Sewer system rethink

17:00, Jun 23 2010
WATER QUALITY: Fresh thinking is needed to improve the water quality of all Far North harbours.

A COMPLETE mind shift is needed to resolve the Far North's most challenging problem – sewage treatment and disposal.

This is the message from elected representatives, including mayor Wayne Brown and councillors Steve McNally and Ann Court.

Ms Court raised the issue at the Eastern Community Board meeting this month, describing the cost of the long-planned $40 million waste scheme for the Bay of Islands as potentially too expensive to implement. She says the situation is "scary".

Mr Brown says he's pleased the public is finally taking notice.

He says the proposed Bay of Islands scheme was probably a wrong design choice by the last council. It is seriously in question and the council is re-examining the wisdom of plowing on with it.

As a registered engineer, Mr Brown was one of the sources of technical information for the writing of TP58, the technical guide for rural effluent disposal.


As someone who worked in the field of sewerage design for many years in the Far North, he says geography and economics require several different solutions and much more innovative thinking than that provided in the past. He says the council's approach to sewerage has, unfortunately, been driven by the resource management process. Further to that, regional council and health department policies and processes don't suit the Far North situation.

"The regional council wants the effluent to be treated to almost distilled water quality, yet it is discharging into a marsh. Why not treat to the standard of the marsh water? And now that a couple of large developments have been approved with lower water treatment standards than council is required to have, the big scheme is seriously in question," Mr Brown says.

The council is looking at affordable solutions that treat nearer the source with innovative environmentally friendly new technologies that may result in several linked but smaller plants than the single big one currently proving to be indigestibly expensive, he says.

"A good long-term outcome for our sewerage problems will require tenacity, technical know-how and relentless pressure from our leaders in order not to fail from unaffordability and the string of hurdles placed in front of progress by remote bureaucrats with the power to insist on only what they know about," Mr Brown says.

Mr McNally agrees that the issue is complex. The $1.5 million already spent on the consent process alone is a result of entrenched views held by various bureaucracies, he says, and he calls for rethinking of the need for a large reticulated sewerage system and of the structure plan process.

Ms Court is urging robust community debate "because the proposed scheme is going to cost one hell of a lot of money".

The cost to build the plant itself is $6m. The rest of the $40m is in the network.

Even with 10,000 connections the cost could be as much as $5000 per connection per year, just to service the loan, according to information provided by council staff, she says.

"That is just horrific. Next to roading, waste disposal has the most profound impact on rates and needs a high level of understanding, commitment and buy-in from the public in order for us to make significant improvements to services, delivery and environmental standards," she says.

The Far North has eight harbours, 42 towns and more than 10 iwi.

"So we do not have the luxury of just dealing with one big-scale city sewerage solution," says mayor Wayne Brown.

Rather than wasting money on long, horrendously expensive resource consent hearings that focus, not on the environment at large but on each sewerage system alone, we need to adopt a long-term approach that will progressively improve the water quality of all of our harbours, bit by bit, over the next 20 years, making the best use of the realistic level of funds that we do have, he says.

A harbour catchment-based approach requires fresh thinking on the part of all involved and is a challenge for the Northland Regional Council and the Ministry of Health, he says.

"The sort of result where Far North District Council is asked to spend $4 million to upgrade a perfectly adequate sewerage system, serving the 90 people who live at Hihi, is just totally unrealistic, nor will it improve water quality in Doubtless Bay," he says.

"Indeed testing of the nine tributaries feeding Taipa River showed that the only one meeting the swimming water standard was the outlet from the Taipa sewerage scheme, yet Northland Regional Council wants money spent there, rather than on improving the other eight whose waters are polluted by failed septic tanks, some from marae, dairy effluent and other causes."

He says we need to learn from the past successes of simple effluent disposal systems, such as at Kohukohu where each septic tank is connected to a communal system that, very cheaply, treats the effluent, rather than raw sewage, in a marsh.

"Recent developments in the designed enzyme field appear to offer very cheap improvements to septic tank operations that couldimmediately benefit the environments, where existing septic tanks systems are not performing well, such as at Riverview."

Councillor Steve McNally is also calling for consideration of new technologies.

Outlining the present situation, he reminds us that the existing discharge permit for the Kerikeri treatment plant wil expire in 2015, so there will be a Northland Regional Council requirement to update the existing consent or find an alternate discharge option.

The Bay of Islands resource consent is for an upgraded plant in the Waitangi forest.

The first stage of work is to upgrade Paihia's treatment system to increase its capacity so it will cope with additional loading from Kerikeri.

"The pipework and pumping stations to get the effluent to the Waitangi treatment plant, running down Inlet Rd, is a significant cost – estimates, at this stage, being $20m – and this is only to pick up the existing sewage discharge from the current reticulation area. There is no expansion of the reticulation area in this cost," he says.

"Local iwi have always been opposed to discharge to water, this has not changed. Water is considered a life force (mauri) to Maori," Mr McNally says.

"Recent resource consent decisions approved by commissioners and environment Court judge Newhook – Borneo Investments and Quail Ridge – have allowed private plan changes, based on these applicants dealing with effluent on site, via smaller package plants."

They'll produce effluent treated to a standard less than that required of the water quality discharged from the council treatment systems and the Northland Regional Council has approved these package plants at the lesser standards, he says.

"These decisions have had an impact on the Kerikeri/Waipapa structure plan rollout for two reasons.

"Firstly the planning staff and allocated budget have been used to deal with these private plan changes, and secondly the planned infrastructure to cater for this growth, such as a large reticulated sewerage system, is not required by these two major developments until the latter stages of their development, as their effluent is treated and discharged on site and, therefore, the opportunity to get critical development contribution income and ongoing rates to cover the operational costs of a large system are lost to this community."

If the Environment Court judge and commissioners who heard these recent plan changes believe that smaller package plants systems discharging/irrigating to land are acceptable solutions and this is endorsed by the Northland Regional Council, then the council must rethink options for sewage treatment, Mr McNally says.

He says several smaller treatment plants reduce the need for miles of piping, reduce the risk of a major failure or spill from a large network, and the new technology available indicates there are some options.

"These smaller plants are not new and have been operating in small subdivisions in the past.

"Technology, brought in from South America, is being used in the South Island, changing the treatment system and costs associated with sewage treatment.

"There are also enzyme solutions that offer rehabilitation to septic tanks," he says.

"Staff are looking at the systems and talking with the council currently operating those alternate systems to find out whether we can use them in the Far North," he says.

This will include considering the costs of these systems to calculate whether several smaller systems are more cost-effective than the one large reticulated system.