by danny dehon monique magee melissa wason shreya purohit
TRANSCRIPT
By Danny Dehon
Monique Magee Melissa Wason Shreya Purohit
Over view
• Introduction• Objective• Criteria• General flow chart• Design• Detailed flow chart• Cost analysis• References
IntroductionWhat is waste water?It is a combination of liquid wastes from industries, commercial and residential areas. It also includes storm water, ground water and surface runoff
Why do we need to treat waste water?Why do we need to treat waste water?
OBJECTIVE
• To design a waste water treatment plant for a town of 10,000 people, which treats 1 million gallons of waste water per day.
• The characteristics of the effluent water are in compliance with current regulatory standards.
Criteria
GENERAL FLOWCHART
Pre-treatment
General Design Considerations
Main sewer linediameter=14 inches
flow 1MGD= 1.54 ft 3/svelocity 1.3ft/s
Q=VAmade of stainless steel
Pumping of water to bar screens• Water is pumped 70 ft• 880kw power needed• Vertical Turbine Solids-Handling Pumps VTSH® Series
pump- specially designed to handle solids
• Head:70 feet and this pump has a head of up to 110 ft
• Pump Capacity: 30,000 GPM• Impeller: non-clogging, blunt, and made of cast iron, • Shaft: stainless steel
CalculationBernoulli’s equation
Wg
Vph
2
211
1 g
Vph
2
222
2
e
WQP
Where h2= 70 ft, V2= .8ft/s, and V1= 1.1ft/s
Bar screens
• Removes sticks, glass, small rocks etc• Climber type bar screen • Spacing ¼ inches• Fine screening• Stainless steel to prevent corrosion• Mechanically scrapped• Solids collected in hopper and disposed
Pre - treatmentProcess
stepRetention
timedimensions velocity power skimmers other
Aerated grit tank
3 minutes 4.4*8.82 ft Opening .5*.25 inches
Skimming tank
10 minutes H: d6.15: 24.6 , ratio 4: 1
8.69ft* .5”, sticks down 4inches
Volume = 928.4 ft3
Aeration tank
25 minutes H: d= 1: 1= 14.35
Velocity of fluid at tip= .75 tip vel.
Paddle = .977 rev/min
2.64 ft-lb/min
Flocculant- aluminum
Paddle- 2 feet smaller than radius, 2ft wide
Pre Treatment CalculationsAerated grit removal chamberVolume
Skimming tankVolume
Tank dimensionsVolume = 4x3
352.27832.2083344.694 ftgalQtV D
34.92844.69441044.694 ftgalQtV D
ftV
x 15.64
4.928
4
3
1
3
1
Primary Sedimentation Tanks
Retention time• 90 minWater velocity.665ft/sDimensions• width 15.8 ft• length 52.77 ft• Depth 10 ft.
Calculations
• Water velocity
• Dimensions
s
ftVV Ts 665.
2
31.1
2
ftV
x
xxxHWLV
77.523
56.8355
3
3)10)(3)(.(
2
1
3
1
2
Trickling Filters
Tipping tray•Retention time: 5 minute•Dimensions: h=r =7.04ftFilter•Dosing cycle : 5 min•Retention time: 25 min•Dimensions h=r=13.04ft•Drainage = 5o slope•ventilation
Calculations.• Volume • R=h=x
ftV
x 04.72.46433 3
1
3
1
Secondary Sedimentation Tanks
Retention Time:• 20 minutes Water Velocity:• drop rest of solids out of suspension• 1/3 of the velocity in the pipes,
or .44 ft/s.Dimension:• Required R: H = 2: 1, • R: H =10.57 : 5.29 ft.Skimmer:• fence with extremely small square
holes, .5 inches by .5 inches• Catches wasteScraper:• mechanically operated • 5 arms. • Scrape off material from the bottom
Calculation• Water velocity
• Dimensions
• R=2h
s
ftVV TW 44.)31.1(
3
1
3
1
ftV
x 29.54
79.1856
4
3
1
3
1
Chlorination- disinfect water
Calculations
• Retention time
• = 68 minutesgal
lbt
gal
lb min7.1025.
De –chlorination chamber
• Remove residual chlorine using SO2- above standards .0058 lb/gal
• The ratio of the reaction is 2.43 x 10-6 lb sulfur dioxide for every 2.20 x 10-6 lb of chlorine.
• .017 lb/ gal chlorine – neutralized with .012/gal of SO2
Calculations • Basic chemistry
• X = 0.012 2
2
2
2
011.000833.0
00917.0
lbCl
xlbSO
lbCl
lbSO
Cost analysisStep Initial cost Daily cost
pumping 2500 950.4
pipes 300 0
Bar screens 8300 432.00
Aerated grit chamber 6500 648
Skimming tank 25000 0
Aeration tank 45000 756
Trickling filters 35000 918
Secondary sedimentation tank 10,000 810
chlorination 665000 233.03
De-chlorination 23,500 233.8
TOTAL COST
INITIAL• $236,100
DAILY • $4981.23
References• Al-Layla, M. A., Ahmad, S., & Middlebrooks, E. J. (1980). Handbook of Waste Water Collection and
Treatment. (G. l. culp, Ed.) Garland STPM Press.• • Droste, R. L. (1997). Theory and Practice of Water and Wastewater. Hoboken: John Wiley & Sons.• • Jern, W. (2006). Industrial Waste Water Treatment. New York: World Publishing Company.• • Metcalf, L., & Eddy, H. P. (1935). American Sewerage Practice. New York: McGraw-Hill Book Company.• • Metcalf, L., & Eddy, H. P. (1930). Sewerage and Sewage Disposal: A Textbook. New York: McGraw-Hill
Book Company.• • Metcalf, L., & Eddy, H. P. (1972). Wastewater Engineering. New York: McGraw-Hill Book Company.• • Noyes, R. (1994). Unit Operations in Environmental Engineering. New York: William Andrew
Publishing/Noyes.• • Sanks, R. L. (1998). Pumping Station. London: Butterworth Heinemann.• • Note: Some of the pictures are not referenced because they were taken by the authors of these papers
during a visit to the Baton Rouge Wastewater Treatment Facility.•