Okhla wastewater treatment plant, (India) - reuse

In 2019, Delhi Jal Board awarded to SUEZ the contract for the design, construction, and operation of this new plant for a period of 11 years. This new plant aims at restoring the water quality of the heavily polluted Yamuna River and addresses new challenges related to the evolution of sludge sanitization regulations.
The new Okhla plant will be the largest in India built in one stage. It will replace all the existing facilities.
The plant incorporates cutting-edgetechnologies to ensure high-quality treated water suitable for non-potable reuse and discharge into the Yamuna River, in accordance with the latest national standards requiring a total nitrogen content of less than 10 mg/L.

Therefore, the treatment line targets to:

• restore the water quality of the Yumana River.
• reduce sludge volume by 40%.
• produce Class A sanitized biosolids to facilitate their recovery as fertilizer for local agriculture.
• produce electricity from biogas to achieve 60 to 70% energy selfsufficiency.
• reduce overall sludge treatment costs.

Key figures

• treatment capacity og 564,000 m³/day
• 182,000 m³/d of water reused for non-potable urban and industrial uses
• close to 107 Nm³/h of biogas converted into electricity and heat

Treament line

The water treament line includes:

• Sedipac^® D lamellar settling tank to remove suspended solids,
• biological treatment using activated sludge for nutrient removal,
• tertiary filtration on Compakblue^® rotary disc filters,
• UV disinfection to eliminate coliforms.

The sludge treatment line includes:

• gravity thickening for primary sludge,
• thickening on Drainis^® Turbo and GDE for secondary sludge,
• advanced anaerobic digestion Digelis^® BHA to produce biogas and Class A sludge,
• Heliantis^® solar drying to achieve a dryness of 60%.