Water and wastewater engineering calculators

Calculators

• Hydraulics

  Pipe pressure drop and head loss calculator

  Friction head loss and pressure drop for water in a full pipe: Darcy-Weisbach with Colebrook-White, fittings, static lift and a Hazen-Williams cross-check.

• Pumping

  Pump head, NPSH and power calculator

  Total dynamic head, NPSH available, flange pressures, power and energy cost for a pumped water system, with system and pump curves, operating point and VSD speed.

• Drainage

  Sewer and drain pipe capacity calculator

  Full-bore and part-full capacity and velocity of a gravity sewer by Colebrook-White, checked against the Water UK Design and Construction Guidance.

• Flow measurement

  Weir flow calculator

  Flow over 90° V-notch and rectangular weirs from head, or head from flow, with weir loading rate for clarifier and DAF launders.

• Water reuse

  Rainwater harvesting tank size calculator

  BS 8515 simplified tank sizing from collection area, rainfall and non-potable demand, with the share of demand met and mains water replaced.

• Storage

  Tank volume and dip table calculator

  Volume at any depth, depth for a volume and a dip table for vertical, cone-bottom, horizontal and rectangular tanks.

• Wastewater

  Activated sludge design calculator

  Sludge age, reactor volume, MLSS, oxygen demand, sludge production and return activated sludge rate from flow, BOD and ammonia.

• Wastewater

  Aeration and blower sizing calculator

  Process oxygen demand to standard oxygen transfer rate, diffuser air flow and blower power, with alpha, beta, SOTE, depth and temperature corrections.

• Chemical dosing

  Chemical dosing calculator

  Dose in mg/L to pump rate, daily chemical use, storage days and cost for coagulants, hypochlorite, caustic, acid and polymer.

• Wastewater

  Clarifier and settling tank sizing calculator

  Surface overflow rate, solids loading, weir loading and retention time for primary and final clarifiers, with diameter and depth.

• Water treatment

  DAF sizing calculator

  Air to solids ratio, recycle rate, saturator pressure, hydraulic and solids loading, tank area and float volume for dissolved air flotation.

• Wastewater

  Population equivalent, DWF and loads calculator

  Population equivalent, dry weather flow, Formula A, flow to full treatment and daily BOD, ammonia, solids and phosphorus loads.

• Hydraulics

  Hydraulic retention time and tank sizing calculator

  HRT from volume and flow, or the volume for a target HRT, with peak flow, dead volume and tank dimensions.

• Drainage

  Storm attenuation storage calculator

  Attenuation storage for a UK site from area, runoff, rainfall intensity and duration, allowable discharge and climate change uplift.

• Sludge

  Sludge dewatering mass balance calculator

  Cake tonnes, filtrate flow, solids capture, polymer dose and cost for thickening and dewatering from sludge flow and dry solids.

• Reference

  Water engineering unit converter

  Flow, pressure and head, concentration and load, velocity, area loading and power in the units used across UK water engineering.

• Wastewater

  Storm overflow spill volume and pollution calculator

  Turn storm overflow spill hours into an estimated volume of storm sewage and the BOD, ammonia, solids, phosphorus and E. coli it carries.