Minimum Liquid Discharge

Minimum Liquid Discharge

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Minimum Liquid Discharge Treatment

Minimum Liquid Discharge (MLD for short) is a process of limiting the amount of waste discharged from various water treatment facilities. In this form of treatment the goal is to lower the amount of waste discharged into the environment by recycling the wastewater within its own system. It’s interesting to note that both MLD and ZLD systems use Crystalizors and Evaporators for the heat needed in the treatment process and then they will release the said heat into the atmosphere. One could argue that MLD treatment systems are far more common than the ZLD ones since the MLD only costs a fraction of ZLD and at the same time it’s able to satisfies many environmental laws and constraints like the ZLD method would. The following benefits can be expected if an MLD system is properly designed and implemented:

Efficiency close to the ZLD method
A good way to protect the environment
Abiding the environmental laws and restrictions
Recovers nearly 95% of the required water from waste
Costs far lower than other purification methods, especially compared to the ZLD method

About the MLD Process

Various industries and power plants are turning to the MLD approach to wastewater treatment everyday. With the help of MLD treatment systems, you can take a big step towards improving the power plant or plant economy by recovering nearly 95% of the water discharged into the process output. More importantly, what makes the MLD method more common and even more effective than ZLD treatment systems is its costs. The cost of setting up an MLD treatment plant only covers a fraction of the cost of setting up a ZLD treatment system, while providing close efficiency to it, so the reason why the MLD method is more effective than the ZLD could be understood. A conventional MLD purification system involves a variety of core processes based on Ultrafiltration (UF), Reverse Osmosis (RO), Nanofiltration and Ion Exchange technologies.

The cost of using reverse osmosis technology to recover and reuse 70% of the waste can compete with the cost of using local freshwater, but unfortunately, this method injects 30% of the waste into the environment without recovery. In low-water areas where drinking water supply is a major challenge or in areas where water prices are high, the amount of water recovered by the treatment system becomes a very important indicator.

The thermal processes used in the ZLD treatment system to recover a larger percentage of the water in the discharged waste also incur higher costs, which are usually not cost-effective and do not increase efficiency. By applying the MLD treatment system, 95% of the factory or power plant effluent can be recovered without incurring the staggering costs of the ZLD method. In fact, unlike the ZLD method, the MLD method uses membrane processes for purification, and in general, the use of membranes is preferred to the use of thermal processes. Finally, the use of membrane processes in the MLD system can save up to 60% on ZLD system costs by eliminating heat processes alone.

In general, the ZLD method has long been considered an appropriate and environmentally friendly method for waste disposal. However, over time, rising water supply costs, along with increasing drought intensity, have posed challenges to wastewater treatment processes, leading researchers to question the use of the ZLD system. The ZLD method is a method that is very complex in terms of technology and requires high costs. At the same time, it can not be considered completely without harm to the environment, because the additives or the amount of heat that enters the environment in this way can cause even minor damage to vegetation or animals. This is why many users and consumers have gradually moved towards replacing the ZLD method with the MLD method. Such a move could reduce unnecessary costs and increase productivity by replacing heating processes with membrane-based processes.

In order to find the best and most appropriate way to deal with the effluent of a plant or power plant, it is necessary for the most important indicator to be investigated; That is, water recovery. If water recovery is of importance, you can use the MLD method to be able to recover the needed water from the waste. If abiding the environmental and government laws and restrictions is a major concern, the MLD system can be used as a component of the whole treatment system, which can include ZLDs, evaporation ponds, and groundwater injection.

Zirsakht Tadbir Arian Company is one of the leading companies providing engineering services such as Petrochemical, Oil & Gas, Water, and Wastewater Treatment. The company has undertaken several large projects and has successfully implemented them. ZETA is committed to carrying out all the steps required to launch various treatment systems, including MLD and ZLD treatment systems, from the design and engineering stage, equipment purchase, installation, and final commissioning. By abiding all the principles and rules of engineering and environmental regulations and with the help of the best engineers and specialists active in the field, Zirsakht Tadbir Arian (ZETA) Company is able to undertake large projects and taking responsibility for all of the necessary steps needed such as system design, purchase and preparation of ​the equipment, installation and final preparation. ZETA does all of these steps with the best and most up-to-date equipment and methods and provides the most efficient and high-quality services to its customers

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