Course 1 Unit 2
Characteristics of urine, faeces and
greywater
Content:
Part A: Characteristics of urine
Part B: Characteristics of faeces
Part C: Characteristics of greywater
Lecturer: Dr. Elisabeth v. Münch
e.vonmunch@unesco-ihe.org
1
Separated „waste“ streams are
easier to treat and reuse
Substance
Treatment
examples
urine
faeces
(yellow water) (brown water)
storage
Reuse
N-rich
fertiliser
anaerobic
digestion,
drying,
composting
biogas,
soil
improvement
= black water (with small
amount of flush water)
greywater
(shower,
washing, etc.)
rainwater
constructed
wetlands, wastewater
ponds, biol.
treatment, membrane
technology
filtration,
biological
treatment
irrigation,
groundwater
recharge,
toilet flushing
water supply,
groundwater
recharge
organic waste
composting,
anaerobic
digestion
soil
improvement,
biogas
Source: GTZ-ecosan project,
resource book
2
“Waste” streams discussed in this
lecture
1. Urine
2. Faeces
3. Greywater
4. Anal washwater
5. Conventional domestic wastewater –
for comparison purposes
3
Course 1 Unit 2
Nutrients are an important
component of waste streams

Macronutrients:







Nitrogen (N)
Phosphorus (P)
Potassium (K)
Sulphur
Calcium
Magnesium
A fertiliser which contains these
three nutrients is called a
“complete” fertiliser
Micronutrients:

Boron, copper, iron, chloride, manganese,
molybdenum and zinc
TN = total nitrogen, e.g. urea-N plus ammonia-N (for urine)
TP = Total phosphorus
4
Role of measurement parameters for urine,
faeces and greywater
Parameter
Purpose of measuring
Dry mass,
moisture content (for faeces)
Solids content, mass to be
transported
Total nitrogen (TN), total
phosphorus (TP), potassium
(K), ammonia-N
Nutrient content for fertiliser value
(or for pollution potential if
discharged to water course)
COD, BOD (chemical /
biological oxygen demand)
Organic matter content
VS (volatile solids)
Organic matter content
pH
pH around neutral is best for reuse
TDS (total dissolved salts)
The lower the TDS the better for
reuse
Electrical conductivity
Proportional to TDS and correlated
with ammonia-N
Pathogens (e.g. helminth
eggs, E. coli)
Assess public health risk (but needs
specialised lab to measure)
5
Course 1 Unit 2
Part A: Characteristics of urine
Most of the data in this part was taken from Jönsson et al.
(2004)
6
Fresh urine




This amount excreted in
one go by one adult in
the morning (full
bladder!): 730 mL
pH: 7.7
TN: 19 g/L (this is
unusually high)
Ammonia-N: 22 mg/L
(during last IHE lab
session: ~160 mg/L)
Source: own determinations in
Triqua laboratory
You see here 14 grams of nitrogen!
7
Human urine quantity facts

Human physiology facts:




The body uses urine as a balancing medium for
liquids and salts
The kidneys filter urine from the blood
At excretion, the urine pH is normally around 6
but can vary between 4.5 – 8.2
Adults excrete about 0.8 – 1.5 L of urine
per day (children about half that amount)
depending on time, person and
circumstances:


Excessive sweating results in concentrated
urine
Comsumption of large amounts of liquid dilutes
the urine
8
Nutrients in human urine



Digested nutrients enter the metabolism
and are excreted mostly with the urine
and the rest in faeces
Urine contains 88% of excreted N, 67%
of excreted P and 73% of excreted K; the
remainder is in the faeces
This ratio of nutrient split between urine
and faeces appears to be more or less the
same worldwide
9
Urea facts



Of the nitrogen in fresh urine, 75-90% is in the form
of urea; remainder is in the form of ammonium or
creatinine
Urea is (NH2)2CO – an organic nitrogen compound
(contributing to CODa content of urine)
Urea is easily converted to ammonium by urease in
the urine piping system or in the sewer


Urea can be made artificially from ammonia and CO2
and is a popular fertiliser world-wide

a
In conventional mixed wastewater, about 78% of the
total nitrogen is therefore in the form of ammonia
already
Urea has the highest proportion of N of all liquid
fertilisers: 46.4% N in urea
COD = Chemical Oxygen Demand (see slide 18)
10
Urine storage
Fresh
(24 March 06)
Fresh
(24 March 06)
Course 1 Unit 2
One month old
(24 April 06)
One month old
(24 April 06)
Three months old
(28 June 06)
Note the change in colour, increasing cloudiness,
sediments
11
Processes during urine storage





There is a risk of losing N in the form
of ammonia with the ventilated air
Sludge forms where urine usually
stands for a while
This sludge largely consists of struvite
and apatite
It is formed because the pH of the
urine increases to 9-9.3 due to the
degradation of urea to ammonium and
at this high pH, precipitation of P, Mg,
Ca and NH4 occurs
Urine is very corrosive (use plastic or
high quality concrete for storage, not
metals)
Ammonia (gas)
Sludge/
precipitates
12
Pathogens in urine



Pathogen types: bacteria, viruses,
parasitic protozoa and helminths
Number of pathogens in urine is very low
One pathogen of concern is Schistosoma
haematobium (causing bilharziasis),
where eggs can be excreted in the urine


In areas where this pathogen is endemic, urine
should not be used near freshwater sources
Hygiene risks associated with diverted
urine are mainly a result of contamination
by faeces
13
Chemical contaminants in urine

Heavy metals (Cu, Zn, Cr, Ni, Pb, Cd):


Urine contains substances that have entered the
metabolism and therefore the levels of heavy metals in
urine are very low
Hormones (endocrine disrupters) and
pharmaceuticals:




A large proportion of the hormones produced by our
bodies and the pharmaceuticals that we consume are
excreted with the urine
Hormones and pharmaceuticals are degraded in
natural environments with a diverse microbial activity
Urine is mixed into the active topsoil and retained for
months (see Course 3 “Reuse of ecosan products in
agriculture”)
It is far better to recycle urine to arable land than to
flush the hormones and pharmaceuticals into recipient
waters
14
Pharmaceutical residues in urine
(continued from previous slide)



You are more likely to find pharmaceutical
residues in groundwater (e.g. in Berlin!)
than in food crops fertilised with ecosan
products
The load of pharmaceutical residues from
animal manure which is freely spread on
land has never concerned anyone
Some research is ongoing in Europe on this aspect, but it
is not an important research question for me; I think it is
rather driven by some unfounded fears of human urine
and some scientists who like to spend money on
expensive analytical chemistry instruments (??)…
15
Course 1 Unit 2
Nutrient excretion by humans is directly linked
to diet
N
Excreta
Diet
N
P
P


Diet is the main factor for amount of nutrients
excreted
Relationship to calculate the amount of nutrients
excreted (in total) from the food intake:
N = 0.13 x total food protein
P = 0.011 x (total food protein + vegetal food protein)

FAO statistics are available for food supply for
different countries (see www.fao.org)
16
Estimated excretion of nutrients per capita
in different countries based on diet
(using data and correlation mentioned on previous slide)
Source: Jönsson et al. (2004), page 6
17
Table 1: Excreted mass of nutrients in urine
per year (typical values for Sweden)
Wet mass
kg/cap/yr
550
L/cap/yr
550
Dry mass
kg/cap/yr
21
Total nitrogen (TN)
kg/cap/yr
4
Total phosphorus (TP)
kg/cap/yr
0.37
Potassium (K)
kg/cap/yr
1
COD
kg/cap/yr
3.6
BOD
kg/cap/yr
1.8
Volume
Values are
countryspecific or
diet-specific
(treat as
guideline
only!)
cap = capita = person
Useful for calculating crop demand or area required
for application.
Source: Jönsson et al. (2004), and Otterpohl (2003) for COD data; BOD
assumed to be half of COD
COD and BOD are measures of organic content; see lecture on
“Fundamentals of conventional biological wastewater treatment”
18
Table 2: Urine data - same data as in
Table 1 but per day
Wet mass
g/cap/d
1507
Volume
L/cap/d
1.5
Dry mass
g/cap/d
57.5
Total nitrogen (TN)
g/cap/d
11.0
Total phosphorus (TP)
g/cap/d
1.0
Potassium (K)
g/cap/d
2.7
COD
g/cap/d
9.9
19
Table 3: Urine data - same data as in Table 1
but given as concentrations
Dry mass
mg/L
38200
Total nitrogen (TN)
mg/L
7300
Total phosphorus (TP)
mg/L
670
Potassium (K)
mg/L
1800
COD
mg/L
6500
BOD
mg/L
3250
-
6 (4.5 – 8.2)
mg/L
5,200 – 10,300
VS (volatile solids) content
%
16-32
Electrical conductivity (EC)
mS/cm
10,600 – 25,100
pH
Concentrations
are useful when
working with
urine of unknown
number of people
Own determinations:
COD
TDS (total dissolved solids)
mg/L
7,800 – 18,000
Results from lab
session on 20 Sept
06 with 18 MSc
students
Urine is “very salty”
20
Some additional information on TDS
and EC



For conventional wastewater, the following
relationship holds (Metcalf and Eddy, page 56)

TDS (mg/L) ~= EC (mS/cm) x (0.55 – 0.70) or

EC (mS/cm) ~= 1.6 x TDS (mg/L)
Urine is not to be used as irrigation water, but as a
fertiliser
Nevertheless, the classification of water in regards to
saltiness is shown below for comparison purposes:
Name of water
Non-saline
Slightly saline
Moderately saline
Highly saline
Very highly saline
Seawater
TDS (mg/L)
< 500
> 500 – 1,500
> 1,500 – 7,000
> 7,000 – 15,000
> 15,000 – 35,000
> 35,000
21
Course 1 Unit 2
Part B: Characteristics of faeces
Most of the data in this part was taken from Jönsson et al.
(2004)
22
Course 1 Unit 2
Faeces quantity and content






Faeces consist mainly of non-matabolised
material combined with some matabolised
material
Undigested nutrients are excreted with the faeces
The lower the digestibility of the diet, the higher
the mass of faeces excreted per day (e.g. Sweden
51 kg/cap/yr (wet mass), China 115 kg/cap/yr,
Kenya 190 kg/cap/yr)
Extremely high number of many different
pathogens
Heavy metal content in faeces is higher than in
urine (heavy metals pass through the intestine
unaffected)
Concentrations of contaminating substance in
faeces are usually lower than in chemical
ferilisers (e.g. cadmium) and farmyard manure
23
What does it look like when faeces
dry out?
(Children have no
problem with faeces…)
24
Air drying of faeces
Fresh faeces
(14 May 06)
2 days old
(16 May 06)
6 weeks old
2 weeks old
(28 June 06)
(1 June 06)
25
Trial # 1
Faeces of a 2.5 year old girl
After two weeks of drying:
appears totally dry,
Dead flies: container was covered but
26
holes in lid, flies could not get out (??)
Data of own faeces drying trials
Start
End
60
15
Trial # 1 (drying time 14 days)
Weight (g)
Water lost (g)
Moisture (calculated) (%)
Dimensions (cm)
45 g
75
4 x 6 x 2.5
3 x 4.5 x 2
60
27
1.17
0.55
Weight
70
20
Moisture (calculated) (%)
71
Volume (mL)
Density (kg/L)
Trial # 2 (drying time 12 days)
27
Course 1 Unit 2
Table 4: Excreted mass of nutrients in
faeces per year (typical values for Sweden)
Wet mass
Volume (at excretion
i.e. before drying)
Dry mass
kg/cap/yr
51
L/cap/yr
51
kg/cap/yr
11
Total nitrogen
kg/cap/yr
0.55
Total phosphorus
kg/cap/yr
0.18
Potassium
kg/cap/yr
0.4
COD
kg/cap/yr
14
BOD
kg/cap/yr
7
Values are
country-specific
or diet-specific
(treat as
guideline only!)
= weight of a
medium-weight
backpack
Useful for calculating crop demand or area required for
application
Source: Jönsson et al. (2004), and Otterpohl (2003) for COD
BOD assumed to be half of COD
28
Table 5: Faeces data - same data as
in Table 4 but per day
Wet mass
g/cap/d
140
Volume (at excretion)
L/cap/d
0.1
Dry mass
g/cap/d
30
Total nitrogen
g/cap/d
1.5
Total phosphorus
g/cap/d
0.5
Potassium
g/cap/d
1.1
COD
g/cap/d
39
this is the mass of
wet faecal matter
excreted per person
per day
this is the mass of
faeces after drying,
per person per day
(= a letter
containing 6 DINA4 pages)
For comparison:
solid waste
production is 200 –
500 g/cap/d in
cities in India
(Source:
Rothenberger et al.,
2006, page 93)
29
Table 6: Faeces data - same data as in Table 4 but
given as concentrations in g/kg wet mass
Dry mass
(at excretion)
g/kg
216
Total nitrogen (TN)
g/kg
11
Total phosphorus
(TP)
g/kg
4
Potassium
g/kg
8
Moisture content
%
78
Dry matter content
(at excretion)
%
22
-
7–9
(?)
pH
Useful when
working with
faeces of
unknown
number of
people
How to measure the organic content (COD and BOD were
developed for liquids)?  Volatile solids content or ignition loss;
TOC
How to measure pH? Dilution with water + shaking, or pH meter
for soil
30
Course 1 Unit 2
Part C: Characteristics of greywater
31
Greywater - definition



Greywater is domestic
wastewater with no or
minimal human excrements
Sources are kitchens, baths,
showers, laundry, washing
Some faecal matter enters if
nappies are washed in the
laundry for example
(households where people use
pit latrines generate
greywater automatically)
32
Greywater quantities generated





Range: 60 – 275 L/cap/d (depending on
country and wealth/attitude of user)
Some new houses in Germany, Norway,
Sweden: less than 100 L/cap/d
Rural Jordan example: 20 L/cap/d (water is
precious, so is used several times)
Note: Basic lifeline water requirement: 25 or 50
L/cap/d (Gleick, 1998)
For comparison: Drinking water requirement:
3-5 L/cap/d
33
Greywater characteristics: organic
matter, nutrients, pollutants


Organic matter (BOD): High concentrations of
easily degradable organic material, e.g. fat, oil
and other organic substances from cooking,
residues from soap, shampoos and tensides from
detergents
Nutrients:



Nitrogen levels low
Phosphorus input from washing and dish-washing
powder (for water softening) – some countries, e.g.
Norway, have banned washing powder containing P
Metals and other toxic pollutants: Metals
originating from water itself, corrosion of pipe
system, dust, cutlery, dyes, shampoos (similar to
conventional wastewater)
Source: Ridderstolpe (2004)
34
Greywater characteristics: pathogens

Proportion of pathogens is low (some
faecal contamination possible)


Greywater has lower pathogen content than
effluent from most advanced wastewater
treatment plants
Amount of faeces in greywater:


Based on measured faecal sterols, the estimate
is that about 0.04 g/cap/d of faeces is mixed
into the greywater
Note: use of indicator bacteria might be
misleading to measure the amount of faeces in
greywater because of growth on organic
matter that is contained in greywater
Source: Ridderstolpe (2004)
35
Course 1 Unit 2
Table 7: Greywater characteristics
L/cap/d
60 275
Total suspended
solids (TSS)
mg/L
365
Total nitrogen
(TN)
mg/L
6
Total phosphorus
(TP)
mg/L
3
Potassium
mg/L
15
COD
mg/L
562
BOD
mg/L
281
-
7-8
Volume
pH
Only to provide an
idea – highly
variable and
dependent on
water use
patterns
Concentrations
are based on
Otterpohl (2003)
mass flows, and
flowrate of 60
L/cap/d
36
Anal cleansing materials used worldwide





Toilet paper: collect in faeces compartment if
material to be composted or incinerated,
otherwise store separately
Water (see next slide)
Vegetable materials: collect in faeces
compartment
Stones or rags: collect separately
Newspaper, card board: treat same as toilet paper
Note: absence of anal cleansing material next to the
toilet can lead to higher incidence of diarrhoea
(Herbst, 2006)
37
Anal washwater





Origin: Practise of many cultures (e.g.
Muslims and Buddhists) to wash anal
area after defecating and after urinating
= Water with a low level of faecal matter
Treatment methods for anal washwater
similar to those for greywater, e.g.
constructed wetlands, soil infiltration
Poorly characterised (few studies)
Should not be mixed with urine; can be
mixed with greywater
38
Table 8: Summary table of mass of
nutrients in urine, faeces and greywater
Parameter
Unit
Urine
Faeces
Total
% in
uri
ne
Wet mass
kg/cap/yr
550
51
601
92%
21900
L/cap/yr
550
51
601
92%
21900
Dry mass
kg/cap/yr
21
11
32
66%
8
Total nitrogen
kg/cap/yr
4
0.55
4.55
88%
0.14
Total phosphorus
kg/cap/yr
0.37
0.18
0.55
67%
0.08
Potassium
kg/cap/yr
1
0.4
1.4
71%
0.32
COD
kg/cap/yr
3.6
14
17.7
20%
12
BOD
kg/cap/yr
1.8
7
8.85
20%
6.2
Volume (before
drying)
For greywater used 60 L/cap/d (quite low consumption)
Source: Jönsson et al. (2004), and Otterpohl (2003) for greywater
data and COD. BOD assumed to be half of COD
Greywa
ter
39
Course 1 Unit 2
Volume of greywater, urine and faeces
greywater
urine
faeces
Can be a good source of
irrigation water if managed
safely
500 L/cap/yr
50 L/cap/yr
Note large variation in volume (related to country and standard
of living) – 66 to 274 L/cap/d
Source: Otterpohl (2003)
40
Mass of nutrients
greywater
6
This is a „complete“
fertiliser
(= containing N, P, K)
urine
faeces
K
P
N
0
Source: Otterpohl (2003)
41
Mass of organic matter (COD)
greywater
20
urine
faeces
Highly beneficial
when applied to
soil as soil
conditioner (see
Course 3 Unit 1
„Reuse of ecosan
products in
agriculture)
0
Source: Otterpohl (2003)
42
For comparison: conventional
domestic wastewater




Wastewater from households connected
to a sewer system, without any
separation of waste streams
Polluted water with high levels of
pathogens
Large volumes that need treatment
Industrial effluent (untreated or pretreated) is mostly mixed together with
domestic wastewater
43
Course 1 Unit 2
Table 9: Overview of characteristics
of “waste” streams
Parameter
(concentrat
ions)
Urine
Faeces
Greywater
Convent.
domestic
ww
Organic
solid
waste
L
N/A
M
M
N/A
H
M
L
M
M
Phosphorus
L
M
M
L
Organic
matter
(COD, BOD)
L
H
M
M
H
H
Pathogens
L
H
L
H
L
Heavy
metals
L
L
M
M
L
TSS
Nitrogen
L Low
M Medium
H High
N/A Not applicable
Toxic substances: heavy metals,
pesticides, chlorinated organic
compounds etc.
44
Table 10: Comparison with
conventional domestic wastewater
Parameter
Urine
Faeces
Greywater
Convent.
domestic wwa
Volume,
L/cap/year
550
51
24,000 –
100,000
95,000
Nitrogen,
kgN/cap/year
4.0
0.55
0.14
5.8
Phosphorus,
kgP/cap/year
0.37
0.18
0.08
0.5
3.6
14
12
55
Organic matter,
kgCOD/cap/year
For US conditions: 260 L/cap/d, 16 gN/cap/d, 1.5 g P/cap/d,
68 gBOD/cap/d, 150 gCOD/cap/d
a
cap = capita = person
Source: Otterpohl (2003)
(for faeces, urine and
greywater data)
45
References







Gleick, P. H. (1998) The human right to water, Water Policy 1, p. 487-503
Herbst, S. (2006) Water, sanitation, hygiene and diarrheal diseases in the Aral Sea
area (Khorezm, Uzbekistan). PhD thesis, University of Bonn (available:
sherbst@ukb.uni-bonn.de)
Jönsson, H, Richert Stinzing, A., Vinneras, B., Salomon, E. (2004) Guidelines on the
Use of Urine and Faeces in Crop Production, Stockholm Environment Institute (get
from www.ecosanres.org)
Otterpohl, R. (2003) New technological development in ecological sanitation.
Proceedings of 2nd international symposium on ecological sanitation, April 2003,
Lübeck, Germany, p. 455 (in IHE library)
Ridderstolpe, P. (2004) Introduction to greywater management, Stockholm
Environment Institute, Sweden (get from www.ecosanres.org)
Rothenberger, S., Zurbrügg, C., Enayetullah, I., and Maqsood Sinha, A. H. M.
(2006) Decentralised composting for cities of low- and middle-income countries - A
users' manual, Eawag/Sandec (Switzerland) and Waste Concern (Bangladesh),
Dübendorf, Switzerland. Available: www.sandec.ch.
Tchobanoglous, G., Burton, F.L., Stensel, H.D. (2003) Wastewater Engineering,
Treatment and Reuse, Metcalf & Eddy, Inc., McGraw-Hill, 4th edition. Good book on
conventional wastewater treatment
46