back to Technical Papers

CONFERENCE: AWA NQ Regional Water 2010

ABSTRACT:
Amendments to the Australian Drinking Water Guidelines are proposed and seek to incorporate a definition of microbial safety and health based targets that will provide a mechanism for identifying appropriate barriers to ensure safety of drinking water supplies. This step forward will follow recent changes made to drinking water legislation in the USA, Canada, New Zealand and at the World Health Organisation.

The Drinking Water Standards in New Zealand were revised in 2005 and incorporated some minor revisions in 2008. The principal objectives of the NZ legislation are:
-  the specification of MAVs for microbial, chemical and radiological determinands of public health
    significance
-  compliance criteria and reporting standards
-  remedial actions.

The NZ Standard gives the highest priority to health risks arising from microbial contaminants because of the risk of major outbreaks of disease.

Asset owners, utility operators and treatment plant designers need to understand the impact changing legislation has on existing plants and facilities. The experience in New Zealand has identified key areas where existing plants do not typically comply and these are:
-  sampling and monitoring (instrumentation)
-  reporting (SCADA)
-  performance of ageing plant
-  identification of the appropriate level of protozoa removal (log reduction required)
-  understanding and interpretation of the Standards (by both the water supplier and the drinking water
   assessors)
-  no central point of reference for interpretation of the standards (interpretation left to the local
   drinking water assessor).

This paper will examine the issues encountered in moving from a more relaxed standard, to a very tight standard (for example, a turbidity standard of 1 NTU to 0.1 NTU) over a short time frame of a few years. It will examine the amenability of ageing plants to be upgraded. It will also identify the problems associated with the interpretation of the standards.

Name: *	Email: *	Company: *
Phone: *