Design of a Wastewater Treatment Plant By Danny Dehon Monique Magee Melissa Wason Shreya Purohit

Over view Introduction Objective Criteria General flow chart Design Detailed flow chart Cost analysis References

Why do we need to treat waste water? Introduction What 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? Save aquatic life algal boom Depletes oxygen levels health can cause cholera and typhoid if consumed reuse drinking water irrigation industries

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.

Level of purification needed Criteria Flow rate Concentration Level of purification needed

Primary sedimentation tanks GENERAL FLOWCHART Main sewer line screening Grit tank Skimming tanks Aeration tanks Primary sedimentation tanks Trickling filters Secondary sedimentation tanks Chlorination De-chlorination Discharge Pre-treatment

General Design Considerations Collection system is separate Topography of the area is used , built at an elevation Gravity flow Cuts down on cost All tanks purchased from Pope Scientific Inc. No tertiary treatment- secondary treatment meets town standards.

Incoming waste water = 1 million gallons per day Main sewer line diameter=14 inches flow 1MGD= 1.54 ft 3/s velocity 1.3ft/s Q=VA made of stainless steel Storm water Sanitary wastes Incoming waste water = 1 million gallons per day

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

Calculation Bernoulli’s equation 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 - treatment Process step Retention time dimensions velocity power skimmers other Aerated grit tank 3 minutes 4.4*8.82 ft Opening .5*.25 inches Skimming tank 10 minutes H: d 6.15: 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 Calculations Aerated grit removal chamber Volume Skimming tank Tank dimensions Volume = 4x3

Primary Sedimentation Tanks Retention time 90 min Water velocity .665ft/s Dimensions width 15.8 ft length 52.77 ft Depth 10 ft.

Calculations Water velocity Dimensions

Trickling Filters Tipping tray Retention time: 5 minute Dimensions: h=r =7.04ft Filter Dosing cycle : 5 min Retention time: 25 min Dimensions h=r=13.04ft Drainage = 5o slope ventilation

Calculations. Volume R=h=x

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 waste Scraper: mechanically operated 5 arms. Scrape off material from the bottom

Calculation Water velocity Dimensions R=2h

Chlorination - disinfect water dosage 0.25lb/ gallon Retention time 68 minutes volume 47222.2 gallons Chlorine residual Water : chlorine = 0.017 lb/gallon

Calculations Retention time = 68 minutes

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

Secondary sedimentation tank Cost analysis Step Initial cost Daily cost pumping 2500 950.4 pipes 300 Bar screens 8300 432.00 Aerated grit chamber 6500 648 Skimming tank 25000 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.