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How to specify net capacity for a municipal UF train
Account for backwash, cleaning, reserve trains and plant downtime in membrane capacity calculations.
HOSON WATER editorial ·
Distinguish gross filtrate from delivered water
A train may produce its stated flow during filtration while consuming some product water during backwash and losing production time during cleaning. Specify net output at the delivery point. Identify whether the claimed figure subtracts internal uses and whether it assumes a particular feed condition, duty cycle or number of trains in operation.
Check capacity when one train is unavailable
Use a simple daily balance for ordinary duty, the most demanding source condition and a maintenance scenario. Set permitted time windows for cleaning and check whether adjacent trains and treated-water storage can bridge the gap. Keep reserve capacity and typical spare inventory visible in the design so reviewers can compare alternatives at an equivalent reliability level.
Ask for the same design basis from bidders
Provide the required net daily output, hourly demand profile, temperature range, incoming solids conditions, filtered-water specification and known utility limits. Require a bid schedule that lists feed, gross filtrate, internal use and net output. During acceptance, record real tank and piping boundaries to avoid counting the same water twice.