ADVANCES IN UV TECHNOLOGY FOR 4-LOG VIRUS DISINFECTION OF GROUNDWATER. Scott Bindner OWWA Annual Conference May 2014

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1 ADVANCES IN UV TECHNOLOGY FOR 4-LOG VIRUS DISINFECTION OF GROUNDWATER Scott Bindner OWWA Annual Conference May 2014

2 BACKGROUND Drinking water treatment varies depending on the source of raw water Surface Water Treatment: Primary Treatment (Coagulation) Filtration Primary Disinfection (SWTR) Secondary Disinfection (Residual) Groundwater Treatment: Natural Filtration (Cleaner Water?) Primary Disinfection? Secondary Disinfection (Residual)

3 DISINFECTION OF GROUNDWATER Environmental Health Perspectives, September, 2012 Demonstrated epidemiological evidence that untreated groundwater can cause gastrointestinal illness Increasing concerns that GW supplies are exposed to pathogens Leaking Septic Systems Degradation of WW Collection Infrastructure

4 DISINFECTION OF GROUNDWATER Health Canada recommends 4-log inactivation of enteric viruses Many groundwater treatment sites provide only residual disinfection and rely on natural filtration to remove pathogens If certain indicators of enteric viruses are detected (Eg. fecal coliforms) then primary disinfection measures might be required before residual and distribution UV for primary disinfection of enteric viruses has historically been used less frequently given the relatively higher required dose compared to other pathogens

5 UV FOR VIRUS TREATMENT

6 VALIDATING UV FOR VIRUS TREATMENT

7 TROJAN S APPROACH: A HIGH RESISTANCE SURROGATE To validate UV reactors to a dose of 186 mj/cm 2, a UVresistant surrogate was required Why use a surrogate? Target organisms can be highly pathogenic EPA recommends surrogates in the UVDGM Validation using adenovirus itself has many difficulties Traditional surrogate organisms like MS2 and T1 are not resistant enough to measure doses of >200 mj/cm 2

8 ASPERGILLUS BRASILIENSIS ATCC SELECTED Fungal spore Meets all EPA recommendations regarding an acceptable surrogate 1. Easily cultured to high concentrations (full scale tests) 2. Easily managed to ensure good repeatability in validation tests 3. Non-pathogenic (safe test procedures) 4. Good stability (shipping, lab handling) 5. High UV resistance (measure high UV doses > 186 mj/cm 2 )

9 RESULT UV SYSTEM VALIDATED FOR VIRUS TREATMENT 4 LPHO UV Units third-party validated to inactivate 4-log virus. Capable of treating over 700 m 3 /hr per unit (4-Log Virus) Additional validation for chlorine resistant microorganisms including Cryptosporidium and Giardia

10 INSTALLING UV FOR VIRUS TREATMENT

11 HALL ROAD, PENNSYLVANIA UV INSTALLATION Background Groundwater Extraction 1.5 MGD (5.7 MLD) Design Flow Operated by Aqua Pennsylvania (Aqua PA) In 2009 PA State Regulators passed legislation mandating ALL groundwater providers install 4-log virus inactivation

12 HALL ROAD, PENNSYLVANIA UV INSTALLATION OPTION #1 IMPROVE CHLORINE TREATMENT Chlorine is an effective method for the disinfection of virus BUT This often requires increasing contact time (CT) Increasing CT involved installing/expanding pipeline Can significantly increase plant footprint

13 HALL ROAD, PENNSYLVANIA UV INSTALLATION OPTION #2 UV DISINFECTION Disinfection is instantaneous No extensive CT required Minimal additional piping required for Hall Road Lower capital expense Much smaller footprint No risk of DBP (HAAs and THMs)

14 HALL ROAD, PENNSYLVANIA UV INSTALLATION FOOTPRINT COMPARISON 100 Added Volumetric Footprint (m 3 ) Chemical Disinfection 3 UV Disinfection Chlorine Disinfection 430 feet of 36 pipe required to increase CT for 4-log virus treatment UV Disinfection 2 UV reactors plus controls

15 HALL ROAD, PENNSYLVANIA UV INSTALLATION PERFORMANCE Validated Dose (mj/cm 2 ) mj/cm Flow (liters/second) Operating Dose Target Dose Flow Rate (L/s) 0.0 Jul-12 Aug-12 Sep-12 Oct-12 Nov-12 Dec-12 Time 0

16 WHY UV FOR VIRUS?

17 WHEN CUSTOMERS DON T WANT HIGHER CHLORINE Increasing CT for virus either means increasing; Storage/contact time Increasing chlorine concentration With distribution system already built, increasing chlorine is an obvious step Increasing chlorine leads to: Chemical, chlorinous taste Higher cost associated with additional chemicals Potential disinfection by-product formation UV enables 4-log virus compliance without increasing chlorine concentrations

18 WHEN AMMONIA IS PRESENT Ammonia in water in leads to formation of chloramines when free chlorine is added Ammonia in source water can come from: Fertilizer application Runoff from animal feed lots Manufacturing of fibers, plastics, explosives, paper, and rubber Some geographies have a consistently high background ammonia If ammonia is present in source water, chloramines formed are ineffective for virus treatment UV enables 4-log virus compliance in the presence of source-water ammonia

19 WHEN CHLORINE LEADS TO WATER DISCOLORATION In plants with iron or manganese present, increased chlorine can: Oxidize Fe/Mn Result in brown water and discoloration of clothes, appliances, etc. At sites that have not previously applied chlorine: New water chemistry introduced by chlorine can erode deposits in pipes Lead to corrosion of pipes from increased chlorine Also resulting in water discoloration UV enables 4-log virus compliance without changing water chemistry

20 WHEN PLANTS HAVE ALREADY CONVERTED TO CHLORAMINES Many plants have converted to chloramines to reduce disinfection byproducts Chloramines in distribution system generally lead to lower DPBs Chloramines are ineffective for virus treatment UV enables 4-log virus compliance when chloramines are used in the distribution system for reducing DBPs

21 SUMMARY Increasing demand for groundwater providers to carry out 4- log virus primary disinfection UV systems are now third-party validated to inactivate 4-log virus in accordance with USEPA standards Use of a high-resistance surrogate to validate UV systems is a preferred approach and is backed by USEPA Possible reductions in footprint and DBPs and improved safety due to reduced chlorine demands.

22 THANK YOU