Inspection of Disinfection Components

1. Inspection of Disinfection Components NC Certified Subsurface Systems Inspector Training School

2. CIDWT Disclaimer These materials are the collective effort of individuals from academic, regulatory, and private sectors of the onsite/decentralized wastewater industry. These materials have been peer-reviewed and represent the current state of knowledge/science in this field. They were developed through a series of writing and review meetings with the goal of formulating a consensus on the materials presented. These materials do not necessarily reflect the views and policies of the Consortium of Institutes for Decentralized Wastewater Treatment (CIDWT). The mention of trade names or commercial products does not constitute an endorsement or recommendation for use from these individuals or entities, nor does it constitute criticism for similar ones not mentioned.

3. NDWRCDP DisclaimerThis work was supported by the National Decentralized Water Resources Capacity Development Project (NDWRCDP) with funding provided by the U.S. Environmental Protection Agency through a Cooperative Agreement (WPA No. X-830851-01-0) with Water Environment Research Foundation (WERF) in Alexandria, Virginia. These materials have not been reviewed by the U.S. Environmental Protection Agency, NDWRCDP, or WERF. The contents of these materials do not necessarily reflect the views and policies of the NDWRCDP, WERF, or the U.S. Environmental Protection Agency, nor does the mention of trade names or commercial products constitute their endorsement or recommendation for use.

4. Disinfection, not Sterilization • Goal of disinfection: • Inactivate pathogens or prevent their reproduction • May not get all of them • Sterilization removes ALL LIFE

5. Chlorine Disinfection • Chlorine is an oxidizer. • Destroys target organisms by oxidation of cellular material. • Critical parameters for effectiveness • Relatively clean effluent • Adequate contact time.

6. Chlorine Residuals • Chlorine still present after the disinfection process • Highly toxic to living organisms in receiving waters • Dechlorination may be required if residual is > 0.2 mg/L

7. Caution: high risk • Safety is critical • Exposure • Handling • Corrosive • Unstable Work safely!

8. Tablet Chlorinators Four Components: • Chlorine tablets • Tube that holds tablets • Contact device • Storage reservoir

9. Tablet Chlorinator

10. Typical Chlorine Tablets Calcium hypochlorite • NOT A POOL TABLET!!!!!

11. Dechlorination • Tablet de-chlorinators • Units and tablets similar to chlorinators • Sodium bisulfate

12. Inspection procedure Form 7.5 Inspection Checklist: Disinfection Unit- Chlorine (DUC)

13. Caution: high risk • Safety is critical • Exposure • Handling

14. 1. Operation of chlorination system a. Manufacturer b. Model # c. Disinfection unit appears in good condition • Level • Watertight

15. Status • Acceptable • Unit is intact, level • Unacceptable • Unit is damaged, off level

16. 2. Tablet chlorination a. Chlorinator appears operable b. Tablets in place (pull cylinder) • Type of tablets c. Tablets in contact with effluent

17. 2. Tablet chlorination (cont.) d. Chlorine residual • Free • Total • Testing method • Chlorine meter • Colorimetric

18. Status • Acceptable • Tablets in feeder and in contact with effluent • Chlorine residual present • Contact chamber is accessible and intact • Unacceptable • No tablets in feeder or tablets not in contact with effluent • No chlorine residual present • Contact chamber is inaccessible or damaged

19. 3. Influent characteristics • Clear or Cloudy? Check at Advanced treatment unit Collect a sample in a clear container

20. 4. Tablet dechlorination • Required? a. Dechlorinator appears operable b. Tablets in place • Type c. Tablets in contact with effluent d. Contact chamber appears operable e. Chlorine residual Should be 0

21. Status • Acceptable • Tablets in feeder and in contact with effluent • Correct tablets in use • No chlorine residual measured • Contact chamber is accessible and intact • Unacceptable • No tablets in feeder or tablets not in contact with effluent • Wrong type of tablets • Chlorine residual present • Contact chamber is inaccessible or damaged

22. Questions?

23. Inspection of UV Disinfection Components

24. UV Disinfection • Is NOT sterilization • Pathogen removal is the goal • Critical parameters for effectiveness • Relatively clean effluent • Adequate contact time

25. Ultraviolet Light Disinfection Units • Destroys microorganisms by altering their genetic material and / or retarding ability to reproduce

26. Caution: high risk • Safety is critical • Exposure • Handling

27. Eye Protection • Proper eye protection should be used when inspecting an UV disinfection unit. • DO NOT look directly at the UV light with the power on.

28. Generating UV light

29. Ultraviolet Light Disinfection Units • Electromagnetic energy (UV light) from source lamp is emitted into a chamber through which effluent passes

31. Inspection of UV Disinfection Unit Form 7.6 Inspection Checklist: Disinfection Unit- Ultraviolet (DUUL)

32. 1. Power supply a. Is unit gravity or pressure dosed? b. Manufacturer and model # c. Is power supplied to the unit? d. Is the UV lamp on? e. Is the electrical system free of corrosion or damage?

33. 1. Power supply (cont.) f. Last ballast replacement date

34. Status • Acceptable • Power to unit • Lamp on • No corrosion or damage to unit • Unacceptable • No power • Lamp off • Unit is corroded or damaged

35. 2. UV controls • Does the unit have a lamp intensity sensor? • If so, what was intensity reading? • Alarm present? • Alarm operating properly?

36. Status • Acceptable • Intensity reading adequate • Alarm present and operable (visible and audible) • Unacceptable • Inadequate intensity • Alarm not present or not operable (visible or audible)

37. 3. Contact chamber, lamp, and sleeve conditions a. Evidence of damage or leakage b. Type of protective sleeve: • Quartz • Teflon • Other:___ c. Protective sleeve free of buildup d. Protective sleeve last replaced: ________ • From ORC report

38. 3. Contact chamber, lamp, and sleeve conditions (cont.) e. Date lamp last replaced: ________ • From ORC report

39. Status • Acceptable • No damage to or leakage from unit • Reasonable build-up on sleeve • Unacceptable • Unit damaged or leaking • Considerable buildup on sleeve • Red flags

40. 4. Influent characteristics • Clear or Cloudy? Check at Advanced treatment unit Collect a sample in a clear container

41. 5. Control Panel (may not be included) a. Controls operating properly b. Is enclosure watertight c. Alarm test switch operating properly d. At time of inspection, control switch was set to: N.A.___________ “Hand/Manual”__ “Auto”_________ e. If auto, setting: Time On:_______ (min) Time Off:________ (min)

42. Status • Acceptable • Water tight enclosure • Alarm switch operating • Control switch on AUTO • Unacceptable • Enclosure not water tight • No alarm operation (audible or visible) • Red flags

43. 6. Housing • Location:_________________ • Appears in good condition • Leaks/Cracks present • Excessive dust present

44. Status • Acceptable • Housing appears in good condition • No leaks or cracks present • No excessive dust present • Unacceptable • Housing damaged • Excessive dust • Red flags

45. Inspections of UV Light Disinfection Are there any questions ?