An
article in The Australian today points out the fact that Singaporeans are drinking recycled “sewage” too. That fact in itself may not seem remarkable since there is
treated effluent in most water supplies of most large cities.
However, what is more interesting in Singapore is the high level of treatment used (including reverse osmosis and UV disinfection). This has made the water highly suited for a number of applications including Singapore’s considerable electronic chip manufacturing industry. Only a very small proportion is then left over to recharge public drinking water reservoirs with (to provide about 1 per cent of the island's total potable water supply).
We have looked at the situation in
Singapore a few times previously on this blog. One of the most interesting aspects for me was the '
NEWater Study' that was undertaken to investigate the health effects of using highly treated recycled water as a drinking water supply.

An Expert Panel was formed in 1999 to oversee the NEWater Study. This Expert Panel was comprised of both local and overseas members with expertise in human health and toxicology, microbiology, engineering, water technology, epidemiology, water quality and environmental chemistry.
A pilot scale (10 ML/day) advanced water treatment plant, known as the NEWater Factory was constructed and commenced operation in 2000. The NEWater Factory received water from the Bedok Sewage Treatment Works, which produced secondary treated effluent. The technologies employed at the NEWater Factory included microfiltration, reverse osmosis and ultraviolet radiation.
An extensive water quality sampling and monitoring program was devised for approximately 190 physical, chemical and microbiological parameters. Samples were tested from the plant feedwater, individual treatment module effluents, final produced NEWater, as well as untreated and treated traditional drinking-water supplies. Overall, almost 20,000 test results from seven sampling locations, including over 4,500 for NEWater were measured between November 1999-April 2002. The physical, chemical and microbiological data for NEWater were shown to be well within current (2002) US EPA and World Health Organization guidelines for drinking-water quality.
The health effects study was conducted with two components. A mice study was undertaken to assess long-term chronic toxicity and carcinogenicity, while a fish study was undertaken to assess toxic and estrogenic effects. In these studies, NEWater was compared with untreated reservoir water.
A sensitive mouse strain (B6C3F1) was used for the mice study. This strain is widely used for conducting long-term health effects studies of new pharmaceuticals. Groups of mice were fed 150-fold and 500-fold concentrates of NEWater and untreated reservoir water over a period of two years. The testing was undertaken with culls at 3, 12 and 24 months. At the time of publication of the expert review panel findings, the 3 and 12 month results were available and these indicated that exposure to concentrated NEWater did not cause any tissue abnormalities or health effects. The 24-month results were due to be completed in October 2002, but as far I know, remain unpublished. I would really like to see these if anyone is able to dig them up.
Fish studies were undertaken in accordance with a recommendation from a recent US National Research Council report. The purpose was to assess long-term chronic toxicity as well as the estrogenic potential (reproductive and developmental). The orange-red strain of the Japanese medaka fish (Oryzias latipes) was selected for the study due to the availability of an extensive biological database for this species.
The fish testing was conducted over a 12-month period with two generations of fish. The NEWater tests were initially undertaken during 2001 and both generations showed no evidence of carcinogenic or estrogenic effects from exposure to NEWater. The fish study was repeated in 2003 (due to some design deficiencies of the aquarium system, fish husbandry issues and weaknesses in the original study protocol) and confirmed the findings of no estrogenic or carcinogenic effects.
I don’t think that these types of live animal studies are necessarily justifiable for the South East Queensland scheme. However, it would be extremely helpful to see some of the existing data to confirm excellent performance of the advanced water treatment barriers.