Wastewater Operator Calculator
Shift Math for Licensed Ops
Free · Designed for iPad. Not verified for macOS.
The professional wastewater calculator is built for licensed operators.
16 essential calculations covering Class I through Class IV certification math — from basic Pounds formulas to MCRT, F/M Ratio, and Volatile Solids Reduction. Every result shows the formula and your substituted values so you can verify the math yourself.
CALCULATORS INCLUDED:
Hydraulics & Loading
• Pounds / Mass Loading (lb/day = MGD × mg/L × 8.34)
• Flow Rate Conversions (MGD, GPM, GPD, cfs)
• Detention Time (accepts GPD, MGD, or GPM)
• Percent Removal
• Chemical Dose / Feed Rate (dry and liquid with SG)
• Surface Overflow Rate (SOR)
Solids Control
• Sludge Volume Index (SVI)
• Return Activated Sludge Rate (RAS %)
• MLSS / MLVSS Inventory
• RAS Solids Balance
Process Control
• Sludge Age — Basic (Class I/II)
• MCRT / SRT — Full (Class III/IV, includes effluent SS)
• F/M Ratio
• Solids Loading Rate
• OUR / SOUR
• Volatile Solids Reduction (Van Kleeck)
BUILT FOR THE FIELD:
• Works 100% offline — concrete bunkers, underground pump stations, rural facilities
• Large, readable results designed for gloved hands
• "Show Your Work" expands to show your exact values substituted into the formula
• Copy Result pastes a formatted summary ready for texts or emails to your supervisor
• Formula reference screen with all formulas, variables, and source attribution
• Calculation history saves your last 20 results
• Dark mode support
SHOW YOUR WORK:
Every result displays the formula that produced it. Tap "Show Your Work" to see your actual input values plugged into the equation — the same way you'd show work on a certification exam.
Based on ABC, Sacramento State OIT, and state certification formula sheets.
Ratings & Reviews
-Integrated anonymous signals for issue resolution
The developer, Mike Watson, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Mike Watson
- Size
- 28.1 MB
- Category
- Utilities
- Compatibility
Requires iOS 15.1 or later.
- iPhone
Requires iOS 15.1 or later. - iPad
Requires iPadOS 15.1 or later. - iPod touch
Requires iOS 15.1 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Mike Watson