Composting toilets for Matapōuri

Name of case study

Composting toilets for Matapōuri

Location

Matapōuri, Whangārei District, Northland, New Zealand

Year

2023

Scale

Building / single site

Area / size

25 sqm appx

NbS employed

Composting / vermiculture toilets

Type of NbS

Hybrid living/engineered interventions

Initiator

Local hapu Te Whanau a Rangiwhakaahu and Whangārei District Council

Funder

Tourism Infrastructure Grant

Budget

N/A

Design group

  • Contractor: Buildsense
  • System supplier: Waterless Composting Toilets
Fig. 1: Ecoflo wastewater management (2023), p. 6. Floor plan of 3 cubicles.
Fig. 2: Whangārei District Council (2023). New composting toilets.
Climate change benefits
  • Indirect health, social, and cultural climate change impacts
  • Reduced soil quality
  • Reduced fresh-water availability
Societal / socio-cultural benefits
  • Climate change adaptation
  • Economic and social development
  • Pressures of urbanisation (waste management, hygiene, etc)
  • Water security and quality
Ecological benefits
  • Decomposition
  • Education and knowledge
  • Nutrient cycling
  • Soil building

Summary of case study

The previous two-cubicle public toilets on Wehiwehi road, next to the beach in Matapōuri, were failing to deal with increased use during the summer and were frequently becoming blocked, necessitating the closure of the facilities while the septic system was repaired. The original septic tank system had various drawbacks, including the difficulty and cost of ensuring an appropriate water supply. Moreover, there was resistance to implementing a sizable septic wastewater system due to concerns related to environmental impact, cultural considerations, and social and amenity aspects, such as toilet placements near the Matapōuri Estuary or along Matapōuri Bay (Whangārei District Council, 2023). Local residents and hapu wished for a more ecologically friendly and culturally appropriate wastewater treatment system. As a result, members of the neighbourhood encouraged the Council to look into adopting waterless composting toilets instead of a traditional septic system.

The new public toilets are part of a larger initiative called Restoring the Mauri of Matapōuri, which has been in the works since 2019 by local hapu Te Whanau Rangiwhakaahu and Council (Whangārei District Council, 2023). The new toilets have two unisex cubicles and one disabled cubicle while the existing toilets also remain open.  The compost from the toilets will require removal at intervals ranging from monthly to every six months, depending on the season and the usage level (Whangārei District Council, 2023).

These composting toilets save water and keep human waste out of waste treatment facilities, transforming it into a beneficial resource that helps topsoil stay healthy while also reducing our reliance on chemicals to handle waste. Moreover, they prevent the risk of hazardous waste spilling into the environment as they don’t require a septic tank. The toilet design needed minimal land area, had low water usage, and aligned with various priorities important to the Matapōuri community (Whangārei District Council, 2023).

References

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