Water treatment calculators

Size the aeration tank from sludge age and MLVSS, not from retention time. Returns volume, HRT, F/M and volumetric loading.

Soluble BOD from Monod kinetics at your sludge age, particulate BOD from effluent solids, and the total your permit sees.

RAS ratio and flow from MLSS and underflow concentration, or the underflow concentration a chosen ratio implies.

Net biological solids, observed yield, and the daily WAS flow from the reactor or from the return line.

Carbonaceous and nitrification oxygen demand, peak and standard-condition values, and the aerator power they imply.

N and P needed from the sludge you produce, the deficit against the influent, and the real BOD:N:P ratio at your sludge age.

Nitrifier growth rate with temperature, pH and DO corrections, minimum sludge age, capacity check, oxygen and alkalinity.

Area from loading rates at average and peak flow, and from solids flux theory for your sludge settleability. Names what controls.

From oxygen demand to air flow, diffuser count, discharge pressure and blower shaft power, for new or fouled diffusers.

Blower power at night, average and peak load, daily kWh, and the cost once each load sits in its tariff window.

Split TKN into the five fractions a nutrient removal model needs, the nitrogen available to the process, and the floor on effluent TKN.

Methane and biogas from COD removed, thermal energy, CHP electricity, and the recovery per m³ treated.

Media volume and area from organic loading, hydraulic checks, NRC efficiency with recycle, effluent BOD and sludge.

Bed volume and area from organic loading, upflow velocity, process air and sludge for a biofilter polishing anaerobic effluent.

Van 't Hoff pressure from TDS or a full ion list, with temperature and osmotic coefficient, and the concentrate value at your recovery.

Which sparingly soluble salt reaches saturation first at the membrane wall, and the recovery it allows, from your feed analysis.

Permeate flow, quality, recovery and pressure drop for a vessel of elements, integrating flux and salt passage along each element.

Standardised permeate flow and salt passage from a day of operating data, so fouling shows through temperature and feed changes.

Mass transfer coefficient from velocity, spacer height and diffusivity, and the factor by which the wall sees more salt than the bulk.

Pump power from feed flow and pressure, energy recovered from the concentrate, and kWh per m³ of permeate with and without recovery.

Feed and concentrate flow from the permeate you need, and the brine TDS from recovery and rejection.

How much raw water you can bypass around the RO and still meet the target TDS, and the membrane capacity it saves.

SDI from the two 500 mL filtration times and the test length, with the verdict against the membrane type.

Rejection and log removal from feed and permeate, including the lower bound when the permeate is below detection.

Clean membrane, chemically reversible and irreversible resistances from flux and TMP before and after a clean, temperature corrected.

CT for a target log inactivation and the inactivation a CT delivers, by Chick-Watson or Collins-Selleck, corrected for temperature.

Decay constant from bench data, corrected to temperature, the residual after contact and the CT a decaying residual delivers.

Chlorine to oxidise ammonia past the breakpoint, the alkalinity it consumes and the TDS it adds.

Transferred dose from the gas balance, CT from a decaying residual, and the applied dose for a coliform target.

Depth-averaged dose from intensity, time and UVT in a Petri dish, with the uncertainty and the conservative dose.

Log inactivation against dose from bench counts, the fit, the dose for your target, and the regulatory credit doses.

Pipeline diameter and dispersion number for a residence time, the dispersion a log goal allows, and t10 for a baffled basin.

Log inactivation of four organisms at one dose of chlorine, chloramine, peracetic acid or UV, and why E. coli is a variable indicator.

THM4 and HAA9 formation potential from UV254, DOC and bromide, an upper bound before chlorination.

For alum or ferric: alkalinity consumed, hydroxide sludge formed, and the caustic, lime or soda ash to replace the alkalinity.

Stage volume, water power for the target G, impeller speed and tip speed from the power number, and Gt.

Terminal velocity of a particle in the right regime, and what an ideal basin removes at its overflow rate.

Limiting solids flux from batch settling tests, underflow flow and the area needed for your underflow concentration.

Saturator air solubility, air released in the contact zone, bubble numbers against the floc, and the separation-zone area.

Basin volume to flatten a diurnal flow profile to its average, from the cumulative inflow curve.

d10 and d60/d10 from sieve data, against the ranges for sand, anthracite, garnet and GAC.

Ergun head loss through a clean sand or anthracite bed from rate, size, depth, porosity and temperature.

Minimum fluidisation velocity, the rate for a target expansion, and the expansion any rate gives, at your water temperature.

Unit filter run volume, backwash and filter-to-waste volumes, and the net recovery of the filter.

Henry's constant at temperature for gases and VOCs, the minimum air to water ratio for your removal, and the stripping factor.

HTU from the mass transfer coefficient, NTU from the stripping factor and removal, the packing height, and the rating of an existing tower.

Blower power from air flow and pressure drop, pump power to the distributor, and the kWh per m³ treated.

Freundlich K and 1/n and Langmuir Qm and b fitted to your batch equilibrium data, with r² for each.

Carbon mass from EBCT, the minimum usage rate from the isotherm, and the longest bed life a single solute allows.

Equilibrium PAC dose from the isotherm for a target effluent, and how it compares with a granular bed.

Oxidant demand for aeration, chlorine, chlorine dioxide, permanganate or ozone, with the alkalinity consumed and the sludge made.

How long iron takes to oxidise with air at your pH, the reactor volume it needs, and the permanganate time for manganese.

Lime, soda ash and recarbonation doses for calcium-only or excess-lime softening, with the sludge and the finished hardness.

Energy per order of removal, the lamp power a duty needs, and how much of the UV the peroxide actually absorbs.

Dry sludge from coagulant, turbidity and polymer, its specific gravity, and the daily volume as a share of plant flow.

Convert electrical conductivity (µS/cm) to total dissolved solids (mg/L) and back, with a factor for brackish, mixed, or seawater.

Estimate evaporation, blowdown, and make-up water from recirculation, temperature range, and cycles of concentration, and the water saved by higher cycles.

Will cooling, boiler, or process water scale or corrode? Enter pH, temperature, TDS, calcium, and alkalinity for the LSI and its interpretation.