Transcript Course2Unit1A_C - Unesco-IHE

Course 2 Unit 1
Part A B C D
Treatment aspects for urine, faeces and
greywater
Teacher
Mariska Ronteltap
1
[email protected]
Course 2 Unit 1
Content:
Part A – Basics and overview
Part B – General treatment aspects for urine
Part C – General treatment aspects for faeces
Part D – General treatment aspects for greywater (in separate file)
Course 2 Unit 1
Course 2 Unit 1
Part A: Basics and overview
Where does Course 2 fit in the overall sanitation
system scheme?
Course 2, Units 1-7
E
Where does C2 Unit 1 fit in the overall sanitation
system scheme?
E
Another way of looking at it: Course 2 in the
scheme of nutrient recycling
Focus of Course 2
Human
excreta
Consumption followed
by urination / defecation
Sanitisation
steps
Sanitised urine and faeces
(“ecosan products”)
Crop &
Harvest
Apply as fertiliser
and soil conditioner
Aims of treatment of urine, faeces and greywater
 The main aims of treatment are:
1. Sanitisation (= pathogen kill)  protect public health
2. Groundwater protection  indirectly, this also protects
public health (see Course 1 Unit 3 Part A)
3. For ecosan: enable safe reuse

There can also be secondary aims, which may vary, but
they need to get lower priority (see later in this
presentation).
Course 2 Unit 1
What is a pathogen and what is enteric?
 Pathogen = disease-causing micro-organism
(a biological agent that causes disease or illness to its host)
 Enteric or enteral = pertaining to the intestine
– Intestine = the portion of the alimentary canal extending from
the stomach to the anus
Source: www.wikipedia.org
Definition of terms:
disinfection, sanitisation, sterilisation
Term
Degree of pathogen
destruction
Examples of technical
processes
Disinfection
Partial
Tertiary treatment step in
conventional wastewater
treatment
Sanitisation /
hygenisation
Most or all
Primary or secondary treatment
step for urine, faeces or
greywater
Sterilisation
All
Medical routines; not practical
for excreta management
Need to weigh up remaining risk versus cost of treatment
 The allowable risk depends on reuse application and other barriers
that are in place ( we will talk about the Multiple Barrier Approach in
C3U1)
Course 2 Unit 1
There are four groups of pathogens
potentially present in human excreta
Pathogen
group
Pathogen
Disease caused by pathogen
Bacteria
Aeromonas spp.
Escherichia coli
Salmonella typhi
Salmonella spp.
Shigella. spp.
Vibrio cholerae
Enteritis *
Enteritis
Typhoid
Salmonellosis
Shigellosis
Cholera
Viruses
Hepatitis A virus
Rotavirus
Hepatitis
Enteritis
Parasitic
protozoa
Giardia intestinalis
Cryoptosporidium parvum
Giardiasis
Cryptosporidiosis
Helminths
Ascaris lumbricoides
(roundworm)
Taenia solium (tapeworm)
Ancylostoma duedenale
(hookworm)
Schistosoma spp.
Ascariasis
Source: WHO
(2006), p.33
Taeniasis
Itch, rash, cough, anaemia, protein
deficiency
Schistosomiasis, bilharzia
Factors that influence pathogen die-off



After excretion, the concentration of enteric
pathogens usually declines with time by
death or loss of infectivity
Bacteria may multiply under favourable
environmental conditions
Protozoa and viruses are unable to grow in
the environment outside the host, hence
their numbers will always decrease
 Time and prevailing conditions are the
overall features affecting survival of
pathogens in the environment
Giardia lamblia
One of the more common
parasitic organisms is Giardia
lamblia. This parasite grows in
the upper GI tract and
produces greasy, smelly
diarrhea.
(microbiology.mtsinai.on.ca/pi
Source: Schönning and
g/helminth11.shtml )
Stenström (2004)
Disinfection methods used in water and
wastewater treatment (for reference)
 Chemical agents
–
–
–
–
–
Chlorine and its compounds
Ozone
Various acids (to achieve pH < 3)
Various alkalines (to achieve pH > 11)
Urea
 Physical agents
–
–
–
–
Time*
Heat*
Dryness*
Light
• Sunlight*
• UV lamps
 All of these could be used as part of ecosan concepts, but the ones
highlighted with * are most commonly used (low-cost applications)
Course 2 Unit 1
Course 2 Unit 1
Part B: General treatment aspects for
urine
Note: For characteristics of urine see
Course 1 Unit 2
Urine storage tank, Hengelo,
the Netherlands (July 2007)
Primary and secondary aims for urine treatment
Primary aim:
1. To kill viruses and pathogens
2. To enable safe reuse
(for urine, that means:
no (ground)water pollution;
no danger for the workers; rather
no ammonia evaporation)
Secondary aims:
1. To obtain monetary value from
(components in) urine
in the form of fertiliser, energy,
an others
2. To reduce the load to the
WWTP or receiving water
bodies
In several countries people know very well the
value of urine as a fertiliser. Here we see an
example from India where you get a rupee if
you use their toilet..
The easiest and most common treatment
method for sanitisation of urine is by storage
Pathogen kill by storage of urine is due to:
1. Rapid conversion of urea to ammonia
which increases the pH
2. Increased ammonia concentration
together with the increase in pH have a
sanitising effect
3. Time by itself also kills many pathogens
(being away from a host)
Urine storage tank in basement of
apartment block Gebers in Stockholm,
Sweden (Aug. 2007) – with Anselme
Vodounhessi from CREPA, Burkina Faso
Which pathogens are present in urine?
By far the most pathogens in excreta are in the faecal part. In
urine also some were found:
 Schistosoma haematobium, Salmonella typhi, Salmonella paratyphi,
Leptospira interrogans
 Mycobacterium tuberculosis in urine of humans with renal TB
infection
Other pathogens come from faecal contamination – you can
imagine that some of the faeces ends up in the urine
opening: an average of 9.1 mg faeces/L urine was
measured.
 Vinnerås et al., 2008)
Dilution, temperature or pH?
Storage was always thought to be the best treatment. Bjorn
Vinneras et al (2008) looked into other aspects: dilution rate,
temperature and ammonia concentration. They found that
dilution rate is an important factor regarding the reduction in
pathogenic microorganisms in urine:
At all temperatures: lower than 40 mM NH3 inactivation is slow
(NH3 is regulated by total ammonia concentration,
temperature and pH)
- At temperatures < 20°C: restrictions on the use of urine as
a fertiliser on food crops, as ascaris and viruses are reduced
at a very slow rate.
Dilution, temperature or pH?
At 34 ° C fast inactivation of all organisms was observed,
even at 1:3 dilution of urine.
If all ammonia is out, pathogens survive even at higher
temperature!
How long should urine be stored for?
 Centralised systems (urine from many households is mixed
together)
– Recommended storage time is 1-6 months, depending on
temperature and type of crop to be fertilised (see next slide)
– 1 month storage sufficient if T > 20°C and crop is not to be
eaten raw
 Individual one-family system:
– No storage is needed (see also slide after next)
 Note: Urine in the storage tank should not be diluted (concentrated
urine provides a harsher environment for micoorganisms and
hence more effective pathogen kill)
Source: WHO (2006)
Course 2 Unit 1
Recommended guidelines for storage times of
urine mixture
Storage
temperature
Storage time
Possible pathogens in
the urine mixture after
storage
Recommended crops
4°C
> 1 month
Viruses, protozoa
Food and fodder crops that are to
be processed
4°C
> 6 months
Viruses
Food crops that are to be
processed, fodder crops
20°C
> 1 month
Viruses
Food crops that are to be
processed, fodder crops
20°C
> 6 month
Probably none
All crops
Urine mixture: urine which may be mixed with water
Source: Schönning and Stenström (2004) and also
adopted in WHO (2006)
New insights: shorter is fine, if undiluted
and warm
For safe unrestricted reuse of urine, it needs to contain
40 mM or more of uncharged ammonia and be stored
above 20 °C. Then the required storage time
according to WHO guidelines could probably be
shortened (Vinnerås et al., 2008)
21
Is urine sanitisation (by storage) really necessary?
YES, because:
 In a healthy individual, urine in
the bladder is sterile, but
different types of bacteria are
picked up in the urinary tract
 Persons infected with
Schistosoma haematobium
excrete the eggs in urine. The
eggs hatch in the freshwater
environment
 Urine could be contaminated
by faeces if users of UD toilet
are not careful
NO, because:
 Urine contains few diseasecausing organisms
 Urine-oral transmission is
much less likely than faecal
–oral transmission of disease
(WHO, 2006, page 34)
 A multiple barrier approach is
used for reuse of urine (see
also Course 3 Unit 1)
You need to weigh this up on a case by case basis
Source: Schönning and Stenström (2004)
Advantages and disadvantages of storing urine
compared to using it “fresh”
Advantages:
 Simple and effective method for pathogen kill
 Allows waiting for the right time for application to soils in
relationship to planting and harvesting times (See Course 3
“Safe reuse of ecosan products in agriculture”)
Disadvantages:
 Cost of urine storage tank
 Some loss of nitrogen possible during storage (via ammonia
gas)
More information on practical aspects of urine storage is provided in
Course 2 Unit 3 “Storage and transport logistics”
Possible secondary treatment aims and treatment
methods specific for urine (most of them require
“high-tech” treatment options)
•
•
•
Nitrogen recovery (to allow reuse of N in fertiliser)
Nitrogen removal (to reduce nitrogen load to WWTP)
– Biological process: nitrification and denitrification (convert
ammonia to nitrate and then nitrogen gas) or ANAMMOX process
Removal of micro-pollutants and pharmaceutical residues (to make
urine even safer for reuse in agriculture)
– Electrodialysis
– Nanofiltration
– Ozonation and advanced oxidation
Some of these treatment aims play a role in projects in the
Netherlands and Switzerland (see next couple of slides).
Struvite precipitation also takes place in the developing
world, see the project in Nepal (STUN)
Course 2 Unit 1
Example for high-tech treatment method for
urine: vacuum evaporation
 Advantages:
– Allows volume reduction
 Technical problems:
– High energy demand
– Pre-treatment necessary
to lower pH
– Distillate is high in
ammonia
Vacuum evaporation (lab
scale). Photo: Felix Tettenborn
Source: Ecosanres Discussion Forum, Felix Tettenborn, TU HamburgHarburg (29 May 2006 and an update with further information on 22
February 2007)
Course 2 Unit 1
Example for high-tech treatment method for
urine: struvite precipitation
 By adding magnesium, a crystal
precipitates with phosphate called
struvite: MgNH4PO4
 Advantages:
- Struvite is a slow-release
fertilizer. By separating this from
the liquid phase, we have a strong
reduction of volume
- Easy and rapid
- The effluent can be used for
irrigation
For a pilot scale example, check the
link here to the right
Nepal: Pee proudly for
healthy vegetables
(this is a link to the internet)
Course 2 Unit 1
Example for High-tech treatment method for
nitrogen removal from urine
 Nitrification (biologial process) to
convert ammonia to nitrate
 Pilot plant at Hengelo
(project of the
Waterboard Regge en Dinkel in Almelo, the
Netherlands)
Pilot-scale nitrification reactor with
attached growth (July 2007): treating 1
m3 of urine per week
Continued from previous slide
Left bottle: Stored urine before treatment
Right bottle: Urine after treatment
(ammonia converted to nitrate)
Here you see Elisabeth doing the smell
test: it does not smell (ammonia is gone)
Some participants on this field trip did
not dare to do the smell test...
Further reading about high-tech treatment
methods of urine
 Maurer, M., Pronk, W. Larsen, T.A. (2006) Review: Treatment
processes for source-separated urine, Water Research, 40, p.
3151 – 3166 *
 Pronk, W., Zuleeg, S., Lienert, J., Escher, B., Koller, M., Berner,
A., Koch, G., Boller, M. (2007) Pilot experiments with
electrodialysis and ozonation for the production of a fertilizer
from urine, Advanced Sanitation Conference, Aachen,
Germany, 12 – 13 March *
* Also provided on the I-LE under Extra Materials for this course unit
What are alternative options if no agricultural
reuse of urine is possible?
 Infiltrate into ground (e.g. in Durban rural areas, South Africa) –
check potential for nitrate pollution of groundwater
 Add to composting operations (but loss of ammonia)
 Discharge to sewer and wastewater treatment plant
 If amounts are small and climate is suitable: evaporation
Other more “exotic” uses of urine (other than
use as a fertiliser)

As an insecticide
– See Ecosanres Discussion Forum on 11 June 2007 and earlier
postings; note: when plants have a good nutritional balance, they
resist the attak of pathogens and insects – so reported insecticidal
properties of urine may be a secondary effect (?) – more research is
needed

As a medicine
– Some people strongly believe that drinking urine is good for you!
(e.g. http://www.rotten.com/library/medicine/bodilyfunctions/pissing/drinking-pee/)
– As a disinfectant for wounds (smearing wounds and sores)
– To improve your skin
To produce the human fertility hormone hCG
– Can be extracted from urine of pregnant women and then given to
other women for fertility treatment (see my entry on Ecosanres
Discussion Forum on 3 July 2007)
To use for odour control in sewers (after conversion of ammonia to
nitrate)
– This is being tested by the Waterboard Regge en Dinkel in the
Netherlands (in 2007)


Can you give examples of such “exotic” uses for urine?
Course 2 Unit 1
Course 2 Unit 1
Part C: General treatment aspects for
faeces
Note: For characteristics of faeces, see Course 1 Unit 2
Reminder: main treatment aims for faeces
 Sanitisation (= pathogen kill)  protect public health !
 Enable safe reuse (desirable)
Possible secondary treatment aims specific
for faeces
– Volume reduction (remember faeces are about 80% water at
excretion)
– Odour reduction
– Prevention of groundwater pollution by pathogens in fresh
faeces
– Change appearance, so that it no longer looks like faeces
Sanitising faeces: What kills pathogens in
faeces?
Factor
Mechanism
Technology
examples
Storage time *
A longer storage time kills pathogens
Storage *
Temperature
At temperatures of 55-65°C all types of pathogens (except
bacterial spores) die within hours
Composting
(thermophilic); solar
drying toilets
pH
Highly acidic or alkaline conditions will have an inactivating
effect (adding sawdust, ash or lime increases pH)
Alkali treatment
Ammonia
Pathogens in excreta can be inactivated by the addition of
ammonia
Addition of urease
Dryness /
moisture *
Pathogens die off with lack of moisture (addition of drying
agents, e.g. sand, ash)
Desiccation *
Solar radiation
/ UV light
Survival time of pathogens on crop and soil surface is
reduced by UV radiation
Spreading faecal
sludge in the open
* Applied in UDD toilets (UDD = urine-diversion
dehydration)
Source: Winblad and SimpsonHebert (2004)
Course 2 Unit 1
Adding ash to faeces in UDD
toilets: a common “pre-treatment”
step
 Promotes pathogen die-off through elevated pH of the ash
 Reduces smell
 Covers material
– reduces fly breeding
– improves aesthetical conditions
 Decreases moisture content
How much should be added?
– One cup, or 200 – 500 mL ash; enough to cover faeces (WHO
(2006), p. 69)
What else can be used?
– Lime, sand, soil, saw dust, leaves, compost or nothing
– Note: we are not adding anything to the UDD toilet in the
UNESCO-IHE building because it has a fan (see presentation
in Course 1 Unit 3 Assigned Reading)
2 levels of excreta treatment: primary, secondary
Urine;
faeces
primary
treatment
Sanitised urine;
partially sanitised
faeces
PRIMARY TREATMENT

Treatment integrated into individual toilet

Usually sufficient when households can
reuse their own products
Examples:

Storage and drying in the toilet (double-pit
collection is preferred)

Alkaline treatment (addition of ash and lime;
pH >9 during >6 months)

Composting (not recommended except for
dedicated users)
secondary
treatment
Sanitised urine;
sanitised faeces
SECONDARY TREATMENT

Treatment at community / block
level (outside of household)

Necessary if project is at
community level, particularly for
faeces
Examples:

See next slide
Secondary treatment options for faeces
Type of process
Description
Is it common?
Storage
One year under tropical conditions (28-30 ºC)
Very common
Composting
Thermophilic preferred (> 50 ºC for > 1 week)
Common
Anaerobic digestion
Works well in conjunction with animal manure
(household biogas plants), but incomplete
pathogen removal
Common in some
countries (e.g. China,
India, Nepal)
Chemical treatment
Mixing with urea to achieve pH increase
Experimental stage
Incineration
Burning, reuse of ash; complete pathogen kill
Not common
based on Schönning and Stenström (2004)
Recommendations for storage treatment of dry
excreta and faecal sludge before use at the
household and municipal levels
Treatment
Criteria
Comment
Storage; ambient
temperature 2-20ºC
1.5 – 2 years *
Will eliminate bacterial pathogens; re-growth
of E. coli and Salmonella may need to be
considered if rewetted; will reduce viruses
and parasitic protozoa to below risk levels.
Some soil-borne ova may persist in low
numbers.
Storage; ambient
temperature > 20-35ºC
> 1 year
Substantial to total inactivation of viruses,
bacteria and protozoa; inactivation of
schistosome eggs (< 1 month); inactivation
of nematode (roundworm) eggs; more or
less complete inactivation of Ascaris eggs
Alkaline treatment
pH > 9 during > 6
months
If temperature > 35ºC and moisture < 25%,
lower pH and/or wetter material will prolong
the time for absolute elimination
* Note: no addition of new material: this storage period is taken from the last addition of
fresh faeces to the pile
Source: WHO (2006), p. 69
Course 2 Unit 1
Example for primary treatment of faeces:
Standardised UDD toilet in Durban, South Africa




Provides primary
treatment for faeces
(sanitisation)
Particularly suitable
for rural areas
Households reuse
their own sanitised
faecal matter (no
secondary treatment
necessary in this
case)
Urine is not reused in
the Durban example
but infiltrated into
the soil
Vault
closed at
bottom
Durban (South Africa) rural areas:
Council is planning to install 47,000 double-vault UDD
toilets by 2007 (17,500 already installed in 2003-2006)
Two openings at the
back for removal of
dried faeces from
faeces vaults (each
vault has its own vent
pipe)
– Photos by Elisabeth,May 2005
Cost information on these toilets:
See Course 4 Unit 1 “Financial, institutional,
social and policy aspects”
Continued from previous slide
Plastic UD pedestal and bucket
with sand
Waterless urinal (plastic)
Closed second vault
Further information on the Durban (=eThekwini)
case
 With the incorporation of vast rural areas into the
eThekwini Municipal area, the Water Services unit
identified the need for a training programme for rural
communities. A facilitator training manual has been
developed for a basic level water and sanitation
education programme. The facilitators are chosen from
a particular community and trained by Institutional and
Social Development (ISD) Consultants.
• Important
Traininglocal
material
is available here:
experts:
http://www.durban.gov.za/eThekwini/Services/water_an
Teddy Gounden
Chris Buckley
d_sanitation/education/sewage_education/rural_water/i
Manager
Community Education and
Pollution Research Group
Councillor Liaison
University of KwaZulu-Natal
ndex_html
eThekwini Municipality
4041 Durban, South Africa
Durban, South Africa
E-mail: [email protected]
E-mail: [email protected]
Course 2 Unit 1
Further publications on the Durban UDD toilet
experience
 Guness, M., Pillay, S., Rodda, N., Smith, M., Buckley, C., and
Macleod, N. (2006) Quality of leachate from buried urine
diversion toilet waste. Water Institute of South Africa
Conference, Durban, South Africa, 22-25 May 2006. Available:
www.ewisa.co.za/frame.aspx?url=~/literature/default.aspx&cat=
8
 Moilwa, N., and Wilkinson, M. (2006) The effect of hygiene
communication on emptying of urine diversion toilets. 32nd
WEDC International Conference, Colombo, Sri Lanka,
November 2006. Available via: http://wedc.lboro.ac.uk/index.php
What are alternative options if no agricultural
reuse of faeces is possible?
 Take to wastewater treatment plant
 Take to sanitary landfill
 Dump into shallow holes and plant trees (check seepage to
groundwater)
 Use in aquaculture
 Can be burned and disposed with household rubbish
Can you think of other options?
Which of these options would be the best for your first ecosan project..??
Course 2 Unit 1
References used in this presentation
 Schönning, C. and Stenström, T. A. (2004) Guidelines for the safe
use of urine and faeces in ecological sanitation systems. Report
2004-1, Ecosanres, Stockholm, www.ecosanres.org *
 WHO (2006) Guidelines for the safe use of wastewater, excreta and
greywater: Volume 4, Excreta and greywater use in agriculture.
World Health Organisation, Geneva, available:
http://www.who.int/water_sanitation_health/wastewater/gsuww/en/ *
 WHO (2004) Guidelines for drinking water quality –
recommendations. Geneva, World Health Organisation
 Winblad and Simpson-Hébert (2004) Ecological Sanitation – revised
and enlarged edition, SEI, Stockholm, Sweden, from
www.ecosanres.org *
• Björn Vinnerås, Annika Nordin, Charles Niwagaba, Karin Nyberg:
Inactivation of bacteria and viruses in human urine depending on
temperature and dilution rate. Water Reserch 42 (2008) 4067 –
4074.