Abel Tasman Sewage Management
Innovative Solutions
Paul Russel outside the Appletree Bay Nerski toilet cubicle. A solar ventilation chimney can be seen above the cubicle.
Septic tank effluent is discharged via a series of drippers located in the slopes above the wetland behind the Anchorage Campground.
COP Outcome development and evaluation
Duty and stand-by septic tanks
Use of duty and stand-by septic tanks would deliver a number of environmental and economic benefits, including reducing the risk of septic tank overflow, providing greater storage capacity in the event of pump malfunction and generally enhancing the robustness of the solution. The dual septic tank system will also enable operators to manage toilet and washing facility discharges in a manner which avoids emergency pump-outs or the uncertainty of knowing when a septic tank will be full. The distribution manhole allows the hut warden to redirect flows simply when required. DOC has already benefited financially from this stand-by solution as expensive barge and associated pump-out facilities were not required during the 2001/2002 high season.
Solar power for pumps
Two types of solar powered effluent disposal systems were considered. The first involved a pump storage system where effluent was pumped to an elevated storage tank during hours of sunlight. The other involved storing electricity in batteries to enable pumping over a longer period. The latter system was selected and involved close liaison between electrical and sewage designers to optimise solar power availability, battery storage and emergency generation, sewage storage and peak use loading.
Ventilation enhanced vault toilets were installed at two locations because there was insufficient water for flushing or because the environment was unstable (sand dunes) and a removable, containment facility was considered the best solution. The vault toilet provides storage for several years. The system also includes a large, solar fan assisted ventilation system designed to avoid odours back-venting into the toilet cubicle. This was considered critical and has received much praise by users during the 2001/2002 season. The vaults have a detachable superstructure and both the vault and superstructure can be relocated by helicopter.
Toilets blocks have low flush toilets and waterless urinals to minimize water demand and to minimise hydraulic sewage load.
Subsurface, dripper effluent disposal systems were installed at the two largest sites. Dripper irrigation of septic tank effluent is a new technological system that enables effluent disposal in a controlled and sustainable way in a difficult topographical environment.
