Another way of living
Beginning a series exploring a few wonderful ideas/ initiatives from the market and the real world, which show another, better way to solve the same difficult problems that the rest of the world faces. Ideas that are commercially viable as well as long-term sustainable and seem to build something positive for the times to come.
Beginning with Water and Wastewater:
Windhoek, Namibia
“In the city of Windhoek in the 1960s, water was primarily supplied by unreliable local subterranean sources, a problem compounded by a lack of rain. Additional water infrastructure was needed in order to meet water demand. Recognizing that wastewater is a valuable resource, Namibia decided to reuse it. They built the Goreangab Water Reclamation Plant, the first water recycling plant in the world to recycle municipal wastewater into drinking water, which is known as direct potable reuse (DPR).”
Windhoek is the capital city of Namibia and is its largest city (country population now 3 million, then 600k , Windhoek now 464k, then ~60k). Not only is it one of the most sparsely populated country in the world (density 3.7 per km sq), but also being the driest country in sub-Saharan Africa, Namibia has had water stress situation (which rest of the world is now waking up to) for a long time, and it has addressed it in one of the most innovative ways. Windhoek now has the world’s longest running DPR plant. DPR is Direct Potable Reuse, implying converting wastewater to drinking water. There are only a handful plants in the world that either do that or are capable of doing that, and only two cities Windhoek and Singapore relying on them. As world water stress increases, and the problem of pollution intensifies, it is worth considering, understanding and perhaps worth exploring further innovation in.
Although the plant exists from 1968, the Windhoek plant has been updated a few times. Latest update was in 2002, since when it has been supplying 5.5 MGD to the city which is almost 14% of the city’s drinking water production. (For context, MGD is million gallons per day. This is the term usually used to compare size of treatment plants. It is estimated that roughly 1 MGD can serve 10k-100k people depending on water needs.)
Water & Wastewater treatment
“Successful DPR projects, such as in Windhoek, involve rigorously treating domestic wastewater to produce an effluent with a consistently high quality, which is then treated further to produce water that is safe to drink.”
Most of water & wastewater treatment solutions are problem-solving, made-to-order customised engineering projects. The nature of the problem require local, specific solutions. There is generally a suite of products and a suite of solutions, and the available source water and topography, and other factors such as end-use of the water which determine what is installed for treating the water for potable use. (More details in attached note).
In the case of Windhoek, the water is treated 9- 10 times to make it cleaner than the usual potable water.
“To transform the wastewater from Windhoek’s 350,000 residents into drinking water, the Goreangab water treatment plant uses a process that mimics nature. “Everything is done biologically. The bacteria help digest the human waste and pull it out of the water, essentially mimicking what happens in nature but a whole lot faster,” The facility features state-of-the-art “multi-barrier” technology: ozone treatment, ultra membrane filtration and residual chlorination. This process eliminates all pollutants and contaminants. The various treatments, coupled with rigorous bio-monitoring programs, guarantee high quality, safe drinking water. It is a global benchmark since the only cities in the world to produce drinking water from their wastewater are Windhoek and Singapore.”
Wastewater reuse (after treatment) for industrial or irrigation purposes has been around for a long time. It helps with water stress and is cheaper than desalination. But Direct Potable Reuse (DPR) such as in Windhoek goes much further and converts it into potable water. The other place that does that at larger scale is Singapore. Its NEWater has 4 plants that meet 30% of the country’s needs, the water generated better than potable water standards.
What DPR does is reclaim water for drinking. It can be Indirect Potable Reuse (IPR) as well – which reclaims it enough to be put back in aquifers. And even at less expense/quality than that, water can be reclaimed for several other activities (such as industrial use, non-food irrigation, landscape) by putting it through secondary treatment, which are cheaper (than DPR) and ensure two things: a) reduced pollution by reduced discharges b) reduced pressure on primary water sources by reusing and recycling.
What it implies that there are various levels and degrees of wastewater treatment, and a city can choose basis its resources. However, it still requires strong sewage infrastructure, and a long-term intergenerational thinking for the city/town to consider the really long-term benefits of these projects.
The above discussion becomes pertinent once one considers the fact that around 80% of the world’s wastewater is wasted, against the fact that around 1.7 billion people live in places where ground water is under stress, and over half the world population faces water scarcity for parts of a year.
In Context: Water & Wastewater
To consider the above well, following are a few context pointers on Water and Wastewater around the world.
- Water usage around the world,
- Water situation around the world,
- Reclaiming water for reuse and further for drinking
1. Water usage around the world
Though all charts relevant to this post are saved in the attached workbook, I wish to add the following to contextualise water usage:
Agriculture is the largest user, followed by industry and then domestic use. Of all the water withdrawn for use, ~70% is for agriculture use, of which ~just over half is consumed, rest gets drained away. Around 20% of total water is used by industries, of which they discharge over 80% as wastewater. And in case of municipal use, the rest 10% of total, of which over 75% is discharged as wastewater. So, for every 100 units of water withdrawn, 8 is municipal waste, 16 is industrial waste (out of total 30 supplied to them) and 32 is agricultural drainage.
There are 37 cities in the world with more than 10 million people living in them, and over 80 cities with more than 5 million people living in them, and over 512 with at least 1 million people living in them. Over 48% of humanity lives in cities with over 50k inhabitants. Most of the world settled around a flowing water source. All historical human cities are generally close to a river. Modern times though rely a lot on ground water which cannot be replenished as quickly. Hence making this discussion all the more timely and relevant. Over 2.5 billion people in the world rely on ground water for daily use, and more than half of them live in places where ground water is under pressure.
The concentration of population in large cities also implies is concentrated wastewater infrastructure and discharge, which with time is going to further increase. Almost 70% of water supplied to cities becomes wastewater. And around 80% of that water is just wasted (not reclaimed).
In developed countries, the available evidence suggests that water demand from the municipal (or domestic) sector has experienced a considerable increase relative to the other sectors and is likely to continue growing as populations urbanize and the water supply and sanitation systems servicing these cities expand.
2. Water situation around the world
Perhaps here a few facts to consider or picture water usage around the world from different sources:
- “over 2 billion people still lack access to clean, safe drinking water. By 2030, water scarcity could displace over 700 million people.”
- “Sub-Saharan regions are experiencing the worst of the crisis, with only 22-34% of populations in at least eight sub-Saharan countries having access to safe water.”
- “Roughly half of the world’s population currently experiences severe water scarcity for at least part of the year. While some areas experience water scarcity a few months per year, others endure severe water scarcity year-round.”
- “As of 2024, approximately 25 countries, housing a quarter of the global population, experience “extremely high” water stress, withdrawing over 80% of their available/ renewable water supply annually.”
For all the ground water drawn or available freshwater used for domestic and industrial purposes, if so much of it is wastewater collected and gathered by sewerage systems, water which could be reclaimed, it could go towards both reducing pollution as well as reducing pressures on the available water supply. Through methods of primary, secondary, tertiary treatments, water can be reused for different purposes.
“Reclaimed water can help irrigate crops, landscape irrigation, industry and groundwater replenishment. All this requires lower levels of treatment than drinking water. “
3. Reclaiming water for reuse
The world population has tripled in the last 70 years. The world crossed its rural-urban divide in favor of urban regions in 2007. The high population and increasing urban conglomeration implies water supplied through municipal pipelines and a much higher increase in wastewater. And hence the current relevance of this direction of thinking.
Recycling and Desalination allow for potable water in places where no other source of water is available.
“2.3 billion people live in water-stressed countries, meaning that their annual water availability is below 1700 m3 per person per year. Yet, each year 380 billion m3 of municipal wastewater is generated globally. And the amount of wastewater is expected to increase by 24% by 2030 and 51% by 2050. Wastewater is not a problem, however. It’s an opportunity.”
Another big reason is compared to desalination, Direct Potable Reuse works out cheaper.
Certain places in US, Singapore, and now Australia are considering this approach. Where desalination has had many successful case studies especially in the countries of Israel, Singapore, Saudi Arabia, Spain, and other Middle Eastern countries, there are two key considerations – the capex given the size of plant and the high ongoing cost of operating it. Wastewater treatment can begin at a relatively lower level of investment. Some countries such as Singapore use a mix of both options – both desalination and Direct Potable Reuse from wastewater.
It is as much a matter of education & awareness as it is of further innovation. Innovation to make these avenues more sustainable, cost effective and easy to put in place for generations to come.
As countries become richer, water pollution does not disappear but evolves. In lower-income countries, poor ambient water quality is mainly due to low levels of wastewater treatment, whereas in higher-income countries, runoff from agriculture poses the most serious problem.
Then there’s Sustainable Development Goal 6, one of its targets is : “By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally.”
Along with Singapore, Israel is perhaps another case study here. Not just for its reliance on desalination. But reuse as well.
“Almost 90% of the country’s wastewater effluent is currently treated for reuse in agriculture, representing approximately half of total water that farmers use nationwide.”
To close the note
Thre are reasons countries still shy away from Direct Potable Reuse – the costs, and the specific need in Namibia is not perhaps as acute in other places, also there’s the mind-block of reusing waste for drinking (But then Singapore as a developed world example). Still, there are stages prior to Direct Potable Reuse that more countries can work on.
Perhaps one of the radical approaches could be ensuring that water users especially beginning with industry are asked to put back in the system better or in the same form what they receive from the system. This would imply more industries installing their own wastewater treatment plants. Many industries are mandated to do so, but this is about expanding the net to almost all manufacturing. It will reflect the true cost of industrial production, which in current world highly underestimates the cost of non-renewable resources built into products.
To sum up, the point of this write-up is little about direct DPR, which is the pinnacle of water reuse. But just a general increase in awareness and introduction of long-term thinking towards attitude and approaches to water use and reuse. Reclaiming water requires long term investment in public infrastructure as well as private infrastructure. It requires a willingness on government to pursue the difficult path with industries about wastewater treatment, but in the long run, across generations, a new kind of sustainable infrastructure can be seeded by taking a few new actions, especially for all new build. A small but significant step towards a scenario where clean water is available to the most number of people without major discharges polluting the future Earth.
What it perhaps calls for:
- Investment from cities, countries, and ideally industries
- Innovation across better, efficient cheaper methods which are long term sustainable rather than expensive ongoing opex
- Intergenerational thinking by government – It is not just the pressure on aquifers, it is about ensuring that we put back into the world system as we receive from it, ensuring a better future earth
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(Note to reader – The information is mainly from desk-research. I knew about the Direct Potable Reuse Windhoek plant through PE and it made a huge impression on me some 20 years ago. The idea is fascinating given the current world. There are many open questions worth further deep-dive here. Happy to be notified of thinking errors. For charts and notes, links, please visit the Open Workbook here.)