The collective treatment plant of Haapiti, located on the island of Moorea in Varari, has been operational since February 2011 to allow the treatment of wastewater from the entire tourist area.
The treatment method of this plant is biological: the wastewater, filtered from the coarse elements, passes over beds of reeds and is carried out to transform it into compost.
The water separated from the sludge is discharged by an outfall directly into the ocean, at the outlet of the pass. However, this conduit has suffered degradation due to strong currents and the passage of cyclone Oli in early 2010. Wastewater discharges are therefore no more at a depth of 70 metres but at a depth of 14 metres, at the level of the breaks.
Since 2017, samples have been taken four times a year to study both the sediments present in the area (particle size, organic matter, nitrogen and organic carbon) and the quality of the surface water (levels of Escherichia coli, faecal enterococci and various nutrient salts). Probes are also left on site for the continuous measurement of physico-chemical parameters (temperature, salinity, dissolved oxygen) and currentology at depth. This is in order to be able to rule on the impact of discharges on the health of the water column for the users of the pass (fishermen and surfers in particular) and the adjacent biodiversity.