How the Converter Works
This converter is powered entirely by the Site canonical unit engines
(src/lib/units/flow.ts and src/lib/units/concentration.ts).
Every flow conversion is resolved through a single internal reference unit —
cubic meters per day (m³/day) — so results are internally
consistent and never depend on hard-coded two-unit factors scattered across a page.
V_to = fromCanonical(toUnit) × toCanonical(fromUnit)(V_from) Where:
-
m³/day= Canonical internal unit for all flow conversions [cubic meters per day] -
Qf= Flow rate expressed in the source unit [varies by selected unit] -
ppm= Parts per million (≡ mg/L for dilute aqueous solutions) [mg/L]
Derived Equations:
V_canonical = V_from × toCanonical(from) V_to = V_canonical × fromCanonical(to) 1 mg/L ≈ 1 ppm (dilute aqueous) Supported Units
Flow Rate (m³/day canonical)
- m³/day — cubic meters per day (canonical)
- m³/h — cubic meters per hour (× 24 to canonical)
- L/day — liters per day (/ 1000 to canonical)
- L/min — liters per minute (× 1440 / 1000 to canonical)
- GPD — US gallons per day (× 264.172052358 factor; canonical = value / factor)
Water Quality Concentration
- mg/L — milligrams per liter
- ppm — parts per million
Worked Engineering Example
Scenario: Desalination Plant Flow & Brine Concentration
An RO facility reports a product delivery of 240 m³/h and a brine TDS of 6,800 mg/L. Convert both to the units requested by the client engineers.
- Permeate 240 m³/h → m³/day (canonical):
240 × 24 = 5,760 m³/day - And 5,760 m³/day → GPD:
5,760 × 264.172 = 1,521,632 GPD - Brine 6,800 mg/L → ppm:
6,800 mg/L = 6,800 ppm(dilute-aqueous equivalence, see limitations)
Engineering Notes & Limitations
- 1 mg/L ≈ 1 ppm is an approximation for dilute aqueous solutions. It is valid for TDS screening in water treatment (density ≈ 1.0 kg/L) but is not a universal conversion for all dissolved solids or concentrated brines.
- Flow conversions are volumetric and assume standard conditions. Actual installed capacity should be verified against pump and membrane data sheets.
- This converter is a unit utility. Scaled conversion factors are internal to the canonical engine — editing a factor updates every calculator that shares the engine.
Frequently Asked Questions
What is the canonical flow unit and why does it matter?
The canonical unit is m³/day. Each flow conversion passes through it, so m³/h → L/min and m³/h → GPD agree with each other exactly. Consistency is guaranteed because there is one source of conversion truth.
Is ppm always equal to mg/L?
In water treatment, 1 ppm ≈ 1 mg/L for dilute aqueous solutions where water density is about 1.0 kg/L. This is the standard screening assumption for TDS. For concentrated brines, chemical dosing, or non-aqueous fluids, the conversion is not exact.
Which flow units are supported?
m³/day (canonical), m³/h, m³/hour (compatibility alias), L/day, L/min, and US GPD. Units are defined once in the central flow engine so all EngiMetric calculators share identical factors.
Engineering Disclaimer
Engineering Note: This calculator provides simplified engineering estimates for preliminary analysis and educational use. Actual RO system performance depends on membrane type, feedwater chemistry, temperature, pressure, recovery, concentration polarization, pretreatment, and operating conditions. Final system design should be verified using manufacturer data, validated design software, applicable standards, and qualified engineering review.
Technical References
- DuPont FilmTec™ Reverse Osmosis and Nanofiltration Technical Manual (Form No. 45-D01504-en).
- AWWA Manual M46: Reverse Osmosis and Nanofiltration, American Water Works Association.