UV Technology Overview provided by The HALMA …Operators...UV Disinfection Guidance Manual –...

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UV Technology Overview provided by The HALMA Group

Steve DoyleAugust 14,, 2018

Presentation Overview

1. Disinfection Options

2. Physics, Chemistry & Biology

3. How UV Works

4. UV Lamps Types

5. Design Considerations

6. Available Configurations

7. Application Examples

Types of Disinfection: Chemical

• Considerations– Storage + Containment– Safety + Spills– Aquifer salinification – Degradation– By-product formation– Resistant pathogens

• Chemical Species

Chlorine

Chloramine

Per Acetic Acid

Chlorine Dioxide

Bromine

Peroxide

Onsite Hypochlorite

Chemical Feed and Analysis Options

• Gaseous, liquid, solid forms of chemicals ----pick what is best for your plant

• Storage tanks and handling facilities required

• Go with onsite generation and now you’re in the manufacturing business

• Gotta mix it after delivering it to the reactor = More equipment to maintain

• Gotta measure it and make sure you don’t overdose or underdose

• Decisions are based on flow rates, loading and temperature

• Read the directions on your test kits make sure you test your instruments too

• Don’t overdose the dechlor either just to be safe…. Or your O2 is out of the stream

• Being too safe kills fish by deoxygenation

Types of Disinfection: Chemical

Chemical Disinfection systems are not always the lowest cost option in long haul

• New tanks with double walls or sumps to meet new codes• Secondary containment cost for concrete• Delivery Station designs and safety at bulk transfer point• Carbon footprint over time for deliveries• Costs for Vapor treatment if leaks and spills occur add to the HVAC bill• Special Materials of construction for feed pumps valves pipe and fittings • Extra costs now associated with SCADA monitoring of systems • Instrumentation incl flow meters, level + pressure, mixers for dilution water

concentration analyzers before and after addition & incl residual monitoring• Paperwork and Hazmat Training – Annual Inspections and Safety Plans

Amperometric

colorimetric

spectrophotometric

Source - Walchem

Ammonia – present or absent

Online analyzers and locations

Conventional Contact Tanks with Concrete Baffles

A) Clean Box Retrofit or B) Use Baffle Walls if wide enough

Types of Disinfection: UltraViolet Light

Solar Halo during 2017 Eclipse + Hubbell telescope in UV spectrum

UV History from various sources

Bactericidal Action of UVIn 1877, Downes and Blunt, two English scientists, discovered by chance that sunlight could kill bacteria. They noted that sugar water placed on a window PETRl dish turned cloudy in the shade but remained clear while in the sun.

Upon microscopic examination of the two solutions, they realized that bacteria were growing in the shaded solution but not in the one exposed to sunlight.

It wasn't until 1892 that Marshall Ward demonstrated that it was primarily the ultraviolet portion of the spectrum that had the bactericidal action. (Kime 1980)

UV Lamp DevelopmentThe first fused PETica quartz arc tube was developed by a pair of Germans, S. Kuch and T. Retschinsky, In 1906. They managed to get more light output from a quartz glass tube as compared to standard glass because the quartz glass tube could endure the higher operating temperature associated with a higher tube pressure that was required to generated more light output. Quartz was also the ideal choice of material because it was less chemically reactive to the hot chemicals and gases encountered within the lit arc tube.

• The development of mercury lamps as artificial UV light sources in 1901 and the use of quartz as a UV transmitting material in 1906 were soon followed by the first drinking water disinfection application in Marseilles, France, in 1910.

• In 1929, Gates identified a link between UV disinfection and absorption of UV light by nucleic acid. The development of the fluorescent lamp in the 1930s led to the production of germicidal tubular lamps.

• Considerable research on the mechanisms of UV disinfection and the inactivation of microorganisms occurred during the 1950s (Dulbecco 1950, Kelner 1950, Brandt and Giese 1956, Powell 1959).

Types of Disinfection: UltraViolet Light

The Sun ~ 4.5 billion years old

21st Centurydown-sizing!

• The first reliable applications of UV light for disinfecting municipal drinking water occurred in Switzerland and Austria in 1955 (Kruithof and van der Leer 1990).

• By 1985, the number of such installations in these countries had risen to approximately 500 and 600, respectively. After chlorinated disinfection byproducts (DBPs) were discovered, UV disinfection became popular in Norway and the Netherlands with the first installations occurring in 1975 and 1980, respectively.

• My first experiences with UV in WWTFs was in the mid 1980s when small Low Pressure Lo Power lamps were used to replace chlorine and avoid dichlorination.

• I have worked with a couple of different manufacturers and can share personal observations as we proceed through the presentation and at breaks

1Process Water travels into the chamber and is exposed to UV light

2Water contains microbes which the UV light takes seconds to destroy their reproductive capability …. But If dose is absorbed or blocked by particles or other compounds ???

3UV light is effective against all known microbes, pathogens, fungi and spores

UV Technology is a chemical-free methodof delivering disinfection of processwater with various levels of bio-security

Types of Disinfection: UV Photolysis

Types of UV Disinfection

• Ultraviolet• Open Channel• Closed Vessel

• Lamp Types• LP• LPHO• MP

• Considerations• Footprint• Power• Operator

Knowledge

Municipal Product Platforms

Medium Pressure (MP)Low Pressure (LP)

LP & MP

Lamp type:

• Low pressure and medium pressure validated product platforms• Bio security and energy efficiency to suit municipal requirements• Platform products “Application optimized” into :

• AmaLine UV• InLine UV• ProLine UV• OpenLine UV

OpenLine(Re-use &

waste water)

InLine+(Larger

Drinking water)

AmaLine (Medium

Drinking water and

reuse, waste water )

ProLine(Small

Drinking water)

Disinfection Chemical vs. UV

•UV is a safe, environmentally friendly technology

• No disinfection by-products

• Chemical-free; no transportation, storage or safety concerns

• Effective against Chlorine resistant pathogens, e.g. Crypto. & Giardia

• Responsible water treatment strategy; WW of upstream communities ultimately becomes DW of downstream communities

1970 1985 2000 2008 2020

Chlorine Disinfection UV Disinfection

Disinfection Chemical vs. UV

Chlorine Ozone UV

Transport & Feed Safety

Crypto Effectiveness -

No By-Products

Residual

Contact Time & Footprint

High High Low

Operating Cost Low High Mid

Capital Cost Low High Mid

Total Carbon Footprint High High Low

Parts of Microbes Affected by Chemical and UV Disinfection

UV Disinfection Chlorine Disinfection

Metabolic Processes

Nuclear Area - Containing DNA

UV 101 – Common Vocabulary

Low-pressure (LP) Lamp – a mercury-vapor lamp that operates at an internal pressureof 0.13 to 1.3 Pa (2 x 10-5 to 2 x 10-4 psi) and electrical input of 40 – 150 watts. This results in monochromatic light output at 254 nm.

Low-pressure high-output (LPHO) Lamp – a low-pressure mercury-vapor lamp thatoperates under increased electrical input 100 to 500W, resulting in a higher UVintensity than low-pressure lamps. It also has essentially monochromatic light output at254 nm.

Monochromatic – light output at only one wavelength, such as UV light generated bylow-pressure and low-pressure high-output lamps.

Medium-pressure (MP) Lamp – a mercury vapor lamp that operates at an internalpressure of 1.3 and 13,000 Pa (2 to 200 psi) and electrical input of 1000-15,000 W. Thisresults in a polychromatic (or broad spectrum) output of UV and visible light at multiplewavelengths, including wavelengths in the germicidal range.

Polychromatic – light energy output at several wavelengths such as with MP lamps.UVDGM p. xiv

UV 101 – Common Vocabulary (con’t)

UV: a spectrum –light wavelengths – (100 nm – 400 nm)

Inactivation: microbe cannot reproduce or infect; some may repair, particularly viruses

Log reduction: Reduction of the amount of Colony Forming Units(CFUs) by– 90% - 1 log– 99% - 2 log– 99.9% - 3 log– 99.99% - 4 log

Hydraulics: Water flow patterns in a water treatment system; can impact disinfection inside a unit

Bacteriophage: a virus that infects bacterial cells and can be used a microbial surrogate (i.e. MS2)

UV Dose Response: How a microbe responds to dose; how much dose does it take to get a specific level of inactivation

UV Action Spectrum : the relative efficiency of UV energy at different wavelengths ininactivating microorganisms. Each microorganism has a unique action spectrum.UVT: UV transmissivity – measure of UV blockers in the water – the % of UV that transmits through 1 cm

UVDGM p.2-17

Electromagnetic Spectrum

ltraviolet

UVA Blacklight315 - 400 nmUVB Suntan280 - 315nm

UVC Germicidal200 - 280 nm

Ultraviolet

Visible light

Invisible

UV-Vacuum100 - 200 nm

Spectral Output of UV Lamps

UV exposure penetrates cell wall, disrupts DNA and prevents cell reproduction

DNA before exposure

Effects of UV irradiation on DNA

UV, The Mechanism

DNA after exposure

And this Photochemical (photo oxidation)reactions happensagain and againup and down the DNA chain

Microbial Response to UV

UV Light Generation

ELECTRODE + ELECTRODE -

UV Lamp Types

Parameter Low Pressure – LP Amalgam – LPHO Medium Pressure - MP

Germicidal UV Light

Monochromatic @ 254 nm

Polychromatic(185 – 315 nm)

Typical Lamp Output (W)

40 - 150 150 – 1000 500 – 10,000

Germicidal UV Output (W/cm)

0.2 0.5 - 3.5 5 - 30

# of Lamps for Given Dose

High Intermediate Low

Lifetime (hrs) 8,000 – 10,000 8,000 – 12,000 6,000 – 10,000

Lamp Types Construction

Spectral Output of UV Lamps

Medium Pressure Lamp

Low Pressure Lamp (254 nm) LPHO increases the peak 2 to 3 x

Spectral Output as a function of Water Temperature

Wipers & Cleaning Mechanisms 1935 to present day

• Acid Cleaning: S. Ellner was issued US Patents 4103167, 4899056 and Re34513 in 1978, 1990, and 1994 respectively for using an acid to clean quartz sleeves either in-place with a recirculation system or after lifting the UV modules out of a channel. All of these methods required that the UV system be taken out of service.

• P. Binot was issued a US Patent in 1998 for using an acid and air injection system for cleaning a pressurized UV system.

• Air Scouring: P. Schuerch et al. was issued a US Patent 5332388 in 1994 for an air scouring system for a vertical lamp UV system for disinfecting wastewater.

Creighton 1935 gear driven wiper

UV Technology Types Many Options and Vendors

UV Dose Origins WW & Reuse

1. NWRI Guidelinesdefined bioassay protocol & regulatedchallenge organism: MS2 phage (~ 20 mJ/cm² / log)suitable for high level reuse (> 30 mJ/cm²)

• California “Title 22”

2. PSS / CFDtheoretical calculationfor all disinfection levels (15 - > 100 mJ/cm²)

3. General Secondary Bioassaytypically inhouse, no defined protocol, not regulatedtypical organism: native fecal coliforms (~ 5 mJ/cm² / log)suitable for low/medium level disinfection (< 25 mJ/cm²)

UV Dose Origins Drinking Water

1. USEPA - UVDGM

UV Disinfection Guidance Manual – November 2006, surface water treatment (LT2), specified dose according to targeted organism (crypto, giardia or virus removal)

2. DVGW

German validation required by law in Europe, dose requirement set to 40 mJ/cm2 regardless of targeted organism

UV Validation Protocol Tests, Trial Runs, Collect Data

UV System Planning and Design

Step 1: Establish Target for Disinfection– Discharge limit of microbe (e.g. 200 FC/100 ml)– Certain log reduction of microbe (e.g. 4 log E.coli or virus)– Deliver a certain UV Dose (e.g. 40 mJ/cm2)

Step 2: Determine how much UV equipment is needed– Function of flow rate, UV-T, Lamp Type, Configuration– Historical site data beneficial

Ultimate goal is to transfer UV light through specific effluent into target microbes ---- to break molecular bonds

25,000 GPD to 1.5 MGD 1.5 MGD to 20 MGDParameter Influence / Effect Typical RangeUV Percent Transmittance

Measure of UV absorption

Effects system sizing requirements

50 – 70 % - WW

85 – 95 % - DW

Turbidity Measure of light scattering

Effects disinfection performance< 5 NTU recommended

Minerals

Coagulants

Can cause scaling on quartz sleeves

Effects UV transmission

Fe < 0.1 mg/l

Mn <0.1 mg/l

Suspended Solids

Absorbs UV light & shields bacteria

Effects disinfection performance

< 30mg/l recommended

< 10 mg/l preferred

Design Considerations: Water Quality

Design Considerations: Footprint

• What works best for the facility?

• Inherent differences in products

– Medium pressure system –typically small footprint

– LO / LOHO systems - larger footprint and higher construction costs.

– Some exceptions – do your homework.

10152025303540

LP LPHO MP

Design of UVT of 65%, 30 mJ/cm2

LP systems 15 X

LPHO Systems 5 XBigger than MP Systems

Design Considerations: Location

• Indoor versus Outdoor Installation?

• Wind Speed + Flying Debris impacts

• Other Factors to Consider and Weigh

– Temperature (AC, Heat)

– Protection (Canopy, NEMA 4X)

– Accessibility & maintenance

– Lamp cable length

– New construction / Retrofit

– Wear and tear on equipment

Design Considerations: General

Maintenance Space

Air Entrapment

Sampling Location

Headloss

Existing Infrastructure

Design Considerations: Reactor Type Selection

Factors to Consider

• Installation location

• New or existing installation

• Water quality

• Total cost; construction & O&MIso 9001 & Iso 14001 Certified

• Lamp Modules suspended in concrete channels

• Modular Design – Vertical, Horizontal or Inclined Lamps

• Key Equipment Features– LP or LPHO or MP Lamps– Level Control– Automatic Cleaning System

• Hydraulic vs Pneumatic

– Electronic Ballasts + Mena 4X or 12 Cabinets• Ancillary Equipment

– Finger Weir Level Control vs Gate Based Control– Hoists, Cranes, Trolley system and Dip Tanks– Compressor or pump– Baffle plates and straight flume lengths

Open Channel Configuration

Berson OutLine 2400

Trojan UV 4000

Open Channel SS Channel Configuration

•Lamp Modules in pre-engineered s/s channels

•Module Design – vertical, inclined or horizontal lamps

•Key Equipment Features– LP or LPHO Lamps– Level Control– Automatic Cleaning System

• Hydraulic vs Pneumatic

– Electronic Ballasts Cabinets

•Ancillary Equipment– Hoist– Compressor or pump– Isolation valves– Baffle plate

• Retrofit into chlorine contact tank at facility • New channel build – 1/8” design • Concrete pad – rebar considerations + forms

Open Channel Concrete Channels

Open Channel Inclined Lamp Designs

• Recent Improvements – 50% fewer bulbs• Higher power lamps – 600 – 1000 w• Self lifting – No cranes or hoists• Shorter Footprint – room in future• More efficient lamps – better power use

• Lamps housed in stainless steel reactor• Lamps arranged parallel or perpendicular to flow• Key Equipment Features

– MP or LPHO Lamps– Automatic Cleaning System– Temperature monitoring– Ballasts Cabinets

• Ancillary Equipment– Air Relief valves– Isolation valves

Closed Vessel Configuration

• Ballast Type– Benefits of Electronic vs electromagnetic

• Sensor Type– Dry DVGW type sensor vs relative sensor

• Automatic Cleaning– Electric with chemical options

• Retrofit into chlorine contact tank at facility • New build• Piping must keep water in unit at all times

Closed Vessel Implementation

Protective Tube –Prevents Pinch Points

Support Rod

Vessel Head plate

Teflon Spacer/Balancer – Keeps Rod centered and prevents scraping Linear Bush and Housing

Wiper Assembly

Handles – make it easy to pull out Assembly

Maintenance Support Arms

Ancillary Devices Comparison

Device Open Channel

Closed Vessel

Hoist xCompressed air /Hydraulic fluid x

Baffle Plate xIsolation gates/weirs/valves

Air Relief xChannel / Piping x x

40 Years Lessons Learned

UV Layout & Interfacing

– Hydraulics

• Upstream straight pipe run

• Flow balancing - design EQ

– MatchingUV process to yours

• Multiple daily start/stops e.g.

Sequencing Batch Reactor

• Filter Backwash

– lamp temperature

– channel level/flow

Water Quality

– Industrial Water Quality Disruptions• Contribute to UVT, TSS and Color • influent fecal spikes possible too

– Algae • Clarifier and channel covers inhibit growth• Mechanical wipers remove from sleeves

– Iron, Manganese & Hardness• Precipitates onto sleeves & requires

chemical cleaning with mild acid rinse

40 Years Lessons Learned

Application: Membrane Process

Insert AQX site photo………

InLine 5000+UVT 75% 5 MGD

Application: Aerated Lagoon Effluent

InLine 100+UVT 20% 95 gpm seasonally til storage ponds are drained

Application: Secondary Treated Effluent

OpenLine CUVT 65% 7.5 MGD

Application: NWRI Reclaimed Water

InLine 7500+UV-T 65% Flow: 1.3 MGDDose: 80 mJ/cm2 RED

Why Use UV?

• Advantages– Low maintenance costs– No DBPs (Chemical Free)– No flavor, odor or physical

effects– Environmentally safe– Non corrosive– No possibility of over dosing

• Disadvantages

– Increase in electricity costs

– Certain system types allow exposure to UV

What did we Learn Today?

Where UV is used it is important to understand…– UV, an environmentally sound alternative

to chlorine disinfection.– Water quality– Footprint– Location– Process

but most of all…..– Evaluate disinfection alternatives!

UV Technology Overview provided by The HALMA …Operators...UV Disinfection Guidance Manual –...

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