Bringing a new perspective to World Water Day
- Dr. Ir. Jules B. van Lier is a professor at Delft University. The opinions expressed are his own. -
The international observance of World Water Day, this year on March 22, is an initiative that grew out of the 1992 United Nations Conference on Environment and Development in Rio de Janeiro.Â This yearâ€™s theme — â€˜Clean Water for a Healthy Worldâ€™ — reflects the fact that population and industrial growth are adding new sources of pollution and increased demand for clean water across the world.
Human and environmental health, drinking and agricultural water supplies for the present and future are at stake, yet water pollution rarely warrants mention as a pressing issue.
It is absolutely right that water quality considerations should be highlighted just as much as water quantity issues going forwards.
However, what is sometimes obscured in this important debate is that, even with a step change in global water treatment efforts, vast amounts of potentially valuable wastewater will continue to be produced for the foreseeable future.
Indeed, in some developing countries some 80 percent of all waste is being discharged completely untreated, because of lack of regulations, resources and control. Globally, it is estimated that 1,500 cubic kilometres of wastewater is produced on an annual basis, whereas the world renewable fresh water reserves amounts to only 40,000 cubic kilometers per year.
Realising that 1 m3 of non-treated wastewater may spoil over 1000 m3 of fresh water for human consumption or other activities, the urgency of the matter is obvious..
My research at Delft University, UNESCO-IHE and my previous employer, Wageningen University, has convinced me that, especially in the developing world, it is crucial that we change our perspective on wastewater for two main reasons:
â€¢Â Â Â In an era of increasing water scarcity, especially in the developed world, it is increasingly vital that we use all our water supplies efficiently.Â As a result of climate change, it is estimated that some 1.8 billion people will live in countries by 2025 with absolute water scarcity.
â€¢Â Â Â Moreover, in recent years, the treatment technologies for removing the harmful components from wastewater have become increasingly effective.Â Thus, far from being a useless by-product which is collected in pipes and gutters and flows into a dump-hole somewhere in the ground, wastewater is actually fast becoming a potential source of valuable raw materials including water and energy that can be reused productively for energy and irrigation.
Going forwards, the potential of wastewater is truly huge, especially in the developing world.
For instance, if we assume only a 50 percentÂ recovery of the chemical energy enclosed in human excreta the potential energy generation equals about 100 watt-hours (Wh) per person per day. This alone would be enough to light a substantial part of the poorest cities of Africa all night long!
Moreover, a city with 1 million inhabitants with an average water consumption of 100 litres a day can theoretically irrigate and fertilise between 1500 and 2000 hectares of farmland through wastewater, while nutrients from the wastewater can also be put to good use and the farmland serve as a sand filter to purify the water.
With our world phosphorous mines being depleted in about 60-70 years from now, we simply have to recover our valuable resources from our urban waste streams. In fact, the word â€˜wasteâ€™ should be replaced by â€˜a stream of non-defined resourcesâ€™ ready for valorisation.
In the past, public sector municipalities, especially in the developing world, have failed to appreciate this potential and have underinvested in sanitary engineering and construction infrastructure and personnel.
Going forwards, however, it is likely that a new generation of developing country entrepreneurs will be able to unlock the value and potential profitability in wastewater and play a key role in the construction and implementation of basic sanitary infrastructure, opening up new opportunities in areas such as micro-financing and environmental engineering.
This would be hugely important in the developing world where 2.6 billion people still have no proper sanitation, resulting in some 200 deaths per hour, with the highest number among children under five.
Indeed, it is perfectly possible in the future that entrepreneurs might, under appropriate regulation, operate municipal-wide sewage treatment systems with investment costs being covered by loans, donations, franchise systems and/or lease contracts, and profit margin coming from sources like sewerage levies, nutrients benefits, stabilised organic matter, and recovered energy.
Such wastewater treatment plants may even eventually become reprocessing plants that produce water suitable for reuse.Â This will lend an entirely new impetus to the process that could lead to the application of new reprocessing technologies, especially in areas where waste water treatment is still seen as a â€˜Western luxuryâ€™.
One final key element that will drive this process forwards is the relaxation of very stringent Western-driven standards that have paralysed construction and implementation of sewerage and waste treatment plants in the developing world.Â The resulting costs are often beyond the means of local municipalities, or encourage development of the wrong kind of sewerage and waste treatment plants for their needs.
A good example here is the city of Amman which, driven by Western donors, has built a high-technology treatment plant with costly wastewater treatment systems.Â Amman would have instead benefited from a decentralised treatment plant that yields an extra 5 to 6 megawatts (MW) of electrical power which could then be used to drive irrigation pumps, for example, to benefit agriculture in local dry regions.
Unfortunately, what has happened in Amman is a common phenomenon in the developing world where insufficient interest is paid to potential alternative sewerage and treatment plants that would be more robust and suitable for these regions.Â The end result is often abandoned or under-performing systems, and or plants that consume so much of the available financial resources that only a fraction of the pollution problems can be handled.
If local entrepreneurs can shift this perspective towards one more focused on adaption towards the local situation and a proper financial cost-benefit analysis, wastewater could easily grow to become an exceptionally valuable source of resource recovery, powering a broader development process in developing countries which still often lack even basic sanitation and water treatment infrastructure.