Recycling Treatment Plants


# Yelahanka Tertiary Treatment Plant

A 10 MLD Tertiary & Treatment plant with recycling facilities at an estimated cost of
Rs.400 Crores. with funding support from KUIDFC/HUDCO under Megacity scheme
and through Indo-French protocol has been commisioned in may 2003.

Recycled water is proposed to be supplied to ITC, Wheel and Axel Plant and the
proposed International Air-Port at Devanahalli.

Photographs of Yelahanka Tertiary Treatment Plant

Of the two Tertiary Treatment Plants (TTPs), planned and executed by BWSSB, the 10 million-liter per day (MLD) capacity plant at Yelahanka, is ready for commissioning.

The Yelahanka Treatment Plant, designed and constructed at a total cost of
Rs. 24 crores, partially funded under the Indo-French Protocol has three stages,
viz., primary treatment, secondary treatment and tertiary treatment. The waster
water collected from areas in Yelahanka is initially screened and grits and grease
are removed in the primary stage. In the secondary stage, through biological
treatments, bio-chemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD)
and Suspended Solids are reduced in three linear phases, viz., primary settling,
activated sludge and through secondary clarifiers respectively. A large chunk
of biodegradable matter in waster water is absorbed and broken down by bacteria
in activated sludge process. To enhance the removal of suspended solids,
aluminum sulphate is used to coagulate secondary treated water on the filter media.

Finally, to remove the fine suspended solids, tertiary filteration has been adopted for
the first time in the country on a large scale.

Filtration is the most important treatment of the plant, in the final phase for removal
of suspended solids. The filter layer, comprising sand and gravel has been designed
in such a way that maximum efficiency is achieved in the filtration process.

A very unique feature in this tertiary treatment plant is that chlorination of the
treated effluent is carried out by saturation of treated water with chlorine followed
by injection of the saturated solution in to the effluent. A minimum chlorine contact time
of 45 minutes is ensured. Finally, the chlorinated recycled water is pumped through
a pipeline to the end users.

The sludge treatment comprising thickeners, which thicken primary and biological
sludge, continuously operate after dewatering. The dewatered sludge undergoes
lime dosing before final disposal.

Quality of influent Wastewater and Tertiary Treated Waste water characteristics:

The entire plant is well equipped with a well-proven PLC (Programmable Logic Control) hardware and SCADA (Supervisory Control and Data Acquisition) software. There are
two SCADA workstations linked to the PLCs through LAN (Local Area Network). The
SCADA software covers various process instrumentations, controls,
graphics, communication, even and interval timer, programmable counters,
alarm management, report generation, dynamic trending date base interface etc.

The large screen active mimic display allows online process monitoring, which is a
State-of-the-Art technology.

SUPPLY OF TREATED WATER TO THE PROPOSED NEW INTERNATIONAL AIRPORT:

A 300 mm dia Ductile Iron pipe line has laid to the proposed New International Airport
at Devanahalli to meet the non-potable water requirement of the Airport. The pipeline
also caters to the requirements of some of the industries en-route.

Total cost of the Sewage Treatment Plant is around Rs.24 crores and the pipeline cost is
of the order of Rs.8.5 crores

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