Is Wastewater Really ‘Waste’?
Originally posted on July 7, 2020 by Nimisha Singla for teachforgreen
Water which flushes down our drains unnoticed — be it our wastewater from kitchen sinks or stormwater which nature blesses us with — is a great potential resource that can be harnessed to generate energy.
The energy demands of the world are ever-increasing and we cannot keep on exploiting our limited conventional resources to satisfy these. We have to start unveiling the hidden opportunities in the things we “reject”. Many of us already use vegetable scraps to compost and prepare a natural fertilizer for house plants. Similarly, the water used in rinsing vegetables can be used to water plants. If you have RO systems installed in your homes, you can use the rejected water (the water which you do not drink) for mopping and vehicle washing purposes.
While these are decisions which we should incorporate in our lifestyles anyway, technology has advanced leaps and bounds to reuse industrial wastewater and stormwater too. Wastewater treatment plants use a lot of energy and also generate greenhouse emissions. We treat wastewater so that it is less harmful when we release it into our oceans. While wastewater has treatment plants in place, stormwater management is relatively new and lacks the required initiative. In urban settings, it becomes dangerous as the stormwater runoffs on roads collect oil from oil spills, all sorts of sediments, and interact with nitrogen, phosphorus, organic compounds, etc. Due to a lack of infrastructure, these are diverted to pipes and ditches, and may ultimately find their way to the nearest water source — further polluting it. Why are we letting go of our wastewater just now?
How can we reuse this water?
The water itself can be used to generate hydroelectricity and the treated waste to generate biogas. Wastewater is water contaminated with human, agricultural, or industrial wastes. While typically seen as a nuisance, the organic matter contained in wastewater from our sewage systems (commonly known as “sludge”) can become a valuable resource with sludge-to-energy systems.
Stormwater can be retained by capturing it and using it in industries that require cooling operations. Floodwater in coastal regions too can be recycled similarly.
Are there other benefits?
Other than being cheap, renewable and a readily available form of energy for many cities, using waste for energy has the following benefits –
1. Self-sufficiency — no more dependency on other industries or even states/countries to satisfy your requirements
2. Emissions reductions — using methane-rich biogas instead of fossil fuels has twofold benefits. It traps methane which is 30 times more effective than carbon dioxide as a greenhouse gas as well as prevents carbon dioxide emissions from fossil fuels.
3. Better waste management — Why pollute the limited land and water resources by using them as dumping sites and thereby endangering health?
Let’s put on our thinking caps and reuse and recycle every resource to the fullest before really declaring it as “waste”. Let’s put our energy to good use 🙂
