KinetiRO Sim — activated sludge and membrane plant modelling in a browser

What it models

21 unit operations

Across seven groups: boundaries, flow topology, preliminary, physical–chemical, biological, tertiary and membranes, and utilities.

Influent · Treated effluent · Sludge outlet · Gas outlet · Flow split · Flow mix · Screen · Equalization tank · Primary clarifier · Fenton reactor · Anaerobic reactor · Anoxic reactor · Aerobic reactor · Secondary clarifier · Multimedia filter · Activated carbon filter · Ultrafiltration · Nanofiltration · Reverse osmosis · Chemical dosing · Blower and air supply.

Biology: ASM3

Thirteen components and twelve processes, solved as steady-state continuously stirred reactors. The stoichiometry is derived from COD, nitrogen and charge conservation rather than hard-coded, so the mass balances close by construction rather than by adjustment. Sludge age is computed over the whole solids system, counting only solids that actually cross a system boundary — solids going round the return loop have not left — and the aerobic fraction is reported separately, because nitrifier washout is governed by aerobic sludge age and not by total sludge age.

Membranes: an element-by-element march

Reverse osmosis and nanofiltration are solved element by element with solution–diffusion transport and film-theory concentration polarisation. Each of fourteen ions is tracked separately — sodium, potassium, calcium, magnesium, strontium, barium, chloride, sulfate, bicarbonate, nitrate, fluoride, phosphate, silica and boron — which is why divalents, boron and silica behave differently in the answer, as they do in the plant, and why the feed ion analysis matters. Spacer pressure drop follows the flow through each element rather than being a flat allowance.

Recycles are torn and iterated

Return activated sludge and internal nitrate recycle are ordinary connections. The solver tears the loops and iterates to convergence; you do not set up the tear yourself.

Design checks, at three levels

Errors, warnings and reported figures. More than fifty of them, and they compare what you built against the design ranges in the references: clarifier overflow rate and solids loading, sludge age against nitrifier washout at your water temperature, screen headloss clean and half-blinded, blower discharge pressure against the submergence of the diffusers it is feeding, ion analysis charge balance, whether the tail of a membrane array has stopped contributing.

What it does not model, stated plainly

This section exists because a tool's limits are more useful to an evaluating engineer than another list of its features, and because a limit you find on your own after buying is a limit that cost you something.

It solves steady state. It is not a dynamic simulator.

There is no diurnal profile, no hour-by-hour march, no storm event and no batch sequence. You give it a condition and it tells you what the plant does at that condition. The way to look at a Monday morning is to solve the Monday morning as its own case.

At steady state an equalization tank is a pass-through.

A consequence worth spelling out. Its mass balance in and out is the same, because damping a load is a transient behaviour and there is no transient. The block is there to hold the volume, the retention time and the design ranges, and its own reference sheet says exactly this. If you are sizing equalization to smooth a peak, the tool will size the vessel and will not simulate the smoothing.

The Fenton block has no textbook design method, and its reference sheet says so.

It is there because Fenton oxidation appears in real industrial trains, not because the reference gives a sizing procedure for it. Treat its output as a stoichiometric bookkeeping exercise, not as a design.

It does not estimate capital or operating cost.

It reports specific energy in kWh/m³ across a membrane train, pump shaft power, and the process air a blower has to deliver. Turning any of that into money is your spreadsheet's job and we have not written that spreadsheet.

It does not do civil, structural, hydraulic-profile or electrical design.

It is a process calculation.

Manufacturer element data is indicative.

The membrane library carries published catalogue figures for preliminary sizing. Confirm any element against the current datasheet and the manufacturer's own projection software — Hydranautics IMSDesign, LG Q+, Veolia Winflows — before a design is issued. That warning is in the source file itself and it is repeated inside the application.

Four further items are on our own list as worth doing and not done.

They are published, in our words, on the verification page.

The verification record

Vendor-neutral, and what that does and does not mean

The membrane library carries 19 named commercial elements side by side: seven from Hydranautics, five from LG Chem and seven from Veolia, across reverse osmosis, nanofiltration and ultrafiltration. Each of the three membrane blocks also offers a generic element and a fully user-defined one, where you type the transport constants yourself.

Nothing ranks them. No brand is the default. No supplier pays to be in the list, is consulted about being in it, or receives anything from us — because we do not sell equipment and we take nothing from anyone who does.

That is a narrow claim and it is the honest size of it. It does not mean we have no view about elements; the design checks will tell you when a selection is running past its own limits. It does not mean the catalogue data is a substitute for the manufacturer's projection software; it is not, and the tool says so on the panel. It means only this: nothing we receive depends on which element you pick.

What it produces

A stream table that closes

Flow, COD, TSS, ammonium, nitrate, TDS, total nitrogen split into TKN and nitrate, organic nitrogen, and BOD₅, on every stream. Four views: stream table, streams by row, unit results, and balance.

Unit results with the reasoning attached

Reactor volume, MLSS, oxygen demand, standard oxygen transfer rate, process air, actual retention time. On membranes: feed pressure, achieved recovery, lead and tail element flux, permeate and concentrate TDS, concentrate Langelier index, overall salt rejection, specific energy in kWh/m³, pump shaft power, pressure drop per element and across the train.

A PDF process flow diagram

Equipment symbols after ISO 10628 and ISA-5.1, a drawing-office title block, an equipment schedule, and the full stream table once the sheet is solved. A long train is cut into bands with numbered match lines the way a drawing office would cut it, rather than shrunk into an unreadable strip. A3 landscape, with A4 portrait continuation sheets. Written by hand as a PDF 1.4 writer, because the application has no build step and does not fetch a library at run time.

An Excel export of the mass balance

Assembled as a real .xlsx that Excel opens without a format warning, rather than a renamed CSV.

A reference sheet on every block

Each unit operation carries its own design ranges with the source cited — Metcalf & Eddy table and equation numbers, IWA Scientific and Technical Report No. 9 for ASM3. You can read where a number came from without leaving the panel.

Export of any kind, in any format, needs a licence. The free plan calculates and stores; it keeps the results inside the application.

Pricing

Free, Pro and Team

The calculation is unlimited on every plan. What a licence buys is the apparatus of professional practice: unlimited stored projects, and export — including sealed, authorship-signed files.

During the beta, none of these limits apply

Every beta account is issued a complimentary licence with full access for the whole beta period: no cap on stored projects and every export format. Sealed files are the one thing not in that — they are still being built. The table below is what the plans will be, not what you get now, and the price is not set yet.

What each plan includes

What each plan includes. Pricing is not set yet — see the pricing page — and during the beta every account has the Team column.
	Free	Pro	Team
Build flowsheets and calculate	Unlimited	Unlimited	Unlimited
Design checks and reference sheets	Yes	Yes	Yes
Stored projects	Up to 5	Unlimited	Unlimited
Export — PDF drawing, Excel mass balance, project file	No	Yes	Yes
Sealed `.eaqua` files, encrypted and authorship-signed	No	Coming	Coming
Licence held by	—	the engineer	the company
Seats assigned and revoked by an administrator	—	—	Yes

Pro and Team unlock exactly the same capability. Team differs in who holds the licence and who administers the seats, not in what the software will do. We do not ship a deliberately weakened paid tier to make a more expensive one look better, and that is a choice visible in the code rather than a promise in the marketing: the application asks one question — is this copy licensed — and a trial, a purchased seat, a company seat and a complimentary licence all answer it identically.

What each plan includes, and what the beta gives you

Sealed files — precisely what they will and will not guarantee

Coming Sealing is not available yet. No certificate has ever been issued, so it has never worked end to end, and it is not something a beta account can do today. This section is here anyway, in full, because what it refuses to claim is the point — and that does not change between a feature being built and a feature shipping.

A sealed .eaqua file will be encrypted to a list of named accounts, and once it opens for a recipient it will keep opening — that is the design target, and the reason the feature is not shipped is that it does not meet it yet.

The construction, which is built: content is AES-256-GCM under a random content key; that key is wrapped to each recipient with ECDH-ES on P-256 through HKDF-SHA-256 and AES-256 key wrap, one stanza per recipient, with a fresh ephemeral key for each file; the whole container is signed with ECDSA P-256 over SHA-256, and the author's certificate — signed by our root key — travels inside it and is verified when the file is opened. It is the JWE ECDH-ES+A256KW / A256GCM construction with a detached signature, in a compact binary container.

What that will genuinely give you

Somebody who is not a named recipient will not be able to read the file, and reading our source code will not help them, because the decryption key is not in the application — it is on the recipient's device. Authorship is real and tamper-evident: a modified file fails verification, and somebody without a licence cannot produce a file that other copies of the tool will accept.

What it will not give you, stated plainly

A legitimate recipient will be able to open the file, read it, and write the contents out again in any form they like. No scheme that runs on the reader's own computer can prevent that, and we do not claim one does. And the licence check is a policy gate inside an application you are running, so a determined local user could patch it out. Doing that decrypts nothing they were not already addressed on, and mints nothing other copies would accept — but it is a gate, not a wall, and calling it a wall to an audience of engineers would be the fastest way to lose them.

If you need a guarantee stronger than that — revocation that actually bites, or content a licensed reader cannot extract — the decryption has to happen somewhere the user does not control, which means a server. We have not built that, and the container format is already shaped for it if we ever do.

One practical warning, for when it ships

The private keys will live in the browser profile. Clearing site data destroys them, and a sealed file addressed only to that device will become permanently unreadable — by us as well as by you. The habit worth forming on day one is to seal anything that matters to a second account as well, so there is more than one way in.

Where your work is stored

Projects are saved in your own browser. They are not uploaded. That is a real privacy property — a design under a non-disclosure agreement never leaves the machine — and it is also a real limitation: they do not follow you to another computer, and clearing your browser's site data deletes them. Export anything you cannot afford to lose.

A Team licence does not today put projects in a shared workspace

It administers seats. There is nothing shared to share yet, and no page on this site may say otherwise until there is. Sealed files are intended to be how a deliverable moves between people — encrypted to a named recipient and signed so authorship is provable — and they are not built yet either. So the truthful description of collaboration today is that there is not one.

Why we publish what the arithmetic rests on

The equations are not ours and we do not pretend they are. ASM3 is IWA Scientific and Technical Report No. 9. The clarifier, screen, filter and anaerobic sizing methods are Metcalf & Eddy, 5th edition, cited by equation number throughout. Solution–diffusion membrane transport is in the same book. The element-by-element march, the concentration-polarisation factor and the temperature correction are standard membrane projection practice rather than textbook material, and we say so on the block that uses them.

What is ours is the judgement about which equations a working design actually needs, and the checks that fire when a design violates one. That is the part worth paying for, and it is not the part that has to be secret.

An engineer putting a stamp on a design wants to know the tool follows a reference they can check, not that it does something proprietary they cannot. So we publish the check.

How it calculates Read the verification Join the beta

An account is required. During the beta every account gets full access, and no card is asked for.