What are the Components of ZLD system?

Zero-liquid discharge (ZLD) is a water or wastewater treatment technique, which purifies and recycles all wastewater, resulting in zero discharge at the conclusion of the treatment cycle. Ultrafiltration, reverse osmosis, evaporation/crystallization, and fractional electro deionization, are all part of the sophisticated wastewater treatment technology, known as zero liquid discharge.

Netsol Water offers unrivalled experience in zero liquid discharge (ZLD), including stand-alone thermal/evaporative processes, membrane processes, and hybrid systems. In this article, we will discuss about some of the components of ZLD systems.

Technologies or components of Zero Liquid Discharge Systems

•  Concentrators for Falling Film Brine,

•  Crystallizer with Forced Circulation,

•  Evaporator with Horizontal Spray Film,

•  Membrane Pre-Concentrators in Hybrid Systems,

•  Biological Therapy,

•  Solid Waste Management.

The following are the chemical ingredients of concern for a zero liquid discharge system:

Chemical Constituents of Particular Concern

The waste water being treated in a zero liquid discharge system is concentrated, to the solubility limits of the dissolved salts. Salts crystallize when their solubility limitations are surpassed, and they can then be collected using the right method.

Design of a Zero Liquid Discharge System

Evaporation systems are usually more expensive in terms of capital and operational costs, than membrane systems, with crystallizers being the most expensive. As a result, and wherever practical, membrane systems are used to lower the evaporation system's capital and operational costs.

1: Depending on the wastewater composition, pre-concentrating with a membrane system, can significantly reduce the size required of the backend evaporation system, as well as the system capital and operational costs.It should be noted that in order to achieve high recoveries in a waste water membrane system, suitable pre-treatment such as softening and pH correction are frequently necessary.

2: Vertical tube falling film brine concentrators are commonly used to concentrate brine solutions, with low total dissolved solids (TDS) of up to 12%, to as high as 25% total solids, and to reduce the design capacity of a downstream forced circulation crystallizer.

3: Brine concentrators are specially developed, to regulate the scaling of sparingly soluble divalent salts, such as calcium sulphate and calcium carbonate, as well as the usually present silica.

Although modest wastewater flows are sometimes processed directly using a forced circulation crystallizer, they are often employed to concentrate brine blow-down from upstream concentration equipment.

4: Crystallizers are designed to handle crystallization of all salts, including sparingly soluble as well as highly soluble sodium salts, such as sodium chloride and sodium sulphate, without requiring significant scale or cleaning. This toughness comes at the expense of increased particular energy consumption, and specific capital cost.

5: Solids produced by a forced circulation crystallizer are typically collected and dewatered, using an indexing belt filter or a centrifuge. As long as the waste passes “Toxicity Characteristic Leaching Procedure (TCLP)” testing, the solids are collected and normally landfilled in a standard landfill.

However, in certain zero liquid discharge applications, the highly concentrated brine is released to an evaporation pond. This layout decreases the evaporation ponds footprint, as well as the labour and price of operating the dewatering machinery.

Conclusion

There are several approaches to achieving zero liquid discharge. Because the ideal system design is site unique, there is no "one size fits all" option. The wastewater composition, numerous streams to be treated, site-specific operating costs, footprint availability, and other considerations, all play a role in choosing the best design.

Our ZLD system aims are to minimize liquid wastewater discharge, produce solids for landfill disposal or re-use, and recycle high-quality water that may be beneficially reused. The design goals are to reduce the capital investment and system running costs, without affecting the amount of labour required for operation. Furthermore, the system must be developed with operational flexibility, to fit the demands of the facility, while being secure and dependable.

Netsol Water is Greater Noida-based leading water & wastewater treatment plant manufacturer. We are industry's most demanding company based on client review and work quality. We are known as best commercial RO plant manufacturers, industrial RO plant manufacturer, sewage treatment plant manufacturer, Water Softener Plant Manufacturers and effluent treatment plant manufacturers. Apart from this 24x7 customer support is our USP. Call on +91-9650608473, or write us at enquiry@netsolwater.com for any support, inquiry or product-purchase related query.