Water Engineering Tools
High-precision calculators, membrane mass balances, and chemical projection models built for water process engineers and desalination specialists.
Quick Jump
Engineering Workflows
RO System Analysis
Follow a membrane system from feedwater to design review, one calculation at a time.
- Feedwater Define feed source and quality
- 1 Recovery Permeate vs concentrate flow
- 2 Mass Balance Salt and flow balance across membranes
- 3 Permeate / Concentrate Quality and concentrate load
- 4 Osmotic Pressure Net driving pressure check
- 5 Scaling Risk LSI / S&DSI tendency
- 6 Design Review Explore staged design scenarios
Featured Tools
RO Recovery Calculator
Calculate RO permeate and concentrate flow from feed flow and system recovery rate.
Recovery (%) = (Permeate Flow / Feed Flow) × 100 RO Salt Rejection Calculator
Calculate membrane salt rejection percentage from feed and permeate TDS concentrations.
Rejection (%) = (1 - (Cp / Cf)) × 100 RO Permeate TDS Calculator
Project expected permeate total dissolved solids based on feed water salinity and rejection specs.
Cp = Cf × (1 - R / 100) Water Engineering Disciplines
Reverse Osmosis (RO)
Membrane recovery, mass balance, salt rejection, and permeate quality.
Explore tools →Desalination Systems
Thermal and membrane desalination energy, recovery, and sizing.
Explore tools →Water Treatment
Coagulation, filtration, softening, and chemical dosing.
Explore tools →Water Quality & Chemistry
Langelier Saturation Index (LSI), TDS conversion, and conductivity.
Explore tools →Hydraulics & Pumping
Pipe friction loss, pump sizing, Darcy-Weisbach, and Hazen-Williams.
Explore tools →Water Resources & Hydrology
Watershed yield, storm runoff, and water storage balances.
Explore tools →All Water Engineering Tools
29 ToolsRO Recovery Calculator
Calculate RO permeate and concentrate flow from feed flow and system recovery rate.
Recovery (%) = (Permeate Flow / Feed Flow) × 100 RO Salt Rejection Calculator
Calculate membrane salt rejection percentage from feed and permeate TDS concentrations.
Rejection (%) = (1 - (Cp / Cf)) × 100 RO Salt Passage Calculator
Determine salt passage percentage through RO membranes and verify complementary rejection balance.
Passage (%) = (Cp / Cf) × 100 RO Permeate TDS Calculator
Project expected permeate total dissolved solids based on feed water salinity and rejection specs.
Cp = Cf × (1 - R / 100) RO Concentrate Flow Calculator
Compute brine/reject flow rates and volumetric stream balances for disposal or ZLD design.
Qc = Qf - Qp = Qf × (1 - Y / 100) RO Osmotic Pressure Calculator
Estimate RO feed osmotic pressure using a simplified van’t Hoff model from TDS, temperature, and solute properties.
π = i × C × R × T RO Design Studio
Build a preliminary RO system design with feed inputs, staging, custom membrane data, sequential element estimates, balances, and warnings.
Q = A × S × (ΔP − Δπ) RO Mass Balance Calculator
Simplified TDS-based dissolved-solids balance for RO feed, permeate, and concentrate flow and quality checks.
Qf · Cf = Qp · Cp + Qc · Cc RO Scaling Risk & Pretreatment Analysis
Screen CaCO3 scaling risk in RO feed and concentrate using the Langelier Saturation Index (ASTM D3739) and the Stiff & Davis Stability Index (S&DSI) for high-TDS and seawater feeds.
LSI = pH − pHS · S&DSI = pH − pCa − pAlk − K RO Membrane Sizing Calculator
Calculate required number of membrane elements and pressure vessels from design flux.
RO Energy & Specific Power Calculator
Determine specific energy consumption (kWh/m³) based on operating pressure and pump efficiency.
RO Operating Cost (OPEX) & SEC Calculator
Estimate RO operating expenditure: pumping energy (specific energy consumption), chemical cleaning, antiscalant, and membrane replacement.
SEC = P_feed × Q_f/(η_pump·Q_p) · OPEX = Σ (energy + chemical + membrane + maintenance) RO Concentration Factor & Salt Load Calculator
Compute RO water concentration factor (CF = 1/(1−Y)) and the salt load carried to concentrate for scaling and disposal analysis.
CF = 1 / (1 − Y) · Salt Load = Q_f × C_f × Y_loading RO Feed Pressure & Specific Energy Calculator
Estimate required RO feed pressure (permeate osmotic gap + net driving pressure) and specific energy consumption with optional energy recovery.
P_feed ≈ Δπ + (J × 100/B·SCP factor) + ΔP_friction RO Antiscalant & Chemical Dosing Calculator
Calculate antiscalant (or chemical) dosing rate and 100% active-equivalent flow from dose concentration and product strength.
Dose Flow = Q_feed × Dose_ppm / (C_prod × 100) (SG-adjusted) RO Membrane & Vessel Element Count Calculator
Calculate number of RO membrane elements and pressure vessels from permeate flow, design flux, and element area.
Elements = Q_p / (Flux × A_element) · Vessels = ⌈Elements / Elements per Vessel⌉ Pump Power Calculator
Calculate hydraulic power, shaft power, and motor electrical power from head and flow rate.
HPump = ρ × g × Q × H / η Engineering Unit & Water Quality Converter
Convert flow rates and TDS concentration units (mg/L ↔ ppm) using the Site canonical unit engines (m³/day internal).
Canonical flow unit = m³/day · 1 mg/L ≈ 1 ppm (dilute aqueous) Pipe Flow & Friction Loss Calculator
Determine pipe velocity, friction head loss, and pressure drop via Darcy-Weisbach or Hazen-Williams.
v = Q / A · hf = 10.67 × L × Q^1.852 / (C^1.852 × D^4.871) Open Channel Flow (Manning′) Calculator
Compute open-channel velocity and discharge with Manning’s equation for trapezoidal, rectangular, and circular channels.
v = (1/n) × R^(2/3) × S^(1/2) · Q = v × A Pipe Flow Velocity & Sizing Calculator
Size a pipe to carry a target flow within a recommended velocity range, or check velocity for a given diameter.
D = √(4Q / (π·v)) · v = Q / A Reynolds Number & Flow Regime Calculator
Calculate Reynolds number for pipe flow and classify the flow regime (laminar / transitional / turbulent).
Re = ρ·v·D / μ Pipe Pressure Drop (Darcy–Weisbach) Calculator
Compute pipe head loss and pressure drop with the Darcy–Weisbach equation, solving the Colebrook friction factor.
hf = f × (L/D) × (v²/2g) · f via Colebrook-White Pump Head / Total Dynamic Head Calculator
Compose total dynamic head from static lift, friction losses, minor losses, and residual pressure.
TDH = H_stat + h_friction + h_minor + h_residual Pressure & Head Unit Converter
Convert pressure and head units: bar, kPa, MPa, psi, m H₂O, ft H₂O, and atmospheres.
1 bar = 100 kPa = 14.5038 psi = 10.197 m H₂O Volumetric → Mass Flow Converter
Convert volumetric flow to mass flow (and reverse) using fluid density, with common water/TDS basis.
ṁ = ρ × Q · Q = ṁ / ρ Water Tank Storage Calculator
Size cylindrical and rectangular water storage tanks from dimensions or daily demand and residence time.
V = π/4 × D² × H · V = L × W × H Water Demand & Flow Requirement Calculator
Estimate community or facility water demand (domestic, commercial, fire) and the design flow requirement for supply and storage sizing.
Q_design = P · q · peakFactor · Q_avg = V_daily / 86400 Tank Fill Time & Filling Rate Calculator
Calculate the time to fill a storage tank from a known filling rate, or the filling rate required to meet a target time.
t = V / Q · Q = V / t Knowledge & Resources
Technical Guides
Aquifer storage & recovery, filtration, desalination concepts.
Explore →Engineering Concepts
RO recovery, osmotic pressure, membrane selection.
Explore →Equipment References
Pumps, membranes, pressure vessels, energy recovery.
Explore →Manufacturers
Membrane and RO component manufacturers.
Explore →Desalination Projects
Source-backed SWRO plant case studies.
Explore →