Page 85 - HUDCO-BPA21
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The possibilities of using the stored water left stagnant in   treatment.    30  ML  of  water  was  drawn  daily  from
         the quarries were explored. The quantity and quality of   quarries. Result achieved are as follows:-
         the available Water in stone quarries were carried out and   Ÿ Augmentation of storage capacity of the city by at
         54 parameters were tested for compliance with IS-10500-  least 1000 mcft.
         1991  standards.  Detailed  bathymetric  and  topographic   Ÿ Availability of water supply to the city. Around 5000
         studies  were  undertaken  for  quantity  availability  and   Million litres of water could easily be tapped in a year
         designing  the  engineering  system.  Based  on  this,  a   for city water supply.
         solution for the drinking water supply for Chennai city
                                                              Ÿ New  reservoirs  with  nil  socio-  economic  and
         was proposed and successfully implemented with public   environmental costs.
         acceptance.  The  proposal  was  designed,  engineered,
                                                              Ÿ During  water  shortages,  they  serve  as  an  effective
         completed and commissioned in 45 days.
                                                                 backup  option.  During  2019,  around  30  MLD  was
                                                                 drawn for more than 6 months which was around 6%
                                                                 of the total water supplied daily, the quarries get filled
                                                                 up by the rainwater and excess flows from surface
                                                                 runoffs.
                                                              Ÿ Water recycling offers resource and financial savings.
                                                                 It is a revenue generating activity as the entire product
                                                                 water is sold to industries.
                                                              Ÿ Improvement  in  the  availability  of  water  for  city
                                                                 supply  by  90  MLD  due  to  swapping  of  present
 Conversion of quarries into the water reservoir                 freshwater  sources  for  industries  with  recycled
                                                                 wastewater.
                                                              Ÿ Uninterrupted  supply  of  water  to  the  industries,
                                                                 thereby  facilitating  industrial  growth  and
                                                                 employment.


                                                              SUSTAINABILITY:

                                                              Chennai is in a state of supply-demand mismatch and
                                                              water  is  drawn  from  multiple  sources  –  surface  water
                                                              reservoirs, well fields, desalination, wastewater reuse and
                                                              inter  basin  water  transfer.    Most  of  these  options  are
                                                              expensive and have their associated socio-economic and
                                                              environmental  impacts.  In  the  case  of  quarries,  water
                                                              stored  in  the  abandoned  quarries  which  were  hitherto
                                                              unutilised has been used for water supply. It is a cost-
                                                              effective and most environmental friendly intervention
                                                              with nearly nil cost for establishing compared to all other
         Transportation of water from Jolarpet to Chennai through rail  expensive options. The water is drawn from the quarries
                                                              and  is  transmitted  to  the  nearest  Chembarambakkam
         RESULT ACHIEVED:
                                                              Water  Treatment  plant  which  is  3  km  away  for
         CMWSSB is the pioneer in using stagnant water in the   conventional treatment. The treatment cost is only Rs.
         abandoned quarries for drinking purposes after necessary   7.00 per Kilolitre. The only cost is the capital cost of


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