Wastewater flow charts sludge journey

There are 15 wastewater treatments plants in the Far North, most using natural processes such as wetlands to treat sewage produced by our communities.

The processes used to treat sewage and wastewater does produce ‘sludge’ as a byproduct. Sludge is a semi-solid residue composed of the solids removed from sewage, along with micro-organisms and chemicals used in its treatment. Managing sludge is complex because it can pose environmental risks if not handled properly.

You can find out what happens to the sludge produced by each of our wastewater treatment plants via a flow chart now available on our website. We have four wastewater treatment plants in the Far North that can treat sludge. These are located at Kaitāia, Rāwene, Kawakawa and Kaikohe. The graphic shows which plants undertake this vital treatment role and where the sludge they process comes from. Here’s what the graphic tells you:

• Kaitāia Wastewater Treatment Plant processes sludge from Kaitāia, Ahipara, Rangiputa, Kāeo, Hihi, Whatuwhiwhi and Taipā
• Rāwene processes sludge from Kohukohu and Rāwene
• Kaikohe processes sludge from Kaikohe, Ōpononi, Paihia and Russell 
• Kawakawa Wastewater Treatment Plant processes sludge from Kawakawa only
• Sludge from Kerikeri is transported to landfill in Whangārei.

Remember, wastewater systems are designed for human waste and toilet paper only. Pee, poo and paper are the only things that should be flushed down any pipe. Any other material flushed down the toilet risks creating a destructive ‘fatberg’ that block and damage pipes.

You can read more about each wastewater treatment plant here.