Pre-Chlorination prior to slow sand filtration
Pre-Chlorination prior to slow sand filtration
(OP)
Hi
I will be responsible for commissioning a pre-chlorination system for the control of zebra mussels in the near future. I would be interested to hear from anyone with regards suitable dose rates (as a Cl2 residual)needed to kill the mussels, together with any tips or suggestions for operating such a plant up-stream of slow sand filtration.
Many Thanks
Paul
I will be responsible for commissioning a pre-chlorination system for the control of zebra mussels in the near future. I would be interested to hear from anyone with regards suitable dose rates (as a Cl2 residual)needed to kill the mussels, together with any tips or suggestions for operating such a plant up-stream of slow sand filtration.
Many Thanks
Paul





RE: Pre-Chlorination prior to slow sand filtration
A very good resource is the "Practial Manual for Zebra Mussel Monitoring and Control". Chapter 5 is quite extensive on Chlorination. (You can find the book on Amazon for $129new). It will give you the tools and knowledge to prepare. Good luck on startup!
Jon Gribble, PE
Paterson Candy North America
A Division of Black & Veatch
Water Treatment Design-Build Process Contractors
RE: Pre-Chlorination prior to slow sand filtration
I have ordered a copy of the manual! I am interested to know of any experience you might have with such systems prior to slow sand filteration? My concern is of a chlorine residual making it onto the beds and wipping out the good bugs in the filter skin.
Thanks again
Paul
RE: Pre-Chlorination prior to slow sand filtration
I have some experience starting up similar systems; however, you've confused me with the comment about "good" bugs on the skin of a slow sand filter. A chlorine residual you will likely not leave any bugs whatsoever unless they have a strong resiliency against oxidation. The mussels being a multicelled organism can withstand quite a bit, whereas smaller or single cell organisms simply don't have the body mass to resist a chlorine residual.
Perhaps you could explain the process you will be starting up and it's purpose to better understand what you are asking.
Jon Gribble, PE
Paterson Candy North America
A Division of Black & Veatch
Water Treatment Design-Build Process Contractors
RE: Pre-Chlorination prior to slow sand filtration
The system will be used to dose sodium hypochlorite at around the 2ppm level to raw water (prior to pre-ozonation and rapid filtration) in order to kill the adult mussels during their "non-breeding" period. Once the adult mussels have been removed the dose of hypo will be reduced to around the 0.5 ppm level to prevent re-infestation during the warmer months. I am interested to know of any control methods I can implement or any experiences in operating such a system that will help to prevent any residual chlorine from reaching the slow sand filters and killing the schmutzdecke.
Thanks again
Paul