Reducing/Replacing RELIANCE ON MEE in HIGH TDS Effluents
Multi-effect evaporators (MEEs) are widely used in industries dealing with high TDS effluent COD testing. They are highly effective—reducing COD by up to 90–95% even when the TDS of effluent water is extremely high. However, the shine of MEE’s efficiency often masks the significant operational costs that come with it. This blog explores whether MEEs can be replaced or minimized and the role of biological systems in reducing reliance.
This blog explores all sides of this technology and how its usage can be reduced or replaced. Get in touch to learn how innovative bioculture-based treatments can optimize COD reduction and lower operational costs in your effluent systems.
What is an MEE- How it works?
A Multi-effect evaporator (MEE) is an energy–efficient system used to concentrate high-TDS effluents by evaporating water in multiple stages or “effects”. It utilizes steam in the first stage to heat the effluent, causing water to evaporate. The vapor generated is then reused as a heating source for the next stage, progressively reducing energy consumption. This cascading use of steam maximizes thermal efficiency and minimizes operational cost. MEEs are widely used in zero liquid discharge (ZLD) systems, especially in industries with high salinity wastewater. The result is a concentrated brine and distilled water, both of which can be handled or reused appropriately.
Why is MEE in trends?
MEE is one of the most trending technologies in wastewater treatment, owing to its high efficiency in reducing higher levels of COD and tackling tough and toxic effluents with compounds like Cyanide, Toluene, Phenols, and aldehydes. Also, the condensate quality is top-notch. MEE is very popular in industries located near the sea, as it has excellent efficiency up to 98% in effluents with COD up to 150000 PPM and above, and delivers in TDS above 100000 PPM as the sea discharge with higher TDS is permissible.
Technology comes at a Cost
Multiple Effect Evaporator (MEE) systems, while highly efficient in reducing wastewater volume and achieving zero liquid discharge (ZLD), are often cost-prohibitive for many industries. The initial capital investment for an MEE plant typically ranges from Rs 50 lakh to Rs 2 crore, depending on capacity and design complexity.
Operational costs are also steep—electricity and fuel expenses can exceed Rs. 3-5 per liter of treated effluent, especially when steam boilers or thermic fluid heaters are involved. Despite incorporating energy recovery through multiple effects, MEEs still consume 1.2-1.5 kg of steam per liter of evaporated water.
Maintenance adds another layer of expense; anti-scalant chemicals, descaling routines, and part replacements can cost Rs. 5-10 lakh annually for a mid-sized plant. Skilled manpower and automation support further raise the cost.
Additionally, industries must manage the disposal of high-TDS concentrate or salts, which may cost Rs. 2-3 per kg in transport and treatment. Pre-treatment requirements—like neutralization, oil removal, or biological treatment-can add another Rs. 0.5-1 per litre.
While MEE ensures regulatory compliance and high performance, the total cost of ownership makes it unviable for many small and medium enterprises. Hence, despite its technical merits, MEE remains financially challenging, pushing industries to explore cost-effective biological or hybrid solutions.
What are the alternatives?
MEEs are known to reduce high COD values in effluents with high TDS values. Hence, it may sound ridiculous, but the best alternatives are BIOCULTURES. Now, the first question coming into the readers’ minds will be Why & How?
Well, let’s first answer Why? There is a certain class of bacteria that survives and thrives in extremely high saline conditions called Halophilic bacteria. These bacteria, when combined with other strains, as biocultures, can effectively work in high TDS effluents and reduce COD with great efficiency.
Now, let’s find out how?
The best way is to gradually divert the primary treated influent stream/inlet stream to MEE to the aeration tank.
Suppose A MEE has a capacity of 30 KLD that treats a stream with COD 75000 and TDS 50000, and the ETP is of 200 KLD that handles an inlet COD of 10000 PPM. In this case, initially, a stream of 5 KLD inlet to MEE can be diverted to the 200 KLD ETP. Then the average COD can be calculated by the below formula:
Hence, the average inlet of 200 KLD ETP after diverting 5 KLD ETP will be approximately 12000 PPM, which can be treated by effective biocultures with strains of halophilic bacteria.
The 5 KLD stream can be increased to 10 KLD and 15 KLD, depending on the performance of the ETP.
How can this strategy be a game-changer?
Well, it is self-explanatory from the above information that diverting the MEE stream can reduce OPEX up to 30-35% straightaway, along with increasing the efficiency of the ETP. However, this strategy is more applicable in industries where sea discharge with High TDS effluent is permitted. But, it is not restricted also; options can be analysed too in other cases.
Technical efficiency and product viability is a must
While, the strategy looks very easy on paper but it is very tough to execute. It requires technical know-how of the whole plant, analysis of trends, and effective identification of strains and its amalgamation into an effective bioculture, its dosing and most important acumen of troubleshooting in real-time as we will be handling a stream which is very toxic , filled with tough-to degrade and shock load inducing compounds.
Team One Biotech is one of the leading Biotech Companies in India, providing advanced microbial solutions like bacteria for ETP treatment and bacteria culture for wastewater treatment.
Reach out now to enhance your wastewater treatment efficiency.
Email: sales@teamonebiotech.com
Visit: www.teamonebiotech.com
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