The increasing demand for water by growing populations in the twenty first century has created the need for increased efficiency in water management policies. Increasing technology in the wastewater treatment field has allowed us to look at the possibilities of recycling water within our water treatment facilities. There are several scientific, economic and political decisions attached with every water management issue, and these must be overcome before policies and solutions can be put in place.
Terminology in the field is a little strange. While some papers have actually given different definitions to water recycling, water reuse and water reclamation, I have found that these words are often used interchangeably, depending on the author. You will find that this website assumes the same definition for each of the different terms. There are other names that have been given to the process (water purification) and the actual water (Singapore’s NEWater) for public perception issues.
Applications of wastewater recycling are closely linked to the water cycle. The process mainly involves changing the distribution of industrial and municipally treated wastewater to better suit the needs of the community. When water is discharged into the ocean, its quality is virtually destroyed. Wastewater recycling allows us to take the water that would have otherwise been wasted, and treat it to a high enough level of water quality to be used again (generally for non-potable uses). By creating another source of water for the community, the amount of water that needs to be extracted from surface and groundwater sources is also minimized. The process of wastewater recycling is ultimately an improvement on the efficiency of our water treatment and distribution systems, allowing us to use water of lower qualities for those processes that do not warrant a high quality supply.
As the world population grows, more and more water is being pumped out of our aquifers, lakes and rivers and into our homes, destroying water tables and causing adverse environmental effects. There are many solutions to this problem, as increasing technology in the field has allowed us to do things that we could have once only dreamed. The introduction of advanced water treatment processes has allowed us to create an almost potable supply from water that was once contaminated. It does not make sense that in areas where water supplies are scarce - or will be scarce, that wastewater recycling applications are not being used.
"It is important to recognize that public acceptance of reuse projects is vital to the future of wastewater reclamation, recycling, and reuse; the consequences of poor public perception could jeopardize future projects involving the use of reclaimed wastewater"
- Takashi Asano, 1996
In 2001, after hearing of the cities proposed plan to recharge depleted aquifers with treated wastewater, the mayor of Los Angeles responded with the following statement: "Lips that touch reclaimed water must never touch mine." (Waldie, 2002) I guess it's kind of ironic that the water pumped from the Colorado River, treated and sent to the taps of the people of Los Angeles has probably already seen several toilets, drains, and lips. Virtually every city along the Colorado River uses it as it's drinking water source - and it's drain. It's also interesting to note that the state of California is one of the largest users in the world of recycled wastewater, and is trying to further educate the people into accepting further means of recycling, as their needs for water are currently heavily outweighing their supply. The possible solution of recycling is being fought politically because of worries over the safety of the water.
Several health studies have been conducted on various health effects of reclaimed water. No study has concluded that areas using reclaimed water have been adversely affected by the use of treated wastewater. Furthermore, most studies even conclude that the use of reclaimed water incurs the same or even less risk than that of the drinking water supply. Because of the limitations in most of the ecologic studies (geographic) conducted, there are still questions concerning the safety of water reuse. See the Epidemiology section for more info.
There are several places in the world right now that have quite literally run out of water, and have no other choice but to find an alternate supply. "Jordan, the West Bank, Gaza, Cyprus, Malta, and the Arabian Peninsula are at the point where all surface and ground freshwater resources are fully used. Morocco, Algeria, Tunisia and Egypt will all be in the same position within a decade." (De Villiers, 2003) This has left these countries with no other option but to find another supply. While many countries look at placing desalination plants along their coasts, some have recognized the need to create a more sustainable method of using our fresh water sources. Why dump water into the ocean and further destroy its quality, when it can be treated and re-used? By recycling our wastewater, we are taking advantage of the fresh water that we have, instead of it being wasted. It seems preposterous to me that a country using desalination plants would not choose to recycle their water as much as possible. Desalination is an expensive solution to water scarcity, and it is important in these situations to be as cost efficient as possible. By dumping wastewater effluents into the ocean, water quality is being further destroyed and will cost even more in the long run to treat.
The amount of treatment necessary to obtain water that is worth recycling is entirely dependent on the use after treatment. This in turn becomes a trade-off between cost and water quality, as more advanced treatment methods are currently expensive, and may not be viewed as a viable option if potable supplies are available. While some places in the world are currently using treated wastewater as a back-up supply for their drinking water supply, it is expected that as water becomes less and less available, these systems will eventually be implemented much more.
For a full overview of water reuse, I would highly recommend reading “Wastewater Reclamation, Recycling and Reuse: Past, Present and Future” by Takashi Asano, and Audrey D. Levine. The paper is cited in the reference section.
Asano, T., & Levine, A. D. (1996). Wastewater reclamation, recycling and reuse: past, present, and future. Water Science and Technology Proceedings of the 1995 IAWQ 2nd International Symposium on Wastewater Reclamation and Reuse, Oct 17-20 1995, 33(10-11TY - JOUR), 1-14.
De Villiers, M. (2003). Water: the fate of our most precious resource. Toronto, Ontario: McClelland & Steward Ltd.
Waldie, D. (2002). Los angeles' toilet-to-tap fear factor. Retrieved 06/16, 2004 from http://www.watereuse.org/Pages/newspaper2.htm