1. Requirements to produce high quality water Stephen Stanley, Ph.D., P.Eng. EPCOR Water Services

2. Capable Plant Model High Quality Treated Water Operation (process control) Capable Plant AdministrationDesignMaintenance

3. Capable Plant  A capable plant means if it is managed, operated and maintained properly, the plant has the required infrastructure to meet all requirements  Criteria for capable plant largely dependent on regulation

4. Capable Plant  Requirements constantly changing as new information becomes available v turbidity requirements have gone from 5 NTU to 1 NTU to 0.5 NTU and now proposed to go to 0.3 NTU  Requirements for a capable plant also dependent on raw water source v ground water - disinfection v surface waters - filtration and disinfection

5. Capable Plant - Giardia Example

6. Capable Plant Multi-barrier Approach  Water treatment uses the concept of multi- barriers to meet treatment requirements v a number of treatment processes which are each barriers for contaminants  Giardia example for 4 log removal v Clarification 0.5 log removal v Filtration 2.0 log removal v Disinfection 1.5 log removal

7. Capable Plant - Cryptosporidium  One of the greatest challenges facing the water industry  Regulations just starting (US EPA and Canada)  Resistant to chlorine (loss of major barrier)  For conventional treatment must rely on particle removal  UV and ozone disinfection effective

8. Capable Plant - Regulation  Regulations generally based on the concept of reducing the risk associated with water to an “acceptable” level v other factors include available technology and economics  Poorer standards result in greater risk that public health can compromised v typically event related (when plant challenged)

9. Capable Plant - Summary  Requirements of a capable plant dependent on regulation  Also dependent on raw water source  Capability of plant restricted to design flow rates  A capable plant only provides the ability to produce high quality water if proper administration, maintenance and operational systems are in place

10. Adminstration  Relates to having administrative policies, and staffing and funding requirements needed to produce high quality water  Requires a commitment from senior administration to produce high quality water  Needs quality assurance and quality control programs to ensure high quality water  Must ensure adequate staffing and funding are available

11. Design  Design of a treatment facility must not only meet requirements for the capable plant but must also consider operational and maintenance realities  Design should also consider technical expertise required

12. Maintenance  To make a capable plant sustainable, regular maintenance must occur  Maintenance activities must consider operational constraints and must be planned accordingly  For critical systems redundancy may be required

13. Operations - Process Control  Water treatment of surface waters, especially those treating river waters is a very dynamic process v raw water quality may vary from a turbidity of 1 NTU to over 1000 NTU v water demand may vary by 3 times  Treatment plants must constantly vary operating conditions (chemical doses, flows, etc.)

14. Operations - Process Control  For process control require: v a measure of the state of the system v comparison of the current state to the desired state v an action (for example a change in chemical dose) to return the system to the desired state

15. Challenges in Process Control  Multiple and conflicting objectives v water quantity vs. water quality v disinfection vs. disinfection by-products  Multiple operating parameters v must simultaneously adjust more than one chemical dose and operating conditions

16. Challenges in Process Control  Long residence time in plant v if treated water turbidity increases and requires change in coagulant dose at front of plant, can have 3 to 5 hours of water in the plant that must pass through before change will be noticed v requires intermediate assessment of treatment process

17. Challenges in Process Control  No standard methods to determine proper chemical dosing v must rely heavily on operator experience v must ensure available tools are being used (jar tests)

18. Operations - Process Control  Upsets can occur in water treatment  Must have clearly defined emergency response plans  Should have programs such as a boiled water notice in place  Can not wait for illness

19. Production of High Quality Water  Requires not only a capable plant but proper administration, design, maintenance and operations  Failure in any of these areas significantly increases the risk to public health

20. The Challenge  Requirements for the production of high quality of water is largely independent of the size of the community  The complexity of the treatment system is largely dependent on the quality of the raw water  The challenge is implementing the requirements in smaller communities