Like oil, water is not going to last forever. Yet, the world's most precious natural resource gets wasted day in and day out. Let’s take the USA as an example: According to the U.S. Geological Survey, about 1.7 trillion gallons of water are wasted every year.
Imagine how much of fresh water we could save if we were to reuse wastewater, and while pondering over wastage, let’s remember that just one percent of the water available in the world is freshwater, ie. safe and good to drink and fit for agricultural purpose. If still not convinced, check this: to produce a single almond, we need a gallon of water, and a cup of coffee requires 55 gallons to grow the beans.
Obviously, the availability of water and its usage is grossly disproportionate, and the only way we can ensure we have enough for the next generation is to find ways of reusing wastewater.
The term wastewater is easy to understand, but water experts will tell you there are two types of wastewater: Greywater is all wastewater except wastewater from flushed toilets. Blackwater is all wastewater, i.e., greywater plus water flushed down the toilet.
Municipalities have found ways to treat wastewater and a large quantum of grey and black water is re-used after a process of filtration, sedimentation or aeration, depending on the quality of wastewater. Wastewater from domestic sources contains soap, oils, food scrap and human waste. The same from industrial installations may contain chemicals, sludge and various contaminants.
By treating both types of wastewater, we can ensure that pollutants or suspended solids are removed and the treated wastewater is discharged into water bodies or the ocean. The development of state-of-the-art treatment systems has led to a better alternative – reuse of treated wastewater for flushing toilets, for gardening at home or in public places, landscaping and for water art (fountains).
Can wastewater be reused for drinking? Though the concept suffers from a negative perception, Singapore, Australia and Namibia, and states such as California, Virginia and New Mexico are already drinking recycled water.
The process of course is extensive but effective – tertiary-treated water undergoes an advanced water technology process, followed by reverse osmosis, which eliminates viruses and bacteria. The water is then disinfected by ultraviolet light or ozone and hydrogen peroxide.
Here is a brief case study from Advanced Watertek, a leader in water treatment systems for over three decades, on the re-use of wastewater. A prominent Mall in Abu Dhabi approached the company to make wastewater usable for Chiller application. The Mall’s Peak Load Water consumption is 1,200,000 litres per day. The engineers at Advanced Watertek installed a water treatment system that would enable use of Treated Sewage Effluent (TSE) Water supplied by the UAE Government as part of its wastewater reuse initiative.
The results: Use of treated wastewater for chillers instead of precious municipality water, no more dependence on private suppliers for excess capacity requirements, and cost savings in the operational budget.
Every day and in every way, leaders in water treatment systems such as Advanced Watertek are coming up with innovative solutions to reuse wastewater. Citizens, government officials and industry leaders reading this may bear in mind that if treated right, waste can be turned into wealth. A fitting closure to this narrative is a poignant call from the Director of UNU Institute for Water, Environment and Health (UNU-INWEH, Canada):
“From the earliest of times, most wastewater has truly been wasted. However, it is a vast resource if we reclaim it properly.”