scope:

The Standard identifies the performance statements that cover the overall design and sustainable management of on-site domestic wastewater systems. These performance statements set performance objectives which are followed by performance requirements and then, when possible, with performance criteria.

Inclusions

This Standard deals with the systems for treating wastewater originating from household or personal activities including water closets, urinals, kitchens, bathrooms (including showers, washbasins, baths, spa baths but not spa pools or hot tubs) and laundries. Such domestic wastewater includes that from facilities serving staff/employees/residents in institutional, commercial, and industrial establishments.

Systems covered

The on-site systems covered by this Standard include primary, secondary, and disinfection wastewater treatment systems. The Standard gives specific details for septic tanks, other wastewater treatment units, and land application systems. Specific details are provided for conventional trenches, beds, evapotranspiration areas, mounds, drip and spray irrigation. These commonly used systems, while given as examples, are not intended to preclude the growing number of new or developing technologies in on-site wastewater management.

Likewise, guidelines and design manuals prepared by other agencies may be accepted as equally valid means of implementing the principles set out in this Standard. In particular, the management principles are appropriate for use in conjunction with the technical provisions of other design guidelines.

This Standard does not preclude the use of any material, system, design, or method of implementation provided the completed system and installation meet the performance requirements of this Standard. Details of such systems and installations and methods should be submitted to the relevant authority for approval. Systems not covered by this Standard require advice from a suitably qualified and experienced person. 

System size

The systems covered in this Standard are normally designed for domestic wastewater flows up to 14 000 L/week, from a population equivalent of up to 10 persons.

Where the principles and practices outlined in this Standard are applied to systems exceeding this limit, the design shall be the responsibility of a suitably qualified and experienced person.

The flow limit of 14 000 L/week represents an average daily flow for design sizing purposes of 2000 L from up to 10 persons in a single residence, or an institutional or commercial facility which may have a varying 7-day or 5-day operation averaged out over a full week. Larger systems often require additional features in light of the need for more centralised operation, maintenance, and monitoring.

Exclusions

This Standard does not cover systems for the treatment of wastewater from commercial and industrial sources, or stormwater.

Although this Standard covers the subsurface land application of greywater after primary or secondary treatment, it does not cover greywater reuse by the direct application onto land or by other means, nor does it provide details of greywater diversion systems.

The use of untreated and treated greywater is complex due to its variable microbial and chemical characteristics. It is recognised, however, that recovery of greywater for treatment and reuse of the resulting reclaimed water is practised under regulatory control within several jurisdictions in Australia and New Zealand.

The Australian EPHC (Environment Protection and Heritage Council) (2002) has produced national guidelines for water recycling (November 2006) which use a risk management framework and provide specific guidance on the management of health and environmental risks associated with the use of recycled water.

Purpose of Standard

The purpose of this Standard is to provide the requirements for treatment units and their land application systems to achieve sustainable and effective on-site domestic wastewater management, to protect public health and the environment.