1. Water Treatment / Waste Water
Infrastructure
Civil Works Projects for Lawyers
American Bar Association
Forum on the Construction Industry
Water Treatment / Waste Water
Presented By:
Your Name Here
Prepared By:
Your Name Here

2. Water Treatment and Distribution
Distribution of Waste Water

3. Treatment is Essential
Manufacturing
Power Generation
Chemical Production
Pharmaceutical
Health Care
¾ of earth surface is covered in water, but only one-half of one % is fresh and even a smaller portion of that is usable

4. Treatment Methods Chemical Process Environmental Process
Mechanical Process
Plant Design features (Civil Engineering)
Filtration Systems
Skimmers
Ultraviolet
Light
Ozone Generators

5. Water is a Universal Solvent
Carry Nutrients and Chemicals
Support Chemical Reactions
Suspend Materials
Supports Life
Carry Disease

6. Environmental Protection Agency (EPA)
Leading Government Agency Establishing and Enforcing Water Quality Standards
Clean Water Act
Standards for Discharge
Safe Drinking Water Act
Standards for impurities in drinking water

7. Purification Must Be measured
Measurements must be taken at the plant and during transmission
Identify Bacteria Viruses or Organics

8. Water Treatment Plants
Design Considerations:
What quality and quantity of water is required?
What raw water supply is available?
What type of plant process is necessary?
Engineering determined by
Water available
EPA standards for the water
Quantity of water needed
Treatment technologies

9. EVALUATING RAW WATER SUPPLY
Variation in Availability
Does water supply vary a lot by season
Control Supply of Water and Quality
Inability to Control Water and Quality
Large or small body of water as supply
River water supply and consistency of flow

10. TESTING Microbial Testing Evaluating Water Chemistry
Testing performed on sample and if present assume others of the same are present and they spring from the same source
Evaluating Water Chemistry
Easier: often instantaneous and possible indicator of microbial presence

11. Treatment Plant Size Cost Considerations Contact Time
Size of Population to be served (75 to 150 gallons per day per person)
Contact Time
How Long does disinfectant need to be in the water to be effective

12. CIVIL & STRUCTURAL DESIGN
Physical Structure Design Transportation of Water Tanks and Pumping

13. Minimize Waste From Plant
SUSTAINABLE DESIGN
Minimize Waste From Plant
Minimize Power Use

14. Plant Instrumentation and Construction
Instrumentation necessary to monitor raw water coming in and effluent going out and distribution system
Construction decision between private and public management
Cost Considerations
Long Term Maintenance Considerations

15. Source of Water to Plant
GROUNDWATER
Springs and Wells
Higher in dissolved solids and hardness
Pumped & Artesian Wells
OCEAN
High Cost to Remove Salt
SURFACE WATER
Affected by the environment
OTHER SOURCES
EXAMPLE – recycled water for non-potable uses

16. Water Purification Processes
Primary Components
Gathering Raw Water
Series of Purification Steps
Storage, pending distribution

17. Intake Structures Choice of Structure Depending on Source
Water Availability
Bathymetry
Sediment Transport
Environmental Regulations
Climatic Conditions
Constructability
Operations and Maintenance

18. Pumping Considerations
Choice of pump varies for pressure needs
Pump needs continuous flow across the blades
Pump choice determined by pressure needed in processing water.
Pump considerations moving water to higher elevations
Pump considerations dependant on size of pipe and allowable pressure
Energy Use – efficiencies derived from variable speed drives

19. Treatment Process Chemical Injection Chlorine Ammonia
Carefully monitored uring the treatment process to maintain maximum efficiency
Chlorine
Effective disinfectant best used on warmer water
Ammonia
Used to limit disinfection by-product caused by chlorine
Potassium Permanganate
Controls color, taste and odors
Acids and Caustics
Used to control PH level of water

20. Treatment Process Ozone Disinfection
Control of carbon based materials in water
Ultraviolet Germicidal Irradiation
Use of light to destroy microbes in water
Flocculation
Add chemicals to water to cause suspended solids to coagulate and become larger to be removed by filters
Sedimentation
Low flow velocity basins allowing solids to drop out

21. Filtration Rapid Sand Filters Slow Sand Filters
Passing water through sand beds to remove solids
Slow Sand Filters
Graded layers of sand filters water as it passes
Activated Carbon Absorption
Uses absorption to capture organics
Membrane Filtration
Operate at the molecular level

22. Membrane Type of Filters
Ultrafiltration
Separate large organic molecules and colloidal silica
Nanofilters
Capable of removing hardness, heavy medals, color, taste and large organics
Reverse Osmosis
Predominately used for desalinazation
Distillation
Separate water from impurities by phase change
Aeration
Increase oxygen content, reduce carbon dioxide and remove hydrogen suphide, methane and other volatile compounds

23. Final Treatment Chemical treatment of water to disinfect
Chemical baths to disinfect water as final process
Final treatment of waster as regulated by the Environmental Protection Agency

24. WASTE WATER

25. How it works A combination of civil engineering, biology and chemistry
Weirs, Clarifiers
Aerobic, Anaerobic
Dissolved Oxygen, Eutrophication

26. Regulatory Scheme Prior to 1947 – no regulation of waste water
1948 to 1970 – Federal Water Pollution Control Act (FWPCA)
1970 to Present – EPA Clean Water Act
Eliminates the discharge of all pollutants into above ground waters
Ensure that surface waters would meet standards necessary for human sports and recreation

27. Preliminary Waste Water Treatment
Screening
Coarse Screens and Bar Screens
Removes Large Items
Fine Screens – Static, Rotary Drum or Step
Removal of Fines
Grit Removal
Removal of coarse suspended material (silt, sand and gravel)
Gravity / Velocity grit removal
Aerated Grit Chamber
Shredding or Grinding
Shred or grind material in the flow to reduce the size of the inert material so it does not interrupt the process

28. Preliminary Treatment
Flow Equalization
Plant is most efficient if constant flow is maintained
Peak flows mid-morning and evening
Construct equalization basin to release constant flow to plant
Must aerate and mix liquids in basin to prevent oder and settling solids.

29. Primary Treatment Remove settled organics and floatable solids
Primary Clarifiers
Flow Velocity Decrease
Sediment settled out – sludge pumped off

30. Enhancing Primary Treatment
Pre-aeration
Introduction of air in the grit chamber
Promotes flocculation, scum floatation and removal
Benefits odor control
Coagulation
Chemical introduction to promote the settling of finely dispersed solids to promote forming large solids out of finely dispersed solids

31. Secondary Treatment
Process to convert organic wastes to move more stable solids that can either be removed by settling or discharged to the environment, without causing harm.
Biological process involve the use of bacteria in the treatment system

32. Secondary Treatment Fixed Film System Suspended Growth System
Trickling Filters – waste water distributed over a media, air added to media and bio-film grows and sloughs off
Suspended Growth System
Treatment Ponds
Secondary Sedimentation
Rotating Biological Contractor
Rotating disks equally apply oxygen to microorganisms attached to disks. The build up is removed

33. Suspended Growth System
Activated Sludge System
Primary effluent is mixed with activated sludge and air added, microorganisms grow and pumped to settling tank to be removed or used as activated sludge
Complete mix activated sludge – Uniformly introduced
Plug Flow
Waste Water flows as a plug winds its way through a series of channels as air is introduced in a decreasing progression. Large clumps of microorganisms removed at end.

34. Suspended Growth System
Extended Aeration
Long detention time and high sludge age
One direction flow through channel in tank
Resilient to shock load
Sequencing Batch Reactor
Batches of flow cycled to multiple basins, eliminate need for clarifier and sludge removal system.

35. Suspended Growth System
Membrane Bioreactor
Effluent pumped across membrane as air is introduced in the bottom of the membrane promoting aerobic condition treating effluent.
Greatly reduces the amount of space needed to treat wastewater.

36. Treatment Ponds Facultative Lagoon / Pond Aerated Lagoon
Different methods to set up an aerobic and anaerobic condition for water treatment
Secondary Sedimentation
Separate solids from treated water
Concentrate and thickens sludge to optimize handling

37. TERTIARY TREATMENT
Enhanced treatment of effluent for the removal of heavy metals and toxic compounds, not filtered in the secondary treatment.
Usually used to remove nitrogen and phosphorus
Very expensive and labor intensive
Nitrogen removal
Nitrification / Denitrification
Convert ammonia nitrogen to nitrate
Ammonia Stripping
Adding Quick Lime

38. TERTIARY TREATMENT Phosphorus Removal Land Application
Add Feric Chloride, Lime or Alum
Land Application
Spray secondary disinfected wastewater or large landmass and use soil filtration

39. Disinfection Chlorination Dechlorination Gas or Liquid
Effective, but hazardous Sodium Hypochlorite.
Liquid bleach less hazardous, but dissipates quickly
Calcium Hypochlorite
Wet or Dry – less hazardous but complicated to store
Dechlorination
Used to remove the chlorine form the effluent so as not to to kill aquatic life down stream

40. Disinfection Ultraviolet Radiation Bromide Chloride Ozonation
Kills virus and bacteria in wastewater
Leaves no residue to kill aquatic life
Bromide Chloride
Mix of bromine and chlorine no downstream residue
Ozonation
More effective than chlorine, but expensive to produce

41. Solids Handeling
All solids from preliminary treatment, primary treatment and secondary treatment, are blended together for final treatment
Thickening
Stabilization
Conditioning
Dewatering
Reduction

42. Solids
Flotation
Adding water in a pressurized environment. When depressurized, bubbles cause dense material to rise to surface for skimming.
Gravity Settling
Sludge settles and compacts in a circular tank like sedimentation, constantly stirred to create channels for water to exit. Dried sludge is removed from bottom of tank.
Stabilization
Lime stabilization – lime added to kill microorganisms and stop odor. Sludge applied to land. Very Expensive and sludge with lime is very heavy.
Anaerobic Digestion – Decomposition of sludge in the absence of oxygen. Traditional method but very dependent on perfect conditions.

43. Dewatering Centrifugation Belt Filter Press Drying Beds
Spun to remove water and dry solids
Belt Filter Press
Sludge formed into a cake by adding polymers and then pressed dry.
Drying Beds
Layers of sludge exposed to air until dry then ,oved to open area to be worked into the ground

44. Final Solids Disposal Divided into two categories Class A Class B
Can be used by general public
Class B
Disposed in landfill OR
Certain agricultural applications

45. Questions?

46. Thank You