Week 8 Tutorial: Drawing the treatment train

Week 8 tutorial — assemble a barrier sequence against your home's actual measured water quality, put a sourced log reduction on each barrier, and cost the running

29 April 2027

Time

90 minutes in the room, plus about 30 to tidy the output

Graded

Checkpoint 7 of 10, 2 % — a good-faith attempt at the output below

Due

5 pm, 30 April 2027

What this tutorial is for#

“Filtered” is not an answer. Today you build a multi-barrier train where every box carries a number somebody else could check, and you find out what running it costs.

Story stage. First design week. The specialist findings are in hand, so the water you are treating is the water the measurement year actually found at your home — turbidity, E. coli, hardness, pH, and the sample taken after heavy rain.

Open these first#

• Your home’s specialist findings — the water-quality table on your client’s findings page, reachable from clients. Look at the post-rain sample before you design anything.
• Week 8’s lecture for the barrier table and the log reduction figures.
• The price schedule for what each barrier costs and what it does not price.

If you missed week 7#

You do not need week 7’s supply curve today. You do need your home’s findings page, which is published and does not depend on anything you have done.

The words this week uses#

• Barrier — one treatment stage: a screen, a first-flush diverter, a sediment filter, a BioSand filter, a UV lamp. Each removes some pathogens and not others.
• Log reduction — an order of magnitude removed. 1 log removes 90 %, 2 logs 99 %, 3 logs 99.9 %. Logs across barriers in series add.
• Pathogen class — bacteria, viruses and protozoa behave differently. A barrier strong against one may do almost nothing to another, so a single figure for “log reduction” with no class attached is not usable.
• Continuous versus intermittent load — a UV lamp that runs whenever the pump might run is continuous; a pump that runs twenty minutes a day is intermittent. They are totalled differently.

Do this#

1. Quiz 3 (20 minutes). On paper, on weeks 6 to 8.

2. Read your own water first (10 minutes). From your findings page: what is the turbidity after heavy rain, and did any sample show E. coli? Write those two numbers at the top of your sheet. They are what the train has to deal with, and a train designed before looking at them is usually inadequate.

3. Build the train left to right (25 minutes) and put a number on each box, by pathogen class, with its source. The box you cannot find a number for is the interesting one — mark it unquantified and say what you would need to measure. Marking it unquantified is a correct answer; inventing a figure is not.

4. Then the field-versus-laboratory exercise (15 minutes). A BioSand filter rates 2.5 log mature, 3.71 log run continuously, 1.67 log run intermittently, and about 1.1 log as a field average. Decide which figure applies to a household that draws water in bursts, and write down why. That sentence is the exercise.

5. Then the certification check (10 minutes). If you have written NSF/ANSI 55 Class A, find an Australian supplier page that claims it. Most will find WaterMark instead, which is a different scheme answering a different question. Claim only what your cited product actually holds.

6. Total the energy (10 minutes). Continuous and intermittent separately, then summed, in kWh/day. The UV lamp alone is 0.6 kWh/day, continuous, and it is the load most designs forget is always on.

The output#

A treatment train drawn barrier by barrier, each with its log reduction by pathogen class and its source, plus the train’s counted energy load split into continuous and intermittent.

Check your own before you submit#

1. Are your home’s own post-rain turbidity and E. coli figures at the top of the sheet?
2. Does every barrier carry a figure by pathogen class, or the word unquantified?
3. Where the source distinguishes laboratory from field, does your sheet?
4. Are continuous and intermittent loads separated, and then totalled?
5. Is every certification you name one your cited product actually holds?
6. Would the train actually work on your water, or does the UV sit behind something too turbid for it?

Where it goes next#

The train’s energy load goes into the week 12 budget, and its treated volume into week 9’s balance.

Back to week 8 overview