Barge option to counter sewage flow

By TONY GEE

Effluent from overflowing septic tanks on some residential properties near Russell is likely to be collected and taken by barge to Opua.

At Opua, the untreated effluent would be discharged through a pump station into the Opua system and then into the bigger Paihia system.

The barging recommendation is a preferred option among a number of Far North District Council alternatives being considered to eliminate effluent overflow problems at the entrance to Waikare Inlet.

Health authorities closed oyster farms in the upper inlet last year after viral gastroenteritis outbreaks in several Auckland restaurants were linked to oysters harvested in the inlet.

Septic tank overflow from some properties at Okiato Point has been identified as one of several possible sources of the virus contaminating oyster farm waters in the inlet.

A consultants' report to the council said the area was "not well suited to on-site land disposal" of sewage.

The same report said that although some septic tank disposal fields were failing at Okiato, oyster contamination in the inlet could not be directly traced back to the area.

The Far North council operations manager, Geoff Cobb, said Okiato Point had 136 residential properties, of which about 100 had houses on them.



Property sizes were small, between 800 and 1200 sq m.

Mr Cobb said these sizes and the unfavourable soil conditions in the area meant traditional on-site septic tank disposal could be expected to have problems.

Proposals to Northland Health and MAF to cover those properties shown after inspection to be discharging off-site include making the area "high risk" to ensure suitable on-site disposal systems, rather than conventional septic tanks, are installed.

Eleven options have now been drawn up for treatment and disposal of sewage from Okiato.

These include on-site solutions, tank content barging or carting for treatment elsewhere, full reticulation or piping to a treatment plant.

Mr Cobb said the solution that seemed most readily able to be undertaken at the lowest cost was to collect overflow effluent and take it off-site.

The capital cost of barging the effluent across the inlet entrance from Okiato to Opua could be reduced to $650,000 by having the council-owned Opua subsidiary company Far North Holdings provide the barge transport.

This would mean each of the 100 households at Okiato would be liable for $6500.

Barge and other operating costs would be financed from pan charges.

"I believe it's the best scenario at this stage for the costs involved," Mr Cobb said.

The council is to meet Okiato residents as soon as possible to discuss all options for sewage disposal in the area before a final decision is made.

nzherald.co.nz/environment