1. Proceedings of the 10
th
International Conference on Environmental Science and Technology
Kos island, Greece, 5 – 7 September 2007
A-120
THE INFLUENCE OF PROPERTY ON THE CITY’S SUSTAINABLE
DEVELOPMENT
M. BAKALI1
and P. CHATZIMPIROS2
1
National Technical University of Athens, Faculty of Civil Engineering,
Dept. of Water Resources, Athens, Greece
2
French Institute of Urban Studies, University 8, Paris, France
e-mail: mariabac@gmail.com
EXTENDED ABSTRACT
Nowadays cities act as economic, social and cultural magnets, often at the cost of the
environmental and aesthetical degradation of their landscape. The consumption patterns
adopted by modern societies have contributed to the downgrade of natural resources and
to the large amount of waste produced. In order to achieve sustainability within the city, it
is necessary to adopt the adequate policies of reduce, recycle and reuse of waste. The
introduction of recycling and water reuse systems in local scale can result both in the
reduction of the city’s waste disposal and in the use of the regained nutrients and water in
favour of the creation of areas of aesthetic pleasure within the building square. Thus,
sustainability is approached both on city level (reduction of used resources and relief of
central systems of waste treatment) and on local level (improvement of living conditions).
However, in order to realize these more sustainable urban forms some changes, such as
social attitudes and long-term planning, are essential. This urban redevelopment can be
achieved under the condition that the mentality of citizens in terms of property and
privatization of space will be altered. The increased competitiveness due to the high
density of cities leads to the scarcity of land and therefore to its higher evaluation.
However, the spare space among the buildings rests unused and is under-priced. The
unification of these fragmented parts and their further transformation into an urban green
space in which an assimilation of waste is achieved can result in their reassessment and
in the promotion of the sustainability within the city. The building square is used as the
main tool for the reorganization of urban space. A typical building square of a
downgraded district of Athens is examined. Appropriate calculations were made in order
to estimate the quantities of reclaimed greywater and compost produced and the
minimum surface of green space required for their assimilation. Furthermore, four
proposals were developed for this typical building square reorganising urban space. One
of them is of specific interest as its estimated required spare space is by only 12% larger
than the existing fragmented one. This means that under a different apprehension of the
notion of property, the cities could be transformed from a barren producer of waste to a
creative processor of it.
Keywords: Property, urban environment, urban green space, building square,
sustainability, recycle.

2. A-121
1. INTRODUCTION
The 21st
century is foreseen to be the first century in the history of mankind where urban
population will outnumber the population of rural areas [1]. Nowadays modern cities act
as economical, social and cultural magnets. The environmental load that is induced by a
city emerges from two separate components. They consume valuable natural resources
and energy and in return, they produce large amounts of waste, of which only a small part
is assimilated, thus disturbing the ecological balance of our planet [2]. Moreover, the
extremely intensive artificial urban environment, which is highlighted by the rather
insufficient amount of open urban green spaces, indicates the degradation of the living
conditions in the city. In this study, it is detected that one of the main reasons for the high
output of waste and the lack of natural spaces that characterize urban areas is related to
the way that the notion of property is conceived by the citizens.
Energy, natural resources and waste production are all parts of the same chain of urban
function. In natural ecosystems what is thought to be an organism’s waste, can be
another’s useful resource and so nothing is completely wasted [3]. In this way, the infinite
chain of life carries on harmonically. However, almost no one will describe the city as an
ecosystem, and certainly not as a component of the human ecosystem [4]. In order to
achieve sustainability within the city, it is necessary to adopt the adequate policies of
reduce, recycle and reuse of waste.
2. THE PURPOSE OF THIS WORK
Cities are a reflection of modern civilization and therefore the effort to improve their
environmental performance and aesthetic appeal is an expression of culture.
An important fraction of the inflow of matter in the city enters the residences. The
introduction of recycling and water reuse systems in local scale could result both in the
reduction of the city’s waste disposal and in the use of the regained nutrients and water in
favour of the creation of areas of aesthetic pleasure within the building square. The
treated water could be used for irrigation purposes, while the treated part of the organic
waste as a soil amendment (compost). Thus, sustainability will be approached both on
local and general level. Locally the living conditions of the urban population will be
upgraded but also on city level an economy of resources will be achieved and at the
same time the introduction of the urban area in the assimilation of waste will relieve the
central waste treating systems (wastewater plants, landfills).
The present work deals with the effect of the property on the sustainability of the city and
suggests that a change in the citizens’ apprehension of their “proper land” can lead to the
development of recycling attitudes at the scale of the building square.
3. THE APPREHENSION OF PROPERTY
Economic development produces urbanization by concentrating production and
consumption in locations that afford the greatest economies of scale, agglomeration and
linkage, and where control over sources and supply can be exercised with maximum
effectiveness and at least cost [5]. The emergence of property is commonly related to the
economic development. As the value of land increases, there is an inescapable secular
trend towards the subdivision of property rights [6]. With land property, legal subdivision
necessarily means physical enclosure. In fact, the prevailing focus on money wealth and
the economic surpluses generated by ‘successful’ cities is positively misleading

3. A-122
respecting ecological health and long-term stability [4]. Kivell [7] noted that the two
themes (land as urban morphology and land as the power) come together to form the
basis of urban planning. Castells observes that urban space is treated much more as an
economic good than as an environmental heritage [8]. Higher density means more
intense competition for resources and land is a scarce resource in the city [9]. Market
pricing mechanisms are the most accurate and efficient way to determine resource
values [10,11]. Such an economic system is better suited to the pricing of finite, or non-
renewable resources, like land, rather than renewable ones [12]. Furthermore, property is
seen rather often as the area which has a right to pollute (Figure 1). And in the case of a
city, the entire population exercises this ‘’right’’ without further thinking. Each building
square occupies a certain space of the urban tissue and it is associated with its
degradation. Additionally, it exports its waste on other spaces of its outer environment.
This contradiction concerning the assumption of the power that the privatisation of space
offers, but not of the responsibility and the obligations deriving from its use, is remarkably
accentuated within the urban environment.
Figure 1. Property is seen as a generator of waste while its outer environment is used for
their disposal
4. THE REFORMATION OF THE BUILDING SQUARE
The emergence of boundaries on urban land can similarly be viewed as an expression of
land value appreciation and of the need to limit competitive consumption. However, in
what the building square is concerned, the spare space that exists among the buildings
as fragmented portions of non-built land are not valorised nor appreciated. The inverse
can be achieved by the unification of all the isolated small parts into a whole and
consequently the creation of a collective green landscaping of recreation and visual
assets [13], that also contributes to the amelioration of the local microclimate [14]. In
order to achieve visual contact to the inner part of the square, that is now transformed
into a park and also facilitate the circulation of people, small galleries could be designed.
Simultaneously, an important gain is that these differently conceived local green spaces
serve for the accomplishment of natural ecosystem’s functions. The non-built parts of the
building squares can provide a location of installations assuring a degree of auto
sufficiency of the sub-division of the city in the assimilation of waste (Figure 2). As it is
mentioned above, a main axe for this work is the exploitation of urban space and the aim
that planning decisions deal with widely differing situations, promote good quality
development and refuse schemes that waste a site’s potential [15].
PROPERTY
LAND
RIGHT TO
POLLUTION
OUTER
ENVIRONMENT
DISPOSAL OF
WASTE

4. A-123
(a)
(b)
Figure 2. Actual (a) and proposed (b) relationships between property and environment
5. CASE STUDY AND METHODS
A typical building square of a rather
downgraded district of central
Athens is examined (Figures 3,4).
The project area of Kato Patission
illustrates rather specifically the
lack of a proper urban design as
well as the scarcity of green
spaces since there is only 0.5m2
of
green space corresponding to each
resident. The square’s total free
space is estimated at 30% of its
total surface, while the number of
its residents is estimated through
statistics [16].
Today the total amount of
wastewater produced in this
building square is directed via the
central sewage system to the
biological waste treatment plant of Psitalia. However, greywater [17] can be used for
irrigation thanks to its features [18]. Therefore, it is suggested that a small rotating drum
system will be installed in each building for the treatment of greywater [19]. This will be
followed by an ultraviolet disinfection [20] for the purposes of tertiary treatment, since the
reclaimed water is used for the irrigation of urban spaces [21]. The daily domestic
wastewater production is divided to 90lt of greywater and 65lt of blackwater per person
[19]. The former is not recycled.
Figure 3. 3D animation of the present building
square
WASTE
ENVIRONMENT
WASTE
ENVIRONMENT
LESS
WASTE
WASTE
ASSIMILATION
CALCULATIONS
CONCLUSIONS
PARK

5. A-124
As far as the treatment of
domestic solid waste is
concerned, the total amount is
discharged to the landfill of Ano
Liossion.
According to our proposal, two
enclosed composting vessels
[22] could be used for the recycle
of the organic part of solid waste,
while the rest recyclable waste is
concentrated in separate recycle
cans.
The calculation of the domestic
solid waste produced was made
in accordance with the following
percentages (Table 1) given by
the Association of Communities
and Municipalities in the Attica
Region [23]. Since recycling
depends a lot on human initiative
and motivation, two recycling
scenarios are formed: according
to the first scenario, the
percentage of the recycled organic parts is rated at 70% and for the rest recyclable waste
at 100%, while according to the second and more realistic one, the proposed
percentages for the recycled organics is estimated at 50% and at 70% for the rest.
SOLID WASTE PRODUCTION
ORGANICS 46%
PAPER/CARTON 24%
PLASTICS 11%
ALOUMINIUM/METALS 3.70%
GLASS 3.40%
Table 1. Production percentages for domestic solid waste
Moreover, for the estimation (in square footage) of the irrigated landscape the following
formula was used [24]: LA = GW / (ET x PF x 0.62),
where: LA = landscaped area (square feet),
GW = estimated graywater produced (gallons per week),
ET = evapotranspiration* (inches per week),
PF = plant factor,
0.62 = conversion factor (from inches of ET to gallons per week)
Finally, the following parameters were taken into consideration for the formation of the
new building square types: the surface of the square, the surface and the form of the
urban space, the height of the buildings, the aesthetic appeal of the city, the view, the
improvement of ventilation and sunlight and the reduction of noise levels.
Figure 4. A plan of the building square as it is
today, where the pink lines show the outlines of the
building plots (grey colours)

6. A-125
6. RESULTS
The estimated daily volume
of domestic wastewater is
88,935.90 lt/day for the
present situation and
37,295.70 lt/day after the
treatment of greywater.
Thus, a reduction of 58%
of the final amount of
wastewater that reaches
the central sewage system
is achieved (Figure 5). In
respect to the treatment of
solid waste - If we assume
that the first scenario is
realized - the amount of
recycled material picks up
to 510kg/day, whereas with
the second one, a total amount of 360 kg/day is achieved. As a result, the final quantity of
domestic solid waste that ends up to the landfill is decreased by 74.3% (Figure 6) and
52.5% (Figure 7) for each scenario. In addition, the amount of produced compost is rated
at 66 kg/day and 47 kg/day respectively.
175,48
682,8
0 200 400 600 800
PRESENT SITUATION
SCENARIO 1 324,535
682,8
0 200 400 600 800
PRESENT SITUATION
SCENARIO 2
Figure 6. Comparison of the final amount
of domestic solid waste that end up to
the landfill (Scenario 1)
Figure 7. Comparison of the final amount
of domestic solid waste that end up to
the landfill (Scenario 2)
In order to estimate the minimum surface of urban green space that is equivalent to the
amount of reclaimed water from the greywater treatment, we consider the amount of
reclaimed water as limiting factor and some typical water needs of plants for the same
period [25]. This surface, which is 1.101.64 m2
, corresponds to the reclaimed greywater
of August, when the 60% of the residents of the building square are away on holiday.
Local species of fauna will be planted as well as grass, which will be supported by the
treated and reclaimed wastewater.
Ten proposals were developed for the regeneration of the examined building square,
which correspond to the residential needs of the number of residents of the existing
building square. Figure 8 illustrates three of those proposals, where it is evident the
variation that occurs by setting each time a different parameter as a priority. These three
types do not differ a lot in terms of building square’s area from the existing one and in
addition their forms favour air circulation and sunlight benefits. There is a fourth type of
square though (Figure 9), that shows particular interest because it corresponds to the
above-mentioned discussion concerning the appreciation of the wasted and fragmented
37.295,70
88.935,90
0,00 50.000,00 100.000,00
PRESENT SITUATION
PROPOSAL
Figure 5. Comparison of the final amounts of
wastewater that end up at the central sewage system in
lt/day.

7. A-126
part of the building square with a minimum intervention. The spare space of the existing
building square is smaller by only 12% from the estimated required free space of this
proposed form. The shaping, the area and the building types of this fourth square are
similar to those of the current one, which indicates that this proposal is realisable since it
requires slight changes.
Figure 8. 3D animations of three different new forms of building square
It is noted that the attempt to redesign the urban building square according to the main
disciplines of bioclimatic design [26] resulted in great demands of land and thus it fails to
directly respond to urban problems.
7. CONCLUSIONS
The confused perception of
importance and its consequent
pressures on the protection of short-
term economic interests over long-
term sustainability interests represents
a barrier to the adoption of
sustainability-oriented action [27]. The
notion of property should be modified
so as to include the privatization of the
responsibility for the assimilation of
the domestic waste at the scale of the
building square. This is feasible when
urban land hosts natural ecosystem
procedures. As it is analyzed in this
study, the spare spaces within the
studied building square can serve this
purpose since the required free space
is slightly bigger than the existing one.
On the other hand there is no ideal
solution or a cure-all proposal for the
ensemble of city’s weaknesses. An effort is made to maximize the environmental and
urban benefits with the minimum of change.
As far as the reduction of the environmental load upon the natural resources is
concerned, this reformation of the building square, which permits the completion of the
cycle of recycling within it, results in the comfort of the possession of green spaces in the
urban tissue without further withdrawal of natural resources.
The pursuit of sustainability cannot evade the reality of conflicting interests arising to a
great extent out of wide differences in the time scales involved [28]. However, the public
apprehension of the importance that the urban environment should also perform as an
ecosystem can result in the reduction of the direct urban environmental impacts.
Figure 9. Proposal for the unification of the
open space in the inner part of the building
square

8. A-127
ACKNOWLEDGEMENTS
The authors would like to thank G.-F. Sargentis.
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