Ever wonder where your grandmother’s antique diamond ring wound up after disappearing down the kitchen sink?
Well, if it wasn’t caught in the S-bend on the way down or at the gully trap, chances are it could have travelled more than 20km underground through the dark recesses of an enormous network of pipes until it hits the Mangere Wastewater Treatment Plant.
But if you think you’re going to be able to retrieve that precious family heirloom, you might want to think again!
Every year around 1500 tonnes of non-dispersible material washes its way into the wastewater system and into the screening room at the Mangere plant where three 'interceptors' meet up in a confluence chamber at the Mangere plants.
From the confluence chamber, the wastewater flows into the screening room to intercept everything that doesn’t squeeze through the 3mm filter - and that's where Grandma’s antique ring is likely to end up!
The screens catch everything from phones to money, toys, passports, golf balls, wipes, sanitary products, carrots, corn kernels and anything else flushed or dropped down the system.
Once they're singled out, these larger items begin a leisurely journey up a long cylindrical chute, where a screw conveyor dries them out. When the residue reaches the top compact and dry, the sediment is dropped in a skip and hauled off to landfill.
Phil Brown has been crewing this room for the last ten years. He fondly refers to it as the 'a**e end of Auckland' and while he say it’s not the “dream job”, it's one he enjoys and takes seriously.
“I’m the eyes and the ears of the control centre. I make sure the pumps and motors are running sweetly, no leaks or faults; I’m making sure the flow of the plant is continuous.”
So, spare a thought for the crews who are called out all hours of the day and night to the screening station to repair machinery strangled by material Aucklanders should not have put down their drains.
“I’m a servant to the people of Auckland; it’s disappointing we’re putting almost two jumbo jet loads a day (10 cubic meters) of wet wipes alone down a system not built for it. Add the fats and oils we throw down, we’re creating one great big mess. It will help if you guys stop putting that stuff down the drains; it causes unbelievable damage to the pipes we’re paying for.”