Worldwide water recycling and reuse

Although it may seem foreign to us here in Australia many cities in the world still do not have a sewage treatment system and discharge raw sewage directly onto the land and into the water.  This type of activity can present a serious health risk.  For example in Hanoi City, Vietnam, their greywater is not treated at all and runs down ditches and urine and faeces are used as organic nutrients.  The urine is usually separated and the human and animal faeces are stored in underground tanks until required.  When required the sewage is taken via bicycle to agricultural fields and aquaculture ponds.  Vegetables are washed in these ponds and children swim in them.

The World Health Organisation (WHO) has published guidelines for the safe use of water in agriculture to protect farmers’ and consumers health.  A meeting of sanitary engineers, epidemiologists and social scientists, organised by the World Health Organization, the World Bank and the International Reference Centre for Waste Disposal in 1985, proposed a more realistic approach to the use of treated wastewater and excreta, based on the best and most
recent epidemiological evidence (WHO 1989).

Water reuse is becoming more common worldwide as a part of countries water resource planning as previous water resources become less and are not recovering to keep up with population increases.  Water recycling occurs the most often in regions which suffer water scarcity, such as the Middle East, Australia or the south-west USA, or in regions with severe restrictions on disposal of treated wastewater effluents, such as Florida, coastal or inland areas of France and Italy, and densely populated European countries such as England and Germany.

Figure 1:  World Health Organisation Flag  


In the United States of America (USA) the Environmental Protection Guidelines for Water Reuse (US EPA 1992) convey information to utilities and state regulatory services when standards don’t exist or are being revised.  It is not a standard that is applied across all of the states.  The guidelines provide a complete review of technical information such as:

  • treatment processes;
  • pathogen organisms;
  • storage requirements;
  • types of recycling applications such as industrial, urban, agricultural and environmental;
  • an inventory of the existing state legislation, legal issues, funding alternatives and public information programs.

It is generally accepted that the US EPA Guidelines are the most rigorous of the WHO guidelines.  One of the main problems regarding water recycling in the USA has been that the agencies that handle water and sewer services vary from state to state.  This makes coordination between these agencies difficult as each has their own goal they wish to achieve.  Although wastewater recycling in the USA is mainly oriented to disposal on land, there are now a number of schemes in place that generate an indirect potable supply.

Figure 2:  The Great Seal of the USA


Generally speaking Canada has a good supply of water in most regions.  For this reason water recycling and reuse is generally only done on a small scale.  This includes agricultural and golf course irrigation in:

  • British Columbia;
  • Alberta;
  • Manitoba;
  • Saskatchewan.

Figure 3:  Canadian Coat of Arms  

Canada does not have any federal guidelines on water recycling although there are some provincial guidelines in British Columbia and Alberta.  The Canadian Council of Ministers of the Environment sponsored a workshop in 2002 that discussed water reuse and recycling issues and consisted of agency representatives and scientists.  The workshop discussed the need for National Guidelines and Provincial water quality standards.  It identified the need for:

  • criteria and validation protocols and technology for treatment facilities;
  • policies that encourage full-cost pricing of water resources;
  • design standards and programs that will educate the public on reuse programs;
  • economic and management systems to assess the possibility of any proposals;
  • public consultation and communication programs;
  • additional research needs including:
    o    emerging health issues;
    o    long-term impacts;
    o    risk assessment methods;
    o    well defined strategies;
    o    economic analysis;
    o    improved collaboration.
  • A standing task force on water recycling with follow-up workshops and greater networking.


Singapore’s water catchment is very small as it is only a small island.  Because of this Singapore imports approximately half of its water from Malaysia as part of an agreement which is not secure and leaves Singapore in a long-term insecure position.  In 2000 a demonstration water recycling plant was commissioned to produce NEWater at its Bedok Sewage Treatment Plant.  This plant was based on recommendations of the National Research Council, USA (1998).
The water demonstration plant is a clarified secondary effluent from an activated sludge treatment process.  Many problems arose during the two year trial of the plant, some due to human error and some due to uncontrollable environmental factors.  It was concluded that after two years that NEWater can be produced consistently and reliably on a large scale and that it is safe for drinking purposes.

Figure 4:  Singapore Coat of Arms  

Since 2002 there are now two full-scale plants, one at Bedok and one at Kranji which mainly serve high technology industries.  The first water was delivered to Wafer Fab Parks and Tampines/Pasir Ris and Woodlands in February 2003.  Visitors and especially school children are encouraged to visit the plants to become informed and familiar with how it operates and therefore hopefully comfortable using the water that is produced.

For further information and more countries please see: