What can we expect from an SDS test?
The “Simulated Distribution System” (SDS) test is misnamed, since it actually measures only the disinfection by-product (DBP) formation with contact time in the water entering distribution, rather than the water in the distribution system. Nevertheless, about 50 percent of SDS tests performed to date have reflected a reduction in total trihalomethanes (TTHM) formation with mixed oxidants in contrast to conventional chlorine. Even if the effect does not occur in an SDS test, TTHMs may still be reduced in actual practice, due to biofilm removal, reduced chlorine dosing, and/or microflocculation. Note that in no SDS study have TTHMs formed with mixed oxidants ever exceeded levels formed with chlorine at the same free available chlorine (FAC) concentrations.
When conducting an SDS test, the experimenter should take into account not only the chlorine dose, but also the chlorine residual. Often, in an SDS test, mixed oxidants will maintain a much higher chlorine residual than conventional chlorine after days of detention time. Doses should be adjusted appropriately to obtain the same chlorine residual with both solutions, after the required detention time. This often means a lower dose upfront with mixed oxidants, which are then more likely to exhibit a reduced DBP formation.
Technical
- How do MIOX salt and energy conversion efficiencies compare to other on-site chlorine generators?
- Do MIOX generators require special salt quality for operation?
- How stable is the mixed-oxidant solution?
- How much sodium is added to the treated water?
- How do mixed oxidants reduce TTHM formation?
- What can we expect from an SDS test?
- What are mixed oxidants?
that the MIOX technology is available in a personal use device called the MSR MIOX Purifier, effective against viruses, bacteria, Giardia, and Cryptosporidium?