Treatment system to get major upgrade

The Kaipara District Council has given the green light for its Taharoa Domain governance committee proposal to spend nearly $400,000 replacing the sewage treatment system for Pine Beach at Kai Iwi lakes.
The council decided at a meeting in Dargaville last week to support the committee proposal and provide a moratorium on repayment from forest harvesting of $168,000 provided to set up the committee and seal the Pine Beach access road.
Assets manager Blair King told the council the wastewater treatment plant now at Pine Beach served 500 campers and up to 250 day visitors, but needed replacing within five years as its effluent disposal methods were no longer permitted.
Pine Beach wastewater from eight flush toilets, eight cold showers, eight basins and three external tubs feeds into a 32cu m holding tank from where it is piped clear of the drainage catchment and sprayed on to a disposal field, usually daily.
The committee proposes spending $393,000 over the next 20 months connecting the facilities to a new system capable of treating up to 50 cu m of effluent daily and using the existing disposal field outside the catchment area.
Operating costs for the new system were estimated at $15,000 a year.
The committee will increase camping fees by 25 percent in summer to help make the upgrade viable, and camp numbers will be reduced to retain the wilderness camping experience sought by visitors to the lakes.
Other wastewater pollution issues concerning the committee include:
• Sandy Bay: Long-drop toilets feed into a "blackwater" holding tank which is pumped out, usually twice yearly, with the effluent trucked to Dargaville for disposal.
It would cost about $100,000 to connect the Sandy Bay facilities to the proposed Pine Beach treatment plant so the committee has decided it would be economic to retain the "blackwater" tanks until replacement is needed then remove the toilets entirely.
• Promenade Pt: About 100 campers and up to 50 day-trippers use roadside longdrop toilets with two hand-basins feeding into a 7cu m "blackwater" holding tank.
Effluent is sucked out, usually three times year, and trucked to Dargaville for disposal at a cost of $450 per trip. No consent is required because there is no discharge.
Issues relate to users' perception of long-drop toilets, concerns that the tanks may leak and inadequate water volumes to ensure public health.
Conversion to composting toilets was not considered feasible as they were unlikely to cope during peak loading.
While the long-term goal was to install flush toilets, they would require the holding tank to be emptied twice daily, and connecting them to the upgraded system at Pine Beach was discounted because of the length of pipe required.
Connection to a secondary treatment system managed as part of a possible lease with the Kai Iwi Lakes Water Ski Club would be feasible if such a system was installed.
Converting the toilets and providing a treatment plant would cost about $245,000 and the annual operating cost would be about $15,000.
In the interim, the toilets will remain as ``blackwater'' longdrops.
• Toilets by ski club: These "blackwater" long-drop toilets are similar to those at Promenade Pt. Conversion to flush toilets and connection to an upgraded secondary treatment plant servicing the ski club would cost about $30,000.
• Ski club: Showers, laundry and toilets in the ski club building are connected to separate greywater and blackwater systems.
Wastewater is pumped to trenches behind the building where treatment occurs by "scrubbing" in the soil.
Both disposal fields are within the Lake Waikare catchment and have the potential to contaminate waterways into the lake, which is already showing evidence of algae blooms.
Disposal fields need to moved clear of the catchment. To achieve this any proposed treatment system would need to be upgraded to a secondary treatment level. Capital and operating costs would need to be met by the club as part of any lease negotiated with the council.