Wastewater treatment

Substantial amounts of fresh water are consumed in modern society and all too often poorly treated wastewater is discharged into the environment. To counter these trends, modern digitalization offers a great degree of controllability in municipal wastewater treatment resulting in higher quality of treated water. And ZLD and MLD processes reduce the volume of industrial wastewater discharge.

To improve the reuse of water and reduce the discharge of industrial wastewater, a zero liquid discharge (ZLD) or a minimal liquid discharge (MLD) treatment system is often used. ZLD and MLD are ambitious wastewater management strategies that enable the plant or facility to recover most of its wastewater for reuse. The standard process is energy intensive, but applying optimized reverse osmosis processes energy consumption can be reduced by up to 75%.

Now these methods combine with energy production within the wastewater treatment plant, to enable entirely new ambitious levels of energy efficiency. Powered by methane produced in the digester of the wastewater plant, the 'bio refinery' or 'Water Resource Recovery Facilities'  demonstrate that wastewater has now become an energy resource.

Some of the most advanced water management systems achieve complete energy self-sufficiency of the water cycle. The energy recovered from wastewater treatment process not only covers the plant's own needs, but also the energy needs for drinking water production and distribution as well as wastewater pumping. In other words, the whole water cycle can be considered energy neutral.

A precondition for energy neutrality is a control handle in the form of an AC drive available for all rotating equipment, so that the fully computer-controlled facility can adapt to the changing load.

The efficient reduction of effluent makes the ZLD and MLD processes highly attractive to industries and utilities. Until now, however, the processes have been constrained by high costs and intensive energy consumption. The traditional thermal-based process used in ZLD/MLD systems is highly energy intensive. By adding a membrane-based process, studies show that energy consumption can be reduced by up to 75%.

Using digitization, and connected to a high-granularity weather radar system, highly accurate rainfall analysis can be integrated. By managing capacity optimally, the utility can reduce capital investment. Digitization also enables them to operate a warning system, in the rare event that a sewer overflow does occur.

Save energy with a membrane-based process

Most ZLD/MLD systems are operated with a thermal-based process as standard. This process puts a great demand on energy consumption, making it a very expensive investment.

One way of reducing energy consumption is to reduce the amount of water that needs to be evaporated by changing from a thermal to a membrane-based process. This is supported by studies that show an efficiency gain of up to 75% when going from the thermal-based to the membrane-based process.

How business benefit from applying a ZLD or MLD treatment system

Zero or minimal liquid discharge are some of the good answers to the global water crisis. Both technologies help to meet discharge and water reuse requirements enabling businesses to meet regulations, protect the environment and improve management of the water produced.