The wastewater calculator works out ss leaving activated sludge process, mlvss weight and volume from average primary treated bod, average primary treated cod, average untreated influent bod, average untreated influent cod, flow of secondary effluence, solids in secondary effluence, effluent flow, flow rate through tank, f/m ratio, f/m ratio, free board, free-board, length, length, mlss conc., effluent ss concentration, settled solids, side wall depth, side wall depth, flow of waste sludge, solids in waste sludge, width and width. Enter what you have and the relationship is applied straight away, so you get the answer without working through the algebra yourself.
What Is the Wastewater Calculator?
The wastewater calculator works out ss leaving activated sludge process, mlvss weight and volume from average primary treated bod, average primary treated cod, average untreated influent bod, average untreated influent cod, flow of secondary effluence, solids in secondary effluence, effluent flow, flow rate through tank, f/m ratio, f/m ratio, free board, free-board, length, length, mlss conc., effluent ss concentration, settled solids, side wall depth, side wall depth, flow of waste sludge, solids in waste sludge, width and width.
Biological relationships are usually approximations rather than exact laws, so the output is best treated as an estimate with a sensible range around it.
How the Wastewater Calculation Works
The calculation applies the relationship as published, step by step, so each intermediate value can be checked against the underlying theory.
Keep the units consistent throughout. Mixing a percentage with a proportion is the single most common source of an answer that is out by a factor of a hundred.
Assumptions Worth Knowing
Any relationship used here assumes a constant rate, a representative sample, or a stable population. Real populations rarely meet those conditions for long, so treat the answer as a guide.
Where the inputs are field measurements, a single misread value can shift the result noticeably. Measure carefully and record what you used.
A Worked Example
Working through an example, with average primary treated bod set to 10, average primary treated cod set to 5, average untreated influent bod set to 2, the calculator returns effluent cod of 95, and effluent bod of -8, and cod loading of 190. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out ss leaving activated sludge process?
Enter average primary treated bod, average primary treated cod, average untreated influent bod, average untreated influent cod, flow of secondary effluence, solids in secondary effluence, effluent flow, flow rate through tank, f/m ratio, f/m ratio, free board, free-board, length, length, mlss conc., effluent ss concentration, settled solids, side wall depth, side wall depth, flow of waste sludge, solids in waste sludge, width and width. The calculator then works through the relationship and reports ss leaving activated sludge process, mlvss weight and volume.
What does the wastewater actually calculate?
It takes average primary treated bod, average primary treated cod, average untreated influent bod, average untreated influent cod, flow of secondary effluence, solids in secondary effluence, effluent flow, flow rate through tank, f/m ratio, f/m ratio, free board, free-board, length, length, mlss conc., effluent ss concentration, settled solids, side wall depth, side wall depth, flow of waste sludge, solids in waste sludge, width and width and converts them into ss leaving activated sludge process, mlvss weight and volume using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter average primary treated bod?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Is the answer exact?
It is as exact as the formula and the inputs allow. The method itself is the standard one for this problem, so the only sources of error are the figures you enter and the precision you ask for.
Do I have to fill in every field?
Only the fields a particular result depends on. If you leave one blank, the results that need it simply show a note instead of a number, and everything else still works.