# Presentation: 912412

## Transient, Non-Community Drinking Water Systems Training Class

**Water Treatment Technologies for**
**   ****Chemical Contaminants**
**	**
**	**** ****Prepared by**
**	****	****Bureau of Reclamation,**
**	****         ****Denver Federal  Center**
**	****Prepared for**
**	****	****Bureau of Land Management**
**              ****	****May 20, 1999**

** **

## Who is the Bureau of Reclamation

- (A bunch of dam engineers )
- Provider of Technical services to Tribes, State  and Federal Agencies
-  Not a Regulatory Agency
-  Protector of Indian Trust Assets

## World’s Largest Desalting Plant Yuma, Arizona

## ROWPU’s for Small Communities 

## Groundwater Remediation using Ion Exchange, Odessa Texas 

## Bureau of Reclamation’s Mission Statement

- To manage, develop and protect water and related resources in an environmentally and economically sound manner in the interest of the American public.

## TSC Organization

- Located at DFC, employs 685 FTE’S
- Directory of  engineers and technical staff
- Service oriented  to BOR facilities,  EPA (Superfund), FEMA (Emergency disaster response), Tribes, and others
- Cost estimators provide official BOR estimates

## Basic Treatment Processes

- MF, UF, RO, NF		AS, U, gross alpha & beta, Ra, 					Zn, NO3, Se
- ED				NO3, Se
- Lime-Soda Precipitation	Se(+4 or+6), As, U, Ra
- GAC				Radon, Hg, Cd, organics, THM’s
- Ion exchange‐anion 	NO3,  alkalinity
- IX‐ mixed bed		gross beta

## Basic Treatment Processes(continued)

- Ion exchange‐cation		radium, Cu, Zn
- Lime Softening			Cu, Pb, Hg, Cd, Zn, 						alkalinity
- Coag'n/floc'n w/FeSO4&filtr'n	Se=,+4,+6, As
- Coag'n/floc'n w/alum&filtr'n	Se=,+4,+6, Cd, Hg, Pb, Cu
- Greensand Filter & KMnO4	Fe and Mn
- Activated Alumina			F, As, Se
- Air Stripping			Radon, Organics
- Distillation				Zn

## Basic Treatment Processes(continued)

- TT1		Crypto/giardia, Turbidity
- TT2		Turbidity
- TT3		E‐coli and Total Coliform, Turbidity
- TT1= screening, rapid mix, polymer, alum, flocculation, clarification, dual media filtration, and chlorination
- TT2= rapid mix, alum, flocculation, clarification, and filtration
- TT3= Dual media filtration and chlorination

## Water Treatment Primer

## Contaminant Fact Sheets 

**Alkalinity**
**Arsenic**
**Copper**
**Cryptosporidium and Giardia Lamblia**
**Fluoride**
**Iron and Manganese**
**Lead**
**Mercury and Cadmium**** **

## Contaminant Fact Sheets

** **

**(***Continued***)**

**Nitrate**
**Organics**
**Radionuclides**
**Selenium**
**Total Coliform and E-Coli**
**Total Dissolved Solids**
**Turbidity and Total Suspended Solids**
**Zinc**

## Primer Contents

- Contaminant-Based Fact Sheets
- Most Removal Techniques Listed
- Process Descriptions and Cost Data for BAT
- Description
- Pretreatment
- Maintenance
- Advantages & Disadvantages
- Construction and O& M Costs for 250,000 gpd

## Primer    (continued )

- Fact Sheet Costs are in November 1996 dollars
- Costs planned to be updated this year
- Contaminants to be completed this year:
- chromium, thalium, nickel, cyanide,
- beryllium, barium, asbestos, antimony
- trihalomethanes and sulfates

## Conventional Water Treatment

- Rapid Mixing
- Chemical Feed
- Coagulation and Flocculation
- Filtration
- Disinfection

## Mixing/Flocculation and Sedimentation

- Instantaneous mix of coagulants
- Neutralizes the negative charges on colloids
- During the gentle mixing of flocculation, allows particles to agglomerate into larger particles
- Heavier particles are removed by settling

## Rapid Mix and Flocculation Tanks

## Rapid Mix and Flocculation Tanks

## Clarifier

## Pressure Clarifier

## Filtration	

- May be mesh screens, cartridges with fibrous elements, or media (sand or carbon or both)
- Removes particles that are too small to be removed in sedimentation basins
- Carbon Filters
- under-counter type or whole house

## Pressure Filter

## Filter’s Blower and Backwash Pump

## Disinfection	 

- Chlorine is most common method
- Gaseous or  tablet form
- May also be accomplished with :
- Chlorine Dioxide
- Chloramines
- Mixed Oxidants
- Ultra violet rays
- Ozone

## Performance Monitoring

- “_Optimizing Water Treatment Plant Performance Using the Composite Correction Program_”, A Handbook numbered  EPA/625/6-91/027
- Pretreatment
- Screens  clog with moss or silt
- variable raw water quality
- potential upstream pollution
- quantity limits
- algae blooms or bacterial problems

## Why Pre-treat?

*Why Pre-treat?*

## Performance Monitoring

- Flow measurement is important to accurately establish chemical feed rates, wash water rates, and unit loadings
- Mixing needs to be adequate
- Chemical feed systems need dosage control
- Monitor pH for optimum conditions

## Solubilities  vs  pH

## Chemical Feed Skid

*Chemical Feed Skid*

## Chemical Feed Skid

## Performance Monitoring, continued Flocculation

- Note inlet and outlet conditions
- Provide variable energy input
- Provide at least two-stage flocculation
- Baffles for even flow distribution; avoid velocity currents from disrupting settling conditions in adjacent settling tank
- Observe size of floc

## Performance Monitoring, continuedSedimentation

- Observe clarity of settled water noting size and appearance of any suspended floc
- Avoid flow density currents by proper design of inlet and outlet pipes
- Note sludge removal mechanism

## Performance Monitoring cont’dFiltration

- Regulate filter flow in an even consistent manner
- Provide backup backwash pump
- Note frequency of backwash
- Backwash on turbidity or headloss

## Performance Monitoring continuedDisinfection

- Configuration and baffling of clearwell
- Proximity of “first user”
- Backup disinfection system
- Consider disinfection ahead of filter
- Flow paced system if flow varies

## Performance Monitoring continuedWastes and Their Disposal

- Familiarize yourself with the filter backwash water and sedimentation tank sludge
- Is discharge permitted?
- Recycle of backwash water may return cysts

## Performance Monitoring continuedLaboratory and Maintenance

- Assess capability to perform process control tests such as pH, alkalinity, turbidity, etc.
- Maintenance requires tools, spare parts and storage
- Filing systems for equipment catalogs and records of plant operation, personnel, equipment condition and as-built drawings
- Preventative maintenance system recommended

## ADVANCED WATER TREATMENT (non-membrane systems)

- Lime Soda Softening or Precipitation
- Alum or Iron compound co-precipitation
- Ion Exchange
- Granular Activated Carbon
- Air Stripping

## Advanced Water Treatment (continued)		

- Package Plants or Point of Use Units are available but not for all processes
- Lime Soda and Co-precipitation processes usually combined in an Upflow Solids Contact Reactor
- Combines rapid mix, flocculation, coagulation and sedimentation in one unit process

## Advanced Water Treatment (continued)	

- Physical-Chemical Processes
- Granular Activated Carbon, Carbon Filters
- Ion Exchange, Softeners
- Air Stripping
- Iron Filters, Greensand Media
- Distillation

## Manganese Greensand Filter(Iron and Manganese Removal)

## Advanced Water Treatment (continued)	 	

- Ion-Exchange  (softeners)
- ion-replacement due to chemical bond attraction affinity
- if sodium enriched resin is used, sodium is added to the water
- removes up to 10 ppm dissolved iron
- oxidized iron or iron bacteria may clog the resin

## Ion Exchange

## Ion Exchange vessels for Chromium 

## Advanced Water Treatment (continued)

- Granular Activated  Carbon
- activated by heating the charcoal to provide additional surface area for adsorption
- available as under the sink or whole house
- removes some inorganics, chlorine, organics, THM’s, pesticides, radon, and taste and odor
- does not remove nitrates, bacteria, or dissolved minerals

## Granular Activated Carbon

## Advanced Water Treatment (continued) 

- Distillation
- Process of boiling water;impurities are left behind; condenser using cooling coils to collect clean water
- Good for nitrates, sodium, sulfates, most organics
- Heat destroys bacteria
- Sizes range from 1 quart /hr to 0.5 gal/hr.
- Disadvantage of bland taste

## Advanced Water Treatment (continued) 

- Air Stripping
- contaminants moved from the water phase to the vapor phase through volatilization
- off-gas may require vapor phase carbon treatment
- good removal for pesticides and volatile organics

## Advanced Water Treatment (continued)

- Pretreatment
- understanding the raw water quality
- turbidity, pH, alkalinity, etc.
- Residuals
- spent carbon or ion exchange resin, or air stripping media
- hazardous or non-hazardous

## Advanced Water Treatment Residuals 

- If hazardous, special requirements for:
-  labeling
-  storing
-  transporting
- approved disposal site  (RCRA)
- permitting

## Advanced Water Treatment Residuals, continued

- Non-hazardous residuals
- regenerate by others
- lined ponds
- no groundwater contamination
- no discharge to septic tanks
- obtain approval from Local Health Authority

## Costs of Water TreatmentTotal cost/1000 gallons

- _Package Plants Filtration _
- Coagulation/Filtration with tube settlers    $1.73
- Pressure depth clarifier/Pressure filter       $1.90
- Pressure depth clarifier/Pressure
- Filter with GAC adsorber                            $2.47

## Costs of Water Treatment Total cost/1000 gallons

- _Inorganic Contaminant Control_
- High pressure reverse osmosis      $4.03
- Low pressure reverse osmosis       $3.40
- Cation exchange                            $1.44
- Anion exchange                             $1.46
- Activated alumina                          $1.47

## Costs of Water Treatment Total cost/1000 gallons

- _Organic Contaminant Control_
- GAC in pressure vessel
- 6-mo carbon replacement                $1.92
- 12-mo carbon replacement              $1.67
- Packed tower aerator                		   $0.45

## Costs of Water Treatment

- Relative Costs of Organic Removal
- From Lowest to Highest Cost
- Air Stripping
- Air Stripping w/Vapor Phase GAC
- Oxidation +Air Stripping + VPGAC
- 2 STAGE Air Stripping +VPGAC
- Oxidation +LPGAC
- Liquid Phase GAC

## Costs of Water Treatment Total cost/1000 gallons

- _Disinfection_
- Gas feed chlorination                   $0.26
- Hypochlorite solution                   $0.33
- Pellet feed chlorinators                 $0.23
- Ultraviolet light (57,600 GPD)    $0.49
- Ozonation-high pressureb		     $0.53

## Opportunities from the Bureau of Reclamation

- 1.  Research
-      Research Awards   $$
-      Water Treatment Primer
-      Mobile Pilot Water Treatment Plant
-      Water Quality Improvement Center
- 2.  Technical Assistance
-       Needs Assessments
-       Design Services
-       Plant Operations and Maintenance Manuals

## Technology Transfer

- Desalting and Water Treatment Membrane Manual
- Water Treatment Primer for Communities in Need
- DesalNet CD-ROM of abstracts for 785 OSW/OWRT reports, with AWWA, demonstration version
- Updating Desalting Handbook for Planners
- Newsletter three times a year
- 25 previous desal reports available

## Technology Transfer

- Updated Internet homepage:
- www.usbr.gov/water/water.html
- www.usbr.gov/water/desalting.html
- Sponsoring technical conferences and workshops

## Mobile Water Treatment Pilot Plant

*Mobile*** ***Water Treatment Pilot Plant*

## Eye Wash

## Reclamation Water Quality 

**Improvement Center**

**  ****Purpose**
**  ****To Provide a Cost Effective Pilot Testing Facility for Private Industry, Municipalities, Universities, Tribal Organizations, and U.S. and Foreign Governmental Agencies to Test Improved Water Treatment Technologies in the Field   **
**  ****Is Offered On a Cost-Shared or Cost-Reimbursed Basis **

## Water Quality Improvement Center

**Water Quality Improvement Center**

## Reclamation Water Quality 

**Brackish (TDS = 3000 ppm)**
**Colorado River & Well Water  (TDS = 800ppm)**
**Services**
**licensed operators**
**experienced engineering staff**
**on-site water quality lab**
**data access via internet **
**customized use agreements**
**permits in place**
**furnished office space**
**hands-on operator training**

**Reclamation Water Quality **

**Improvement Center ****(Continued)**

## Reclamation Water Quality 

**Improvement Center (Continued)**

**Process trains**

**sedimentation**

**lime softening**

**chemical addition**

**multi-media filtration**

**microfiltration**

**ultrafiltration**

**nanofiltration**

**reverse osmosis**

## Water Quality Improvement Center

**Water Quality Improvement Center**

## Water Quality Improvement Center

**Water Quality Improvement Center**