Friday, May 25, 2007

Canberra: ‘Health and Public Safety in Water Purification’ report

We have been discussing Canberra’s Water2Water proposal to develop an indirect potable water recycling scheme in some detail on this blog recently.

The proposal’s appointed Expert Panel on Health released their Issues Paper 'Health and Public Safety in Water Purification' today.

I recommend downloading a copy of the report from the above link. However, hopefully I wont find myself in any trouble over copyright for posting the executive summary below.

I’d be keen to discuss the issues addressed.

Executive Summary

This issues paper has been prepared by the Expert Panel on Health (EPoH) to assist the community in understanding the nature of ACTEW’s Water2WATER proposal for water purification from the Lower Molonglo Water Quality Control centre (LMWQCC), to supplement Canberra’s drinking water supply.

It considers the present drinking water quality and treatment in Canberra and the safety issues that arise from wastewater purification for supplementing existing drinking water sources. It is not the role of this panel to consider water resource or environmental issues.

Canberra has a water reticulation system supplied with treated drinking water by two water treatment plants (WTPs), the older Googong plant and the new Mt Stromlo plant. Both use well tried and validated treatments to provide water that meets the Australian Drinking Water Guidelines (NHMRC, 2004). Both plants have enhanced capacity to treat variable quality raw water by dissolved air flotation (DAF). The Googong plant now also has capacity for powdered activated carbon treatment, and the Mt Stromlo water treatment plant is shortly to be further developed by ultraviolet light disinfection.

The quality of the discharge from the LMWQCC into the river system is monitored as a requirement of its authorisation from the ACT Environment Protection Agency. The water currently is substantially better than the required quality. However the qualities that are measured are basic, and will need to be vastly expanded to include a wider range of health-related parameters if Water2WATER is to proceed. These monitoring measures will need to include a range of pathogens and endocrine disruptors together with other components of discharge waters.

The Panel has received details of three proposed treatment train options for water purification from ACTEW. These options are each in use overseas and produce purified water that complies with the relevant regulations for drinking water quality.

The suggested mechanism for transferring the purified water into the Cotter reservoir is to allow it to flow down an existing creek, which may incorporate a wetland. At present the Cotter reservoir has limited capacity, which would only provide a short residence time for the water. The multiple barrier approach to water safety would be enhanced by an enlarged Cotter reservoir, with higher water residence time. This provides a safety element in the treatment sequence and an opportunity for natural pathogen reduction.

The quality of the purified water from the proposed plant is crucial to the health and safety of the community, and must not be compromised. To ensure this the Panel expects ACTEW to have Hazard Analysis and Critical Control Point (HACCP) accreditation for both the new water purification plant and for the existing LMWQCC. A extensive sampling and monitoring program will be required, with the purified water to meet the Guideline Values for the existing Australian Drinking Water Guidelines and also the requirements of the recycling water guidelines for potable reuse, which are under development. The quality of purified water would be subject to ACT Health regulatory audits, with an external audit carried out at specified intervals.

The studies of health risks from purified water reuse overseas have been few, due to recent adoption of the technology. A review of the available material concluded that no clear deleterious health risks have been observed.

The community views on the Water2WATER proposal have received considerable public and media interest and a number of health issues have been raised. These include water security and the need for water, types of contaminants in recycled water, health effects of contaminants, efficacy of water purification technologies, the treatment train and its use elsewhere, risks for people with special health needs, adequacy of monitoring and the regulatory framework.

The panel has released two communiqués reporting on its meetings, and has encouraged contact through its website. The views expressed by the public will be considered in preparation of the final report, due at the end of June.


suspicious said...

interesting to see Ian Law ex-CH2M Hill has squirrelled his way in there.

suspicious said...

The studies of health risks from purified water reuse overseas have been few, due to recent adoption of the technology. A review of the available material concluded that no clear deleterious health risks have been observed.

At least they admit there are few studies and it is new technology

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