Infrastructure Strategy The graphs below shows the expenditure and drivers of water supply capital projects Introduction With an asset value of $226 million, wastewater is the second largest asset group owned by the Council. The huge success of the Marlborough wine industry has created challenges for the Council. During vintage there is a ten-fold increase in the discharge of trade effluent from the wineries. The total load on the Blenheim wastewater treatment plant is five times as much as normal. For a few weeks between March and May each year the wastewater treatment plant is required to process a load equivalent to the wastewater produced by 120,000 people. In terms of wastewater Blenheim becomes the fifth largest city in New Zealand. To meet this demand the treatment plant has undergone a number of upgrades. Capacity was significantly increased in 2009 with the addition of an advanced dissolved air flotation (DAF) treatment plant. Tertiary treatment wetland ponds (established in 2013/14) improve the quality of the final discharge and allows a portion of the final effluent to be returned to irrigate the land. The Council will continue to collaborate closely with the wine industry to ensure additional wastewater processing capacity is available as production grows. Wastewater processing capacity may also need to increase at other treatment plants to manage growth. For example, the relatively small treatment plant at Havelock For Marlborough to achieve its vision for the future the infrastructure must be sufficient cannot accommodate high loads of organic trade waste (from seafood processing) and and functioning; achievable and sustainable with the resources available. may need to be upgraded if further seafood processing plants establish in the area. Wastewater The discharge of human waste to the aquatic environment is a cause of cultural offence to the indigenous iwi. Council is working with the local iwi to remove or For Marlborough to achieve its vision for the future the infrastructure must be sufficient minimise the discharges from the treatment plants and functioning at the same time as being achievable and sustainable with the resources available The following table provides a summary of the Council’s wastewater systems Wastewater Goals Treatment Pump Grinder Mains Wastewater Treatment Plants will fully comply with current and anticipated discharge Area Plants Stations Pum ps (kms) Connections standards. Blenheim 1 37 86 187.7 9,714 Wet weather sewer overflows will not occur from storm events with a frequency of less Renwick 1 14.9 826 10 year ARI. Spring Ck/ Grovetown Decomm. 2 291 20.8 457 Future treatment plant upgrades will be designed to avoid cultural offence by removing St Andrews 18 incl. 6 or reducing effluent discharges to the aquatic environment. Riverlands 5 21.4 86 Picton 1 9 50.1 1,297 2018-2028 Long Term Plan Page 194