FAQ
- What is the benefit of collimated beam testing?
Collimated beam testing takes the guesswork out of sizing a UV disinfection system. Suppliers of UV systems can use the results of collimated beam testing to optimise the design of their system, reducing capital and operating costs while ensuring resource consent compliance (providing the UV system is maintained appropriately).
- What results does your testing provide?
We provide viable faecal indicator organism counts at a range of UV dose rates, typically 0, 5, 10, 15, 20, 25 and 30 mJ/cm2, and produce a dose response curve. We also analyse the sample for TSS, %UVT, and filtered %UVT, and include these results in our report.
- How frequently should collimated beam testing be undertaken?
As a minimum, we recommend undertaking collimated beam tests on at least three separate occasions. The more tests undertaken, the better your UV system supplier will be able to optimise the design of the UV system for your WwTP.
- How does a UV system supplier use the results of collimated beam testing to design a UV system?
The dose-response curve generated from collimated beam testing determines the effectiveness of UV disinfection under closely controlled conditions. Your UV system supplier will apply "real world" multiplication factors to the data set. These multiplication factors will be influenced by the resource consent conditions you need to achieve (e.g. median, mean, 90-percentile, or maximum faecal indicator organism concentrations), and the type of treatment processes prior to the UV system.
- What volume of wastewater do you require for testing?
2 litres
- Are your collimated beam tests accredited?
No. The tests are based on the methodology outlined in Appendix C of USEPA (2008) “Ultraviolet disinfection guidance manual for the final long term 2 enhanced surface water treatment rule”, but are not accredited.
- How repeatable are your collimated beam tests?
Test conditions are closely controlled, so the tests are very repeatable.
- What is the cost of your collimated beam testing?
The cost of testing will depend on which, and how many types, of faecal indicator bacteria you are interested in. e.g. Escherichia coli, faecal coliforms, and/or enterorocci. This will probably be dictated by the conditions of your resource consent. Please contact us to discuss your requirements.