R.M.Bhardwaj, Scientist

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R.M.Bhardwaj, Scientist C Central Pollution
Control Board, Parivesh Bhawan, East Arjun
Nagar,Delhi-110032 (INDIA) rmbdelhi_at_yahoo.co.in,
scrmb.cpcb_at_nic.in
Questionnaire survey and data acquisition onStat
us of Wastewater Management in India
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Increase in Urban Population
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Steps followed for Questionnaire survey on Water
Supply, Wastewater Generation, Collection,
Treatment in Urban Centres in India and
limitations of study

• Step 1
• List out candidate Cities/Towns for data
  collection-various classes categorised by Census
  Deptt.(Calcutta case)
• Information is available for city specific rather
  than outer growth/urban agglomeration.civic
  agencies does not keep record for non municipal
  areas.
• Information is difficult to obtain for
  development region/authority area as the census
  is held once in a decade.Growth rate figures are
  used for estimation wherever information gaps are
  observed.

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Step 2Identification of Civic Agency Dispatch
of Questionnaire

• Multiple agencies are involved in providing civic
  services and the administrative set up varies
  from State to State. The civic agency may be
  Municipality/ Corporation/ State Water Board/
  Public Health Engineering Deptt or Private
  Agencies.There may be gaps in information/data
• Dispatch of Questionnaire for Data Acquisition
  to one and all possible sources, followed by
  reminders periodically. Persuasion and follow up
  through concerned Ministries of State Govt. and
  Union Ministries. Ultimate option-use of
  Statutory power.
• Personal visit to urban centres for Questionnaire
  survey and to verify contents wherever doubt
  arise.

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Step 3Data receipt, entry,Checking, Validation
and Processing

• Data received from Civic agencies is entered in
  dbase/ Excel format.Replies received from
  multiple agencies for the same city needs careful
  integration.
• Data checking to find errors in reporting of
  population figures, units on volume of water
  supply/ wastewater generation, per capita
  figures, checks on the ratio of water supply v/s
  wastewater generation, level of wastewater
  collection, treatment capacity, type of treatment
  process and mode of disposal(irrigation,
  recipient water body etc.)
• Checking, if data is within the limits of
  national norms, if the data is within the
  expected ranges for a parameter, if data are
  physically or scientifically possible(general
  checks),if the correlation of parameters(some
  conditional checks) does exist.

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Step 3(Contd.)

• Data verification/validation by using maps/atlas,
  topo sheets, past records for each city, water
  mission reports on per capita level of water
  supply for different classes of urban centers in
  the country and various studies carried out by
  the organisation on environmental issues
• Personal experience of Scientists/Engineers on
  specific urban centers
• Data processed to prepare National,State wise and
  river basin wise tables on class I cities and
  Class II towns covering a number of parameters
  i.e population, volume of water supply in a
  city,per capita water supply,source of water
  supply, of population covered with water
  supply, wastewater generation, sewered
  population, wastewater collection, treatment and
  place of disposal.

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Step 3 (Contd)

• Another study on performance evaluation of sewage
  treatment plants(STPs) is carried out to assess
  the efficiency of units and compliance level for
  discharge of pollutants such as pH,Suspended
  Solids, Chemical Oxygen Demand and Biochemical
  Oxygen Demand in the treated wastewater, apart
  from a number of other parameters.The performance
  of the STPs is inconsistent due to a number of
  reasons and frequent monitoring is not possible.
  

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generation
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generation
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Data on Water Supply
Discussion on Questionnaire and Data Collection
Exercise

• Source of Organised Water Supply and Volume
  (mld/mgd)-River / Canal /Lake /
  Subsurface/Sea-need caution on the
  unit/source/multiple source
• of population covered-information not précised
• Source of unorganised water supply
• Proposed plan for augmentation of water Supply
  (source/Volume) and target year of commissioning
• In case of multiple supplying agencies-verificatio
  n of figures/ sources/ jurisdiction is difficult,
  estimation based on pumping hours are made-Case
  of NCT of Delhi-DDA/CPWD/Private builders

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Data on Treatment of Raw Water for municipal
supply

• Type of treatment-Conventional/only
  Chlorination/ Raw water Supply
• Number and name of Treatment Plant(Govt.owned or
  under BOOT)
• Design Capacity of each Plant
• Actual Volume of Water Treated (not metered only
  pumping capacity and period of pumping is
  available)
• Disposal of back wash water(Volume/Place) and
  does alum recovery process adopted
• Continuous/Intermittent Supply

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Generation of Wastewater

• Volume of Wastewater Generation (mld/mgd)
  Municipal Domestic/Industrial-information
  provided is based on engineering estimates i.e
  80 of water supply-industrial figures are based
  on production that is under reported.
• Volume of Wastewater reaching pump houses through
  sewers (mld/mgd)- calculated figures are based on
  pumping hours.Pumping capacity reduce
  considerably by ageing of pumps.
• of population covered by sewers-information is
  estimated zone wise.
• Volume of wastewater flowing in open drains (old
  city areas/unplanned growth) is difficult to
  account
• Specific studies undertaken indicates wastewater
  generation is more than the water supply figures-
  unaccounted water-bore wells by individuals due
  to inadequate supply from civic agency.Official
  figures of water supply in Delhi is 640 mgd
  whereas measured flow of drains is 727 mgd.
  Possibility of effluent from subsurface does not
  arise in case of Delhi because the water table is
  quite deep and going down further due to over
  abstraction.

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Waste water Collection

• Volume of Wastewater Collected through sewerage
  system(mld/mgd) Municipal Domestic/
  Industrial-estimated figures-Total generated
  volume is not collected due to settlement/choking
  of sewers and disruption of pumping due to power
  shortages.
• Volume of Wastewater collected through open
  drains/storm water drains and pumped for
  irrigation or pumped for treatment
  (mld/mgd)-objective of data is to prioritise
  efforts for sewerage.
• Is there separate sewers for domestic and
  industrial wastewater-only planned industrial
  estates have separate sewers
• of wastewater collected-figures are not
  available with civic agencies.Attempt made to
  estimate in Delhi during the performance
  assessment of sewage treatment plants indicates
  that only about 42 wastewater is collected
  through sewers rest is flowing in open
  drains.Figures varies widely from city to city.

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Sewage (Wastewater) Treatment

• Installed Treatment Capacity (mld/mgd)
• Number and name of Sewage Treatment Plant
  (Govt.owned or under BOOT), specify agency
• Level of treatment plant-Primary/Secondary/Tertia
  ry
• Treatment Technology and Design Capacity of each
  Plant (mld/mgd)-Primary/Secondary/Tertiary.
  Activated Sludge Process/Trickling Filter/Upflow
  Anaerobic Sludge Blanket/Other Anaerobic (Bio
  Filter) process, Oxidation pond,any other process
• Actual inflow of Wastewater in each Sewage
  Treatment Plant (mld/mgd)
• Actual volume of wastewater (Sewage) Treated
  (mld/mgd).
• Experience of Delhi indicates that despite having
  sewage treatment capacity of 2300mld only about
  1400 mld is treated upto secondary level through
  ASP.

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Performance Evaluation of Sewage Treatment Plants

• Sewage treatment plants evaluated based on
  composite sampling of each treatment unit to
  assess the efficacy of system and compliance to
  prescribed standards.
• Intermittent Power Supply is one of the main
  constraint in activated bio mass treatment
  systems that reduces the performances to a great
  extent.
• It is observed that non energy intensive
  technologies such as Oxidation Pond/Facultative
  Pond are performing relatively better than
  mechanised systems.Reduction percentages vary
  from parameter to parameter.

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Harmonisation with International Questionnaires
and availability of data

• Methodology adopted in India is quite similar to
  International pattern however there are number of
  issues needs to addressed for data gaps in
  respect of developing economies.
• Population is growing at fast pace and process
  of infrastructure development is a dynamic in
  developing economies.Frequent updating of
  information is not possible as being followed in
  EU.Records are not computerised, Data variation
  are evident.
• Statistics on water/wastewater management is not
  compiled,collated and published by civic agencies
  and State Govt.Hence methods for gross estimates
  are required to be designed .
• Infrastructure development for municipal water
  supplies is priority, in contrast to wastewater
  collection and treatment.Hence data is broadly
  lacking for the letter part.
• Data related to treatment of wastewater and their
  performance may be a difficult proposition.

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Thanks to UNSD for giving me this opportunity to
share findings.
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T H A N K Y O U