|Technology||:||Electrodialysis Reversal (EDR)|
Client was treating raw water for potable purposes and was using salt (NaCl) to regenerate resins which reduce hardness. Over time, the salt content increased in the ground leading to increased TDS in groundwater. Client then embarked on a water treatment plan with an aim to maximise recovery in raw water and minimize external salt addition.
SUEZ designed a Electrodialysis Reversal (EDR) solution for with more than 90% recovery and no external chemical addition for hardness removal. EDR is a brackish water desalination process that uses DC current by means of periodic reversal of polarity to remove dissolved solids. They are chlorine tolerant, allowing it to operate on biologically challenging waters.The design was in line with the objectives of maximizing recovery and minimizing external salt addition.
|Feed Water||Borewell/Well Water|
|Application||Potable & Domestic Usage|
|Feed Water Quality||2000 ppm (mg/L) TDS|
|Product Water||Less than 250 mg/L TDS|
The EDR based drinking water treatment plant consists of Multimedia Filter followed by EDR stacks designed to take the feed TDS of 2000 ppm and produce output of <250 ppm TDS. The EDR reject water stream of <10% is blended with treated sewage water and used for irrigation purposes in conformity to pollution control regulations. EDR technology has helped replaced multiple domestic RO systems on site that were operating at far lower recoveries, thus conserving precious fresh water.
SUEZ’s EDR based drinking water system has consistently and reliably achieved 91% to 93% recovery and has helped in signification reduction of external salt addition (upto 300 tonnes per year). This system is the largest EDR based plant in the drinking water segment in India.