Technical Clarification
Septic tank and anaerobic digester treatment systems
Technical Clarification Number
EMI6-T-RC1-0395
Guidance
2012-07-26
The application of onsite blackwater treatment systems may contribute to reduced flow of sewage to the municipal sewage system, or may be a necessity where no municipal sewage system is provided.
For the purposes of Green Star SA in the scenario where no municipal sewage system is provided to the project site, septic tank systems or anaerobic digestion systems may only be considered as “blackwater treatment systems” where the effluent emanating from such systems undergoes appropriate treatment (in accordance with applicable Provincial or National requirements) such that it may be discharge into the environment without causing adverse environmental impacts. The direct discharge of effluent from septic tank systems or anaerobic digestion systems into French drains or soak-away fields is not considered best practice nor deemed appropriate treatment for the purposes of Green Star SA. Such treatment methods pose a contamination risk to groundwater and/or watercourses (see Emi-5 Watercourse Pollution).
Where septic tank or anaerobic digestion effluent undergoes appropriate treatment, the inflow to such systems may be entered as a blackwater ‘resource’ in the Wat-1 Potable Water Calculator, permitting projects to claim benefit in the Emi-6 Discharge to Sewer credit for both occupant amenity water efficiency initiatives and onsite blackwater treatment.
Where septic tank or anaerobic digestion effluent does not undergo appropriate treatment, the inflow to such systems must not be entered as a blackwater ‘resource’ in the Wat-1 Potable Water Calculator. In this scenario, projects may only claim benefit in the Emi-6 Discharge to Sewer credit for occupant amenity water efficiency initiatives only, and not onsite blackwater treatment.
Technical Clarification
Evidence of approval from the relevant authority
Technical Clarification Number
EMI6-T-RC1-0288
Guidance
2011-06-09
Where rainwater collection or water reuse systems are installed, project teams are no longer required to provide 'evidence of approval from the relevant authority' within their documentation submitted for a Green Star SA Design / As Built rating.
Whilst this documentation is no longer required to be included wihin the submission for Green Star SA certification, the GBCSA would expect that project teams adhere to all relevent authority regulations and requirements (including approval of such systems where required).
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