The unit operation pages are free to everyone. A subscription opens every design sheet, and the workbook is the same sheets as a file you own. One per cent of either goes to carbon removal through Stripe Climate.
Twenty-four design sheets: four routes to solids separation, media and carbon filtration, iron and manganese removal, ion exchange, the whole membrane range from microfiltration and ceramic through to reverse osmosis, continuous electrodeionisation, membrane degasification, UV and chlorine disinfection, heat transfer, chemical reaction tanks, and sludge dewatering and drying by decanter centrifuge, filter press, thermal dryer and solar bed. Each sheet gives the governing equations, the design envelope industry practice actually accepts, and a calculator that recomputes as you type — so you can size a train in the browser before you open a spreadsheet. Pipework and pumps have a page of their own, as does chemical dosing.
The full method, the equations and the calculators stay open. If a sheet saved you an hour, the most useful thing you can do is share it with the engineer who needs it next.
Share this page on LinkedInEvery sheet on this page as a linked Excel workbook — every formula visible, unit-consistent, with water properties computed from your temperature rather than assumed. Change the plant flow once and every sheet that depends on it follows. Includes a summary tab, an equipment list and a revision-controlled calculation record for design submissions.
SGD 19.90 until 31 December 2026 — both files, one payment. It doubles to SGD 39.90 on 1 January 2027. Currently v1.7. Buy once and every version after it is free — see the version history.
The same sheets, in Excel. The workbook holds the same 28 design sheets a subscription opens across the site, as a file you own: it works offline, it goes in a design submission, and the calculation record is revision-controlled for exactly that. A subscription keeps the browser version always current; the workbook is the copy that stays on your disk and in your project folder. Buy it once and every later version is free.
Anything at all — something on this site, the workbook, a project, water treatment in general, or getting into the field. Pick a subject, write the question, and it reaches me directly.