What is Zero-liquid discharge?

December 15, 2022

Zero liquid discharge (ZLD) is an engineering approach to water treatment where all water is recovered and contaminants are reduced to solid waste. While many water treatment processes attempt to maximize recovery of fresh water and minimize waste, ZLD is the most demanding target since the cost and challenges of recovery increase as the waste water gets more concentrated. Salinity, scaling compounds, and organics all increase in concentration, which adds costs associated with managing these increases. ZLD is achieved by stringing together water treatment technology that can treat waste water as the contaminants are concentrated.

There are a number of benefits to targeting zero liquid discharge for an industrial process or facility:

1. Lowered waste volumes decrease the cost associated with waste management.

2. Recycle water on site, lowering water acquisition costs and risk. Recycling on-site can also result in less treatment needs versus treating to meet stringent environmental discharge standards.

3. Reduce trucks associated with off-site wastewater disposal, and their associated greenhouse gas impact and community road incident risk.

4. Improved environmental performance, and regulatory risk profile for future permitting.

5. Some processes may recover valuable resources, for an example, ammonium sulfate fertilizer or sodium chloride salt for ice melting.

Several methods of waste management are classified as zero liquid discharge, despite using different boundaries to define the point where discharge occurs. Usually, a facility or site property line that houses the industrial process is considered the border or ‘boundary condition’ where waste water must be treated, recycled, and converted to solids for disposal to achieve zero liquid discharge. Certain facilities send their liquid waste off-site for treatment, deep well disposal, or incineration and they consider this to qualify as zero liquid discharge. This approach to zero liquid discharge eliminates continuous discharge of liquids to surface waters or sewers, but can significantly increase cost.

Some engineers describe their designs as near-zero liquid discharge or minimal liquid discharge to highlight that they discharge low levels of wastewater, but do not eliminate liquid in their waste. For some facilities, it may be more economic to approach but not achieve complete ZLD by concentrating brine to lower volumes. Furthermore, it may be possible to avoid the creation of liquid waste on-site through careful water conservation or by treating contaminants at their source before they can enter the main flow of water.

What are the benefits of using Zero Liquid Discharge?

A zero liquid discharge system can assist with rising water costs and droughts. ZLD contributes to water conservation, reducing intake of fresh water, and avoids the environmental impacts of wastewater discharge. Although it is not possible to completely recover all of the influent water, the process maximizes the treatment and recycling of wastewater.

Why is Zero Liquid Waste Important?

In a world where freshwater is an increasingly valuable resource, industrial processes threaten its availability on two fronts, unless the water is treated. Many industrial processes require water, and then reduce the availability of water for the environment or other processes, or alternately contaminate and release water that damages the local environment. India has been leading the drive for zero liquid discharge regulations in the last decade. Due to heavy contamination of numerous important rivers by industrial wastewater, India has created regulations that require zero liquid discharge. They identified that the best means to ensure safe water supplies for the future is to protect rivers and lakes from pollution. By operating an in-house ZLD plant, disposal costs can be reduced, more water is reused, and fewer greenhouse gasses are produced by off-site trucking, which minimizes impact on local ecosystems and the climate.

All of us are aware of the fact that water is life, but still gallons of water are being wasted on a daily basis by industries as well as by people in their houses. We, at JB Ecotex Limited, are working with the Go Green concept as a responsible and sustainable RPSF manufacturer. We are a recycled polyester staple fiber supplier across India. At JB Ecotex Limited, we have installed an effluent treatment plant with all the latest available technology which enables us to process and reuse all the waste-water generated by us during the process. Thus, there is no liquid discharge from the recycling process which certifies us as a ZERO LIQUID DISCHARGE unit with the adoption of zero water discharge methodology. JB Ecotex Limited impressively decreases the requirements of water which helps to keep environmental resources intact for the future generations, an endeavor to being an efficient EPR services agency in India.