Implementing a zero liquid discharge water treatment plant in Ethiopia seemed like the appropriate next step after a successful 1997 set-up in Gujarat for Ahmedabad-based water-recycling provider Arvind Envisol.
Ethiopia, despite numerous foreign green industrialisation set-ups over the past few years, is still suffering from major water treatment problems and water shortages. According to a 2017 report by the Government of Ethiopia and United Nations Office for the Coordination of Humanitarian Affairs (OCHA), 10.5 million people will not have regular access to safe drinking water this year.
Though the project has been in effect for over a year-and-a-half, CEO Dinesh Yadav sees a lot of growth to be had. The company saw an opportunity to build a small plant in Hawassa Industrial Park, and former Prime Minister of Ethiopia Hailemariam Desalegn used to be a water engineer, much to Yadav’s delight.
The businessman noted the country wanted to do something very effective for the environment: to achieve the highest purity of water whilst reducing routine maintenance, which is needed in these harsh summer months.
Every drop counts
Observing the plant from its nascent stages, Yadav currently sees, “If someone wants to achieve a lot in terms of water treatment, there are two things to be noted: conserving water itself and stopping the discharging of water. I may sound a bit harsh but, suppose you recycle 70-80% water with the help of largely commercially viable membrane-based systems, that 20% rejected water still comprises of harmful substances; which is harmful to the environment.”
So given this commonplace circumstance, Envisol’s ZLD aims to ensure that 100% of the water flowing through the system is clean after processing.
So how does it work?
The water flowing into the plant undergoes two treatments, the first removing basic impurities such as oils and suspended solids, while the second degrades any organic material present in the waste that may oxidise, ultimately reducing the Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) quotients.
Then follows a slew of meticulous treatments: Micron Disc and Ultra filtration systems, followed by reverse and forward osmosis in a stage of membrane-based Total Dissolved Solids (TDS) reduction. Evaporation and sludge management technologies add to the detailed processing — specifically, the patented Polymeric Film Evaporation Technology (PFET) based on a mechanical re-compression technique.
And what of the cost of operating such a project? After all, keeping the equipment free of corrosion and the scaling potential to zero-minimum is taxing. According to Yadav, “significant advantages in operating costs can be achieved through PFET because of the minimal steam consumption, the lower temperature differences and the fact that the cleansing is done by the water itself rather than chemicals.”
An on-site Envi-lab tests the customer’s source water with a spectrometer for a final verdict on whether the water is usable, and Yadav says it always is.
Now treating over 11 million litres a day, the project has led to Arvind Envisol mapping out how to bring it to India on a much larger scale.
