Transcript Sustainable Sanitation for the 21st Century

1.3
Resource Flows
From where do resources come,
and where do they end up?
Linear flow
Jan-Olof Drangert, Linköping University, Sweden
Features of present policies and practices –
and an anticipated paradigm shift
• Prime fertile soils converted to town areas
• Reduced recycling of organic material
• Less urban agriculture, etc.
More linear flows
while we instead need more short loops for substances
J-O Drangert, Linköping University, Sweden
What comes in ……
Water 
20-200 kg/p/day
Food

1-2 kg/p/day
household
Consumer
goods 
Energy

1- ? kg/p/day
> 1 kg/p/day
Jan-Olof Drangert, Linköping University, Sweden
… must go out
Urine
1.5-3 kg/d/p
Faeces
0.3 kg/d/p
pollutants
Greywater 
20-200 kg/p/day
household
Solid waste
1 - ? kg/d/p
Jan-Olof Drangert, Linköping University, Sweden
The trick is to bend today´s many linear
resource flows
• Solid waste is the most visible output. It may be
discarded or sorted and recycled. Scavengers perform
an important service
• Faecal matter is very small in volume, but is a major
health threat unless treated and used wisely
• Urine (urine) volumes are small. Bad odour may be a
problem unless urine is returned to the soil
• Greywater is voluminous and a major challenge in
dense areas but can be a useful product if handled well
• Stormwater may be a serious problem but harvesting it
can augment household and irrigation water supplies
• Energy is invisible but heat may be recovered
Jan-Olof Drangert, Linköping University, Sweden
Water and nutrient ’kretslopp’
food
Rural home
City with
linear flows
Wastewater = (greywater,
urine, and faeces)
food
Wastewater
WWTP
water
Leaking
pipes
Sorting
city
J-O Drangert, Linköping University, Sweden
Three examples of ’kretslopp’ thinking
Fraction:
In Stockholm
Solid ‘waste’
sorted
in 8 fractions,
Provides
collected and reused
In Kimberley
No sorting, burnt in situ,
the rest to landfill
heating/energy
No sorting, collected
and put on landfills
Organic ‘waste’
Faecal matter
Urine (urine)
Greywater
Stormwater
organics composted
Provides
together
with soil
hygienconditioner
ised dry faecal
material
In Kampala
banana peels etc to
animal
feed
Soil conditioner
dried
and composted
Soil conditioner
dried
composted
Soil and
conditioner
collected and trucked
toLiquid
farm fertiliser
used in situ or by
Liquid
fertiliser
truck
to council
gardens
in situ or collected
in situ after
Irrigation
water
biological
treatment
Greywater to pond
after biological
treatment, and
rainwater to the
same pond. Little
rain.
Infiltrated in situ and to
drains
and biogas
infiltration
(no heavy
Groundwater
rains)
recharge
Liquid fertiliser
In drains but flooding
due to heavy rains
Jan-Olof Drangert, Linköping University, Sweden
Where do we go from here?
S
u
s
t
a
i
n
a
b
i
l
i
t
y
- protecting & promoting human
health,
- not contributing to
environmental degradation or
depletion of resource base,
Solid
- being technically and
institutionally appropriate,
waste
economically viable and
socially acceptable
Interpretation
of the ’waste
hierarchy’
NEW! Reduce generation and
polluting content in goods
Reuse/recycle
Incinerate
Land
fill
Sludge
Liquid
waste
Reuse/recycle
Polluting
discharges
Jan-Olof Drangert, Linköping University, Sweden
Material Flow Analysis for human settlements
MFA uses the principle of mass balance:
input = output + accumulated stock in the system
and provides a systematic description of the flow of
goods, materials or substances through various
processes and out of the system.
output
Process 1
input
Process 3
Process 2
output
Jan-Olof Drangert, Linköping University, Sweden
A resource flow model for a hamlet
10
Courtesy of Jenny Aragundy, Ecuador
The Stockholm model to improve sustainability
11
Courtesy of Stockholm Water Company
Modelling the situation (MFA)
• Select the material,
product or chemical you
are interested in
• Decide
the boundaries of
your system (dashed line)
• Include all the flows, uses,
losses and disposals
agriculture
• Find estimates for
all flows and stocks
food
consumption
urine
faeces
livestock
waste
handling
deposit/
landfill
4 STEPS in modelling:
hydrosphere
Description of the system
(2) Formulation of model equations, (3) Calibration, and
(4) Simulation incl. sensitivity and uncertainty analysis
(1)
Jan-Olof Drangert, Linköping University, Sweden
Actual reuse of nutrients
from urban households in agriculture
Example 1:
Proportion
being reused
100%
Glass, tins,
ceramics
Heavy
metals
50%
waste pits
+urine diversion +WC
1910
1870
only WC
1950
+WWTP
stop
2000
Jan-Olof Drangert, Linköping University, Sweden
Ex. 1 cont.:
Examples of ranges for parameters
Table 1: Data for the pri mar y and s econdar y was te tre atment for Li nköping, 1870 -2000
Year
No of
inhabitants
Primary was te treatment/
toilet s ys tem
0% WC
10% water-tight buckets
90% dug pit/outhous e
2% WC
5% urine s eparation
30% water-tight buckets
63% dug pit or equiv.
8% WC
16% urine s eparation
76% water-tight buckets
0% pit latrine or equiv.
20% WC
10% urine s eparation
70% water-tight buckets
50% WC
0% urine s eparation
50% water-tight buckets
1870
7 300
1885
10 700
1900
14 500
1920
26 900
1940
38 650
1950
54 500
90% WC
10% water-tight buckets
1975
78 000
100% W C
Co mments
Level 3
bas ed on (1)
Level 3
bas es on (1)
80-100% to s oil
0-20% to anima l
fodder
Level 3
bas ed on (1)
80-100% to s oil
0-20% to anima l
fodder
Level 3
bas ed on (2)
95-100% to s oil
0-5% to animal
fodder
Level 2
(3)
40-60% to s oil
40-60 % to landfill
Level 2
(4)
was tewater treatment
plant (WWTP), no P
reduction unit
WWTP with 90% of
P to s ludge;
0-20% to plant/s oil
WWTP with 95% of
P to s ludge;
20-30 % reus ed
(of which 2/ 3 to
energy fores t and 1/3
to farmers )
70-80% to landfill
WWTP with 97% of
P to s ludge;
21% reus ed (10-40%)
(of which 2/ 3 to
energy fores t and 1/3
to farmers )
79% to landfill
(6), (7)
1990
82 600
100% W C
(5), (6), (9)
2000
94 000
100% W C
(5), (8), (9)
Sources :
Neset and Drangert, 2010
Secondary was te
treatment or s torage
70-90% to s oil
10-30% to anima l
fodder
Co mments
60% of W C
connected to WWTP
All W C connected to
WWTP
s ame as s umptions as
for the year 2000
Ex. 1 con´t
Sensitivity analysis
Phosphorus reuse and phosphorus losses 1870-2000
The filled curves represent calculated averages, while
coloured areas between the dotted curves indicate
uncertainty ranges due to estimated input data
(in kg phosphorus per capita per year)
Source: Neset and Drangert, 2010
Example 2:
Eutrophication of Lake Dianchi, China
Production
Consumption
385 tonnes
Farmland
P leakage
55% of TP
33 tonnes
Kunming city
Jan-Olof Drangert, Linköping University, Sweden
Ex. 2 Con't
Urban P flow
to Dianchi Lake, China
Dianchi
roof runoff
street runoff
denitrification
runoff
industrial
discharge
separate
storm water
drainage
storm sewer
wrong
connection
bath
sludge
kitchen
laundry
HH
urine flush
comb. sewer
WWTP
CSO
tank
faeces flush
infiltration incl.
river water
treated
wastewater
overflow out
of CSO tank
overflow out
of combined
sewer
exfiltration
Source: Huang et al., 2007
Ex 2 Con't
Outcome to guide a new strategy
1. A major problem is that during heavy rains the wastewater
bypasses the WWTP and washes all wastewater straight
Do not mix waste streams
into the lake.
2. Groundwater and stormwater enter the poor-quality sewers
and make up a large portion of the water coming to the
WWTP
Infiltrate rainwater locally
3. Even with the best available treatment technology (BAT with
98% P removal etc.) the discharge would still be twice what
the lake can accommodate.
Source separate urine
4. Source-control measures such as urine-diversion toilets and
P-free detergents and body care products are required to
avoid discharging untreated wastewater downstream the
lake and, thus, just moving the environmental problems.
Source: adjusted from Huang et al., 2007
Example 3 :
P flows through Hanoi City
Source: Montangero et al., 2004
Ex. 3 con't
Phosphorus flows in Hanoi City
Organic waste
collection
Water
supply
Households
On-site
sanitation
Sewerage
& drainage
Market
Agriculture
Landfill
Composting
Courtesy of Agnes Montangero, 2007
Ex. 3 con't:
2007
(3 M)
Feeding the people of Hanoi
- a sensitivity analysis
Business No septic
as usual
tanks
No-meat
diet
2015 (5 M residents)
Source: Montangero et al., 2007
Nutrients and food securitya simplified global mass balance
Example 4:
Source: Clift and Shaw 2011, based on Cordell and others
Ex 4 con't
Securing a sustainable phosphorus future
The future is not all dark!
Strategies for sanitation improvements
Principle:
• Organic ≠ other solid waste
• Stormwater ≠ sewage
• Industrial ≠ household wastewater
• Black toilet water ≠ greywater
• Faeces ≠ urine
Jan-Olof Drangert, Linköping University, Sweden