# Presentation: 504269

## Practical Applications and Engineering Aspects of UV for Drinking Water Treatment

*Practical Applications and Engineering Aspects of UV for Drinking Water Treatment*

- John E. Dyksen
- United Water Management & Services

## Today’s Talk  

- History of UV
- Fundamentals of UV
- UV Applications
- UV System Components
- Costs of UV Systems
- Atlanta UV Project
- Conclusions

## History of UV

- Late 1800s - Germicidal effects of energy from sun
- Early 1900s -  First practical application
- Mid 1900s -  Disinfection of industrial process water
- Mid 1980s - BAT for wastewater treatment
- Mid 1990s - Interest for municipal drinking water disinfection

## UV Disinfection for Drinking Water

- 1920s - Used on ships
- 1970s Residential applications (POU)
- 1985 - Over 1,000 installations in Europe
- Today - Over 2,000 installations in Europe 		     - Over 1,000 installations in U.S.

## Fundamentals of UV

- What is UV?
- Terms
- Concept of UV Dose
- Types of UV Reactors

## Ultra Violet - Beyond the Violet

## Ultra Violet - Beyond the Violet

## Terms

- UV Output  -  Energy Delivered (W/lamp)
- UV Irradiance  -  Rate of Energy Delivery 				 (uW/cm2)
- UV Transmittance  -  Ability of water to transmit 			        UV light

## UV Dosage

- Dosage  	=  	Irradiance 	x  	Time
- 			= 	 uW/cm2     	x  	sec
- 			=	(uW - sec)/cm2
- 			=	mJ/cm2

## Measuring UV Dosage

- Irradiance
- Chemical actinometry
- Radiometers or UV sensors
- Mathematical models
- Time
- Calculate using simple equations
- CFD models
- Bioassay Methods

## UV Reactors

- Low Pressure Lamps (LP)
- Low Pressure High Output lamps (LPHO)
- Medium Pressure Lamps (MP)
- Flash Lamps  -  Pulsed Output

## Path of UV Light in Water

- Lamp Encasement
- Water Quality
- Target Organism

## UV Applications in Drinking Water

- Disinfection of Surface Water
- Disinfection of Ground Water
- Oxidation of Organic Chemicals
- Oxidation of NOM

## UV Effectiveness

- Crypto/Giardia	10-20			4 log
- Bacteria		20-40			4 log
- Virus			50-150		4 log
- Geosmin		3000			90%
- MTBE		9000			90%
- EPA			40-140		-----

- 		         _Dose_		_Removal/Inactivation_
- 		       (mJ/cm2)

## UV Treatment Application

- Pretreatment

- Raw Water

- Filtration

- UV Reactor

- To Distribution

## UV System Components

- Lamps
- Sleeves
- Electronics
- Reactors
- Sensors

## Lamp Construction

- Tungsten Electrode

- Tungsten Electrode

- Mercury Vapor and Argon

- Quartz Envelope

## Key Design and Operating Factors

- Target Organism
- Water quality matrix
- UV Sensors
- Lamp type
- Cleaning mechanism
- Reactor type

*Key Design and Operating Factors*

## Effects of Water Quality

- Turbidity
- Iron, Manganese, Calcium, Magnesium
- NOM
- Temperature

## By-Product Formation

- THMs		-	none
- AOC		-	35 - 85% increase
- Aldehydes	-	minimal
- Nitrite		-	none

## Costs of UV Systems

- Capital		--	$50,000/mg
- O+M		--	1c/1,000 gallons

## Comparison of Disinfection Costs (3 MGD)

## Atlanta UV Project

- 12 Month pilot study
- UV Reactors
- Aquionics	-	MP
- IDI		-	LPHO

*Atlanta UV Project*

## Atlanta UV Project Objectives

- Reliability
- By-product Formation
- Regulatory Requirements
- Construction Issues
- Costs
- Comparison with other technologies

*Atlanta UV Project Objectives*

## Benefits of UV

- No chemicals added to water
- Small footprint
- Pressurized system
- Cost Effective
- No DBPs
- Oxidize organic chemicals

*Benefits of UV*

## UV Issues

- Performance monitoring
- Giardia Inactivation
- Algae Growth
- Fouling
- DBP formation

*UV Issues*