New Zealand’s wastewater treatment systems are often overloaded and fail to meet existing discharge conditions. Wastewater treatment plants nationwide will require substantial investment and innovation over the next 10–20 years to meet the demands for population growth and climate change.

However, upgrading wastewater treatment plant infrastructure is likely to be difficult in many cases as the vast majority of wastewater treatment plants in New Zealand only service a small portion of the total population. As a result, there is limited funding for wastewater treatment plant services by local councils, restricting plant design and the infrastructure upgrades required for adequate treatment of municipal wastewater.

Algal bioremediation has the potential to help alleviate economic pressures through cost-effective wastewater treatment, wastewater reuse and resource recovery. There is an increasing demand for greener infrastructure and sustainable cities, creating a paradigm shift where wastewater effluent is not perceived as a human health and environmental concern but as an ecological solution from which water, nutrients, and other valuable resources could be recovered. Additionally, recovery of nitrogen and phosphorous from municipal wastewater through algal bioremediation can offset operational and maintenance costs, with the potential for treatment plants to become profitable.

Indi Novak is a current PhD student in biological sciences based at the University of Waikato’s Coastal Marine Field Station.  Her research has focused on the use of algae ponds in rural wastewater treatment as a potential solution to nutrients and bacteria entering the aquatic environment at the Coastal Marine Field Station, Tauranga, under the supervision of Dr Rebecca Lawton, Dr Marie Magnusson, and Dr Rupert Craggs at the National Institute of Water and Atmospheric Research (NIWA). Her research is primarily funded through the MBIE Research Programme and is due for completion by November 2023.

She says her project aims to, “halve rural and Māori community wastewater treatment costs: mainstreaming novel ecocultural technologies”, with support from the Tertiary Education Commission funded Entrepreneurial Universities Macroalgal Biotechnologies Programme.

Indi’s research recognises municipal wastewater treatment plant effluent contributes to nutrients and bacteria entering the aquatic environment.  Her research investigates the ability of high rate filamentous (threadlike) algae to remove nutrients and bacteria from wastewater discharges; including whether algal ponds can provide a viable alternative to current wastewater treatment systems.  A potential side benefit, which is also being looked at, is the recovery of nutrients as algal biomass.  “This research will provide the first demonstration of the feasibility of a high-rate filamentous algal pond system for municipal wastewater treatment at scale, over multiple seasons, in New Zealand,” says Indi.  “It provides the potential for a new eco-cultural, technological approach to municipal wastewater treatment”.   

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The University of Waikato’s Coastal Marine Field Station at Sulphur Point was established in December 2011.  As part of the University’s Environmental Research Institute, the Coastal Marine Field Station is involved in teaching, environmental monitoring and coastal and marine research and discovery. It has become a major centre of marine research excellence in New Zealand. 

In 2020 a state-of-the-art facility for seaweed cultivation was opened to support applied research and development in marine and freshwater macroalgal biotechnologies.  In particular, there is a focus on:

1. the diversification of species for aquaculture;
2. improvement of water quality in aquatic systems using macroalgal bioremediation technologies; and,
3. the development of innovative macroalgal bioproducts.

Collaborating with industry, academia, independent science organisations, and Crown Research Institutions, the aim is to deliver sustainable enterprises that can move quickly from pilot demonstration to commercial scale.