healthy ganga: selecting sanitation solutions

Selecting sanitation solutions

Image: WSUP

Overview of presentation

• Background

• Sewerage systems

• Septage management

• Options analysis

• Discussion

Background

Safe collection, treatment & dispoal –Goal of NUSP100 % 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.

Service Chain to Meet Sanitation Needs for Different Customers

Water

closetSewer network

Treatment

plantReuse

/disposal

TreatmentReuse/

disposalTransportEmptyingContainment

Centralised system

On-site systems

Decentralised system

Water

closetSewer network

Treatment

plantReuse

/disposal

Latrine/Septic tanks etc

Vacuum truck or simpleremptying and transport

Simplified or conventional network

Reuse

6100%88%

WC tosewer

On-site facility

Septic tanks, covered pits,

VIPs etc.

Open defecation (including open pits)

Unsafelyemptied

or discharged

33%

19%

TreatmentReuse/

disposalTransportCollectionContainment

Source: Census 2011

Not treatedbut 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

WatersLocal 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%

Sanitation Service Delivery World-Wide

Figure from Boston Consulting Group, 2013

Sewerage systems

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 11788Potential 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)

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 construction6%

Not operating STPs19%

Not meeting BOD Standard

32%

Meeting BOD standards

43%

PERFORAMNCE ASSESSMENT OF 152 STPS BY CPCB

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

Septage management

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

Why empty septic tanks?

Source: USAID, 2010

The septage management cycle

Options analysis

18100%88%

WC tosewer

On-site facility


VIPs etc.


Unsafelyemptied

or discharged

26%20%

TreatmentReuse/


Source: Census 2011


Tiruchirapalli

36%10%

Not treated

to standard

6%

Treated

54%

36%

Leakage

27%10%

80%Receiving


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

19100%88%

WC tosewer

On-site facility


VIPs etc.


Unsafelyemptied

or discharged

16% 12%

TreatmentReuse/


Source: Census 2011


Kumbakonam

55%13%

Treated

32%

55%

Leakage

16%13%

88%Receiving


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

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

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

Comparison sewer-based sanitation and fecal sludgemanagement in Dakar, Senegal

X 28

Dodane et al, 2012

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

Thanks

healthy ganga: selecting sanitation solutions

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