Major domestic petrochemical complexes are adopting modern water treatment approaches, including zero liquid discharge (ZLD) systems, to curb excessive water consumption.
Zero liquid discharge can be defined broadly as a process to achieve maximum water recovery from a wastewater source that would otherwise be disposed of. This water is beneficially reused and the salts and other solids contained in the wastewater are discarded in a landfill.
According to Mohammad Ayazi, Research Institute of Petroleum Industry's director for development and optimization of Energy Technology Division, five petrochemical companies, namely Fajr, Maroun, Razi, Arvand and Ilam, have so far adopted the ZLD recycling system that has significantly reduced their water intake from nearby rivers, NIPNA reported.
"The ZLD system will also virtually eliminate the return of wastewater from the manufacturing sector into the river water and prevent the further deterioration of natural resources," he said.
--- Futuristic Move
Describing the modern system as a "futuristic strategy", Ayazi said the move can help the power industry as well as oil and gas, chemical, petrochemical, mining and other industries generate smaller volumes of wastewater, which would bear positive operational and economic results.
The drivers for zero liquid discharge include a growing concern by the public about the impact of such discharges on the environment, and in many areas of the world, water scarcity.
Ayazi noted that ZLD systems in Fajr Petrochemical Company in southern Khuzestan Province and Shahid Hasheminejad Gas Refinery in Sarakhs, northeastern Iran, have been designed and implemented by domestic experts at the Research Institute of Petroleum Industry.
"Fajr complex recycles over 62,400 cubic meters per day of wastewater from its reverse osmosis blocks via ZLD system," he said.
The refinery project involves the recycling of over 650 cm/d of wastewater as well as changing the methods of producing boiler feedwater from evaporation to reverse osmosis.
Reverse osmosis is often used down the line in the boiler feedwater treatment system to eliminate most of the harmful impurities that can foul and clog the facility membranes.
Ayazi noted that "ZLD system is deemed useful for complexes seeking to reuse their wastewater, though it would be better to adopt strategies that help curb water consumption".
"This would be especially helpful in complexes situated far from major resources like sea," he said.
Amid growing environmental concerns, governments are trying to devise regulatory measures on industrial water usage. Such concern is resulting in increased regulations in water scarce areas.
Even without the regulatory push, many companies in various industries are implementing initiatives to reduce water discharge through recycling and ZLD to decrease their ecological footprint and improve sustainability.
