Semi-centralized water systems for rapidly
growing urban areas

Martin Wagner*, Peter Cornel**Technische Universitaet Darmstadt, Institut WAR, Petersenstr. 13, 64287
Darmstadt, Germany
Abstract: The rapid development of big cities worldwide leads to infrastructure
problems regarding water supply and sanitation systems. Conventional systems
cannot keep up with the rapid growth of the cities. In recent years there havebeen many discussions about alternative supply and sanitation systems, which
are to solve the discrepancy between city growth and the demand for supply andsanitation systems. Furthermore, these systems should deal in a sustainable way
with natural resources. Different kinds of sanitation systems are discussed, as
alternatives for conventional central sanitation systems, so-called “End of Pipe”
systems. The existing experience about conventional supply and sanitation
systems must be evaluated and new systems must be adapted to the local
boundary conditions of future cities. The paper presents a supply and sanitation
system (semi-centralized sanitation system) which might prove as a solution for
rapidly growing big and also mega cities.
Keywords: rapid city development, big cities, sanitation systems, semicentralized sanitation systems

Introduction
In the future, modern city planning should put a higher emphasis on the principleof sustainable development than it has done until today. Furthermore, city planning should deal conscientiously with the environment in order to get a higher
acceptance on the part of the cities' inhabitants. Infrastructure planning is one of
the most important sectors of city planning. Therefore, infrastructure planningshould follow the development of the cities (spatial spread) to guarantee efficient supply and disposal services. However, there are multifaceted problems
especially in rapidly growing cities, and infrastructure cannot fulfil its duties andresponsibilities. Thus, the supply of the city with drinking water, the treatmentof waste water and the disposal of waste cannot be ensured.
In this paper, after some facts about future city development are listed, sanitation
systems will be introduced in detail. Then so-called semi-centralized sanitation
systems and semi-centralized supply and treatment systems are described andcompared with conventional centralized and decentralized sanitation systems.
Finally, a conclusion rounds off the paper.

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Semi-centralized water systems for rapidly growing urban areas

2

Future city development
There are several main reasons which might influence the development of big
cities worldwide. Three of them will be discussed below:x

The development of cities is different all over the world. In 1994, only
three of the world's 10 largest cities were located in developed countries. By 2015, this number is expected to decline further to two, onewill be Tokyo (Japan). However, whereas Tokyo’s population is estimated to increase by less than 5 percent during this period, cities likeJakarta (Indonesia), Karachi (India), Lagos (Nigeria), and Dhaka(Bangladesh) are expected to grow 60 to 75 % [Biswas et al., 2004]. In
2015, from the estimated 27 mega cities - cities exceeding a populationof ten million inhabitants - there will be 15 in Asia [cp. Dhakal, 2002].

x

There is a difference between the growth of big cities in the developed
and the developing world. For example, New York, Paris and London
are three mega cities in the developed world. These cities have growncontinuously throughout the 20th century. The growth tendency of mega
cities nowadays has changed. The development in a gradual process
over a long period, such as New York and London, allowed progressive
and effective development of the necessary infrastructure systems, e.g.
sanitation systems [cp. Biswas et al. 2004]. In contrast, the development of big or mega cities in developing countries is much faster.
Therefore, necessary infrastructure development cannot keep up withthe rapid growth of these cities.

x

Beside the rapid growth of big cities urbanization is increasing, too. In
2000, more than half of the world’s population lived in cities. During
the past 30 years, the urban population in developing countries has tripled. Urban areas in Africa, Asia and Latin America are growing withan average rate of one million people per week [Perlman et al., 1998].
Africa has the fastest rate of urban growth in the world. It is expectedthat by 2025 the continent’s urban population will have grown from
300 million to 700 million or from 30 % to 52 % of the total population[Cross and Morel, 2004]. Developing countries will absorb nearly all of
the world’s population increase between today and 2030. The estimatedurban growth rate of 1.8 % per year for the period between 2000 and
2030 will double the number of city dwellers. Meanwhile, rural populations are growing hardly at all. Likewise by 2030 more than half of all
Asians and Africans will live in urban areas. In Latin America and the
Caribbean, at the same time, 84 % of the inhabitants will live in urban
areas, a level comparable to the United States [Abhat et al., 2005]. Urbanization in developing countries is increasing, even with declining
industrialization and infrastructure and despite fewer jobs and decreasing salaries. Infrastructure development cannot keep up with the risingnumber of city dwellers. Therefore, the new big cities in the developingworld have particular problems with insufficient infrastructure systems.

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Semi-centralized water systems for rapidly growing urban areas

One result of the rapid growth of big cities is lack of water. The local water demand of big cities is much higher than the availability of usable natural water
resources, a fact almost independent from the regions' climatic conditions. The
high population density of big cities leads to a great demand for water in a comparatively small area and thus to the exploitation of water resources. Furthermore, because of the rapid city development the lack of sanitation systems andwaste water treatment plants leads to additional pollution of the available water
resources. Thus, the usable water resources will be reduced twice: (1) by theenormous water demand due to the high population density, (2) by polluting thenatural water resources via discharging untreated waste water into the water bodies.
Evaluating the above mentioned facts one may state, that in the future, the improvement of infrastructure systems, especially in rapid growing big cities in thedeveloping countries, is one of the greatest challenges for countries throughout
the world. For the development of future cities sustainable and adapted solutions
are needed taking into account local boundary conditions. Therefore, future city
planning and in particular infrastructure planning in rapidly growing cities are achallenge for all sanitary engineers, sociologists, architects, traffic and transportation engineers etc.

Sanitation systems
The development of future cities and thus the infrastructure is highly dependent
on the efficiency of the sanitation system.
Sanitation systems can be classified into three categories. In Tab. 1 three different categories of sanitation systems are listed, which will be discussed below.
Figure 1: Categories of sanitation systems
Category
I

II

III

Description
conventional “End of Pipe” systems with a combined sewage system or a separate sewage system
and a wastewater treatment plant (WWTP)
separate collection of yellow water (urine) andblack water (all other water). This system realizes
a closed nitrogen and possibly phosphorus cycle
without water reuse
separate collection of yellow water, grey water(from showers) and brown water (from toilet).
This system realizes a closed water and nutrient
cycle with water reuse

With conventional “End of Pipe” sanitation systems (category I) waste water iscollected in conventional sewage systems (combined and separate sewers) andtreated in a wastewater treatment plant (WWTP) – quite often located at thecity's borders. In advanced treatment plants the nutrients nitrogen and phospho-- 281 -

3

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Semi-centralized water systems for rapidly growing urban areas

rus are removed in order to avoid eutrophication of the receiving water bodies.
The treated waste water is discharged into water bodies (river, sea, groundwateretc.). Most of these “End of Pipe” sanitation systems are so-called centralized
systems. In industrialized western nations these conventional centralized system
are very common.
In sanitation systems of category II, waste water from different water flows, e.g.
yellow water, brown water, grey water, is collected separately. Yellow waterconsists of human urine and has the highest percentage of nitrogen compoundsof all wastewater flows. Separately collected yellow water can be used - after acertain storage time - as fertilizer in agriculture. Brown water and grey water are
not collected separately. They are pumped into a WWTP and discharged after
treatment. In this kind of sanitation system water reuse is not realized but thenutrient nitrogen in the yellow water is reused in agriculture.
In sanitation systems of category III, sanitation is similar to category II regarding the collection and treatment of waste water; the water flows are collected
separately. Water reuse in this system is realized by reusing the grey water for
toilet flushing, garden irrigation etc. Grey water, which originates from showers,
wash basins and washing machines, is only slightly polluted waste water, with
COD levels < 400 mg/L, low in ammonia, phosphorus and faecal coliform bacteria. No complex treatment process is needed to clean this water. After treatment it can be used as service water in private households or in public buildings,
e.g. for toilet flushing, which is approx. 30 % of the total water demand in private households. As a result, the city's demand for drinking water is reduced
significantly, thus solving part of the problems of insufficient water supply. Furthermore, due to water and nitrogen recycling, the cycle of water and nitrogen ispartly closed. All described systems can be realized as centralized as well as
decentralized systems.
Sanitation systems of category I (see Tab. 1) are normally realized as centralized
systems. In centralized systems waste water from all parts of the city is collected, transported in a sewage system, treated in a central treatment plant and isthen discharged into the receiving water bodies. Beside domestic waste water thecollected waste water also contains industrial waste water. Because of the potential existence of hazardous substances in industrial waste water, the reuse of thiswater might turn out difficult. A centralized system is designed and dimensioned
for a defined period of time. Therefore, the necessary capacity of the sewage
systems and treatment plants must be estimated and calculated prior to the planning stage.
Sanitation systems of category II and III (see Tab. 1) can be implemented depending on local conditions. In totally decentralized systems, i.e. within small
living communities (about 10 to 1000 inhabitants), the waste water is collected,
transported, treated, discharged or reused in each individual house or a relatively
small house cluster, respectively. The length of transport units (pipes, sewers) isvery short; treatment units are located near the houses, and in the majority ofcases the user himself operates the treatment units.

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Semi-centralized water systems for rapidly growing urban areas

Sanitation systems to be implemented in future cities, must be dependable, economical, and sustainable. Therefore, a flexible sanitation system with a closed
cycle for water and nutrients (category III in Tab. 1) will be the preferred system, fulfilling the requirements of future sanitation systems in big cities. Besidecentralized and decentralized sanitation systems there is a third system to bementioned. In the next chapter this system – the semi-centralized sanitation system – is described as a sustainable sanitation system for rapidly growing big
cities.

Semi-centralized sanitation systems as a solution for
future cities
Conventional centralized sanitation systems are developed using modern process
technology, are designed to work reliably and to reach a high treatment efficiency, while fulfilling the economic demands at the same time. In order totransport drinking water and waste water, pipes and sewers of great lengths andlarge diameters are needed. The mixture of industrial and domestic waste waterand the long distances between consumers and treatment plants prevent an economic water reuse [Cornel et al., 2004]. Centralized systems are not flexible
enough when considering the rapid growth of the cities in the future; size adaptation is very difficult. These cities need a very high capital investment and haveto consider the estimated development prior to starting the implementation of thesanitation systems. Especially construction and enlargement measures cannot
keep up with the rapid growth of the new big cities, thus resulting in higher costs
compared to big cities nowadays.
The major drawback of decentralized systems is that it is difficult to guarantee
constant professional operation and maintenance. The treated water for reuse
purposes needs a good quality standard, and the health protection of the consumers must be ensured. These conditions cannot be guaranteed by the operators
in a decentralized system (house owners). Furthermore, low-level technology
will mostly be used in decentralized systems, thus achieving low maintenancecosts and thereby low-cost systems. This may result in insufficient effluent quality.
Semi-centralized supply and sanitation systems encompass the scale of application, responsibility, operation, treatment processes, and scope of reuse. Semicentralized systems combine both the advantages of centralized and decentralized systems with the avoidance of their disadvantages. Compared to conventional centralized systems, in semi-centralized systems short pipe and seweragesystems are realized, hence the recirculation of water for reuse might be economically interesting. A separation of industrial and municipal waste water ispossible, thus relieving the wastewater treatment plant as well. In relatively
small areas the implementation of dual piping (for supply and reuse) is feasible,
thus allowing water reuse. By using modularization, semi-centralized systems
offer a higher flexibility and a better potential for enlargement and adaptation.
Due to the larger scale of semi-centralized systems compared to decentralized
systems, professional operation and supervision of the treatment systems are- 283 -

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Semi-centralized water systems for rapidly growing urban areas

guaranteed. Accordingly, semi-centralized systems can keep up with the quality
standards of water reuse and consumer health protection.
For future cities the semi-centralized sanitation system concept based on category III of sanitation systems (see Tab. 1) is a progressive and economic system
which will offer improved water reuse in urban areas compared to today’s centralized systems. With these “Semi-centralized Supply and Treatment Systems”(SESATS, see Weber et al, 2005) an efficient integrated city planning can berealized, including the necessary infrastructure measures. The relatively small
service areas for SESATS allow short transport distances between the treatment
units compared to centralized systems. The treatment units are situated close toeach other. Therefore, the effort for integrating planning, construction and connection of different parts of infrastructure (water supply, wastewater treatment,
solid waste disposal) can be reduced, compared to large centralized systems.
When applying SESATS, well organized operating teams and systems are required to guarantee the successful and safe water reuse within the city regions.
In Fig. 1 centralized and semi-centralized supply and treatment systems arecompared. Centralized systems supply the whole city with tap water and also
treat all of its waste water and waste. Semi-centralized systems supply single
districts within a city with water and treat waste water and waste from single
districts.
emissionenergypotablewater
products

City

wastewater

districts

solid waste

Figure 1: Comparison of centralized and semi-centralized supply and sanitation systems [Weber et al., 2005]
The SESATS - as described above - combine treatment facilities for water,
waste water and (organic) waste. These plants also supply service water forhousehold use and intra-urban irrigation for one district within the city (see Fig.
2). Furthermore, because of the combined treatment of organic waste and sewage sludge from wastewater treatment, the production of electrical energy andheat is feasible, which then can be used at the treatment plants themselves or in
the neighbourhood.

- 284 -

energypotable water

service waterSemi-centralized water systems for rapidly growing urban areas

residual
w atertreatm ent

raw w ater

w aste w ater
residual

Supply and Treatm ent Unit
waste water

w astew ater
treatm ent

w astetreatm ent

w astew asteFigure 2: Scheme of one unit of a semi-centralized supply and sanitation
system [Weber et al., 2005]

Conclusion
The infrastructure of water supply and sanitation systems is deficient in the majority of the rapidly growing cities in developing and emerging nations. The welldeveloped big cities do not only have problems with insufficient infrastructure,
but also with the necessary extension measures and regular maintenance of thecurrent infrastructure. Thus, it is important to evaluate, how the infrastructuredevelopment can keep up with the city's rapid growth. The sustainability of cityand infrastructure development should be considered in the progress. Semicentralized supply and sanitation systems, which are based on nutrient recycling
and water reuse in relatively small units, may be a suitable ecological, economical and sustainable solution for the big cities. It is not possible to determine astandard size for semi-centralized systems. It is rather necessary to evaluate thesize for each big city under investigation, thereby taking into account the local
boundary conditions (e.g. population, size of city area) and individual needs.
Furthermore it has to be considered that the spatial, administrative and juridical
frameworks of a developing area take serious influence on the optimal size. The
calculated size from 50,000 up to 100,000 inhabitants of the ’ideal developmentsize‘ is based on several model-assumptions which have to be depleted by theactual figures of the actual development area. The specific local and regionalparameters determine the recommendable size of the supply- and disposal-areaon the one and the choice of the best-possible adopted treatment methods udn
techniques on the other hand. Generally it can be acted in consumption that thecalculated developing-size from 50,000 up to 100,000 inhabitants is reliable interms of a guide value or benchmark.

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Semi-centralized water systems for rapidly growing urban areas

Acknowledgement
The authors want to thank the German Ministry of Education and Research forthe founding of the research project “Semi-centralized supply and treatment systems for urban areas in China”. This project was the fundament of the present
paper.

References
Abhat, D. Dineen, S.; Jones, T,; Motavalli, J. ; Sanborn, R. ; Slomkowski, K. (2005):
Cities of the Future – Today’s “Mega-cities” are Overcrowded and Environmentally
Stressed, Environmental Magazine, Volume XVI, Number 5, September/October
2005
Bismas, A. K.; Tortajada, C. (2004): The water challenges of Megacities, Third World
Centre for Water Management; Professor Jan Lundqvist, SIWI; and Dr. Olli Varis,
Helsinki University of Technology
Cornel (2003); “Semicentralized supply and treatment systems for urban areas in China”
Research project, financed by the German Ministry of Education and Research, project number: 02WD0607
Cornel and Wagner (2002): Decentralized Sanitation Concepts for Urban Areas, presentation at EET Paris, 17th Nov. 2002
Cornel, P.; Wagner, M.; Weber, B. (2004): Semi-centralized Sanitation Concepts for
Urban Areas in China, not published, Institut WAR, TU Darmstadt, 2004
Cross, P.; Morel, A (2004): Pro-poor strategies for urban water supply and sanitation
services delivery in Africa, Water and Sanitation Program Africa, Abstract Volume,the 14th Stockholm Water Symposium August 16th – 20th 2004
Dhakal, S. (2002): Mega--Cities in Asia: An (Un) Sustainable Development?, international science roundtable for the media – 4th June 2002, Bali, Indonesia
Perlman, J.; Hopking, E.; Jonsson, Å (1998): Urban solutions at the poverty/Environment
intersection, the Mega-Cities Project, Publication MCP – 018, 1998
Weber, B., Cornel, P., Wagner, M. (2005): Semi-centralized Supply and Treatment Systems for (fast growing) Urban Areas, IWA Conference Wastewater Reclamation andReuse for Sustainability (WRRS2005)”, Jeju, Korea Nov. 7 - 11, 2005

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- 287 -Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Introduction

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

guarantee efficient supply and disposal services• infrastructure planning should follow the development of
the cities:• dealing conscientiously with the environment:
better acceptance of the inhabitants• in future: modern city planning should put a higher
emphasis on the principle of sustainable development

InstituteProf. Dr. Martin Wagner

Semi-Centralized Water Systems
for Rapidly Growing Urban Areas

Institute

3

1

Content

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Semi-centralized supply anddisposal systems for fast
growing urban areas in China• development of cities worldwide– more large cities in developing countries– by 2015, 60 % to 75 % expansion of the populationin large cities in developing countries– by 2015, 15 of 27 of the largest cities – with apopulation of more than ten millions – in developing
countries• difference of city development in developed anddeveloping countries– developing countries: very fast growthin only some decades– developed countries: slow growththrough the whole 20th century

Future city developments

Institute• Conclusions• Semi-centralized sanitation systems as a solution
for future cities• Future city development• Introduction

Institute42

- 288 -Semi-centralized supply anddisposal systems for fast
growing urban areas in China[Taubmann n.d.]

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

semi-centralized sanitation systems

flexible system with a closed cycle for water and nutrients• requirements of sanitation systems in future cities:– dependable– economical– sustainable– flexible• preferred systems:• problems of cities:– insufficient infrastructure systems– lack of water resources– additional pollution of available water resources

Future city developments

Instituterural population

urban population

e.g. growth-rates of urban populationin P. R. China (1962 up to 2001)

Institute

7

5

137

City

437

solid waste

wastewater

emission

urban districts

semi-centralized system

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

3 3

8

6

OceaniaSouth-East-Asia

Asia

208 East115

South-Asia

234

West-Asia

23 38

303

749

a number of semi-centralized supply and treatment units
instead of one big unit

products

potablewater

energy50

Eurasia20

Sub-Saharian
Africa288

North-Africa

15 40

centralized system

Institute

Latin America
and Caribbean

60

15 20

developed countries

without sanitation

without clean drinking water

938

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

So many people live in these regions (in million)

Water deficiency

Institute

- 289 Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

shorter and smaller pipe and sewerage systems

water (and nutrient) recirculation for reuse

separation of industrial and municipal waste
water

modularization of treatment units

better potential of enlargement and adaptation

•

•

•

•

•

advantages:
semi-centralized vs. centralized sanitation
systems

Institute

Institute

11

9Institute

Institute

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

1210

w aste w ater

raw w ater

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

w atertreatm ent

w astew ater
treatm ent
w astetreatm ent

Supply and Treatm ent Unit

service water(supply and treatment)

potable water

w astew asteresidual

w aste w ater

residual• one unit of a semi-centralized sanitation system

Institute

Instituteenergy- 290 15

13

treatment stepenergysludgewaste

process waste waterend productprocess water

waterworks sewage

black water

grey water

material flows

drinking water purification

Legendewaterworks
sewagedrinking water
purification
treatment

raw water(surface water)

Institute

Institute

black water

grey water

process
wastewater

waste

energyreceiving stream/use

sludgeresiduelactic acid14

16

integrated system

black water
treatment

grey water
treatment

waste
handling

process waterSemi-centralized supply anddisposal systems for fast
growing urban areas in China

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

- 291 -treatment stepenergysludgewaste

process waste waterend productprocess water

waterworks sewage

black water

grey water

material flows

drinking water purificationwaterworks
sewagedrinking water
purification
treatment

raw water(surface water)

Legendegrey water

black water

grey water

black water

material flows

Institutetreatment stepenergysludgewaste

process waste waterend productprocess water

waterworks sewage

black water

grey water

drinking water purification

Legendewaterworks
sewagedrinking water
purification

raw water(surface water)

Institute

black water
treatment

grey water
treatment

waste
handling

process
wastewater

waste

black water
treatment

grey water
treatment

waste
handling

process waterSemi-centralized supply anddisposal systems for fast
growing urban areas in China

process
wastewater

waste

process waterSemi-centralized supply anddisposal systems for fast
growing urban areas in China

energyenergy19

receiving stream/use

sludgeresiduelactic acid17

receiving stream/use

sludgeresiduelactic acidSemi-centralized supply anddisposal systems for fast
growing urban areas in China

•

•

•

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

black water:
waste waster from toilettes flushing and kitchengrey water:
waste water from showers and bathtubs, hand basins andwashing machines

sludge: combined treatment with residual waste

treated black water: discharge or reuse in urban zones

treated grey water:
service water for using in private household orafter treatment:••

waste water treatment

Institute• because of the reuse of water there is a saving of tap
water• available rain water by rainwater harvesting satisfies
only a third of the needed amount for toilet flushing,but is useable for irrigation and street cleaning• use of ground water is often forbidden especially inurban areas, because of scarce volume problems:
underground subsidence, salt water intrusion

Water supply

Institute

20

18

storage withcold /warm precipitation
aggregate /flocculation

biofilter

influent„Grey water
concentrates“

precipitants/flocculants
storage

Institute

screenings

fine screen

storageblowerSBR

MBR II

sludgeUV-Disinfection

sludgesludgeeffluent

effluent

effluent

effluent

effluent

UV-Disinfection

blowersludgeceramic
membrane

blowerMBR I

biologicalsand filter

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Backwash water- 292 -

21

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

mixing station grey water• SBR Thailand Water house

Institute

Institute24

22

- 293 -Institutematerial flows

black water

grey water

black water
treatment

grey water
treatment

waste
handling

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

process
wastewater

waste

process waterSemi-centralized supply anddisposal systems for fast
growing urban areas in China

outputreactorbiogas exhaust

input
preparation
27

25

receiving stream/use

sludgeresiduelactic acidenergyPilot Plant for lactic acid fermentation

treatment stepenergysludgewaste

process waste waterend productprocess water

waterworks sewage

black water

grey water

drinking water purification

Legendewaterworks
sewagedrinking water
purification
treatment

raw water(surface water)

Institute
Semi-centralized supply anddisposal systems for fast
growing urban areas in China

treatment stepenergysludgewaste

process waste waterend productprocess water

waterworks sewage

black water

grey water

material flows

drinking water purification

Legendewaterworks
sewagedrinking water
purification
treatment

raw water(surface water)

Institute

black water

grey water

process
wastewater

waste

energyreceiving stream/use

sludgeresiduelactic acid26

28

integrated system

black water
treatment

grey water
treatment

waste
handling

process waterSemi-centralized supply anddisposal systems for fast
growing urban areas in China

challenges: process control for mono substrates is wellknown and state of the art technology
in Contrast, organic waste is very inhomogeneous andinconstant in it‘s composition

solution: optimization of process control for the generation ofother products, e.g. lactic acid. The technology is acombination of classical anaerobic waste treatment and silage
production processes

problem: main product of anaerobic waste treatment (thermalenergy from the biogas) has no preferable user under the given
spatial situation (mono functional habitation)

waste treatment

Institute

- 294 -Institutemoderate density
housing areas(housing with up to 4
storeys proper)- 6% -

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Example:City
Qingdao
Example:City
ofof
Qingdao

access road
(1st and 2nd order)

31

29

low desity
housing areas(single-family and twofamily houses with up to
2 storeys proper)- 8% -

high density
housing areas(housing with up to 6
storeys proper)- 42% -

13,000residents
residents
13.000

general public demandarea(social infrastructure aswell as supply anddisposal center)- 8% -

total area
500.000 m²

Model Cell

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

green space-16% -

total area 500,000 m²

Institute

1

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

2

4b

4a

Institute

5 (b)Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Location of supply and disposal centre

Model-cell with 13,000 residents

3b

3amodeling recommendable dimensionsof space and residents

Institute32

30

- 295 -Key Questions

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Semi-centralized supply anddisposal systems for fast
growing urban areas in China• what are the challenges in integrated planning and approval
processes (for organisational reasons)?

• are there other strategies to reach sustainability (in cases ofsupply and disposal systems)?

• is the idea feasible to make development in fast growing
urban areas (more) sustainable?

Institute

Institute

35

33

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Semi-centralized supply anddisposal systems for fast
growing urban areas in China

presented paper

This project was the fundament of thetreatment systems for urban areas in China”.

research project “Semi-centralized supply andFederal Republic of Germany for the founding of theThanks to the Ministry of Education and Research of the

Acknowledgement

Institute• developing integrated planning and approval processes for
integrated semi-centralized supply and disposal systems• optimising technical concepts

actual research• integrated supply and disposal systems of a size between
50,000 and 100,000 residents should be preferred

Current research status

Institute36

34

- 296 -Semi-centralized supply anddisposal systems for fast
growing urban areas in China

Thank you for your attention
37

Thank you for your attention

Institute