1st Block: Decentralized WWT Systems (10:30 – 11:30)
• Definition of decentralized wastewater management
in Germany and in Jordan
• Technologies for decentralized wastewater treatment
2nd Block: Exercise: Decentralized WWT – City Sanitation Planning
(11:30 – 12:30)
3rd Training Block: Organization of Decentralized WWT (13:15 -14:45)
• Operational/business models for decentralized wastewater manage-
ment
• Financing of decentralized wastewater management
• Operation and maintenance of decentralized wastewater treatment
systems
Overview Training Blocks
Decentralized WWTS, T. Reckerzügl, 26.09.2016
Decentralised wastewater treatment systems
1st Block
Thorsten Reckerzügl, BORDA, 26.09.2016
Training financed by GIZ - BMZ
• Definition of decentralized wastewater management
in Germany and in Jordan
• Technologies for decentralized wastewater treatment
1st Training Block:
Decentralized WWT Systems
Decentralized WWTS, T. Reckerzügl, 26.09.2016
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Decentralized WWTS, T. Reckerzügl, 26.09.2016
Size structure of wastewater treatment facility operators
in Germany 2010
(without DWWT)
German Wastewater Ordinance, Annex 1
Decentralized WWTS, T. Reckerzügl, 26.09.2016
Size classificationCOD
(mg/l)
BOD5
(mg/l)
NH4-N
(mg/l)
Ntotal
(mg/l)
Ptotal
(mg/l)
1
< 1.000 pe
150 40 - - -
2
< 5.000 pe
110 25 - - -
3
< 10.000 pe
90 20 10 - -
4
< 100.000 pe
90 20 10 18 2
5
> 100.000 pe
75 15 10 13 1
pe – population equivalents
No clear definition of decentralized WWT exist in Germany (smooth
transition).
Common understanding:
• Decentralized WWT exist where single houses or some neighboring
houses have an individual WWTS (normally no pubic sewer)
• WWTS’s operated by a municipality can be understood as semi-
centralized or centralized system depending on the size.
• WWTS operated by bigger municipalities and by multiple
municipalities can be classified as centralized systems
Decentralised WWT in Germany
Decentralized WWTS, T. Reckerzügl, 26.09.2016
single houses - housing clusters - settlements – municipality - multiple municipalities
decentralized semi-centralized centralized
Small sewage treatment plants for WWT below 50 population equivalent (pe).
• They are commonly applied in individual houses, small villages etc. where connection to large municipal WWTS is not possible for technical, legal or financial reasons
• A whole range of technical solutions from simple, cheap to expensive high-tech solutions exists
• For a long time small sewage treatment plants have not been a standard solution in Germany
• Understanding changed in the last 20 years. It is now more common to consider DWWT where the right framework conditions exist
Def. small sewerage treatment plant
Decentralized WWTS, T. Reckerzügl, 26.09.2016
• For a long time centralised treatment systems (96% coverage) have
been in favour of decentralised solutions (3% coverage).
• Central WWT very sophisticated with high coverage and discharge
standards.
• But Germanys existing sewerage systems has evolved in a period of
150 to 200 years. Investment cost are very high. Replication on a
short term would not be feasible.
• It can be questioned whether a lot of these centralised systems
especially in rural settings are the most cost efficient and
sustainable solution.
• Views have changed meanwhile and decentralised systems are
more accepted. But also in future they will probably play a minor role
since centralised system coverage is already very high.
Conclusion Decentralised WWT in
Germany
Decentralized WWTS, T. Reckerzügl, 26.09.2016
• What is the status of decentralized WWT in Jordan?
• What is the current way forward?
• What is different to the situation on Germany?
Decentralised WWT in Jordan
Decentralsied WWTS, T. Reckerzügl, 26.09.2016
Demo Site Fuhais, Jordan Source: UFZ Leipzig
• Strong National Framework for decentralized treatment of
domestic WW exists
• Decentralized WWT has been identified and is promoted as
sustainable solution for rural and suburban communities
• It has been identified that a strict framework is required to
assure effectiveness and sustainability of the sector
• Decentralized WWT is understood as a complementary
approach to centralized WWT in rural and suburban settings
• Under this conditions Decentralized WWT are seen as more
cost effective, reliable, resource efficient, environmental friendly,
and equal convenient
• Strong emphasize on groundwater protection and freshwater
substitution (reuse & recharge of aquifers)
Jordan National Framework for
decentralized WWT
Decentralsied WWTS, T. Reckerzügl, 26.09.2016
Jordan's National Implementation
Committee (NICE) and framework topics
Decentralsied WWTS, T. Reckerzügl, 26.09.2016
Source: Effective Decentralized Wastewater Policy, MWI & NICE, 2015
• Groundwater Protection: (a) contamination hotspots, (b) WW mgt. in groundwater protection zones
• Technology Selection: 25 technical modules are listed and procedure for multi criteria analysis is proposed
• Urban Planning: (a) enforce structured planning. (b) integrate WW planning
• Participatory Planning: CLUES (Community-Led Urban Environmental Sanitation Planning)
• Economic Feasibility: ALLOWS (Assessment of Local Lowest –Cost wastewater solutions
• Standards & Monitoring: Requirements < 500 pe and between 500 and 5000 are different; Standards vary depending on discharge option, multi barrier approach for irrigation is proposed
• Operation & Maintenance: Technical and Institutional Challenges are identified and Operator models are summarized
NICE framework topics
Decentralsied WWTS, T. Reckerzügl, 26.09.2016
Jordan's three categories for Decentralized
WWT
Decentralsied WWTS, T. Reckerzügl, 26.09.2016
Source: Effective Decentralized Wastewater Policy, MWI & NICE, 2015
Discharge standards for WWTS of 501 to
5000 pe
Decentralsied WWTS, T. Reckerzügl, 26.09.2016
Source: Effective Decentralized Wastewater Policy, MWI & NICE, 2015
Discharge standards for WWTS of 50 to
500 pe
Decentralsied WWTS, T. Reckerzügl, 26.09.2016
Source: Effective Decentralized Wastewater Policy, MWI & NICE, 2015
• Standards equal to 50 to 500 pe discharge standard; except for TSS
standard
• Secondary biological treatment compulsory
Discharge standards for WWTS of 5 to
49 pe
Decentralsied WWTS, T. Reckerzügl, 26.09.2016
• Very comprehensive and innovative framework for
decentralized WWT exist in Jordan
• If this can be put into practice on a large scale, Jordan
has a very good practice example for complementary
approaches of centralized and decentralized WWT on
national level.
• For successful implementation of this framework an
emphasize should be put on sustainable finance,
performance monitoring, operator models and O&M, as
well as user awareness and willingness to contribute.
Conclusion Decentralised WWT in
Jordan
Decentralsied WWTS, T. Reckerzügl, 26.09.2016
Decentralsied WWTS, T. Reckerzügl, 26.09.2016
Comparison between Decentralized
and Centralized Systems
• Centralized
– High capital costs
(especially of sewer lines)
– Energy intensive
(especially where pumping
is required)
– Requires skilled, fulltime
man power
– System failure affects the
entire settlement
– Centralized and therefore
more complex for O&M
– Treatment costs may be
lesser than DEWATS
– Low social control
• Decentralized
– Shallow sewers reduce
overall costs considerably
– Almost no electrical energy
is required
– Less skilled man power
required
– Effects of system failure is
localized
– Sustainability (less risky,
easier reuse)
– Easy to add units/scale up
– Also require proper
management and O&M
– Chance for TAP high20
Whether a centralized, a semi centralized decentralized clustered or a
completely decentralized system is the best choice depends on framework
conditions (mostly similar to points from Jordan's Decentralized WW policy):
Systems choice & framework conditions
Titel der Präsentation/Name des Autors/Datum
Framework conditions Relevant factors
Economy Settlement structure, discharge standards …
Safety Health, environmental safety, resource efficiency, disaster risk (flood, drought) …
Environment/ Natural resources Groundwater, ecosystems, GHG, space availability…
Operation & Maintenance WW composition (variation), HR, finances, accessibility, electricity …
Social Cultural acceptance, experiences, participation …
Legislation Effluent values, monitoring schemes …
… …
Multi criteria analysis for technology choice
Titel der Präsentation/Name des Autors/Datum
Source: Effective Decentralized Wastewater Policy, MWI & NICE, 2015
Summer of key issues for DWWT
Titel der Präsentation/Name des Autors/Datum
Key issues for decentralization in municipal wastewater treatment, Bernal, Restrepo, 2012
SDG will have substantial influence on
WW policy and practice
Titel der Präsentation/Name des Autors/Datum
Other relevant agreements:
• UN Climate Change Conference, COP 21
• Sendai Framework for Disaster Risk Reduction
• Conf. on Financing Developm. Adis Abbeba
• Habitat III, Quito
SDG‘s require a more holistic and complex
approach on water & sanitation
Titel der Präsentation/Name des Autors/Datum
• Definition of decentralized wastewater management
in Germany and in Jordan
• Technologies for decentralized wastewater treatment
1st Training Block:
Decentralized WWT Systems
Titel der Präsentation/Name des Autors/Datum
DEWATS- Combination of Treatment
systems
sedimentation pond biogas digester
Sedimentationseptic tank
Anaerobic
digestion
Aerobic and
facultative
decomposition
Post treatment
aerobic-facultative ponds and aerobic polishing ponds
Other systems such as UASB, sequencing batch reactors, rotating discs, activated sludge reactors, etc. do currently not belong to DEWATS
Wastewater Treatment Systems (DEWATS)
anaerobic filter anaerobic baffled reactor
planted gravel filter
Primary treatment• Anaerobic treatment unit (no oxygen)
• Biogas (methane and carbon dioxide) formed due to the anaerobic digestion of settled organic matter in the biogas settler
• Treatment efficiency 25% to 40% organic matter
Raw sewagepartially treated
wastewater
Sludge Sludge
Scum
Biogas
Septic Tank
• Kind of treatment: sedimentation, sludge stabilisation,
CODrem 20 - 50%
• Type of wastewater: domestic and others with settleable
solids
• Advantages: simple, durable, underground, area
required: 0,5m²/m³ wwpd
• Disadvantages: only pre-treatment,
effluent not odourless
Characteristics of Septic Tanks
Imhoff-Tank
►Sedimentation
► Protection against upflow of sludge particles
► Fermentation of bottom sludge
cross section
longitudinal section
Inflow
Outflow
Floatation
outside
funnel
Sedimen-
tation
inside
funnel
Imhoff Tank
Cross Section Longitudinal Section
liquid
flow tank scum
sludge
1
2
3
Characteristics of Imhoff-Tanks
• Kind of Treatment: Sedimentation, sludge
stabilisation, CODrem 20 - 50%
• Type of wastewater: Domestic and others with
settleable solids
• Advantages: Simple, durable, underground,
odourless effluent, area required: 0,5m²/m³ wwpd
• Disadvantages: Less simple than septic tank,
needs very regular desludging
Secondary treatment• Anaerobic treatment unit (no oxygen)
• Activated sludge formation at the bottom of each chamber
• Treatment efficiency 75% - 85% organic matter
part. treated
wastewater
from settler
Biogas
Activated
Sludge
Gas Gas
partially treated
wastewater
Anaerobic Baffled Reactor
Characteristics of Anaerobic Baffled
Reactors
• Kind of Treatment: Anaerobic degradation of suspended
and dissolved solids, CODrem 60 - 90%
• Type of wastewater: Pre-settled domestic & strong
industrial wastewater of narrow COD/BOD ratio
• Advantages: Simple, reliable and durable, high
efficiency, underground, area required: 1 m²/m³ wwpd
• Disadvantages: Larger space during construction, less
efficient with weak wastewater, longer time for
maturation
Principle of the Anaerobic Filter
• Sedimentation/floatation of solids
• Anaerobic digestion of suspended and dissolved matter inside the filter
• Anaerobic digestion (fermentation) of bottom sludge
gas manhole
inflow
outflow
sedimentation tank filter units
sludge
scum
• kind of treatment: anaerobic degradation of suspended • and dissolved solids, CODrem 65 - 85%
• Type of wastewater: pre-settled domestic and industrial • wastewater of narrow COD/BOD ratio
• Advantages: simple and durable if well constructed, high treatment efficiency, underground, area required: 1 m²/m³ wwpd
• Disadvantages: costly in construction because of filter material, clogging possible, effluent smells slightly
Characteristics of Anaerobic Filters
Principle of the Vertical Filter
plants keep filter surface porous
flooded with wastewater
fine sand
coarse sand
coarse gravel
ventilated channel
O2O2
O2
O2
O2
O2O2
O2
O2
waste
water
• submerged for equal distribution of wastewater through flush charging
• oxygen follows the percolating wastewater by vacuum
• oxygen is available for decomposition during resting time
• plants keep filter
• surface porous
• Continuous oxygen supply to the upper layers only
• Anaerob-facultative conditions in the lower layers
• Roots of plants provide favourable environment for bacteria diversity
internal water level
inflow manhole
upper sand layer central outlet shaft
final outlet
cross
distribution
trench filled
with rocks
main filter body filled with coars gravel cross
collection
trench filled
with rocks
perforated pipe
connected to
swivel pipe for
adjustable height
O2O2O2O2
Principle of the Horizontal Filter
• Horizontal filter and polishing pond for a bungalow
• (Auroville, Tamil Nadu, India, CSR)
DEWATS
Treatment Systems.
Characteristics of Horizontal
Gravel Filters
• Kind of treatment: Aerobic-facultative-anaerobicdegradation of dissolved and fine suspendedsolids,CODrem 60 - 95%
• Type of wastewater: Suitable for pre-treated domesticand weak industrial wastewater
• Advantages: High treatment efficiency when properlydesigned and constructed, pleasantlandscaping possible, no wastewater above ground, no nuisance of odour
• Disadvantages: Large permanent space, costly, difficult construction, experienced supervisionrequired in the beginning, area required: 30m²/m³ wwpd
Characteristics of Anaerobic Ponds
► Kind of treatment: sedimentation, anaerobic degradation,
sludge stabilisation, CODrem 50 - 70%
► Adequacy: strong and medium industrial wastewater
► Maintenance: regular removal of scum and aquatic plants,
every 2 to 5 years: removal of sludge
► Advantages: simple in construction, flexible degree of
treatment, little maintenance, no electrical energy and
chemicals required
► Disadvantages: occupies open land, can be stinky, difficult
mosquito control, area required: 4m²/m³ wwpd
Caracteristic of Aerobic Ponds
► Kind of treatment: aerobic-facultative degradation, pathogen
reduction, CODrem 60 - 95%
► Adequacy: weak, pre-treated domestic and industrial wastewater
► Maintenance: regular removal of scum and aquatic plants, every 2
to 5 years: removal of sludge
► Advantages: simple in construction, reliable if properly designed,
high pathogen removal rate, fish farming possible, no electrical
energy and chemicals required
► Disadvantages: large permanent space requirement, mosquitoes
and odour can become a nuisance if undersized, algae can
increase effluent BOD, area required: 25m²/m³ wwpd
Byproducts of the process & re-use
Irrigation
Gardening
Flushing
Cooking
Heating
Lighting
Treated Water Biogas Sludge
Horticulture
Sludge Drying
Closing the loop
Laundry
Toilet
Kitchen
Sources of WastewaterUse of treated
WW for Gardening &
Flushing Use of Sludge for Gardening
Use of residues for Biogas
DEWATS- Combination of Treatment
systems
sedimentation pond biogas digester
Sedimentationseptic tank
Anaerobic
digestion
Aerobic and
facultative
decomposition
Post treatment
aerobic-facultative ponds and aerobic polishing ponds
Other systems such as UASB, sequencing batch reactors, rotating discs, activated sludge reactors, etc. do currently not belong to DEWATS
Wastewater Treatment Systems (DEWATS)
anaerobic filter anaerobic baffled reactor
planted gravel filter
Titel der Präsentation/Name des Autors/Datum
So
urc
e: E
ffe
ctive D
ece
ntr
aliz
ed
Wa
ste
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ter
Po
licy,
MW
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01
5
• Decentralized Wastewater Treatment Systems (DEWATS) and Sanitation in Developing Countries – A Practical Guide
• CLUES Guideline (https://www.eawag.ch/fileadmin/ Domain1/Abteilungen/sandec/schwerpunkte/sesp/CLUES/CLUES_Guidelines.pdf)
• Compendium of Sanitation Systems and Technologies, EAWAG/ Sandec; http://www.iwa-network.org/wp-content/uploads/2016/06/Compendium-Sanitation-Systems-and-Technologies.pdf
• SWWM online-compendium; http://www.sswm.info/
• MOOC EAWAG/ SANDEC: e.g. Planning & Design of Sanitation Systems and Technologies, https://www.youtube.com/watch?v=bNSQz3zInwM
Further Information on
Decentralised WWT
Decentralsied WWTS, T. Reckerzügl, 26.09.2016
water, sanitation, energy: essential public services for all.
Thorsten Reckerzügl
Regional Advisor West & Central Asia
E-Mail [email protected]
Phone +49.421.40 89 52 – 29
Thank you very much!
Decentralized WWTS, T. Reckerzügl, 26.09.2016