Guidelineson the Quality of Stormwater and Treated Wastewater

forInjection into Aquifers for Storage and Reuse

ReportNo WSAA 109

July 1996




Urbanstormwater and treated wastewater generated in wet months can be used as awater resource in dry periods if they can be stored. Aquifers may provideadequate and cost-effective storage below ground, but need to be protected fromcontamination. A major barrier to the storage of reclaimed waters in aquifersvia injection wells (ASR) has been a lack of scientifically based guidelinesfor the quality of water to be injected. This report expands on previousdocuments on artificial recharge or reclaimed waters (AWRC 1982, and NRC 1994)and is a first attempt (internationally) to provide a sound basis for theinjection of non-potable waters into aquifers for a range of beneficial uses.


Thisstudy has reviewed international practice and guidelines for artificialrecharge of reclaimed waters by injection. It has given particular attention torelevant existing Australian guidelines and aimed to refine and improve these.The resulting draft guidelines draw on Australia’s existing National WaterQuality Management Strategy (NWQMS)) for its principles, objectives, and forguideline values for maximum contaminant levels in water for a range ofbeneficial uses. They also take account of scientific evidence on:


·        The quality of urban stormwater and treated wastewater

·        pretreatment performance of passive systems

·        clogging and redevelopment of injection wells

·        attenuation of chemical and microbiological contaminants in aquifers

·        preliminary results at a pilot study of ASR using stormwater


Theseguidelines adhere to widely accepted principles but are quite different fromthose currently used to regulate ASR sites in other parts of the world, as theydo not presume potability as an essential objective, and they allow fortreatment of water by natural processes in the aquifer. The guidelines arepresented after consideration and comment on a draft by water companies and otherpotential proponents of ASR-based water supply/wastewater reuse schemes, and bystate and federal authorities with responsibilities for licensing ASRfacilities. Knowledge gaps are also revealed which may focus research to enablethese guidelines to be improved.


Theguidelines, which are summarised (in section 9) cover licensing, pretreatment,monitoring, guidance for maximum contaminant concentrations in injectant,residence time prior to recovery, and management of ASR operations. The reportalso makes recommendations (in section 10) on; revision of these guidelines;concentration of research at selected sites; and establishment of a nationalASR research program to coordinate and conduct ASR research, to collate allmonitoring data and reports from Australian ASR sites, and to produce a designmanual for ASR.


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