1

Doulaye Koné & Martin Strauss

SANDEC / EAWAG – Switzerland

www.sandec.ch

kone@eawag.ch

strauss@eawag.ch

Tel.+41 44 823 5020 / 5553

Faecal SludgeManagement

The links which matters

Urban sanitation upgrading in developing countries

2

Excreta

sewered sanitation

Septic tanks Latrines

Wastewater treatment plant

(WWTP)(co-treatment of small flows

of FS)

“on-site” sanitation

FS treatment

Septage

Effluent to soakageor drains (alt. 2)

Faecal sludgeLiquid to dischargeinto receiving waters

No-mix latrines:biosolids and urine

to horticultureEffluent to agricultural use or

discharged into receiving waters

Biosolids to agriculture for soil conditioning and

fertilization

The System of Faecal Sludge and Wastewater

Greywater

3

Current thrusts in urban

sanitation development• Latrinization (improved

systems; increased coverage) – improves hygiene

• Hygiene promotion (hand-washing; 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?

Engineers’ thrusts and beliefs How to empty this pit ?

What happens next ?

Challenges: how to shift our mind set?

• 2-2.5 billion urban dwellers on on-site sanitation !

• Number and share growing !

e.g. Bangkok, M anila, Accra

e.g. London, Paris, Berlin

0 20 40 60 80 100

Bangkok

Manila

Philippines

Ghana

Tanzania

Latin America

Percent of population served byon-site sanitation

On-site sanitation = the hidden reality

6

1. 70-100 % of cities and towns in developing

countries served by on-site sanitation (latrines

and septic tanks)

3. Lack of regulations, illegal

dumping and use of FS

untreated

2. All installations produce

FS to be collected

( trucks replacing sewer lines ?)

On-site sanitation = the hidden reality

On-site sanitation = the hidden reality

Nutrient in kg

Nutrient In urine In faeces Total Required for

cereals

4.0 0.5 4.5 5.6

0.4 0.2 0.6 0.7

K Potassium 0.9 0.3 1.2 1.2

500 l/year 50 l/year 250 kg of

N Nitrogen

P Phosphorus

Faecal sludge = resource

On-site sanitation = the hidden reality

Reuse

Technology

Managerial, institutional, financial

FSM – the pillar of urban sanitation improvement

11

• FS management = integral part of sanitation planning!

• Decentralized system of disposal/treatment sites

Treatment plant

Minimising haulage distances

FSM – the pillar of urban sanitation improvement

12

The Challenge

Guarantee pit emptying, FS haulage, treatment and reuse

The Challenge

Guarantee pit emptying, FS haulage, treatment and reuse

The challenge

13

Problems

Pit emptying and FS haulage

No access to pits

Traffic congestion

Poor management of emptying services

The challenge

14

WWTP

FSTP

Condominial septic tank• Condomenial septic

tanks at easily accessible sites

Sludge composition - Flow Behaviour (Bösch & Schertenleib, 1985)

0

20

40

60

80

100

0 2 4 6 8 10 12

% Volatile (TVS)

% H

2O

1

2

3

4

Low -

Low- : Low

+

Med: m

ed +

High - : High +

1.low- viscosity zone

2.low- : low+ viscosity zone

3.med : med+ viscosity zone

4.high- : high+ viscosity zone

The chosen technology influences the FS characteristics and determines the emptying procedure and technology

Inte

gra

ting F

S M

into

the u

rban S

anit

ati

on p

lannin

g

Manual emptying where trucks cannot access/pump or households cannot pay the service

Transportation of manually-emptied solids and liquids

In the street

Manual emptying (70%)

Dumping in the street,

Reuse in agriculture

Manual emptying where trucks cannot access/pump or households cannot pay the service

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?

20

• Emptying companies are not always equipped with appropriate vehicles

e.g. Haiphong: Tanks in narrowlanes accessible by small vehicles

Mechanical emptying lacking the support of local government

Mechanical emptying (30% )

Mechanical emptying lacking the support of local government

Faecal Sludge ManagementLatrines 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 !

• Expertise widely lacking (still bias on sewered sanitation)

need for capacity building of individuals and institutions

• FSM not recognised as a crucial component of urban sanitation upgrading

need for advocacy and awareness raising

The challenge for mitigation

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 ?

Defining new goal for mitigation

(MDGs)

How to sustain local expertise ?

28

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”

What is faecal sludge ?

29

Sludge drying beds

+ co-composting

Constructed wetlands

How to treat ? e.g. by ...

Affordability

Enforceable regulations, improved public health, reduced pollution

Competitive survival

Improved FSM means different things for different stakeholders

Affordability + better soil Affordability + better soil

MunicipalAuthority

Households

Manual Emptiers

Mechanical emptiers

Farmers

National water&Sanitation

Agency

National line agencies

Donor Agencies

Waste collectionNGOs

Service

Financing

Leasing

Control

Fees

Cooperation

Tool for guaranteeing the business : stakeholder identification and analysis

Universities & research institutes

32stakeholder cost money flow

Legend

revenue

Pit

em

pty

ing

fe

e

Sanitation taxS

ub

sid

y

External Funds

Household (pit owner)

Municipal authority

Administration, office cost, etc.

Profits Collection company

Vehicle capital and O+M cost

Biosolidssale

O+M cost Capital cost

FS treatment plant

Licensing

Discharge premium

“Reversing the money flux”

A planning tool helping to create the MARKET for a sustainable business

-10

-5

0

5

10

15

20

25

0% 20% 40% 60% 80% 100%

Percentage of sanitation tax reinvest in the money flux

US

$

Emptying fee [US $/trip]FS dumping remuneration [US $/trip]

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?

Money flux model for decision making (Ouahigouya)

Mechanical Emptier

National Water & Sanitation

Agency (ONEA)Households

Farmers

MunicipalityCapital cost

0 €

O & M Costs11.5 €

Profit- 1.0 €

Current money flow

Invest.14 €

?

Pit

em

pty

ing

fee

Pit emptying fee

FS sale

Lic

en

ce

12 €

14 €

1.5

€

Mechanical Emptier

National Water & Sanitation

Agency (ONEA)Households

Farmers

MunicipalityCapital cost

0 €

O & M Costs11.5 €

Profit- 1.0 €

Current money flow

Invest.14 €

?

Pit

em

pty

ing

fee

Pit emptying fee

FS sale

Lic

en

ce

12 €

14 €

1.5

€

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

Mechanical Emptier

National Water & Sanitation

Agency (ONEA)

Households

Treatment Operator

FarmersMunicipalityVehicle

Amortization2,5 €

O & M Costs12 €

Profit2,5 €

Profit1,8 €

3 €(24%)

O & M Costs5 €

Control cost1,5 €

Pit

emp

tyin

g f

ee

Sanitation taxB

ioso

lids

sale

Tre

atm

ent

cost

Discharge premium

12 € 11

€

14 €

6.5 €

2.3

€

Lic

ence

1.5

€

Mechanical Emptier

National Water & Sanitation

Agency (ONEA)

Households

Treatment Operator

FarmersMunicipalityVehicle

Amortization2,5 €

O & M Costs12 €

Profit2,5 €

Profit1,8 €

3 €(24%)

O & M Costs5 €

Control cost1,5 €

Pit

emp

tyin

g f

ee

Sanitation taxSanitation taxB

ioso

lids

sale

Tre

atm

ent

cost

Discharge premium

12 € 11

€

14 €

6.5 €

2.3

€

Lic

ence

1.5

€

Sustainability of mechanical emptying

36

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

Policy; regulatory; institutional (“PPP”)• Shit hauled to designated sites

• Financially and economically sustainable

Financial / economical

Institutional; financial

• Sanitation stewardship by local entrepreneurs

Engineering• Cesspit truck operation and maintenance

Sanitation = Business I can do it at low-cost !

Domestic liquid waste

(faecal sludge, wastewater, feces, greywater, urine, ...)

Same product hauled by sewer !

Legalize it

!!

Sanitation = Business I can do it at low-cost !

The above-ground sewer system

The trucked sewer system

The mobile honey sucker

Sanitation = Business

The above-ground sewer system

The trucked sewer system

The mobile honey sucker

Private entreprises can perform well in the job of bringing the shit to the site – efficiently and affordably !