Disinfected industrial pond E.coli levels lower than found in the local river!
Critical parameter is UVT transmittance
A meat processing plant operates a multi-stage pond system for the treatment of their wastewater before irrigation or discharge into the local river. While pond systems can provide adequate treatment of solids and organics, the disinfection capability of ponds are typically variable and highly dependent on climatic conditions.
A critical parameter when considering UV disinfection is the UV transmittance (UVT) of the liquid. UVT is a measure of how much UV light can pass through a liquid. A UVT of 100% means all the UV light can pass through the liquid, whereas a UVT of 0% is opaque not allowing any light through.
Figure 1: UV transmittance through different liquids.
Conventional UV technology was deemed infeasible
Pond effluents always have low UVTs and for industrial effluents this makes the situation even worse. In this case study the meat plant pond was known to have a UVT typically less than 10%. Due to this low UVT, conventional UV technology was deemed infeasible.
In a month-long evaluation, a full-scale NovoLabs™ Supercritical UV™ disinfection system was set up to treat the effluent at the end of the pond system. 48 million litres of wastewater with an average UVT of only 3.5% were disinfected across the month-long test. The results are shown in Figure 2.
Figure 2: Disinfection achieved at end of meat works pond system compared to the local river E.coli concentration.
As shown in Figure 2, NovoLabs™ Supercritical UV™ technology was not only able to effectively disinfect the meat plant pond effluent, but it was able to reduce the E. coli concentration to below the average found in the local river!
