Alfa Laval Decanter Centrifuges for salt dewatering in a ZLD plant

Conventional ‘Physico-chemical-biological’ treatment does not remove salinity in the treated effluent. The TDS content is well above the statutory limit of 2100 mg/l. Discharge of saline but treated wastewater pollutes ground and surface waters. 

Several states in India are water stressed. Competing demands for water from agriculture and domestic use has limited industrial growth and several landmark pollution cases and court battles have hastened this. High cost of water and statutory regulations are prime drivers for Zero Liquid Discharge effluent treatment plants. 

A ZLD system involves a range of advanced wastewater treatment technologies to recycle, recover and re-use the ‘treated’ wastewater and thereby ensure that there is no discharge of wastewater to the environment. A typical ZLD system comprises of the following components:

•  Pre-treatment (Physico-chemical and Biological)
•  Reverse Osmosis (Membrane Processes)
•  Evaporator and Crystallizer (Thermal Processes)

Alfa Laval Decanter Centrifuges play a crucial role in removing the water content from salt slurry coming out of crystallizer. The drier the sludge, the smaller its volume and the lower its weight, both of which significantly reduce disposal and transport costs.

Compared with even high-performance conventional equipment, the innovative design of ALDEC G2 Decanter Centrifuges for this application in special material of construction provide the driest possible sludge cake at the lowest possible cost.  

Dewatering of large volumes of sludge effectively requires consistently high torque and effective control. ALDEC G2 decanter centrifuges are the only design currently available that provides both, right across the whole range of throughput. 

The ALDEC G2 is also the only sludge decanter designed for effective protection against the effects of abrasion. Special wear-resistant materials are used for all critical parts, resulting in low maintenance costs. This helps make ALDEC G2 solutions a solid long-term investment.

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