The recent open day for the Dairy Effluent Conversion Project provided a great opportunity to share ideas and outline the innovative concepts being trailed, with some attendees coming from as far afield as Taihape.
Around 60 people attended the open day held on a dairy farm near Katikati. The open day was jointly hosted by DairyNZ and Bay of Plenty Regional Council and was an opportunity to demonstrate the farm trial of a process to convert dairy effluent into fish food and improve water quality in the drainage system.
The innovative project, jointly funded by the Bay of Plenty Regional Council and Ministry for Primary Industries Sustainable Farming Fund, is working to convert waste nutrients from dairy shed effluent into algae and zooplankton that can be used to feed native fish.
Regional Council Rivers and Drainage Manager, Bruce Crabbe, was pleased with the open day and the enthusiasm from visitors to the farm.
“The project is really just kicking off so we don’t have any long term monitoring results or data to share. But having the ponds built and some of the associated infrastructure in place meant that we could have some great in-depth conversations about what the project expects to achieve and some of the blue-sky possibilities for the technology,” Mr Crabbe said.
The Project expects to see improved water quality and more fish and healthy aquatic life in the farm’s drainage system including native species such as tuna (eel), inanga (whitebait), and mullet.
“We had a tour of the sites with briefings at a few key points of interest and a question and answer session at the end. There were informative presentations from key members of the project team - NIWA, Raglan EELs and Bay of Plenty Polytechnic followed by some very insightful questions. The feedback was very positive.
“Farmers showed a natural interest in the economic possibilities around creating a feed source or energy source from the ponds or selling the products produced. While the Project isn’t focussed on that aspect of the process, it was great to see visitors catch on to the possibilities that open up if we can show that the technology works in this trial,” Mr Crabbe said.
Further open days will be held over the coming three years of the Trial.
Project outline - Dairy effluent is used at the bottom of the food chain, providing nutrients to promote algal growth in purpose-built High Rate Algal Ponds (HRAPs) developed by NIWA. The algae is settled and harvested in the Algal Harvest Ponds (AHPs) then piped in slurry form to a separate zooplankton pond constructed within the farm drainage system. Zooplankton (minute shrimp-like crustaceans) in this pond feed on the algae and grow to provide a live food source for fish. With the consistent availability of an abundant and nutritious food supply, fish will be encouraged into the farm drainage system from the Aongatete River through a fish-friendly passage.
For more information visit www.boprc.govt.nz/dairyeffluentconversion
Funding is provided by the Ministry for Primary Industries Sustainable Farming Fund and the Regional Council's Bright Ideas Innovation Fund. The Fund was established in 2010 to help fund innovative staff projects and ideas that are likely to improve the value of the Regional Council's work in the community, but which fall outside standard work programmes.