Estimate energy cost for small pump-injector system for Ozon treatment

[MartinLe]

We are considering options for ozone treatment of wastewater (trace pollutant elimination). One reactor type would be a pump injector system, a small pump circulates a part stream of the tank volume through a venturi (wher ozone is added) and then a static mixer (I think, I'm still learning about this type of reactor). I'm at loss to estimate head losses of these components. Though I doubt the energy cost of the pump will be that significant compared to the ozone generation, we have to consider it.

 

[nondimensional]

Pump headloss calculation is no different in any other situation. Downstream of the injector, you will need a mixer - usually a static mixer by Mazzei, Sta-ti-Flo or equal - followed by the rest of the pipe. Static mixer adds about 5 to 7 psi of head to the pp besides the piping friction and fitting losses. If the discharge point back in the tank is below water level, then you don't have any static head. Pump total head should not exceed 30 to 40 ft.

Annual energy cost = ((Q x H / (3956×Pump Efficiency × Motor eff) × 0.746 (kw/ hp) × $/kWh x 8760 (hrs/yr)

Q is in gpm
H is in ft of H2O

 

[MartinLe]

Thanks! 5 - 7 psi for the static mixer was one missing puzle piece, the other was the headloss of the venturi pump. Do you have any idea or guidance here?

 

[nondimensional]

When you say a venturi pump, are you talking EDUCTOR? If so, the eductor manufacturer should give you the requirements for this.

This below is based on the assumption that you are using an eductor/venturi for extracting Ozone. See image below. In this image, you know a given required Ozone flow from the SUCTION side. Based on the pressure on the ozone side and required flowrate of O3, the eductor manufacturer will give you the MOTIVE flow and pressure. Add additional static mixer loss, and other dynamic losses in the piping and you size the pump on the MOTIVE flow side.