In an attempt to address the issue of pollution in the Yamuna, Delhi government has undertaken a comprehensive project through which all the polluting drains 
shall be cleaned before they merge into the river.
The Delhi Jal Board (DJB) will set up an interceptor sewer with a length of 59 kms along the three major drains (supplementary, Najafgarh and Shahdara) to intercept sewerage from around 190 subsidiary small drains and transport it to the nearest Sewage Treatment Plant (STP) to ensure that only treated effluent is discharged into these major drains.
“Around 70 per cent of pollution load in the river shall be reduced by this effort,” said a statement issued by the Lt Governor’s office today.
The already existing interceptor sewer between Aruna Nagar JJ Cluster up to the outfall of Khyber Pass drain, which intercepts untreated sewage from Sweeper Colony, Magazine Road and Khyber Pass drain, will be made fully-functional by June 2015.
The discharge intercepted from these drains shall be pumped to Nigam Bodh SPS and taken to the existing Okhla STP, which has a total treatment capacity of 170 MGD.
Metcalf House, Qudsia, Mori Gate, Tonga Stand, Civil Military drain shall be intercepted into the existing Ring Road trunk sewer which has recently been rehabilitated under Yamuna Action Plan-II.
The sewage collected from these drains shall be pumped to Okhla STP through Ring Road SPS and this work shall be completed by June next year.
The capacity of the STP at the mouth of the Delhi Gate drain can be augmented from existing 2.2 to 17.2 MGD by constructing an additional 15 MGD STP, said Delhi government officials.
The move comes after a team of Delhi government officials visited Gujarat earlier this month to study Ahmedabads Sabarmati riverfront project.
Concurrently, to utilize all the STPs at their treated capacity, around 100 kms of Trunk Sewer has been rehabilitated and the rehabilitation of peripheral sewer in a length of 168 kms is under process, which will take another 3 years.
All the new STPs at Pappankalan, Nilothi, Delhi Gate, Chilla and Kapashera have been designed for achieving high standards of treated effluent — Bio Oxygen Demand (BOD) below 10 and Suspended Solids (SS) below 10 PPM.
The DJB is also in the process of laying of sewerage system in unsewered area for which Sewerage Master Plan 2031 has been prepared.
Till date, 541 out of total 567 unauthorized colonies, 129 out of 135 Urban villages, 44 Resettlement colonies out of 44, 34 out of 189 Rural villages and 104 out of 1639 unauthorized or regularized colonies have been provided with sewerage facility.
The work of laying of sewerage system in 162 colonies is under progress and for another 142 tenders have been invited.
The cost of all the projects is estimated to be more than Rs 25,000 crores.