Wairewa Marae is affiliated with the Ng膩i Tahu Iwi and is located in Little River township on the Banks Peninsula. The marae is a cultural and community hub where gatherings occur regularly. The generated wastewater must be treated before discharge to protect public health and the environment. The marae has historically been served by a septic tank and holding tank system, from which sludge has had to be hauled off-site regularly. However, Iwi values discourage the handling and transporting of sewage sludge. The marae strives for nature-based and innovative approaches to wastewater treatment that produce high-quality effluents, preserve the receiving environment and align with Iwi values. Many marae, such as the one at Wairewa, are in rural and remote areas where reticulated sewerage systems are not available and are expensive to install. Advances in onsite wastewater treatment systems that are effective and culturally appropriate would benefit not only Wairewa but also many other marae that require improved wastewater treatment to meet increased use.
To address these challenges, an innovative, nature-based onsite wastewater treatment system was recently installed at Wairewa Marae. The system includes an anaerobic digester, a vertical flow wetland, a denitrifying woodchip filter, and a mounded effluent disposal trench. Particular attention has been paid to using nature-based solutions and co-design processes to meet Iwi cultural needs. This PhD project will evaluate the overall performance of the system as well as that of the separate components and how performance is affected by marae use and seasonal temperature variations. The findings would provide a basis for transferring this technology to other Ng膩i Tahu marae.
The successful candidate will investigate the following research questions:
1. Is the nature-based system capable of handling high loading rates, for example, during events at the marae, and seasonal variations in temperature?
2. What is the most sustainable way to minimise and manage greenhouse gas emissions, including methane, from the system?
3. How does the overall system and its separate process units perform in removing suspended solids, carbon, and nutrients in the wastewater?
4. What is the system's efficiency at removing pathogens and emerging contaminants, such as pharmaceuticals?
5. Is an onsite sludge treatment wetland a feasible alternative to sludge hauling off-site?
Cultural aspects will be considered alongside technical aspects throughout the project, and the system's running cost and operational aspects will be examined.
The research will involve regular water sampling and analysis. The water quality parameters to be monitored include dissolved oxygen, pH, suspended solids, total organic carbon (TOC), nitrogen in all forms, phosphate and E. coli. Wastewater flows will also be monitored. Methane content will be measured using a portable landfill gas meter. Pharmaceuticals of interest could be monitored if funding allows.
The research activities will be conducted in close collaboration with the Wairewa Marae community. Workshops will be conducted to gather the community's views around the wastewater treatment system鈥檚 benefits, potential areas for improvement and cultural appropriateness.听
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Supervisors
First Supervisor:听
Second Supervisor:听听(NIWA)
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Key qualifications and skills
Bachelor's with honours degree or master's degree in civil, environmental or chemical engineering or environmental, ecological, biological, or chemical sciences. Experience or willingness to learn laboratory methods for the physical, chemical and bacteriological analysis of water and wastewater.
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Does the project come with funding
UC Connect Doctoral Scholarship - stipend and tuition fees are covered
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How to apply
Applications must be made through the UC Scholarships portal here:听
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Final date for receiving applications
30 September 2025
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Keywords
Wastewater treatment; water quality; nature-based solutions; onsite treatment; marae; te mana o te wai
