GJINALI and NIKLAS 2009 Wastewater treatment using constructed wetlands Tirana - draft_0

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GJINALI and NIKLAS 2009 Wastewater treatment using constructed wetlands Tirana - draft_0
Case study of sustainable sanitation projects
Wastewater treatment using constructed wetlands
Tirana, Albania - draft
Combined gravity sewer system
(pour-flush toilets, showers,
kitchen sinks)
Wastewater treatment in constructed
wetlands, sludge treatment in
composting beds
Treated wastewater
used for irrigation
Fig. 2: Applied sanitation components in this project
Fig. 1: Project location
2 Objective and motivation of the project
1 General data:
Type of project:
Full scale, urban research and demonstration project
Project period:
Start of planning: September 2008
Start of construction: September 2009
End of construction: December 2009
Start of operation: January 2010
Monitoring ongoing
Project scale:
Design value: 16.8 m /d domestic wastewater flow rate for
471 inhabitants or 220 population equivalent.
Design value and actual utilisation is identical.
Capital cost: EUR 60,000
As part of Albania’s convergence with the EU, environmental
standards in the water supply and sewerage sector are
gaining in importance, particularly the EU Water Framework
Directive. This calls for considerable legal and sector policy
reforms accompanied with appropriate technologies.
Within the BMZ (German Federal Ministry for Economic
Cooperation and Development) financed project on “Advice
on the Decentralisation of the Water and Sewerage Sector in
Albania” the GIZ and MPWT (Albanian Ministry of Public
Works and Transport) initiated the pilot constructed wetland to
raise awareness for low cost, appropriate and decentralised
sanitation technologies in line with EU standards. It is aimed
to be used as a model treatment plant by the main actors of
the sector for training, demonstration, research and replication
in peri-urban and rural areas of Albania.
Address of project location:
SOS Children’s Village Albania, Rr. “Hermann Gmeiner”,
Sauk, Tirana, Albania
Planning institutions:
ÖKOTEC GmbH, Belzig, Germany
Environmental Engineering Department at the Faculty of
Civil Engineering at Polytechnic University of Tirana,
Tirana, Albania
Executing institution:
Gener2 Construction Company, Tirana, Albania
Supporting agency:
Deutsche Gesellschaft für Internationale Zusammenarbeit
(GIZ) GmbH/ German International Cooperation,
Eschborn, Germany
General Directorate of Water Supply and Sewerage
(GDWSS), Tirana, Albania
Financed by:
German Federal Ministry for Economic Cooperation and
Development (BMZ) via GIZ Albania: 80%
Albanian Ministry of Public Works and Transport (MPWT):
Last update: 31 March 2011
Fig. 3: Elementary School of the SOS Children’s Village in
Sauk, a suburb of Tirana (Sep. 2010) Who took the picture?
Being the first system of its kind in Albania, the construction
provides for an applied science perspective on this “low rate”
wastewater treatment process which uses a combination of
both vertical and horizontal subsurface flow constructed
wetlands (also called reed bed filters). The application of this
technology demonstrates an appropriate way to establish
sanitation systems which protect natural resources and
promote sustainability.
Case study of sustainable sanitation projects
Wastewater treatment using constructed wetlands
Tirana, Albania - draft
3 Location and conditions
Despite promising reform processes in the water and sewage
sector, the country is still confronted with major challenges in
providing sufficient access to drinking water and sanitation,
particularly in providing wastewater treatment. In its National
Strategy for Development and Integration the Albanian
government aims to reach 98% water access in 2015 from
73% in 2007. In the same period, the connection rate to
sewage systems is to improve from 43% to 80% and
wastewater treatment from almost 0% to 50%.
In Tirana, the capital of Albania, untreated sewage is
discharged into the Lana River. So far, the public sewer
system does not cover the suburban areas. For peri-urban as
well as rural areas the most important means of sewage
disposal are seepage pits. In these facilities the solids are
kept back, while the liquid waste infiltrates into the ground
where groundwater is contaminated by the nutrients and
pathogens contained. The SOS Children’s Village is located in
Sauk, a suburb of Tirana, with no access to the municipality is
sewerage system, therefore a decentralised solution was
Prior to the project, the SOS Children’s Village had a sewage
system collecting wastewater in a septic tank with three
chambers and then discharging the effluent into a natural
stream next to its property. This had negative effects on the
4 Project history
To upgrade the existing treatment unit, GIZ, the SOS
Children’s Village and the Tirana Municipality (Unit 2, What
means “unit 2”?) agreed to build a constructed wetland
system on the village’s premises under technical guidance of
Oekotec GmbH and in collaboration with the Polytechnic
University of Tirana. The aim was to improve the
environmental situation of the village while at the same time
raising awareness for decentralised sanitation technologies to
relevant stakeholders and the public in Albania.
The planning phase started in September 2008, followed by
the implementation phase which began in September 2009
and ended in December 2009. The treatment plant started
operation on 29 January 2010.
The construction and start-up was scientifically monitored by
the Polytechnic University of Tirana (Environmental
Engineering Department), and a first PhD thesis in the area of
the wastewater treatment using constructed wetlands for
small communities was launched.
5 Technologies applied
Fig. 4: Arial view of the SOS Children’s Village (Google, Oct.
The SOS Children’s Village is a worldwide operating orphan
and abandoned children's charity which provides shelter and
education to children living within and in the surrounding of
the community. This international NGO is financed by funded
by donations. The SOS Village in Tirana has thirteen “houses”
for orphans and other children who do not have proper family
structures. Each house has 5 to 7 children in residence, plus
one adult taking care of them. The village also serves children
that come on a daily basis for schooling and other activities as
children’s nursery and elementary school. On total there are
around 500 people living, visiting or working at the Village.
Typically for the Mediterranean climate, Tirana has hot, dry
summers up to 40°C and cold, wet winters down to -8°C. The
average annual temperature is 16°C and with an annual
rainfall of 1,200 mm. The city lies on a plain with an average
altitude of 110 meters beside the Mount Dajti. The distance to
the Adriatic Sea is about 30 km. In Albania, the under-five
child mortality rate as surveyed in 2008 is 14 children per
1000, which is low.
The under-five mortality rate is the probability (expressed as a rate
per 1,000 live births) of a child born in a specified year dying before
reaching the age of five if subject to current age-specific mortality
rates (http://www.childinfo.org/mortality.html and
Last update: 31 March 2011
Using the existing sewer network, the constructed wetland
system contains the following components: a) a settling tank
for separation of the suspended solids, b) a pump chamber
for application of the wastewater to the filter beds, c) a sludge
drying bed, d) two-stage filter beds for optimised hygienic
treatment and e) a storage tank for the treated wastewater for
reuse on irrigation plots with overflow into the stormwater
Wastewater generated by toilets, showers and kitchen sinks
of the houses, school, kindergarten, administration office and
canteen, is first pre-treated in the former 3-chamber septic
tank which is now rebuild to a Dortmund settling tank, which
reduces both BOD and TSS, a second settling tank and a
pump chamber. The sludge collected in the settling tank flows
to a sludge drying bed.
Case study of sustainable sanitation projects
Wastewater treatment using constructed wetlands
Tirana, Albania - draft
To irrigation
Filter bed IA
Filter bed IB
Existing sewer
Pump chamber
Filter bed II (horizontal)
Settling tank,
former septic tank
drying bed
Existing stormwater drain
Storage tank
overflow to sewer
Fig. 5: Flow diagram of the wastewater treatment plant
(WWTP) (filter beds IA and IB are vertical flow, filter bed II
horizontal flow (subsurface)) (source: adapted from J. Niklas,
year); Size of the whole area?
From the first settling tank the liquid effluent flows into the
second settling tank and then to the pump chamber, from
which it is pumped to a series of two vertical and one
horizontal constructed wetland systems (filter bed I and filter
bed II). The surface of the filter beds is planted with a local
variety of reeds: phragmites communis. The surface is
planted with 5 plants per m². (Is this correct?)
Currently (Extension expected?) the wastewater of about 500
people an equivalent of 220 population equivalent is treated
(see Table 2). The total wastewater generation is calculated
with a flow rate of 16.8 m³/d coming down to a generation rate
of 76 L/person/day.
6 Design information
Primary treatment system
As a primary treatment step for solids removal, a settling tank
is used. This device was reconstructed from the former
3.36 m septic tank. The main installation was an inverse
cone that helps to concentrate the sinking solids at a point of
the bottom of the tank, where they can easily be pressed out
through a valve and connected pipe onto the sludge drying
bed. The wastewater influent happens in the centre of the
tank, 10 cm below the water surface, within a metal cylinder,
which forces the water flow down. This enhances the desired
settling of the solids. A baffle at the effluent point prevents
scum from overflowing the tank. This type of settling tank is
called “Dortmund settling tank” in Germany.
The discharge for de-sludging is installed only 20 cm (instead
of more than 1 m) below the water surface. Through opening
a valve, the sludge is forced out by the water pressure and
flows into the sludge drying bed, therefore, there is no need
for a pump.
By passing the filter layers, the water is treated by microbial
activity and adsorption to the filter material. The extraction
and later decomposition of persistent organic compounds as
well as the removal of pathogens is best in this combined
system which results in hygienic water quality standards.
The flow from the pump chamber is distributed across the
filter bed influent surface by means of perforated distribution
pipes installed in filter beds Ia and Ib, alternating daily, and
from there by gravity flow into filter bed II. Filter bed I is a
vertical flow wetland system, wherein the influent is distributed
across the inflow surface area and the wastewater is allowed
to infiltrate vertically down to a collection layer at the bottom of
the bed. From there it flows by gravity to filter bed II where it
enters through a gravel layer, and percolates horizontally
through the root-sand media of this horizontal flow bed. The
series connection of constructed wetlands is very helpful to
guarantee good effluent values. Especially the combination of
a horizontal flow bed behind a vertical flow bed has proved to
be very successful.
The treated wastewater is collected at the end of filter bed II
by a gravel layer with discharge into a small control shaft at
one corner of the wetland cell. From this sump, the
wastewater is transferred by gravity into a storage tank and
either reused for irrigation of the garden or toilet flushing in
the school. Treatment achievements are within international
WHO standards for wastewater quality (see Table 1).
Table 1: Measurements of influent and effluent quality (How
many samples?)
Influent (mg/l)
Effluent (mg/l)
Last update: 31 March 2011
Fig. 6: Lining and drainage piping of Filter Bed IA during
construction, before filling with gravel and sand (source: E.
Gjinali, Sept. 2009).
The tank is very shallow and leads to a moderate degree of
sludge separation. The third chamber of the former septic
tank has been rebuilt to an additional settling tank and
connected to the Dortmund tank in September 2010 to
improve the degree of sludge separation. The overflow goes
to the third chamber and then into the former second chamber
of the septic tank, where a pump is installed to feed filter beds
I and II. The pump can pump 60 m³/h. This value is derived
from the porosity of the filter layer. The resulting diameters of
the main pipe are 100 mm and the distribution pipes 65 mm,
respectively. In the main pipe, near the pump chamber, there
are two valves, which are used to feed filter bed IA or,
alternatively, filter bed IB.
The pump is controlled by a level switch. The volume of water
pumped each time is 5 m³. The volume of the settling tank,
limited by the available emergency overflow into the existing
Case study of sustainable sanitation projects
Wastewater treatment using constructed wetlands
Tirana, Albania - draft
sewer, is 35 m³. Due to occasional electricity breakdowns, the
contingency volume lasts for two days.
Table 2: Basic design assumptions for the constructed
wetland system at SOS Children’s village Tirana
No of
„Mothers and aunts“
Family of the
External children in
Tutors in nursery
Cleaning ladies
External pupils
Canteen staff
Duration of
presence (h)
8-15 (17)
8-15 (17)
8-15 (17)
8-15 (17)
8-15 (17)
8-15 (17)
Filter bed IA and IB (vertical flow)
Filter bed I is divided into two separate compartments, which
can be operated independently. Each bed has a surface area
of 165 m². The wetland media in which the reeds are planted
is primarily sand, with a network of perforated collection pipes
in the bottom covered by gravel. The depth of the bed is
0.6 m. Additionally, there is the provision of 0.3 m of
freeboard. The bed is sealed at the bottom using a geomembrane (polyethylene liner) towards the soil. The gravel
layers in the bed are protected by geo-textile. The beds are
fed alternately. Always, one is fed for one week and the
remains out of service and recovers in this time.
The distribution of the wastewater takes place by distribution
pipes that are perforated with 8 mm holes in spaces of less
than 1 meter on two sides. The 65 mm pipes are fixed on
stone slabs and laid parallel lengthwise at 2 m distance. The
collection system at the bottom of the bed is composed of
perforated PVC pipes covered in gravel, all discharging into
the outlet sump. The ends of the perforated pipes are
extended into the atmosphere, at one side of the cell, for
flushing in case of clogging, and to prevent vacuum conditions
at the bottom layer.
The pump installed to bring the water to the wetland system
has a capacity of 60 m³/h. At one feeding interval 5 m³ are
pumped to the active vertical flow bed. During dry periods
feeding takes place 3 to 4 times a day. During rainy periods
additional rainwater enters the system, the feedings takes
place more often (detailed numbers do not exist).
Filter bed II (horizontal filter)
Filter bed II has a surface area of 220 m² and is sealed with
geo-membrane and geo-textile protection like filter bed I. The
wetland media in which the reeds are planted is primarily
sand. The surface level of the reed bed media is slightly lower
than the outlet pipe of filter bed I, therefore the effluent from
the filter bed I can flow to filter bed II by gravity which results
in a continuous feeding of this filter bed. Along one side of the
filter bed I is a 60 cm wide strip of gravel, which comprises the
inlet area.
Table 3: Dimensioning of the constructed wetland system
according the needs/ person equivalents of the SOS
Children’s village Tirana
Total population at full occupancy
Total WW* generation flow rate
Per capita WW generation rate
Design hydraulic loading
BOD concentration (estimated)
Total BOD load
Area of filter bed I
Area of filter bed II
Area per population equivalent
Hydraulic load, bed I
Hydraulic load, bed II
BOD load, bed I
* WW: abbreviation stands here for wastewater.
On the other side of the bed is a similar strip of gravel which
serves as outlet area. The wastewater flows horizontally from
inflow area to outflow area. The filter bed has a slight slope of
1% at the base, while it is exactly horizontal at the surface.
Therefore the depth of the bed ranges from 0.6 m to 0.83 m. It
has no freeboard which could lead to the risk of an overflow of
wastewater into the terrain after heavy rains.
Sludge Drying Bed
The sludge drying bed has a surface area of 72 m and is
similar to Filter Bed 1, but with thinner layers, which are only
15 cm thick. The inflow of the sludge happens by an open
flexible pipe, which can be moved manually for even
distribution of sludge. The filtrate passes the sand layer and is
collected by drainage pipes, similar to Filter Bed I. It is
channelled to the pump chamber and treated in Filter Bed I
together with the rest of the wastewater.
Dewatered and stabilised sludge needs to be removed when
the sludge layer reached the height of 30 cm after approx. 3-4
years. The amount of sludge produced ranges around
12 g TS/capita*a (TS stands for total solids).
7 Type and level of reuse
In the near future the SOS Children’s Village will start making
use of the treated effluent for nitrogen-enriched irrigation of
the garden. Waiting for results.
Fig. 7: Filter bed IB at inauguration with the minister of
MPWT/ GDWSS. Reeds have not yet grown (source: A.
Kanzler, Jan. 2010).
Last update: 31 March 2011
Another important point of use, planned in the future, is
supplying the flush water for the toilets in school and
kindergarten by treated wastewater. The dried sludge from
the sludge drying beds is envisaged for application on the
garden compound as natural compost after mineralization has
taken place. This won’t be possible before 2014/2015.
Case study of sustainable sanitation projects
Wastewater treatment using constructed wetlands
Tirana, Albania - draft
8 Further project components
By locating the constructed wetland in a SOS Children’s
Village the project combines access to sustainable sanitation
with practical education of children. The pilot plant serves as
an applied and illustrative aid in the curricula of schools to
better understand natural and biological processes and
sensitise the young generation for the protection of the
environment and ecosystem. Especially the reuse of the
treated wastewater in gardening shall motivate the students’
participation. In addition, different actors (sector policymakers,
waterworks directors, supervisory board members of water
utilities) use the site as training, demonstration and promotion
platform for mainstreaming sustainable decentralised
wastewater treatment adapted to small and medium sized
While the treatment plant serves as technology and
knowledge transfer at micro level, there are complementary
project measures at meso and macro level to develop
capacities of key stakeholders and provide advice to the
sector reform process. As such the pilot constructed wetland
is embedded in a multi-level approach with substantial
potential to mainstream sustainable sanitation approaches
and technologies to a wider public.
GIZ, the MPWT and the Polytechnic University of Tirana plan
to integrate decentralised, low cost wastewater treatment
technologies into training programmes, student internships
and workshops in order to promote appropriate replication in
other peri-urban and rural areas of Albania.
9 Costs and economics
The construction cost for the treatment plant was around
EUR 60,000. Major cost categories thereof were earmarked
EUR 50,000 for material and construction service, EUR 5,000
for supervision and training as well as EUR 3,000 for
documentation and PR. The remaining was consumed for
permissions and other administrative costs. Cost break down:
material – labour
The constructed wetland system treats the wastewater of 500
inhabitants with a low operating cost of about EUR 500 per
year which is solely covered by the SOS Children’s Village.
The management requires one pump and only one person on
a part time basis for supervision and operation. O&M costs
per year, how are they calculated?
balanced quantity and quality of the raw sewage (most
importantly avoiding chemicals, oils and salts).
Maintenance activities concerning the sludge reuse won’t take
place before 2014/2015 when the sludge drying beds will be
11 Practical experience and lessons learnt
The operation of the treatment plant has started in January
2010. The inauguration ceremony attended by the minister of
MPWT of Albania and broadcasted in the national media
however indicates the significant interest in the first
constructed wetland in Albania. This will help to promote the
approach and technology.
There have been some problems with blockages since the
start in January 2010 due the weak performance of the pretreatment. In September 2011 the problems have been
identified and solved. Some pipes and valves in Dortmund
tank have not been built as planned and the third chamber of
the former septic tank has been rebuilt to an additional settling
tank. A Dortmund tank was chosen as pre-treatment due to
the already existing septic tank system but normally another
pre-treatment system would have been more appropriate as
the Dortmund tank is not able to handle solids and
In the vertical filter, the outlet holes in the discharge pipes
were placed in such way that the wastewater was leaving the
distribution pipes in 2 m high fountains. This caused a bad
smell. The pipes were cleaned and turned that the holes are
now going to the sides as well as additional holes on the
opposite side were drilled.
The effluent pipe from the shaft (placed between horizontal
filter and storage tank) to the storage tank was placed too
high what caused hydraulic overloading during heavy rain falls
(in winter). It was replaced by a lower pipe. The same was
done with the overflow outlet (in the storage tank) to the
rainwater sewer.
Moreover, at certain parts in the system infiltration water
entered the system due to not tight shafts and unfavourable
positions within the location. These minor problems were
readjusted and stopped.
12 Sustainability assessment
and long-term impacts
10 Operation and maintenance
The SOS Children’s Village technician, who was trained in
operation and maintenance, is assigned to undertake routine
operations of the system. These include: weekly inspections
and regulating the outflow of sludge of the settling tank,
pumping the wastewater daily into filter bed 1A and 1B
alternatively as well as removal of weeds. Emptying of the
grease trap and removing plant roots in some of the shafts.
Harvesting of reeds as well as reuse of treated water for
gardening is supported by school children.
Furthermore information, education and communication
campaigns are undertaken to ensure that the community is
using the constructed wetland properly and generate
Last update: 31 March 2011
A basic assessment (see Table 4) was carried out to indicate
in which of the five sustainability criteria for sanitation
(according to the SuSanA Vision Document 1) this project has
its strengths and which aspects were not emphasised
Table 4: Qualitative indication of sustainability of system. A
cross in the respective column shows assessment of the
relative sustainability of project (+ means: strong point of
project; o means: average strength for this aspect and –
means: no emphasis on this aspect for this project).
Case study of sustainable sanitation projects
Wastewater treatment using constructed wetlands
Tirana, Albania - draft
Sustainability criteria
health and
environmental and
natural resources
technology and
finance and
socio-cultural and
Project owner
General Directorate for Water Supply and Sewerage
(GDWSS) of the Ministry of Public Works and Transport
Rr. "Sami Frasheri" Nr. 4
Tirana, Albania
Tel.: +35542256091
Email: [email protected]
Sustainability criteria for sanitation:
Health and hygiene include the risk of exposure to pathogens and
hazardous substances and improvement of livelihood achieved by
the application of a certain sanitation system.
Environment and natural resources involve the resources
needed in the project as well as the degree of recycling and reuse
practiced and the effects of these.
Technology and operation relate to the functionality and ease of
constructing, operating and monitoring the entire system as well as
its robustness and adaptability to existing systems.
Financial and economic issues include the capacity of
households and communities to cover the costs for sanitation as
well as the benefit, such as from fertiliser and the external impact
on the economy.
Socio-cultural and institutional aspects refer to the sociocultural acceptance and appropriateness of the system,
perceptions, gender issues and compliance with legal and
institutional frameworks.
For details on these criteria, please see the SuSanA Vision
With regards to long-term impacts of the project, the main
expected impact of the project is to contribute to improved
environmental sanitation in rural and peri-urban areas by
technologies which are within the EU Water Framework
Directive. The constructed wetland treatment and reuse
system demonstrates the appropriateness and potential of the
technology in the Albanian context. As such the technology is
recommended with priority in the national policy and strategy.
13 Available documents and references
Gjinali, E., Shkenza, T. (2010). First research and
demonstration wastewater treatment system in Albania
using constructed wetland reuse technologies. Tirana.
Gjinali, E. (2009). Trattamento delle acque residenziali in
Albania. Tendenze significative verso la protezione delle
acque e della natura. (in English: Treatment of domestic
water in Albania. Significant trends towards the protection
of water and environment.) Georesources and
Environment Association, Polytechnic University of Turin,
Turin, Italy.
Gjinali, E. (2009). Trajtimi I Ujit te Ndotur Urban dhe
Realiteti Shqiptar (in English: Urban wastewater treatment
and the Albanian reality). INFBOTUES,Tirana, Albania.
Niklas, J. (2010). Reconstruction of constructed wetland
SOS-children’s village Tirana. GIZ internal document.
Niklas, J. (2008). Wetlands operation & maintenance
manual - Feasibility study and design of a constructed
wetland treatment plant for water reuse, SOS Children’s
Village Tirana. Tirana, Albania.
14 Institutions, organisations and contact
Last update: 31 March 2011
Local construction company
Rr. Mustafa Matohiti, P.7, Sh. 1
Tirana, Albania
Mob.: +355 69 40 45 321
Email: [email protected]
Project location and operators
SOS Children’s Village Albania
Rr. “Hermann Gmeiner”, Sauk
Tirana, Albania
Tel.: +355 4 22 48 313
Email: [email protected]
Technical monitoring and research
Polytechnic University of Tirana,
Faculty of Civil Engineering/ Environmental Engineering
Rr Muhamet Gjollesha
Tirana, Albania
Tel.: + 355 42 274 829
Email: [email protected]
Technical design and supervision
Bergholzer Str. 2
14806 Belzig, Germany
Tel.: +49/33841/3889-20
Email: [email protected]
Web: www.oekotec-gmbh.com
Technical and financial support
Deutsche Gesellschaft für Internationale Zusammenarbeit
(GIZ) GmbH/ German International Cooperation
Project “Advice on the Water Supply and Sewerage Sector
Reforms in Albania”
Dr. Enkeledja Gjinali
Rruga “Pjeter Bogdani”
Pallati “Teuta”, Ap. 5/4
Tirana, Albania
Tel.: + 355 42 245 101
Mob.: +355 68 20 27 713
Email: [email protected];
Technical upgrading of the system
Jens Nowak
Case study of sustainable sanitation projects
Wastewater treatment using constructed wetlands
Tirana, Albania - draft
Case study of SuSanA projects:
Wastewater treatment using constructed wetland system,
Tirana, Albania
SuSanA 2011
Authors: Dr. Enkelejda Gjinali (GIZ Albania), Dr. Joachim
Niklas (Oekotec Company)
Editing and Reviewing: Hendrik Smid (GIZ Albania),
Elisabeth v. Münch, Rahul Ingle and Philipp Feiereisen (GIZ,
[email protected])
© Sustainable Sanitation Alliance
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Last update: 31 March 2011
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