This document discusses options for sanitation solutions in urban areas. It provides background on the goal of safe collection, treatment and disposal of human waste. It then describes sewerage systems and issues like inadequate treatment. It also covers septage management, including the characteristics and need to empty septic tanks. The document analyzes options for two cities in India and compares costs and factors for treatment options like centralized sewerage, on-site systems, and decentralized systems. It finds that centralized sewerage has the highest capital costs but economic payback after two times, while decentralized can have lower operation and maintenance costs.

1. Selecting sanitation solutions
Image:
WSUP

2. Overview of presentation
• Background
• Sewerage systems
• Septage management
• Options analysis
• Discussion

3. Background

4. Safe collection, treatment & dispoal –
Goal of NUSP
100 % of human excreta and liquid wastes from all sanitation
facilities must be disposed-off safely.
This will be achieved by:
• Ensuring that all human wastes are collected, treated and
disposed off safely;
• Promoting proper disposal and treatment of sludge from on-
site installations (septic tanks, pit latrines, etc.);
• Promoting proper functioning of network-based sewerage
systems and ensuring connections of households to them;
• Encourage recycle and reuse of treated waste water for non-
potable applications, wherever possible.

5. Service Chain to Meet Sanitation Needs for Different Customers
Water
closet
Sewer network
Treatment
plant
Reuse
/disposal
Treatment
Reuse/
disposal
TransportEmptyingContainment
Centralised system
On-site systems
Decentralised system
Water
closet
Sewer network
Treatment
plant
Reuse
/disposal
Latrine/
Septic tanks
etc
Vacuum truck or simpler
emptying and transport
Simplified or
conventional network
Reuse

6. 6
100%88%
WC to
sewer
On-site
facility
Septic tanks,
covered pits,
VIPs etc.
Open
defecation
(including
open pits)
Unsafely
emptied
or
discharged
33%
19%
Treatment
Reuse/
disposal
TransportCollectionContainment
Source:
Census 2011
Not treated
but unknown
where it goes
Urban sanitation situation?
Urban India – 1 Lakhs Plus
41%
9%
Not treated
to standard
14%
Treated
50%
41%
17% Leakage
17%
9%
81%
Receiving
Waters
Local area and beyond, via
drains
Sewer coverage No of Cities % of population
<10 % 191 16.45%
10 - 30% 158 20.10%
30 - 60% 75 24.22%
>60% 78 39.23%

7. Sanitation Service Delivery World-Wide
Figure from Boston Consulting Group, 2013

8. Sewerage systems

9. Status of STPs and sewage treatment
9
Class I cities Class II cities Total (MLD)
Wastewater generated (mld) 35558 2697 38255
Wastewater Treated (mld) 11554 234 11788
Potential for additional treatment
(mld) 24004 2463 26467
Untreated effluent (%) 68% 91% 69%
CSE (2014) report on Ganga Basin says
that sewage generation is
underestimated and hence the
treatment capacity needed is much
higher
Source: The river, its pollution and what we can do to clean it – A CSE Breifing Paper, 2014)

10. Status of STPs and sewage treatment
11
Inadequate treatment
performance:
• Evaluation of 152
STPs reveals that:
• 30 non operational
• 9 under
construction
• 114 operational, of
which 49 do not
meet discharge
standards
• Only 43% of total
STPs meet discharge
norms
Under construction
6%
Not operating STPs
19%
Not meeting BOD
Standard
32%
Meeting BOD
standards
43%
PERFORAMNCE ASSESSMENT OF 152 STPS BY CPCB

11. Options for cost recovery
• Normally determined by the funding agency,
• User charges in cities studied ranges from Rs. 75 – 115/month for households and between
Rs 150 – 230/month for commercial establishments.
• Can contribute to 50 – 200% of O&M cost
User fee
• A portion of the property tax is apportioned to water and drainage
• In TN for example:
• ~22% of PT allocated to water and drainage
• ~5.5% of PT generally earmarked for sewerage system.
Property tax
•Deposits can help to reduce the debt service burden (10 – 30%) and hence the
user charge (Rs. 50/HH)
Public
deposits
•~80% of energy needs of STP can be met from sludge based power generation.
~40 – 50% of O&M costs are on account of the energy needs. Results in overall
reduction of the O&M Costs .
Energy
recovery:
•Can meet almost 100% of plants O&M needs
•Examples from various ULBs regarding sale of treated wastewater
Sale of
treated
wastewater
12

12. Septage management

13. Septage characteristics
S. No. Characteristics Value (mg/l)
1. Total Solids 12,000 – 35,000
2. Total suspended solids 45 – 73% of TS
(0.5 – 2.5%)
3. BOD 840 – 2,600
4. COD 1,200 – 10,000
Source: http://www.eawag.ch/forschung/sandec/publikationen/ewm/dl/fsm_2.pdf

14. Why empty septic tanks?
Source: USAID, 2010

15. The septage management cycle

16. Options analysis

17. 18
100%88%
WC to
sewer
On-site
facility
Septic tanks,
covered pits,
VIPs etc.
Open
defecation
(including
open pits)
Unsafely
emptied
or
discharged
26%
20%
Treatment
Reuse/
disposal
TransportCollectionContainment
Source:
Census 2011
Not treated
but unknown
where it goes
Tiruchirapalli
36%
10%
Not treated
to standard
6%
Treated
54%
36%
Leakage
27%10%
80%
Receiving
Waters
Local area and beyond, via
drains
27%
Coverage by piped sewer Number of Wards Share of city population
<5% 8 17%
5-10% 9 18%
10-20% 20 33%
20-30% 14 19%
> 30% 9 14%
Total 60

18. 19
100%88%
WC to
sewer
On-site
facility
Septic tanks,
covered pits,
VIPs etc.
Open
defecation
(including
open pits)
Unsafely
emptied
or
discharged
16% 12%
Treatment
Reuse/
disposal
TransportCollectionContainment
Source:
Census 2011
Not treated
but unknown
where it goes
Kumbakonam
55%
13%
Treated
32%
55%
Leakage
16%13%
88%
Receiving
Waters
Local area and beyond, via
drains
4%
16%
Coverage by piped sewer Number of Wards Share of city population
<5% 7 16%
5-10% 10 23%
10-20% 11 24%
20-30% 2 5%
>30% 15 32%
Total 45

19. Factors influencing treatment options
*- Average of HPEC Estimates and actual cost incurred for several Sewer systems implemented in Tamil Nadu under World
Bank Project
# - System serving 100 - 1000 households. Data provided by CDD, Bangalore
Boston Consulting Group 2013

20. Selection of options: Urban
 The highest cost
option of
centralized
sewerage has
economic payback
of two times
Data source: WSP 2012
Urban China
Courtesy of WSP

21. Comparison sewer-based sanitation and fecal sludge
management in Dakar, Senegal
X 28
Dodane et al, 2012

22. Comparison of treatment options
Details Network* On-site Decentralized#
Capex Rs/HH 25000 - 30000 5000 – 10,000 13500 - 32500
Opex Rs/HH 1600 1000 145 - 630
*- Average of HPEC Estimates and actual cost incurred for several Sewer systems implemented in Tamil Nadu under World
Bank Project
# - System serving 100 - 1000 households. Data provided by CDD, Bangalore
WSP 2015

23. Thanks