There is 6ha in rural Martinborough that on first glance the viewer would think is irrigated via aquifers. This South Wairarapa District Council land is lush and green even in Wairarapa’ s near drought conditions and only slightly hampered by a recent baleage cut of over 60 round bales. The land on Weld Street, is of course part of Council’s Martinborough wastewater treatment plant and Ultraviolet (UV) treated wastewater has been irrigated under test conditions for the last 6 weeks to the land adjacent to the wastewater ponds.
On 21 December, Mayor Viv Napier ‘flipped the switch’ on a sophisticated computer that signalled the end of the test phase for Stage 1A of the Martinborough wastewater project and handover to Council’s normal operations for the next 22 years.
Chief Executive Officer Paul Crimp said “We are very proud of adding a second green wastewater solution to our portfolio. Lake Ferry has been irrigating 100% of its UV treated wastewater to land for over 10 years and it is pleasing that 100% of wastewater discharge from the Martinborough site will now be removed from our river systems over the summer months”.
The wastewater is treated to a very high standard, 99+% of pathogens are eliminated through the Ultra Violet treatment process. The key benefit of irrigation to land is the removal of nitrates and phosphates from the freshwater ways, which promote algal and plankton growth. “It is interesting to note that the nitrates and phosphates that are applied to land via treated wastewater are only in trace quantities, if we wanted to actively produce baleage we would have to add more of those nutrients” Mr Crimp said.
The entire system is monitored by a computer housed in a small concrete block building and sited between the oxidation ponds and the 6ha of land. The computer reports flow information directly to Greater Wellington Regional Council, the body in charge of ensuring Council’s consent conditions are complied with, and sends reports and operational information to Council officers and contractors. The site could be completely controlled by this computer which is not ‘self-aware’ but regardless, able to take control of Martinborough’s wastewater. Council’s contractors will visit the site once-a-day to provide a human sanity check on conditions and to ensure the computer is correctly assessing wind speed and direction as well as flow information.
Greytowns’ wastewater irrigators are scheduled for test monitoring in April 2018 with handover to normal operations in June.
Delays have been experienced with turning Featherston ‘green’ as the resource consent application lodged with GWRC in February 2017 is not expected to be notified for public consultation until early 2018.