During storm events, many wastewater plants may be unable to achieve the required effluent quality and, in worst cases, untreated wastewater may bypass the plant.

A serious health and environmental concern

Combined sewer overflow may contain particulate and soluble wastes from domestic sewage, industrial and commercial wastewaters. These waste products include suspended solids, bacteria, viruses, nutrients, toxic pollutants, oil, grease and debris, posing significant risks to receiving water quality, public health and aquatic life.

Municipalities are being challenged to eliminate all discharges of untreated wastewater caused by Combined Sewer Overflows (CSO).

Actiflo® Clarifier

Veolia applies its Actiflo® process for high rate clarification and removal of total suspended solids and particulate biochemical oxygen demand materials during wet weather conditions.

  • The Actiflo® effluent typically achieves higher than 90% removal, making flows easily disinfected with UV or chlorination.
  • The Actiflo® process can be used in parallel with a conventional water treatment plant or at a satellite facility within the collection system.
  • Offering unlimited treatment capacity, the Actiflo® process allows elimination of overflows.
  • Process trains can be used for primary and/or tertiary treatment during dry weather flows.

The effectiveness of Actiflo® in treating wet weather flows has been proven at facilities around the world.

Hydrovex® line of wet weather technologies

With more than 10,000 installations across North America, the HYDROVEX® line of wet weather technologies (John Meunier products) offers a wide range of sustainable, efficient and high quality solutions, including:

  • Flow control for stormwater runoff
  • Flow control for combined and sanitary flows 
  • Level control in collection systems
  • Floatables screening
  • Off-line or in-line retention and treatment
Flow Control  

Without energy, no moving parts

Hydrovex® FluidGate Valve

Hydrovex® FluidHook Valve 

Hydrovex® VHV/SVHV Vortex Flow Regulator 

Hydrovex® Pond Vortex Flow Regulator

Hydrovex® IHV Euro Type Vortex Flow Regulator

Hydrovex® IHV/HHV Inclined Flow Regulator


Without energy, with moving parts

Hydrovex® Turbo Flow Regulator 

Hydrovex® FluidMoon Adjustable Gate Regulator

Hydrovex® FluidCasca Float Gate Valve 

Powered Flow Control

Hydrovex® HHV-E Regulator

Hydrovex® FluidMid Flow Metering with Siphon (Type G) 

Hydrovex® FluidMid Flow Metering without Siphon (Type U)

Flow measurement 

Hydrovex® Tipper Flow Measuring 

Check Valves 

Hydrovex® CCV  

Hydrovex® LCV 

Membrane Regulator 

Hydrovex® TTT

CSO Storage & Treatment  

Vortex Separator

Hydrovex® Fluidsep 

Sediment Flusher

Hydrovex® SFT 

Self Regulating Outlet Slit

Hydrovex® Clari

Overflow Control  

Overflow Weir Profile

Hydrovex® FluidWing 

Bending Weir

Hydrovex® BW 

Spring-Loaded Weir 

Hydrovex® Flap 

Air Regulated Siphon

Hydrovex® ARS 


Oscillating Static Screen 

Hydrovex® Fluidscreen

Storm Overflow Screen 

Rotarc® SOS

Low Profile Overflow Screen


Rotary Drum Sieve 

Hydrovex® RDS

Overflow Screen


Overflow Fine Screen

Rotarc® SAS