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M3: Ecosan Systems and Technology Components
M 3-2: Ecosan Technologies to Close the
Water Loop
Source: P. Jenssen
Prof. Dr. Petter Jenssen, Department of Mathematical Sciences and
Technology, Norwegian University of Life Sciences
Dr. Johannes Heeb, International Ecological Engineering Society
& seecon international
Dr. Ken Gnanakan, ACTS Bangalore, India
Katharina Conradin, seecon gmbh
© 2006
seecon
International gmbh
ACTS
Agriculture -Crafts Trades - Studies
Credits
Materials included in this CD-ROM comprise materials from various organisations. The
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Therefore the user should please always give credit in citations to the original
author, source and copyright holder.
We thank all individuals and institutions that have provided information for this CD,
especially the German Agency for Technical Cooperation GTZ, Ecosanres, Ecosan
Norway, the International Water and Sanitation Centre IRC, the Stockholm Environment
Institute SEI, the World Health Organisation WHO, the Hesperian Foundation, the
Swedish International Development Cooperation Agency SIDA, the Department of Water
and Sanitation in Developing Countries SANDEC of the Swiss Federal Institute of
Aquatic Science and Technology, Sanitation by Communities SANIMAS, the Stockholm
International Water Institute SIWI, the Water Supply & Sanitation Collaborative Council
WSSCC, the World Water Assessment Programme of the UNESCO, the Tear Fund,
Wateraid, and all others that have contributed in some way to this curriculum.
We apologize in advance if references are missing or incorrect, and welcome feedback
if errors are detected.
We encourage all feedback on the composition and content of this curriculum. Please
direct it either to [email protected] or [email protected].
K.Conradin
Conradin
K.
seecon
Credits
ecosan Curriculum - Credits
Concept and ecosan expertise:
Compiling of Information:
Layout:
Photo Credits:
Text Credits:
Financial support:
Johannes Heeb, Petter D. Jenssen, Ken
Gnanakan
Katharina Conradin
Katharina Conradin
Mostly Johannes Heeb & Katharina Conradin,
otherwise as per credit.
As per source indication.
Swiss Development Cooperation (SDC)
How to obtain the curriculum material
Free download of PDF tutorials:
www.seecon.ch
www.ecosan.no
www.gtz.de/ecosan
K. Conradin
Order full curriculum CD:
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seecon
Contents
1. Introduction
2. Source
Separated
Collection/Treatment Systems
3. Greywater
• Volumes
• Characteristics
• Source Control
4. Greywater Treatment Options
• Pretreatment
• Drip Irrigation
• Soil Infiltration
• Mound Systems
• Sand Filters
• Constructed Wetland
• Ponds
• Biofilters
P. Jenssen
Wastewater
Contents
4. Greywater Treatment Options (cont.)
• Biofilters
• Conventional biological Treatment
• Chemical Treatment
• Membrane Filtration
5. Reuse
6. Complete System for one household
7. Rainwater Harvesting
8. Conclusion
P. Jenssen
Introduction
This module will explain how the water loop can be closed. As in the module before, source separation is a
prerequisite. Greywater makes up for the largest volume of the generated “wastewater”, but contains the
lowest share of nutrients and pathogens.
Energy
Water
(drinking
water)
Nutrient
Filtration
(membra
ne, sand)
Groundwater
recharge
Greywater
Recreational
water
Biological TreatWatering
garden
ment
Fertilizer
(N, P, K)
Blackwater
Organi
c waste
Aerobic
treatment
(compos
ting)
Anaerobic
treatment
(biogas)
Soil
amendment
Source Separated Wastewater Collection/Treatment Systems
P. Jenssen
Greywater Volumes
Source: Jenssen (8)
 Greywater amounts per person can vary greatly.
 Here: range from 81 -133 l/person/day
Norway
USA
Ecovillage
Norway
Kaja
(Norway)
Blackwater
40
57
0
7
Greywater
120
133
81
112
Total
160
180
81
117
Source: (8)
Source: Vinnerås (2)
Greywater Characteristics
 Greywater volumes can constitutes >90%
 Limited amount of nutrients in greywater, depending on use.
 Phosphate content: depending on whether detergents contain phosphate or
not
Source: (9)
Greywater Characteristics
NUTRIENTS IN GREYWATER
 normally low levels of nutrients
 high concentrations of phosphorous possible (washing and
dish-washing detergents)
 P-free detergents available
 detergents containing phosphorous banned in some
countries for water protection
SUSPENDED SOLIDS AND BIODEGRADABLE ORGANIC
COMPOUNDS
 Composition of greywater varies greatly  reflects lifestyle
of residents
 Greywater often contains high concentrations of easily
degradable organic material (fat, oil and other organic
substances from cooking,
 Separate collection of cooking oil for conversion to biodiesel
 Cooking oil can be added directly to anaerobic digesters 
biogas.
K. Conradin
Greywater Treatment in Luebeck, Germany
Greywater Characteristics
Source: Ridderstople (3)
PATHOGENS
 Generally low proportion of pathogens
 Faecal contamination: showering, washing of clothes and diapers
 Indicator bacteria such as faecal coliforms may multiply in the septic tank
 overestimation of risk possible
Mixed
Mixed wastewater,
wastewater,
treated in
untreated
advanced WWTP
Greywater,
untreated
Greywater, treated
in vertical soil
filter bed
Levels of potential pathogens in different waters. Levels of pathogens in the untreated
waters are based on measured faecal load to greywater in Vibyåsen, Sweden, compared
to the faecal contamination in normal mixed wastewater.
Greywater Characteristics
METALS AND OTHER TOXIC POLLUTANTS
content of metals and organic pollutants in greywater is
generally low
 increase by addition of hazardous substances
Levels of metals:
 approximately same as in mixed wastewater from a
household,
 Origin: water itself, corrosion of the pipe system and
from dust, cutlery, dyes and shampoos etc.
Organic Pollutants:
 Most organic pollutants in the wastewater are found in
the greywater fraction: similar level as mixed wastewater
 Origin: household chemicals, shampoos, perfumes,
preservatives, dyes and cleaners
 Content of metals and organic pollutants in
greywater is heavily affected by human behaviour!
Source: (3)
K. Conradin
Greywater: Source Control
Managing greywater:
 attention to the composition of soaps,
cleansers and other household chemicals.
Main criteria for sizing of greywater system:
 Hydraulic load
 load of easily degradable organic matters and
BOD
 Reducing these parameters gives more cost
efficient and volume- and area-saving
solutions.
Source control includes:
 water-saving equipment (taps, showerheads)
 BOD load: controlled use ofdetergents,
shampoos, soaps, controlled disposal of grease
/ oil.
 Removing of all larger particles:
Source:
Use(3)filtes and screens
Drawing: Per Hardestam, Karlstad
Reklam AB (Source: 3)
Greywater Treatment Options
Here: Focus on natural systems:
 soil infiltration, constructed wetlands, ponds:
• small energy cost
• no chemicals
• require larger areas than the conventional systems
Source: (9)
P. Jenssen
P. Jenssen
K. Conradin
Activated Sludge Treatment
Constructed Wetlands
Greywater Treatment Options
P. Jenssen
Greywater Treatment Options
 lower hygienic risk a environmental
problem than mixed wastewater
 large amounts of easily degradable
organic matter
 Anaerobic conditions  smell
 primary target:
compounds
remove
organic
 secondary treatment target
 reduce levels of pathogens
 reduce
levels
of
organic
pollutants and heavy metals.
 important if used for irrigation
Pretreatment
P. Jenssen
Pretreatment
 to avoid clogging of the subsequent treatment system
– solid-liquid separation
– by gravity, flotation, screens
– septic tanks (most common), settling tanks, ponds, filter systems such as
filter bags.
Source: Adapted from (29)
Small systems: direct use of greywater possible (e.g. mulch bed)
Drip irrigation
P. Jenssen
Drip Irrigation




long, flexible tubing with engineered openings or emitters.
to drip at slow rate into the surrounding soil
vegetation can also adsorb the nutrients
Vegetation helps to clean greywater
 efficient use of water.
Emitter or dripper
Source: Adapted from (29)
Wetted root
zone
Source: FAO
Soil Infiltration
P. Jenssen
Soil Infiltration
 After leaving the septic tank/pre-treatment unit the effluent is distributed to the
soil through open ponds or shallow trenches or infiltration basin.
 Efficient way of treatment
P. Jenssen
Infiltration in open basins/ponds (above) and in buried shallow trenches
(below) the percolation down to the groundwater and subsequent flow towards
a stream is indicated.
Soil Infiltration
 water percolates down through an unsaturated
zone to the groundwater (saturated zone).
 Most of the treatment: unsaturated zone
 Size according to local soil conditions!
 Careful design necessary:
 systems may endanger groundwater quality.
 Suitable sites:
 deep, well-drained, well-developed, mediumtextured soils
 Impermeable soils, shallow rock, shallow water
tables, or very permeable soils such as coarse
sand or gravely soils are considered unsuitable
sites  special design necessary
Trench for Soil
Infiltration
P. Jenssen
Source: Adapted from (29)
Mound Systems
P. Jenssen
Mound Systems
Water level monitoring pipes
Distribution Layer
Sand
P. Jenssen
P. Jenssen
Mound System under
construction

Similar to soil infiltration

technique when existing soil is unsuitable for greywater disposal

layer of soil on top of which the sand mound is built, is still biologically and
chemically active  helps in treatment
Sand Filters
P. Jenssen
Sand Filters
Water level monitoring pipes
Geotextile/insulation
Distribution Layer
Sand
P. Jenssen
Bottom drainage
 well known method for wastewater and greywater purification
 planted sandfilter: often termed vertical flow wetlands,
 Vertical water flow
 Plants: help to avoid clogging, otherwise not much difference between planted
and unplanted systems.
Constructed Wetland
P. P.
Jenssen
Jenssen
Constructed Wetland
 Constructed wetlands: Artificial shallow ponds vegetated with macrophytes
 Often: subsurface flow constructed wetlands
 Porous media: sand, gravel, light weight aggregate, crushed brick etc.
 Fine grained soils: not suited (low hydraulic conductivity)
K. Conradin
Subsurface Flow Constructed
Wetland for greywater treatment.
Ecological Settlement, Luebeck
Flintenbreite, Germany
Constructed Wetland
 Geometry: based on hydraulic calculations
Cold climate:
– pre-treatment is recommended
– deeper systems
Warmer climate: 0.4 – 0.6 m deep systems common
P. Jenssen
P. Jenssen
Constructed Wetland in Ås, Norway, in the summer and in the winter, an area of 2 m2 per Student
is needed (Total 48 Students)
Constructed Wetland
Constructed wetlands:
 generally good reduction of BOD and total nitrogen
 Phosphorus removal: dependent on the phosphorus sorption capacity of the
porous media
 good pathogen removal
 In warm climates: possible without pretreatment biofilter.
P. Jenssen
A subsurface flow wetland with and without integrated biofilter (14)
Ponds
P. P.
Jenssen
Jenssen
Ponds
 Ponds: developed for combined wastewater
 also well suited for greywater treatment
 shallow man-made basins  wastewater flows  retention time of several
days
 effluent is discharged low in BOD
 Nitrogen reduction; 70-90%
 Phosphorus removal 30-45%
 Very robust design
 Limiting factors: size
P. Jenssen
Source: Adapted from (29)
Biofilters
P. P.
Jenssen
Jenssen
Biofilters
Biofilter:
• covered by a compartment which facilitates spraying of the greywater (septic
tank effluent) over the biofilter surface.
• standard depth of 60 cm
• grain size within the range 2 – 10 mm
• Filling material: light weight aggregate, gravel etc.
• biofilm develops: reduction of BOD and pathogens.
• Clogging: has not been observed
• uniform distribution of the liquid is important
0,6m
Jets
LWA
Diameter 2,5 mm
Surface area
> 5000m2/m3
Biofilters
Pump/siphon
Septic tank
Level control &
sampling port
Pretreatment
biofilter
Horizontal subsurface flow wetland
filter
Conventional Biological Treatment
P. Jenssen
Conventional Biological Treatment
Conventional biological treatment
 (enhanced) active sludge treatment
 fixed film systems: trickling filters or rotating biological contactors
 Advantage: compact setting (i.e. in densely populated urban settings)
 Efficient reduction of organic matter
 Bacteria and virus requirement: succeeded other methods such as sand
filter, subsurface flow constructed wetland
 Chemical treatment also possible
Active Sludge Treatment
 aeration concrete: greywater mixed with
recycled sludge containing active
aerobic bacteria
 Sludge decanting in attached tank -->
returned to the aeration tank.
 Pretreatment necessary
 Assumption: low treatment efficiency
due to low nutrient content, but
probably good for heavily loaded
greywater
P. Jenssen
Conventional Biological Treatment
RBC – Rotating Biological Contactors
 Series of closely spaced circular discs
 high surface area for the growth of micro-organisms
 discs submerged about 50% and rotate slowly
 aerobic biological film alternatively exposed to air or wastewater
 Dead biofilm drops  sludge.
Source: Adapted from (29)
rotating disc
inlet
outlet
submerging
biomass
sludge
outlet
Source: (24)
post
treatment
Source: www.wee-engineer.com
Conventional Biological Treatment
Trickling Filter
– concrete column filled with a coarse carrier material (crushed rock, slag,
gravel or plastic modules)
– conventionally 1 to 3 m deep.
– Even distribution of wastewater  bio-film develops
– micro-organisms of the bio-film degrade wastewater pollutants
– Aeration from the bottom
inlet
outlet
Source: (24)
Pre-treatment
Trickling filter
Chemical Treatment
P. P.
Jenssen
Jenssen
Chemical Treatment
Chemical treatment




primarily used to reduce phosphorus, but also organic matter
chemical precipitation also reduces virus and bacteria.
Compact systems (suitable for urban areas)
post treatment in a sandfilter or wetland
Membrane Filtration
P. P.
Jenssen
Jenssen
Membrane Filtration
 semi-permeable membrane + osmotic or lower pressure
 dissolved solids or other constituents captured as the retenate
 semi-permeable membrane + osmotic
or lower pressure
 dissolved solids or other constituents
captured as the retenate
 Retaining of different particle sizes:
• Microfiltration
• Ultrafiltration
• nanofiltration
• reverse osmosis
 Use in greywater treatment: tertiary
removal of dissolved salts, organic
compounds, phosphorus, colloidal and
suspended
solids,
and
human
pathogens,
including
bacteria,
protozoan cysts, and viruses
Source: (26)
Membrane Filtration
P. P.
Jenssen
Jenssen
Reuse
Reuse of all greywater makes water savings exceeing 90% possible when a
water efficient toilet is used (1).
Local discharge into water bodies:
•where sufficient water is available
•If high quality effluent is reached
P. Jenssen
Use in Irrigation:
•closes the water cycle
•Local in garden or big scale
P. Jenssen
Reuse
Inhouse Use:
 Inhouse uses:
 especially where no drinking water
quality is required, (toilet flushing,
clothes washing, or showering)
 Reduces consumption of drinking
water
 Drinking water quality possible with
reversed osmosis
P. Jenssen
Groundwater Recharge
 Where groundwater table has been
lowered
(c) Siegrist et al. 2000 (11)
Complete System for One Household
Biofilter
Blackwater
holding tank
Pump
chamber
Septic tank
Conclusion
Pilot project Hui Sing Garden Greywater treatment (Malaysia)
1st chamber of oil
and grease trap
Pump sump
Final discharge
P. Jenssen
Three water samples from the Hui Sing Garden Greywater Treatment, working
with a constructed wetland.
The picture visualises the treatment efficiency.
END OF MODULE M3-2
Source: P. Jenssen
Prof. Dr. Petter Jenssen, Department of Mathematical Sciences and
Technology, Norwegian University of Life Sciences
Dr. Johannes Heeb, International Ecological Engineering Society
& seecon international
Dr. Ken Gnanakan, ACTS Bangalore, India
Katharina Conradin, seecon gmbh
© 2006
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++ References
Alsén, K.W. & Jenssen, P. D. (2005): Ecological Sanitation – for mankind and nature. Norwegian University of Life Sciences,
As, Norway
(2) Vinnerås, B. (2002): Possibilities for sustainable nutrient recycling by faecal separation combined with urine diversion. Agraria
353 - Doctoral thesis. Swedish University of Agricultural Sciences, Uppsala. - In: Jenssen, P.D., Greatorex, J.M, & Warner, W.
S. (2004): Sustainable Wastewater Management in Urban Areas. = Kapitel 4. Kurs WH33, Konzeption Dezentralisierter
Abwasserreinigung und Stoffstrommanagement. Universität Hannover.
(3) Ridderstolpe, P. (2004): Introduction to Greywater Management. Ecosanres Publication Series, Report 2004-4. Ecosanres, SEI.
(4) Stenström, Th.-A. (1996): Sjukdomsframkallande mikroorganismer i avloppssystem. NV, Socialstyrelsen och
Smittskyddsinstitutet, Rapport 4683 In: Ridderstolpe, P. (2004): Introduction to Greywater Management. Ecosanres Publication
Series, Report 2004-4. Ecosanres, SEI.
(5) SWEP (1982) Specifika föroreningar vid kommunal avloppsrening, Sedisk EPA, PM1964. (In Swedish) - In: Ridderstolpe, P.
(2004): Introduction to Greywater Management. Ecosanres Publication Series, Report 2004-4. Ecosanres, SEI.
(6) Vinnerås, B. (2001): Faecal separation and urine diversion for nutrient management of household biodegradable waste and
waste water. SLU. Report 244. In: Ridderstolpe, P. (2004): Introduction to Greywater Management. Ecosanres Publication
Series, Report 2004-4. Ecosanres, SEI.
(7) Eriksson, Helena (2002): Potential and problems related to reuse of water in households, Env.&Resources DTU, Techn. Univ.
of Denmark, Ph.D Thesis. In: Ridderstolpe, P. (2004): Introduction to Greywater Management. Ecosanres Publication Series,
Report 2004-4. Ecosanres, SEI.
(8) Jenssen, P.D. (2001): ”Design and performance of ecological sanitation systems in Norway”, Paper at The First International
Conference on Ecological Sanitation, Nanning, China. In: Jenssen, P.D., Greatorex, J.M, & Warner, W. S. (2004): Sustainable
Wastewater Management in Urban Areas. = Kapitel 4. Kurs WH33, Konzeption Dezentralisierter Abwasserreinigung und
Stoffstrommanagement. Universität Hannover.
(9) Jenssen, P.D., Greatorex, J.M, & Warner, W. S. (2004): Sustainable Wastewater Management in Urban Areas. = Kapitel 4.
Kurs WH33, Konzeption Dezentralisierter Abwasserreinigung und Stoffstrommanagement. Universität Hannover.
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http://themes.eea.eu.int/Specific_media/water/indicators/bod/index_html (Accessed 28.10.2005)
(11) Siegrist, R.L., E.J. Tyler and P.D. Jenssen (2000): Design and performance of onsite wastewater soil absorption systems.
Report presented at National Research Needs Conference Risk-Based Decision Making for Onsite Wastewater Treatment, St.
Louis, Missouri,19-20 May 2000. USEPA. – In: (29) WHO (2006).
(12) Jenssen, P.D. and R.L. Siegrist (1990): Technology assessment of wastewater treatment by soil infiltration systems. Wat. Sci.
Tech., 22 (3/4) pp. 83-92. In: Jenssen, P.D., Greatorex, J.M, & Warner, W. S. (2004): Sustainable Wastewater Management in
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Hannover.
(1)
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(13) Engelbert, E. & Regan, W.R. (no year): A Lexicon for Alternate On-Site Wastewater Treatment Systems. College of Agricultural
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Department
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and
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Available
at:
www.abe.psu.edu/extension/factsheets/f/F170.pdf Accessed 14.12.2005
(14) Crites, R., and G. Tchobanoglous (1998): Small and decentralized wastewater management systems. McGraw-Hill.
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for Wastewater Treatment in Cold Climate. Accepted in the Journal of Environmental Science and Health. Vol 40 (6-7) 13431353. – In: (29) WHO (2006).
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Engelbert, E. & Regan, W.R. (no year): A Lexicon for Alternate On-Site Wastewater Treatment Systems. College of
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++ Abbreviations
BOD
RBC
SS
STE
WSP
Biochemical Oxygen Demand
Rotating Biological Contactors
Suspended Solids
Septic Tank Effluent
Wastewater Stabilization Ponds
++ Glossary: Greywater
Greywater is only slightly polluted wastewaters from dishwashing, showers, laundry
GREYWATER
machines, water from sinks etc. Greywater makes up for the largest share of wastewater.
Yellow water is either urine diluted with flushwater or pure urine. Urine contains most of the
nutrients we excrete again, but only has a very low, if at all, pathogen count. However, we also
excrete micro-pollutants or endocrine substances through urine.
Brownwater refers to faeces mixed with (flushing) water, but no urine. Most of the
pathogens and a high proportion but rather little of the nutrients are contained here.
Blackwater is urine and faeces mixed with or without domestic wastewater from showers,
washing machines, sinks etc.
BIOCHEMICAL OXYGEN DEMAND
++ Glossary: Biochemical Oxygen Demand (BOD)
Biochemical oxygen demand (BOD) is a measure of how much dissolved oxygen is
being consumed as microbes break down organic matter. A high demand, therefore, can
indicate that levels of dissolved oxygen are falling, with potentially dangerous implications for
the river’s biodiversity.
High biochemical oxygen demand can be caused by:
• high levels of organic pollution, caused usually by poorly treated wastewater
• high nitrate levels, which trigger high plant growth
Both result in higher amounts of organic matter in the river. When this matter decays, the
microbiological activity uses up the oxygen. Biochemical oxygen demand is therefore one of
the main parameters used in the Urban Wastewater Treatment Directive for controlling
discharges. Unsurprisingly, large rivers – where wastewater plants are more likely to be
located – register higher levels of oxygen demand than smaller rivers. Improvements in
wastewater management causes biochemical oxygen demand to fall in all sizes of rivers (10).