1. Design of Water and Waste Water Management System Er.j.n.sharma

3. Evolution of Wastewater system

4. Treatment Process fudamentals

5. Objectives (Regulatory requirement)

6. Treatment Process selections

7. Different Treatment Technologies

8. Design of Waste water Treatment System

10. Ironically, only 2.5 % of the world’s water is fresh, with a mere 0.3 % available from rivers, lakes and reservoirs

11. Unfortunately, the number of people with access to clean water for drinking and sanitation is decreasing rapidly due to a number of factors

12. Each year, roughly 450 cubic kilometres of waste water is discharged into rivers, streams and lakes

13. According to a development report by the United Nations, every human being needs to consume 20-50 litres of freshwater, free of contaminants, each day.

15. Many hydrological systems in developing regions are, or are getting close to, being stressed beyond repair.

16. Industrial pollution, uncontrolled domestic discharges from urban areas, diffuse pollution from agriculture and livestock rearing, and various alterations in land use or hydro infrastructure may all contribute to non-sustainable use of water resources, eventually leading to negative impacts on the economic development of many countries or even continents.

18. However, technology cannot be expected to solve each pollution problem.

19. Typically, a Wastewater treatment plant transfers 1 m3 of wastewater into 1-2 litres of concentrated sludge.

25. To protect receiving environment f rom degradation or contamination

27. PRIMARILY PRELIMINARY TREATMENT PROCESS

28. Chemical process (coagulation, neutralization etc)

29. MAINLY PRIMARY TREATMENT PROCESS

30. Biological process (activated sludge, biofilm)

31. MAINLY SECONDARY TREATMENT PROCESS

32. --- AEROBIC

33. ANERO BIC

34. FACULTATIVE

35. Hybrid (wetland, MBR etc)

38. AERATED LAGOON

39. TRICKLING FILTERS

40. ROTATING BIOLOGICAL CONTRACTORS

42. MOVING BED BIOLOGICAL REACTOR (MBBR)

44. Oxidation

45. Respiration

46. Synthesis

47. Products :

48. Water

49. CO2

50. NH3

51. Additional microorganismsIn any biological treatment system there will be an accumulation of microbial and non-biodegradable solids that need to be managed and disposed properly

52. Typical Aerobic TreatmentSystem

54. 2 to 6 days: 50 – 90%

55. Organic matter:

56. 5 to 7 days: over 95%

57. Nitrogen:

58. Intermittent aeration, 7 days min: 80 – 95%

59. Phosphorus:

60. Intermittent aeration, 7 days min: 70 – 80%

61. Bacterial indicators:

64. Requires proper design and trained Operators

66. Selection of Reactor types,

67. Process variations

68. Technology know-how

69. EXTERNAL FACTORS

70. Construction cost

71. Operation and maintenance difficulties & cost

72. Space limitations (sizing of units and treatment system)Activated sludge systems

74. Effluents characteristics,

75. Solid retention time (SRT),

76. Organic loading rate (ORT),

77. Food to microrganism ratio (F/M),

78. Mean Cell residence time ( 0c),

79. Aeration period,

80. Sludge production-----(rate of return sludge & excess sludge wasting ),

81. O2 Requirements & transfer,

82. Nutrient requirements, (12.4% by wt.of nitrogen & 20% of this value is for Phosphrous),

83. Control of filamentous organisms,

84. (Settleability test, Sludge volume index, SVI)

86. IN MORE EFFICENT BIODEGRATION,

87. SMALLER REACTOR SIZE ,

88. ECONOMICAL IN COST

90. OR, ALTERNATIVELY, the tank capacity may be designed from the F/M & MLSS Conc. F/M = Q S0 / XV

92. TYPICAL SUSPNDED SOLIDS MASS BALANCE FOR RETURN SLUDGE CONTROL S AERATION TANK SECONDARY CLARIFIER Q S0 X0 V Q+Qr X ____________________________________________________________________________ QeXe Qr, Xr Q*w,Xr Schematic Diagram of Activated-Sludge Process the Mass balance around the settling tank is as follows :-- Accumulation = Inflow -- Out flow = X ( Q + Qr) - Qr.Xr- Xr Q*w , Qr = XQ –XrQ*w Xr - X

93. LATEST BIOLOGICAL TREATMENTS Fixed media attached growth Process

94. Membrane Bioreactors •Suspended growth – similar to activated sludge •Two parts – biological unit and membrane filter •High effluent quality BOD<5 mg/L, TSS<5 mg/L •Greater potential for removal of endocrine disruptingchemicals, pharmaceuticals,

97. Polythelene with density les than water but almost same as aerated water

98. Very High Surface Area (>300m2/m3)

99. 30% to 50% reactor filled with media

101. Sequencing Batch Reactor (SBR) Cyclic processes of fill, react, settle, effluent removal, and idle are controlled by time to achieve objectives. Short aerating/non-aerating periods at a HRT = 10 days resulted in removals of COD (93%), SS (98%), and all NH3 converted to NO3.

102. Sequencing Batch Reactor (SBR) • Type of activated sludge process • Five steps • Fill • React (aeration) • Settle • Draw (decant) • Idle •Example – Duke

104. Rotating Biological Contactors •Aerobic system •Series of closely spaced circular disks rotate -submerged in wastewater •Reliable - withstand hydraulic and organic surges •Low energy costs •Potential mechanical failure

106. Hydraulic: 5 to 7 days

107. Solids: 15 to 30 days

108. Aeration type:

109. Continuous

110. Intermittent

111. Aeration level:

112. Low level: between 0 and 1 mg/L

114. Facultative lagoon

115. Oxidation Ditch

116. Amount of oxygen Removal of odor Oxygen demand = 1/2 to 1/3 BOD Removal of organic matter Oxygen demand = BOD Removal of nutrients Oxygen demand = BOD + NH3-N

118. Floating aerators provide continuous aeration.

122. Diffusers

123. Surface Aerators

124. Aerator Design

125. Aerator Design

126. Calculating HP Requirement