Backwash strategy · Energy · Contamination load
Estimate the economically sensible backwash point.
The quick check compares the current backwash strategy with an economically optimized switching point. It considers additional pump work, backwash costs and the hydraulic fouling rate derived from the observed backwash interval.
Cost minimum depending on the backwash point
Increasing additional pump work meets decreasing backwash frequency. The intersection yields the economic minimum.
Current and optimized annual costs
Only additional pump work influenced by fouling and backwash costs are compared.
Calculation logic
The real contamination load is approximated from the observed behavior of the existing filter.
GHGavoided = net electricity savings · electricity emission factor
Assumptions: constant average flow, linear differential-pressure increase between two backwashes, unchanged backwash effect and constant variable backwash costs per cycle. The unavoidable clean filter pressure loss is identical in both strategies and cancels out in the comparison. Non-cycle-dependent annual costs – for example unchanged secondary filtration of the same contamination load – should not be treated as additional backwash costs. If flow varies strongly, the calculation must be performed time-dependently with Q(t), Δp(t) and η(t). The greenhouse gas figure considers only electricity consumption. Emissions from water supply, disposal, chemicals, transport and production are not included. Optional electrical energy demand per backwash is included in the net electricity and greenhouse-gas balance, but is not monetized additionally because it is typically already included in the entered backwash costs.
Validate the result with real operating data.
For variable load profiles, multiple filter trains or pumps and a robust business case, we analyze your time series on a site-specific basis.