Water Re-use Standards and Codes

Transcription

1 Water Re-use Standards and Codes - What is Important from a Water Treatment Perspective Water Quality Association

2 The Water Quality Association The Water Quality Association (WQA) is a notfor-profit international trade association representing the residential, commercial and industrial water treatment industry. WQA Membership: Manufacturers Dealers Allied Industries

3 Water Reuse - What is Important from a Water Treatment Perspective Microbiological Safety Material Safety Structural Integrity Contaminant Reduction Performance Proper installation and maintenance

4 Microbiological Safety Ensuring the right level of microbiological protection is one of the most important challenges for water reuse applications The source water is likely to contain pathogens, and you may need to collect the raw source water into a storage basin that is conducive to microbiological growth Depending on the intended application for this water, some type of treatment may be needed to protect public health

5 Common Microbiological Treatment Technologies Chemical disinfectants Ozone generators UV treatment Mechanical reduction / Membrane technology Distillation / Heating

6 Chemical Disinfection In the United States, efficacy is already established through the FIFRA registration process (Federal Insecticide, Fungicide and Rodenticide Act) For potable water applications, Public Health concerns due to formulation (or contamination of formulation) can be avoided by using chemicals which are certified to NSF/ANSI 60

7 Microbiological Drinking Water Treatment Devices In the United States these systems are called Purifiers Examples of water treatment devices commonly used for potable applications include UV systems, Carbon block filtration, Ultrafiltration membranes, Ozone generators and Distillation units Efficacy of these systems is currently evaluated against drinking water treatment unit (DWTU) standards such as the USEPA Guide Standard and Protocol for Testing Microbiological Water Purifiers

8 USEPA Guide Standard and Protocol for Testing Microbiological Water Purifiers USEPA Guide Standard establishes performance criteria for reduction of bacteria, virus and cyst. Examples of intended applications include: Backpackers and campers; Motor homes and trailer; Non-standard military requirements; Floods and other natural disasters; Foreign travel and foreign stations Contaminated wells and sources Not intended for extreme contamination situations or for conversion of waste water to potable water

9 Comparison of Microbiological Reduction Standards Partial List of Microbiological Reduction Standards which are Applicable to Water Re-use Standard USEPA Guide Standard Source water application Unknown source water (but Not Wastewater) Treated water Application Drinking water NSF P231 [ Same as the USEPA Guide Standard ] NSF 350 Greywater or Blackwater Restricted and unrestricted urban water use (e.g., toilets, subsurface irrigation, restricted crop irrigation) NSF Greywater Subsurface discharge

10 What Level is Safe? Knowing how the water will be used is critical To estimate health based risk levels for drinking water we assume a consumption rate of approximately ½ gallon per day We then examine the infective dose for oral consumption of that pathogen: Infective dose - The amount of a pathogen (# of microorganisms) that is required to cause an infection Potential Gap: For some pathogens the infective dose is lower for respiratory infections than it is for gastrointestinal infections, therefore inhalation of airborne pathogens from a decorative fountain or a sprinkler system could be a exposure route that requires more evaluation for some applications.

11 Water Reuse - What is Important from a Water Treatment Perspective Microbiological Safety Material Safety Structural Integrity Contaminant Reduction Performance Proper installation and maintenance

12 Material Safety for Potable Applications Material safety of components is covered under NSF/ ANSI 61 Material safety of treatment systems is covered under various Drinking Water Treatment Unit (DWTU) standards published by CSA, IAPMO, NSF and WQA. How is material safety evaluated? Expose the product to water, and test the water to determine if any harmful chemicals were leached into the water due to formulation, or contamination, of the product

13 Exposure Water for Material Safety Testing of Drinking Water Treatment Units Potential gap: Is the exposure water we are using to test representative of water reuse? Exposure water used is designed to simulate tap water, example of exposure water from NSF/ANSI 42: 45 to 55 mg/l TDS 0.45 to 0.55 mg/l free chlorine ph of 6.5 to 7.0 Temperature of 21 to 25ºC

14 Water Reuse - What is Important from a Water Treatment Perspective Microbiological Safety Material Safety Structural Integrity Contaminant Reduction Performance Proper installation and maintenance

15 Structural Integrity for Potable Applications Structural Integrity of treatment systems is also covered under DWTU standards Potential gap: These standards are not always clear about what to do with treatment systems, or portions of a treatment system, which are not exposed to standard line pressure (e.g., a system that is only exposed to pump pressure)

16 Water Reuse - What is Important from a Water Treatment Perspective Microbiological Safety Material Safety Structural Integrity Contaminant Reduction Performance Proper installation and maintenance

17 Contaminant Reduction for Potable Applications Contaminant Reduction for potable applications is also covered under DWTU standards. What type of testing is required? Systems are challenged with a contaminant, and reduction of that contaminant is measured down to the EPA Maximum Contaminant Limit (MCL) or a level which minimizes the risk to public health

18 Exposure Water for Material Safety Testing of Drinking Water Treatment Units Potential gap: Testing assumes a relatively clean source water Example - Challenge water for testing a carbon filter used for the reduction of Nitrate and Nitrite in accordance with NSF/ANSI 53: 24 to 36 mg/l Nitrate plus Nitrite 200 to 500 mg/l TDS >1.0 mg/l Total Organic Carbon <1 NTU Turbidity ph of 7 to 8 Temperature of 17.5 to 22.5ºC

19 Residential RO Systems Potential gap: Green codes are not harmonized to encourage the reuse of water from residential RO systems LEED encourages reuse of the reject water from RO systems ICC and IAPMO Green code disallow the reuse of reject water

20 Water Reuse - What is Important from a Water Treatment Perspective Microbiological Safety Material Safety Structural Integrity Contaminant Reduction Performance Proper installation and maintenance

21 Installation and Maintenance of the Water Treatment Device It is critical to utilize a water treatment specialist for installation and maintenance of the water treatment device. Improper installation or lack of maintenance could lead to: Poor performance Fouling Low water pressure Contamination The WQA Professional Certification and Modular Education programs incorporate field experience, comprehensive exams and continuing education to ensure that water treatment specialists are qualified to install and maintain water treatment devices.

22 Thank you Eric Yeggy Director of Technical Affairs Water Quality Association