Sustainable Development

The NRSBU can be proud of a range of initiatives it has undertaken over the past decade or more, to enhance environmental outcomes and ensure sustainable development.

Cleaning up the Waimea estuary

Trade waste contracts

Prior to the scheme being in place, there were many point source discharges of partially treated and untreated effluent into the estuary. Monitoring every five years of the receiving environment shows a continual improvement in the water quality and benthic environment since the treatment plant was installed.

The contracts between NRSBU and its five customers are the first of their kind in New Zealand. The contracts apportion costs, control discharges and minimise environmental and financial risks to the owners. The contracts put in place

penalities for non-compliance
better load and flow projections
encourage waste minimisation at the source
continuous monitoring of discharges to give feedback and improve control

Pond sludge on pastures

In the early 1990s the oxidation ponds at Bell Island Treatment Plant were overloaded because the sludge had built up. As part of an upgrade to the plant in 1993/4, the pond sludge was removed and applied to the sandy, infertile paddocks surrounding the ponds. For the first three years the grass was cut for silage and ever since it has been leased for grazing.

Inflow and infiltration

Peak wet weather flow (PWWF) can be up to six times the average daily dry weather flow (ADDWF), so reducing the inflow and infiltration reduces the cost of reticulation and treatment, as well as overflow risks.

Other Ventures

Working on options with Nelson Golf Club and Nelson City Council parks department for the use of treated wastewater for irrigation of the golf course and parks
Centre pivot irrigation joint venture with Julian Raine on Bell Island is a success of the reuse of treated wastewater used for the irrigation of pastoral land