The notion of sustaining the life of a landfill is a sound one. If you are filling a hole in your backyard with rubbish, it makes sound environmental sense to avoid having to dig another hole.
And another one. And another one. Especially when you fill it with rubbish that takes a long time to break down.
What if Whangarei was a small island? Let's say I own the hole the rubbish goes into, and I charge each islander a nominal rate to put rubbish in it.
The island isn't that big and eventually I am going to run out of land to fill with rubbish.
We don't want the island to end up being a graveyard for non-biodegradable waste with land that can't be built on, or sustain crops or animals.
So I make a plea to the islanders - less rubbish, please!