Council Approve Discharge for New Sewerage Scheme

By MORGAN, Jared

ENVIRONMENT SOUTHLAND has granted consent for discharge into the Mataura River from a new sewerage scheme for the Edendale and Wyndham townships.

The Southland District Council applied in July for resource consent to build a $13.7 million sewerage scheme, which includes new pipe connections to residents, at an existing gravel quarry on the Edendale-Wyndham Rd.

The council intends to use either a traditional pond-based method or a Biofiltro system that uses worm-based organic degradation for the sewerage plant.

If it chooses Biofiltro, it will be the first council in New Zealand to adopt the technology, which processes effluent using sawdust and worms. At an Environment Southland consents committee hearing, held last month, the applicant’s consultant Murray Sorrell said the Edendale township relied on septic tanks and there was potential for contamination of groundwater to happen. Wyndham had septic tanks that discharged — combined with stormwater — without treatment into the Mataura River.

The consents committee approved the discharge permit after it decided wastewater treatment for both communities was necessary and appropriate particularly in the case of Wyndham’s scheme, which sometimes exceeded Australia New Zealand Conservation Council guidelines. The Southland District Council lodged its application based on both options under consideration.

The options: wOption A: Pond-based. Comprised of an aerated lagoon and maturation pond — providing primary and secondary treatment.

Treated sewage will then pass through a wetland area with alternating planted and open waterzones before being conveyed to an outfall into the Mataura River.

Ponds will be built on to the existing gravel pit floor.

wOption B: Biofiltro. The proposed treatment system is comprised of an inlet screen, storage-equalisation tanks, Biofiltro unit and UV disinfection unit to provide primary and secondary treatment of sewage.

Treated sewage will then be conveyed to an outfall.

The units will be constructed on the existing gravel pit floor.

jared.morgan@stl.co.nz

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