Retrofitting Step Type Sewage Screens. Do You Replace With a New One?

April 14, 2020

Step Screen was invented by HUBER’s Swedish subsidiary Hydropress AB in the early 1980’s and has been the most copied fine screen.

Across Australia and New Zealand hundreds of step type screens have been installed with many now reaching the end of life.
So do you replace the step screen with a new one or with an alternative technology?
Since the invention of the step screen many different screen types are now available on the market which offer higher screening capture rates.
A summary of solutions from Hydroflux Epco is as follows:

Screen Type	Advantage	Disadvantage
RakeMax Mutli Rake Bar Screen	High screening efficiency Totally enclosed Easy to retrofit with similar dimensions to step screen Handles very high levels of grit, sand and screenings NSEF certified for 75% capture	Submerged bearing One dimensioning screening profile
Escamax Band Screen	High screening efficiency Totally enclosed Easy to retrofit with similar dimensions to step screen NSEF certified for 84% capture	Higher headloss than step type screen Reliance on washwater supply

There are numerous items to consider when replacing a step type screen:

Screening capture rates
Additional headloss and hydraulic considerations that the inlet works can sustain
Reliable washwater supply is required with some screen types
Channel modifications to accommodate a new type of screen

Hydroflux Epco’s staff have been involved with sewage screening technology since the mid 1990’s and can provide advice on how to approach the replacement of your existing step type screen with either a new or alternative screen type.
For more information on the Hydroflux Epco’s Screens and screening systems please click here.