Wastewater and Water Plant Operators
Operate plant to store, distribute and treat water, including purifying water for human consumption and removing wastes from sewage.
A storm night at the treatment plant
You are the operator on the night shift at a wastewater and water plant, with heavy rain forecast to last until morning. It is 2:50am and the rain has been falling for hours. The creek is rising, the inflow is surging, and alarms are starting to sound. A few decisions tonight will decide whether the town's water stays safe and the plant stays in control.
Choose what you would do. Then see what happens. There are often good reasons for each choice.
The cloudiness alarm on the incoming water has gone to the high level, and the pumps are running flat out. Stuart says he can reset the alarm so we do not have to listen to it all night. Should he do that?
Let him silence it so you can concentrate, and watch the readings by eye instead of listening to it all night
Without the alarm, you miss the next jump in the reading. The plant is slow to respond, and cloudy water reaches the next stage before you catch it.
Keep the alarm active, check the readings against a hand sample and ring the on-call manager
The hand sample agrees with the instrument. The manager approves a change to how the plant is running, and you have a record of what happened and when.
Silence the alarm but write down the readings every ten minutes in your notebook
The notebook helps you keep track, but a silent alarm means you are relying on yourself alone to notice a change. A tired operator at 3am needs every warning the plant can give.
I am sorry to ring so late, but my tap water smells odd and looks a bit cloudy. I have a baby at home and I do not want to give him anything from the tap. Is it safe? Just tell me yes or no.
Reassure her that the water is fine, because the plant readings are still within the limits and nothing has gone wrong at the plant
The readings were fine at the plant, but you cannot see her pipes. If her tap really is cloudy, you have dismissed a genuine report and given her no way to know what to do.
Take her address and details, explain you cannot say yes or no yet, and offer a quick check and a call back
She is relieved to be taken seriously, but she wanted an answer now. The call back takes an hour, and she and the baby are on bottled water in the meantime.
Listen, record the address, tell her what you know and do not know, and pass her report to the on-call team to check
She is not given a yes or a no, but she is told honestly what is being done and when she will hear back. The team finds a stirred-up pipe in her street and flushes it by morning.
I have been looking at the figures from home. The water leaving the plant is still within the limits, though only just. I would prefer not to tell the council yet. If we say something, we may cause a panic. What do you think?
Agree not to tell the council yet, since the water is within limits and you do not want to worry people
At six, the numbers move past the limit and the council hears about it late. They ask why they were not told when the trend was clear, and trust is harder to rebuild than a warning is to give.
Say you think the council should be told now, with a clear note of what is known and what is not
Dr Tan agrees. The council has a quiet heads-up, and when the numbers do rise, a plan is already in place. An early, calm warning is not a panic.
Suggest waiting until the next reading in an hour before deciding anything
The next reading is worse, and you have lost an hour. Waiting for certainty is sometimes the same as deciding not to act.
How it went
By morning the storm had passed, the water was safe and every call had been logged. Water and wastewater operators work behind the scenes of everyone's day. Does the idea of being the person who keeps the town's water safe, quietly and carefully, appeal to you?
This is a simplified, fictional situation to help you explore. It is not professional instruction or a test of your ability.
Case study: The reading that crept upward
A fictional case set in a water treatment plant and a sewage treatment plant that serve a fictional river town.
The situation
Aroha was the operator on the morning round at Kestrel Creek Water Plant. For three days, the cloudiness reading on the incoming water had been creeping up by small amounts, always within the plant's alarm limit. No alarm had sounded and nothing in the plant looked wrong. The numbers were in the daily log, but nobody had asked about them. The weekend was coming, and the manager would be away.
What they did
Aroha plotted the three days of readings on a sheet and noticed that the rise happened at the same time each afternoon. She rang the manager and the catchment contact, and went to the creek upstream to take a sample and look at the banks. She found that a new road works site had started clearing land beside the creek, and soil was washing in each afternoon.
How it turned out
The road works crew was asked to put up sediment barriers, and the plant adjusted its treatment for the extra cloudiness before it caused a problem. The water supplied to the town never changed in quality. Aroha's chart was added to the plant's handover file as an example of what to look for.
What would you do?
- How would you have noticed a slow trend when no alarm had gone off?
- Why might it matter that the rise happened at the same time each day?
- Who else might need to know about something that is happening upstream?