Septage Study – Rarotonga

The Ministry of Infrastructure Cook Islands (ICI), with funding from New Zealand Aid (NZ Ministry of Foreign Affairs and Trade), and the European Union is delivering a four year ‘Sanitation Upgrade Programme’ (SUP), with the overall aim of protecting and improving the quality of streams, groundwater and lagoons. 

A key component of the SUP is the upgrade of domestic on-site sanitation systems at up to 1,000 homes on Rarotonga and Aitutaki to ensure compliance with relevant Regulations and Standards.

Prior to beginning the second stage of the SUP, this study was commissioned by the Water, Waste and Sanitation (WATSAN) Unit of the ICI to assess whether sludge collection and transfer services and the sludge management arrangements at the waste treatment facilities on Rarotonga and Aitutaki have the capabilities and capacities to process anticipated future septage and sludge loads, as well as landfill leachate.

This study was undertaken by Fraser Thomas and including the following works:

  • Review of relevant background information
  • Assessment of sludge collection and disposal arrangements on both islands, including meeting with relevant personnel in Rarotonga and Aitutaki
  • Inspection of landfilling and septage handling practices, treatment system condition and operation on both islands
  • Provide options for enhancement of the treatment and disposal systems
  • Analysis of septage, sludge and leachate generation for assessment of treatment system capacity.  Current system performance was determined by collection of wastewater samples on Rarotonga, which were analysed by a laboratory in New Zealand
  • Review of available marine, surface water and groundwater monitoring data
  • Environmental Impact Assessment for septage treatment and disposal systems on both islands.

Expertise provided:

  • Environmental

Project cycle:

  • Investigations
  • Specialist reporting