The CHB Council is (inch)worming its way toward progress in cleaning up its sewage discharge into the Tukituki.

On Tuesday the Council will hold a special session to consider replacing its proposed ‘effluent to land’ sewage treatment scheme with a less expensive scheme that would discharge substantially cleaner effluent into the Tukituki … using worm farms to clean the effluent.

The alternative scheme is less expensive and is based on a proposal made to CHB several years (and consultants) ago. At the time, the worm clean-up was less tested in New Zealand and so was rejected. However, recent data from such schemes in New Zealand seem to indicate that the process could in fact put CHB in full compliance with the more stringent water quality standards the Environment Court has said the two sewage treatment facilities must meet by 2014.

Faced with 20 submissions opposing the consent application CHB has just filed for the ‘effluent to land’ scheme, it appears CHB officials are worried that conditions imposed during an appeal of that application might lead to even more expense, over and above the higher costs now anticipated for the ‘effluent to land’ plan after new consultants updated the construction estimates.

So, from an environmental standpoint, the ‘effluent to land’ approach involves putting 50% less (but essentially untreated) effluent into the river, while the worm clean-up would arguably reduce contaminants substantially (readily meeting tougher standards if the performance results reported hold up), but still discharge the treated effluent into the river.

The worm clean-up option deserves consideration (if the Council indeed decides to entertain it at its extraordinary Tuesday session). Here’s the staff report.

My sense is that key environmental objectors to the land-based scheme might well prefer the worms to the forest discharge (at least as the latter now stands). That said, the worm scheme will need to be vetted thoroughly, with plenty of evidence produced as to its viability.

Effectively, the matter must be decided during CHB’s long term plan review process … which must end with LTP adoption by June 30.

Tom Belford

Join the Conversation


  1. Crickey, I've never seen a more blatant conflict of interest, worm farm recommendation by a council officer name of Steve THRUSH!

    No its not April Fool's Day yet, I've just double-checked.

    More to the point, I can't help wondering whether this is just another example of greenwash. I mean really, what happens to all these worms that grow from the never-ending supply of biomass input into the system, do we just keep on building more pens for them & their doings or is someone going to harvest it all? I suspect not, hard to imagine being able to get over the biohazard issue.

    Also got to question the process, I mean whatever happened to the time-honoured process of going out to an open tender for a solution? Surely all that's needed is to specify the inputs and outputs required & then assess competing tenders of whatever technology the bidders want to propose. Seems at the moment there's a grave risk that the CHB council just hand the deal over to the worm-rancher without a proper competitive tender & without subjecting the competing technologies to an equally objective assessment process.

  2. Oh my goodness!!!Where is your senses? have yous not got a brains?If you were the shet they want to put on the trees in the forest???think about what would happen to you if the rain like the rain that is happening now comes along an pelts down on you…hello…you won't break down…you will just roll down into the already polluted waterways and yes my whanau will go fishing and catch the fish that are feeding on you(shet)and yes Maori are at the bottom of the health scales because we catch food from the polluted waterways that you leachate the shet into. Have a lovely day in the shet

Leave a comment

Your email address will not be published.