How to Economical operation of ZLD in Textile industries?
ZLD (Zero Liquid Discharge) is a treatment method that eliminates all liquid waste from a system. The goal of ZLD is to reduce wastewater costs while also producing clean water that may be reused (for example, irrigation), saving money and benefiting the environment.
ZLD systems purify and recycle nearly all of the wastewater produced using modern wastewater/desalination treatment technology.
ZLD technologies also assist plants in meeting discharge and water reuse standards, allowing enterprises to:
1: Comply with Government discharge rules;
2: Achieve greater water recovery (percent);
3: Treat and recover valuable materials such as potassium sulphate, caustic soda, sodium sulphate, lithium, and gypsum from wastewater streams;
Thermal technologies including evaporators multi stage flash (MSF), multi effect distillation (MED), and mechanical vapour compression (MCV)) and crystallizers are used to reach ZLD and recover their condensate. As a result, ZLD plants generate solid waste.
A ZLD system usually consists of two phases:
1. Pre-concentration; Brine is usually pre-concentrated using membrane brine concentrators or electrodialysis (ED). These techniques concentrates the stream to a high salinity and can recover up to 60%–80% of the water.
2. Evaporation/Crystallization; The following phase in thermal processes, or evaporation, is to evaporate all of the remaining water, collect it, and drive it to be reused.The remaining waste is sent to a crystallizer, which boils all of the water until all of the contaminants crystallise and are filtered out as a solid.
Use of ZLD: Textile Industries’ requirement for ZLD Technology
The “Central pollution control board” has implemented a ZLD policy that mandates industries to install ZLD systems in their units if discharge parameters are not below acceptable levels. Due to a dropping ground water table and contamination of local water sources, there is a lack of desirable quality fresh water.
ZLD's Benefits and advantages
1: The highest rate of recovery (95-98%)
2: Fully automated system with minimal human intervention
3: No need for chemical treatment
4: There is no chemical sludge
5: The least amount of steam and electricity is used
6: Lowest cost of operating
7: Tailored Solutions
8: There are no limitations in terms of space
9: A salt recovery technology that produces pure salt that can be reused
10: Effluent cooling and equalization
Biological treatment refers to the biological removal of BOD and COD from wastewater using microbes in the presence or absence of air. Biological treatments come in a variety of forms. However, the most technologically advanced in this field is: MBR (Membrane Biological Reactor), which is a type of membrane treatment. When biological treatment is correctly designed and operated, sludge formation is minimal.
The removal of a high organic load employing OH ions as an oxidising agent with the highest oxidation potential is referred to as physio-chemical therapy.The treatment uses ozone and UV/Hydrogen Peroxide to create highly oxidising agents that significantly reduce organic burden. There is very little chemical consumption and very little creation.
Purification of Membranes or use of RO
Membrane purification refers to the use of membrane technology to remove TDS (Dissolved Solids). We employ Membrane technology to acquire maximum permeate of specified parameters to be reused in the process, with a minimum recovery of 93-97 percent. The technology focuses on maximising recovery with a low reject rate of less than 5%.
Evaporator with Dryer and Multi-Effects
Final RO reject is fed to MEE for evaporation of concentrated reject in this process. MEE efficiency is determined by RO Reject Feed settings. If the TDS of the RO Reject is low, the recovery of the membrane purification system is low, the steam consumption will be high, resulting in an inefficient ZLD.
Salt dryers are employed at MEE reject to obtain dried salts, resulting in a total liquid output of zero.
What can we offer?
Netsol Water is a significant water and wastewater treatment firm in India, offering WTP, WWTP, STP, ETP, RO Plant, ZLD Plant, and MBR manufacture, among other services. The company creates equipment’s and is committed to providing practical solutions that help businesses flourish. We are committed to providing our valued customers with hands-on service, expert counselling, and training.