Transcript Document

Urban sanitation upgrading
in developing countries
Faecal Sludge
Management
The links which
matters
Doulaye Koné & Martin Strauss
SANDEC / EAWAG – Switzerland
www.sandec.ch
[email protected]
[email protected]
Tel.+41 44 823 5020 / 5553
1
The System of Faecal Sludge and Wastewater
Excreta
“on-site” sanitation
sewered sanitation
Greywater
Septic tanks
Wastewater
treatment plant
(WWTP)
Latrines
Effluent to soakage
or drains (alt. 2)
(co-treatment of small flows
of FS)
Septage
FS treatment
Liquid to discharge
into receiving waters
Effluent to agricultural use or
discharged into receiving
waters
Faecal sludge
Biosolids to agriculture for
soil conditioning and
fertilization
No-mix latrines:
biosolids and urine
to horticulture
2
Current thrusts in urban
sanitation development
• Latrinization (improved
systems; increased
coverage) – improves
hygiene
• Hygiene promotion (handwashing; school
sanitation; soap usage;
.............)
• Ecosan – source
separation (feasible in
urban areas ?)
• Low-cost + conventional
sewerage (< 20 % of pop.
Coverable in many cases)
.... and who is taking care of the
remaining?3
Challenges: how to shift our mind set?
Engineers’ thrusts
and beliefs
How to empty this pit ?
What happens next ?
On-site sanitation = the hidden reality
e.g. Bangkok, Manila, Accra
e.g. London, Paris, Berlin
Percent of population served by
on-site sanitation
Latin America
Tanzania
Ghana
Philippines
Manila
Bangkok
0
•
•
20
40
60
80
100
2-2.5 billion urban dwellers on on-site
sanitation !
Number and share growing !
On-site sanitation = the hidden reality
1. 70-100 % of cities and towns in developing
countries served by on-site sanitation (latrines
and septic tanks)
2. All installations produce
FS to be collected
( trucks replacing
sewer lines ?)
3. Lack of regulations, illegal
dumping and use of FS
untreated
6
On-site sanitation = the hidden reality
Faecal sludge = resource
Nutrient in kg
Nutrient
In urine In faeces Total Required for
250 kg of
500 l/year 50 l/year
cereals
N Nitrogen
4.0
0.5
4.5
5.6
P Phosphorus
0.4
0.2
0.6
0.7
K Potassium
0.9
0.3
1.2
1.2
On-site sanitation = the hidden reality
FSM – the pillar of urban sanitation
improvement
Managerial, institutional,
financial
Reuse
Technology
FSM – the pillar of urban sanitation
improvement
•
FS management = integral part of sanitation planning!
•
Decentralized system of disposal/treatment sites
Treatment plant

Minimising haulage distances
11
The challenge
The Challenge
Guarantee pit emptying, FS haulage, treatment and reuse
12
The challenge
Problems
Pit emptying and FS haulage


No access to pits

Traffic congestion
Poor management of
emptying services
13
• Condomenial septic
tanks at easily
accessible sites
Condominial
septic tank
FSTP
WWTP
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Sludge composition - Flow Behaviour (Bösch & Schertenleib, 1985)
% H2O
Integrating FS M into the urban Sanitation planning
The chosen technology influences the
FS characteristics and determines the
emptying procedure and technology
100
1
80
2
3
60
4
40
20
0
0
2
4
6
8
10
12
% Volatile (TVS)
1.low- viscosity zone
2.low- : low+ viscosity zone
3.med : med+ viscosity zone
4.high- : high+ viscosity zone
Manual emptying where trucks cannot access/pump or
households cannot pay the service
Transportation
of manually-emptied solids and liquids
Manual emptying where trucks cannot access/pump or
households cannot pay the service
Manual emptying (70%)
Dumping in the street,
Reuse in agriculture
In the street
Transportation
of manually-emptied solids and liquids
• Distance?
• Reuse potential?
• Humidity (hygienic quality)?
• Additional treatment
(storage)?
• Greywater collection
transpotation and treatment?
• Quantity (size of
neighbourhood)?
• Business opportunity?
Mechanical emptying lacking the support
of local government
• Emptying companies are not always
equipped with appropriate vehicles
 e.g. Haiphong: Tanks in narrow
lanes accessible by small vehicles
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Mechanical emptying lacking the support
of local government
Mechanical emptying (30% )
Faecal Sludge Management
Latrines without it = simply moving
the shit around !
1 truck of latrine sludge
carelessly dumped
= 5,000 people shitting in the open!
Latrines without FSM =
promoting open shitting !
Latrines without it
= diarrhoea
= waste of money
= own-goal !
The challenge for mitigation
•
FSM not recognised as a crucial
component of urban sanitation
upgrading
 need for advocacy and awareness
raising
•
Expertise widely lacking (still bias
on sewered sanitation)
 need for capacity building of
individuals and institutions
Defining new goal for mitigation
(MDGs)
 A strategy for sustainable faecal sludge
management is elaborated and validated
Specific questions
 What institutional and legal framework
to obtain optimum involvement of
stakeholders?
 What financial framework to allow all
stakeholders to profit?
 How to carry it away - what type of
sludge from what type of latrine ?
 How to sustain local expertise ?
What is faecal sludge ?
Thick and yellow .......
Sludges from unsewered public or
family toilets emptied at weeks’
intervals  “unstable”
Thin and black .......
Sludges from septic tanks emptied
at years’ intervals  partially
“stable”
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How to treat ? e.g. by ...
Constructed wetlands
Sludge drying beds
+ co-composting
29
Improved FSM means different
things for different stakeholders
Affordability
Competitive survival
Affordability + better soil
Enforceable regulations, improved
public health, reduced pollution
Tool for guaranteeing the business :
stakeholder identification and analysis
Households
National
water&Sanitation
Agency
Farmers
National line
agencies
Mechanical emptiers
Municipal
Authority
Manual Emptiers
Service
Financing
Waste collection
NGOs
Leasing
Control
Fees
Cooperation
Donor Agencies
Universities &
research institutes
A planning tool helping to create the
MARKET for a sustainable business
“Reversing the money flux”
Vehicle capital
and O+M cost
Collection
company
O+M cost
Discharge premium
Household
(pit owner)
Subsidy
Sanitation tax
Capital cost
FS treatment
plant
Pit emptying fee
Profits
Administration,
office cost, etc.
External
Funds
Biosolids
sale
Municipal
authority
Legend
stakeholder
cost
revenue
money flow
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Money flux model for decision making (Ouahigouya)
If the dumping of FS is remunerated (Blue line), how much
external money (i.e. sanitation tax) is needed to finance a
treatment plant and what is the correspondent emptying fee?
Emptying fee [US $/trip]
FS dumping remuneration [US $/trip]
25
20
US$
15
10
5
0
-5
-10
0%
20%
40%
60%
80%
Percentage of sanitation tax reinvest in the money flux
100%
Sustainability of mechanical emptying
Current money flow
?
Municipality
FS sale
Farmers
12
12 €€
O & M Costs
11.5 €
Mechanical
Emptier
fee
Pit
Pit emptying
emptying fee
Profit
- 1.0 €
1.5
1.5 €€
Licence
Licence
Capital cost
0€
Households
14 €
Pit emptying fee
National Water &
Sanitation
Agency (ONEA)
Invest.
14 €
Sustainability of mechanical emptying
• The current money flow is balanced if 75 % of
the sanitation tax is recycled into the system.
• A professional service provider could lower
this contribution
Control cost
1,5 €
Municipality
14 €
Households Sanitation tax
O & M Costs
5€
Treatment cost
Treatment
Operator
11 €
6.5 €
Biosolids
sale
2.3 €
Discharge
premium
12 €
O & M Costs
12 €
Mechanical
Emptier
Pit emptying fee
Profit
2,5 €
Farmers
1.5 €
Licence
Vehicle
Amortization
2,5 €
National Water &
Sanitation
Agency (ONEA)
Profit
1,8 €
3€
(24%)
Features of improved FSM
Feature, component
Domain
• FSM ↔ on-site technology
Engineering
• Recycling of organic matter and
nutrients contained in human “waste”
(hyg. safe)
Engineering;
health; agronomic
• Shit hauled to designated sites
Policy; regulatory;
institutional (“PPP”)
• Financially and economically
sustainable
Financial /
economical
• Sanitation stewardship by local
entrepreneurs
Institutional;
financial
• Cesspit truck operation and maintenance
Engineering
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Domestic liquid waste
(faecal sludge, wastewater, feces,
greywater, urine, ...)
Same product hauled by sewer !
Sanitation = Business
I can do it at low-cost !
The above-ground sewer system
The trucked sewer system
The mobile honey sucker
Sanitation = Business
I can do it at low-cost !
Private entreprises can perform well in the job of
bringing the shit to the site – efficiently and affordably !