A wallet, a $20 note, fast food outlet toys, a baseball, a tennis ball - you name it and it is likely to have turned up at the Hastings' Wastewater Treatment Plant in Clive.
Treatment plant manager Bob McWilliams has been at the plant for 26 years, and has seen it all. That makes him the perfect person to host an open day at the plant on November 11.
Between 35,000 and 70,000cu m of mostly liquid matter goes through the treatment plant every day.
There are larger flows during the height of the horticultural season, from February through to April.
Open day visitors will see the initial screening process, which takes out solids larger than 3mm, the pumping process, video of the way the trickling filters work, and samples of the treated wastewater.
Once treated the water goes through a cultural process which passes it through the rakahore channel.
That reconnects the water with Papatuanuku before it is pumped about 3km out to sea and dispersed through a 300m-long diffuser pipe. Recently a new diffuser was installed and there is a display section where its operation can be explained.
That cultural process along with the technical aspects of the plant has seen it win "all sorts of awards" over its eight years of operation, says Mr McWilliams.
Hastings District Council's works and services committee chairman Kevin Watkins says the highly technical process is very interesting.
"Probably the children who attend are a bit keener than the parents - they're a bit more curious.
"We do think it is important that people realise where the wastewater goes every time they flush the toilet.
"That leads to people being more careful about what they put down the general wastewater pipes and flush down the loo."