Wastewater Treatment Plant Design Calculation Xls Better [SAFE]

While there are many basic templates out there, I'm looking for something more robust — better organized, transparent formulas, user-friendly input/output sections, and preferably with built-in unit conversions and error checks.

: Calculations for Food to Microorganism (F:M) ratio , Sludge Retention Time (SRT) , and Hydraulic Retention Time (HRT) . wastewater treatment plant design calculation xls better