 20-50% Mn 20-50% Ag 20-50% Cd >50% Fe >50% Cr >50%
- 29. Classification of Stabilization Ponds Stabilization ponds may be aerobic, anaerobic or facultative. Aerobic ponds are shallow ponds with depth less than 0.5 m so as to maximize penetration of light throughout the liquid depth. Such ponds develop intense algal growth. Anaerobic ponds are used as pre-treatment of high strength wastes. Such ponds are constructed with a depth of 2.5-5m as light penetration is unimportant. Facultative pond functions aerobically at the surface while anaerobic conditions prevail at the bottom. They are often about 1 to 2 m in depth. The aerobic layer acts as a good check against odour evolution from the pond.
- 31. Oxidation Ditch The oxidation ditch is a modified form of "extended aeration" of activated sludge process. The ditch consists of a long continuous channel oval in shape with two surface rotors placed across the channel.
- 32. A Typical Oxidation Ditch
- 33. A View of Oxidation Ditch
- 34. Tertiary Treatment Process Tertiary treatment process consists of following process. • Filtration Process (Trickling Filter) • Disinfection Process Trickling Filter is an attached growth process i.e. process in which microorganisms responsible for treatment are attached to an inert packing material.
- 35. Removal Efficiency of Trickling Filter The Removal efficiency of Total Organic Carbon (T. O. C.) from Trickling Filter is greater than 90%
- 36. Working of Trickling Filter
- 38. Top view of Trickling Filter
- 39. Thank You