economic feasibility for the recycling of construction waste
Resources,Conservation and Recycling 54 (2010) 377–389
Contents lists available at ScienceDirect
Resources,Conservation and
Recycling
j o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /r e s c o n r e
c
Evaluation of the economic feasibility for the recycling of construction and demolition waste in China—The case of Chongqing
W.Zhao a ,R.B.Leeftink b ,V.S.Rotter c ,?
a
Institute of Construction Management and Real Estate,Chongqing University,Shabei Street 83,400045,Chongqing,PR China b
Decistor bv,Bilderdijkstraat 4,2013,EJ Haarlem,Netherlands c
Department of Waste Management,Institute of Environmental Engineering,TU Berlin,Sekr.Z 2,Strasse des 17,Juni 135,10623,Berlin,Germany
a r t i c l e i n f o Article history:
Received 15January 2009
Received in revised form 3September 2009Accepted 6September 2009Keywords:
Construction and demolition waste recycling
Economic feasibility Model China
a b s t r a c t
In the recycling chain of construction and demolition waste,it is impossible to guarantee a certain quality of recycled products and to recycle a large amount of materials in recycling centers without mechanical sorting facilities.This counts even more when the produced materials have a low economic value,as is the case with crushed and cleaned debris,also called aggregates.In order to assess if recycling can be done effectively,a feasibility study of the recycling of construction and demolition (C&D)waste is necessary.In the paper,the economic feasibility of recycling facilities for C&D waste in China’s Chongqing city was assessed.Investigations on the current situation of C&D waste recycling in Chongqing showed that there were a large quantity of waste and an enormous demand for recycled materials due to the busy ongoing construction activities,which generated a large market potential and also brought a challenge to the strengthening of the recycling sector.However,a full cost calculation and an investment analysis showed that,under current market conditions,operating C&D waste recycling centers in Chongqing might face high investment risks.Thus,the regulations and economic instruments like tax that can support the economic feasibility of recycling are discussed,and the recommendations for the choice of instruments are provided.
? 2009 Elsevier B.V. All rights reserved.
1.Introduction
Construction and demolition (C&D)waste is one of the largest waste ?ows in the world.In China,urban C&D waste has reached 30–40%of the total urban waste generation because of the large-scale construction and demolition activities resulting from the accelerated urbanization and city rebuilding (Chui and Yang,2006).Typical emissions from land?lling C&D waste are chemicals leach-ing from wood,drywall and concrete, e.g.,chromated copper arsenate (CCA)-treated wood containing a lot of hazardous sub-stances such as chromium and lead is contributing to toxic impact on ground and surface water and soil (Symonds,1999).Further-more,hydrogen sul?de (H 2S)as a major odorous component from C&D land?lls contributes to acidi?cation (Reinhart et al.,2004).Additionally,non-recycled waste will result in the loss of construc-tion materials and the occupation of land?ll space for ?nal disposal.From a broad point of view,disposal of C&D waste is not only a simple environmental concern,but also has major in?uence on the conservation of resources for the whole society,since it avoids exca-vation of raw materials and provides substitution for materials like
?Corresponding author.Tel.:+4903031422619;fax:+4903031421720.E-mail address:vera.rotter@tu-berlin.de (V.S.Rotter).cement and plastics which requires a signi?cant amount of raw material,energy and funding to produce.
In China,the recycling lacks a central,stable and ?exible inter-mediate between waste generation and land?ll like recycling centers to transform the waste into recycled secondary construc-tion materials.Unorganised collection and subsequent sorting out by waste pickers is an obstacle to plant operators of construction materials.One key concern of an operator in a recycling center is to assure the secure quantitative and qualitative supply of recyclable waste materials.
The objective of this paper is to evaluate the economic feasibility for the recycling of C&D waste.By further simplifying the structural model of a feasibility study of a complex project,the essential steps in pre-feasibility study of C&D waste recycling are identi?ed with reference to Kohler (1997).a.Estimated generation of C&D waste.b.Market analysis of recycled materials.c.Estimated costs of recycling facilities.
d.
Analysis of investments (including payback period,internal rate of return and breakeven point).
As a case study,these steps were applied to the situation in Chongqing.The C&D waste generation was estimated,the waste
0921-3449/$–see front matter ? 2009 Elsevier B.V. All rights reserved.doi:10.1016/j.resconrec.2009.09.003
378W.Zhao et al./Resources,Conservation and Recycling54 (2010) 377–389
composition was quali?ed and the potential demand in the mar-ket of main recycled materials(aggregates,brick,wood and metal) was analyzed.The economic feasibility of different recycling facil-ities was evaluated by cost estimation and investment analysis. Meanwhile,the estimated cost and revenue of a recycling center in Chongqing were compared with that in the Netherlands to?nd out successful factors of recycling centers,since it had been proved by our interviews with managers that C&D recycling centers in the Netherlands could be pro?table over the last25years of operation. Eventually,a set of recommendations were concluded for policy makers through addressing the related regulations and economic instruments like tax contributing to the success of such a recycling facility as well as recycling market strategy.
2.Background
2.1.De?nition of C&D waste
In general,although there is no uniform de?nition of C&D in the world,the waste is mainly classi?ed based on the origin and the composition of C&D waste.
In the United States,construction and demolition waste is a waste material that is“produced in the process of construction,ren-ovation,or demolition of structures.Structures include buildings of all types(both residential and non-residential)as well as roads and https://www.sodocs.net/doc/5d2879099.html,ponents of C&D debris typically include concrete, asphalt,wood,metals,gypsum wallboard,and roo?ng”(Franklin, 1998).
In China,a National Guideline,Regulations for Construc-tion Waste Management in Cities de?nes C&D waste as:“The soil,material and others are discarded and generated by any kinds of construction activities,including the development,reha-bilitation,refurbishment of construction projects”(Ministry of Communications of the P.R.China,2005).
These two de?nitions are both based on construction activities. However,the former is more complete and clearer than the latter, since structure and waste composition are described in the former.
2.2.C&D waste composition and generation
Dolan et al.(1999)identi?ed as factors in?uencing the amount of C&D waste produced:
?The extent of growth and overall economic development that drives the level of construction,renovation,and demolition.?Periodic special projects,such as urban renewal,road construc-tion and bridge repair,and unplanned events,such as natural disasters.
?Availability and cost of hauling and disposal options.?Local,State and Federal regulations concerning separation,reuse, and recycling of C&D waste.
?Availability of recycling facilities and the extent of end-use mar-kets.
C&D waste contains broken concrete(foundations,slabs, columns,?oors,etc.),bricks,mortar,wood,metal and roo?ng materials(windproof,waterproof and insulating materials)as well as packaging materials(paper,cardboard,plastic?lm and other materials as buffer like wood and foam plastics).C&D wastes are categorized in a variety of ways,and different composition and characteristics of waste are described based on each category.There are three main factors that affect the characteristics of C&D waste (ICF,1995):?Structure type(e.g.,residential,commercial,or industrial build-ing,road,bridge).
?Structure size(e.g.,low-rise,high-rise).
?Activity being performed(e.g.,construction,renovation,repair, demolition).
The direct methods for the determination of waste genera-tion and its composition is really weighing,measuring,sorting of the total?ow of waste or based on sampling and extrapolation (Brunner and Ernst,1986).Indirect analysis uses primary statistics on consumption,trade or other economic indicators or a descrip-tion of the stocks in order to estimate the generation rate.This approach was applied by Hsiao et al.(2002).
2.3.Potential demand for recycled materials
The demand for recycled material is determined by quality and price.The following application for secondary construction mate-rial can be identi?ed.
2.3.1.Aggregates
Natural aggregates(NA),containing sand,gravel,crushed stone and quarried rock are used to prepare the foundation material for construction purposes(Poon et al.,2006).In China,there are exist-ing national standards for?ne aggregates(GB/T14684,National Standard of Sand Utilization,General Administration of Quality Supervision,Inspection and Quarantine of the P.R.China,2001a) and coarse aggregates(GB/T14685,National Standard of Crushed Stone,General Administration of Quality Supervision,Inspection and Quarantine of the P.R.China,2001b).Nominal sizes of two kinds of aggregates ranging from less than2.36to37.5mm,comply with the grading of GB/T14684and GB/T14685,respectively.
Tam and Tam(2006)described the following application for recycled aggregates(RA)sourced from the C&D waste recycling facility:foundation material for road construction,hardcore for foundation works,base/?ll for drainage,aggregate for concrete manufacturing and general bulk?ll.Recycled concrete aggregates (RCA)differ from natural aggregates,due to the fact that impurities like the cement-stone are still attached to the surface of the original natural aggregates even after the process of recycling.These highly porous cement-stone and other impurities contribute to a lower particle density and higher porosity,variation in the quality of the RCA and the higher water absorption(Paranavithana and Abbas, 2006).In China,RCA is simply shredded by a crusher and used as an additive for producing concrete by mixing with cement and water. Considering the impact of RCA on quality of concrete based on par-ticle density,porosity and absorption,Chen(2005),Poon and Chan (2007),Wu(2004),Zhang and Qi(2004)indicated that the substi-tute rate of NA is equal to or less than20%and RCA could only be applied in concrete equal to or less than C30(“C”is an abbreviation of concrete,30means the compressive strength on a concrete cube is30MPa)with reference to GB/T14684and GB/T14685.Accord-ing to GB50010(code for design of concrete structures,Ministry of Construction and Administration for Quality Supervision and Inspection and Quarantine of the P.R.China,2002),concrete equal to or more than C30could be applied in prestressed reinforced con-crete https://www.sodocs.net/doc/5d2879099.html,ly,applications of concrete equal to or less than C30are mainly limited to low-rise buildings and some pub-lic concrete structures such as park place.The application of RCA in Shanghai ecological building in China is mainly used in foun-dations and walls(Li,2009).In order to be more conservative,it is assumed that the RCA content is5%in concrete equal to or less than C30,same with the substitute rate of NA for reinforced con-crete work in Kuwait(Kartam et al.,2004).Report of China Cement Association showed that about78%of total concrete production is C30and less than C30concrete in China(Anhui Development
W.Zhao et al./Resources,Conservation and Recycling54 (2010) 377–389379
Table1
The potential applications of recycled wood depend on their quality.
Approach Quality A wood a B wood b C wood c
Use for erosion control and groundcover
Organic soil amendment(in agriculture)after composting
Chipboard production
Wood chips for animal bedding
Fertilizer amendment in composing
Energy recovery by means of incineration
=feasible.
a A-quality wood—clear wood.
b B-quality wood—slightly contaminated,e.g.,with paints,glues and coatings.
c C-quality wood—hazardous woo
d wast
e contaminated with heavy metals,?re retardants and wood preservatives.
and Reform Commission,2007).The composition of concrete with cement:water:aggregate is1.2:0.8:8and60%of countrywide out-put of cement is used to make concrete(Shi and Xu,2006).
RA and RCA are better as road foundation/basement than vir-gin material,for the strength caused by residual non-hydrated cement and the wide particle size distribution.To meet the strength requirement of base and foundation of roads,according to the?rst application of RAC in pavement in Shanghai,a RCA content of50% was used in order to be more conservative(Xiao,Wang,Sun,&Li, 2005).Meanwhile,RA is only used in II and below II class high-way(for II,III and IV class highway,design speeds are limited to below80,40and20km/h,respectively)with reference to JTG B01(National Standard of Road Grate,Ministry of Communications of the P.R.China,2003).In addition,blast furnace?y ash is only allowed up to a certain(low)percentage in aggregates to enforce the road foundation,because of the high content of heavy metals. Coal slag is to a certain extend used in Western Europe for the same in road foundation(Feuerborn,2005).
2.3.2.Brick
Presently,brick is the largest component of C&D waste due to the traditional building habits and old-line production technology. However,converting building fashion from traditional brick struc-ture to reinforced concrete or steel structure,results in a decrease of the brick demand.At the same time,a ban on using clay as a raw material of brick had been implemented from2003by China Coun-cil for the Promotion of International Trade,since excavation of clay damages agriculture land.The substitutable bricks supported by patented technologies on bricking and cavity block made from inert materials(concrete,brick,mortar)(State Intellectual Prop-erty Of?ce of P.R.China),are gradually being applied in building industry.Broken bricks are mixed with adhesive and cement to produce blocks.Considering environmental protection and qual-ity of bricking from mixed C&D waste,it is assumed that bricking and cavity block are mainly used for non-residential structures and non-buildings(enclosure,ground tile and greening).Using broken Table2
Unit operations for C&D waste treatment.
Technique Function
Manual separation Separate recoverable materials,disturbing
materials
Crushers Size reduction
Wind-sifting Separate light and heavy materials in solid waste
by means of density separation
Screening Make a size separation
Shaking-table Separate light from heavy materials in solid waste Magnetic separation Remove ferrous metals from non-magnetic
materials
Eddy current separation Recovery of non-ferrous metals
Flotation Use the buoyancy produced by the attached tiny
air bubbles to the dispersed hydrophobic particles
and lift them to the surface of the chamber brick as substitute for raw material for brick production must be the third main recycling approach of crushed brick next to road foundation and construction?ll.
2.3.3.Wood
Although wood is not increasing in the waste stream,new technologies of recycling wood are being explored.For instance, Logistics Engineering College successfully developed“arti?cial wood bricks”(mixture of wood?our and cement)as pre-embedding device of electricity,water,gas supply(Lu,2006). Considering wood quality in terms of speci?c contaminants,there are several potential and normal applications for recycled wood in developed countries,such as those listed in Table1(Kartam et al., 2004;Rijpkema,1999).
In China,clean and de-nailed timber and boards are ef?ciently recycled and reused by contractors to avoid disposal fee and extra purchase cost of construction materials(Chen,2005).Uncontam-inated wood is used for chipboard production and furniture at present.Moreover,Finite market like animal bedding is an obstacle to decrease further unit cost by enlarging output,according to the economy of scale.Waste wood can be used to increase the calori?c value of municipal solid waste(MSW)for the waste incineration, which has under the high proportion of organic waste in China a calori?c value below the self burning temperature resulting in the substitution of additional oil and coal for the combustion process. However,for painted and waterproof wood,the market potential is limited due to the limited number of waste incinerators with suf?cient?ue gas cleaning,in China(Ji,2003).
2.3.4.Metals
The market for recycled metals such as steel or aluminum is fast growing because of their high economical value.Steel con-sumption of construction industry has increased from14.56Mt (1991)to78.1Mt(2001)in China(You,2005).Increasing prices of metals encourage contractors to separate as much as possible reinforcement bars from crushed concrete on construction sites. Furthermore,metal industry also purchases deformed reinforce-ment bars from individuals scavenging at dumpsites.
2.4.Technologies for recycling centers
At present,recycling technologies of C&D waste mainly come from mining industry based on mechanical https://www.sodocs.net/doc/5d2879099.html,mon separation techniques are described in Table2(Xing and Charles, 2006).The technology used at recycling plants is determined by the scale of investment,quality requirement for recycled materials, cost and revenue of recycled production.A recycling plant usually consists of crushers,screeners,magnetic separators,wind-sifting and manual separation as demonstrated in Fig.1.To attain higher quality of recycled production,recycling plant contains a second separation or more by means of combination of these technologies shown in Table2.
380W.Zhao et al./Resources,Conservation and Recycling
54 (2010) 377–389
Fig.1.Flowsheet of a C&D waste recycling plant in the Netherlands (Jong and Kuilman,2008).
2.5.Cost estimation and investment analysis of recycling facilities Dolan et al.(1999)and Duran et al.(2006)proposed a structural model of economic feasibility of recycling facilities and correspond-ing assumptions.Results of economic feasibility analyses for C&D waste recycling facilities in the Taiwan,USA,Hong Kong and India were quoted in some studies,but few details about the method-ology used and data collected were presented (Huang et al.,2002;MACREDO,2006;Tam and Tam,2006;TIFAC,2006).Duran et al.(2006)and Nunes,Mahler,Valle,and Neves (2007)discussed eco-nomic feasibility of future recycling facilities in Ireland and Brazil based on different scenarios such as capacity.Symonds (1999)showed detailed calculations and assumptions used to estimate the cost of C&D waste recycling center in the USA.Klang et al.(2003)although considered environmental and social aspects besides eco-nomic aspect to evaluate recycling feasibility in Sweden,data in economic aspect were not comprehensive.Additionally,there has been relatively little research about economic feasibility of C&D waste recycling in China.
Cost estimation models are mathematical algorithms or para-metric equations used to estimate the costs of a product or project (Dean,1995).The results are typically necessary to obtain approval to proceed,and are factored into business plans,budgets,and other ?nancial planning and tracking mechanisms.The total costs of a product or project are divided into ?xed costs (including costs for maintenance,depreciation,insurance and ?nancing)and variable costs (including costs for labour,energy,transportation,etc.).
The de?nition of investment analysis is that a study of the likely return from a proposed investment with the objective of evaluating the amount an investor may pay for it,the investment’s suitabil-ity to that investor,or the feasibility of a proposed real estate development.There are various methods of investment analysis,including “cash on cash return”,“payback period”(PP),“internal rate of return”(IRR),and “net present value”(NPV).Each method provides some measures of the estimated return on an invest-ment based on various assumptions and investment horizons.For investors,there are two necessary preconditions of the investment:?Life time of main equipments exceeding PP (time required to recover an investment)of investment on disposal facilities.
?Estimated pro?t from IRR (the discount rate for which the total present value of future cash ?ows equals the cost of the invest-ment)exceeding opportunity cost of capital investment with reference to interest of saving.
To achieve economic feasibility of recycling,unit recycling cost (Rc )and acceptable unit pro?t (P )must be covered by main rev-enue from the gate fee to recycling per ton (Gf )and the revenue of
recycled materials per ton (RCp ),as the following Eq.(1).Rc +P ≤Gf +RCp (1)
3.Methodology
For this study,the data collection is comprised of three activities.?The data about generation and composition of waste in Chongqing were collected from 66construction and demo-lition sites through questionnaires sent to contractors and visiting some of the municipalities and contractors and data from the Chongqing Statistical Yearbook (Statistical Yearbook is a large annual statistical publication compiled by Chongqing Municipal Bureau of Statistics ,which covers comprehensive data on Chongqing’s social and economic development per year.).The data about potential demand for C&D waste came from various literatures with priority being given to recent literature con-taining extensive bibliographies and the Chongqing Statistical Yearbook.
?Data concerning the ?xed costs,especially equipment costs and corresponding certi?cations of recycling facilities,were obtained from various literature references and interviews with managers in recycling centers in the Netherlands as reference,since there are no such C&D waste recycling centers in China at this moment and thus no reliable cost data available.
?Data of operating costs like unit labour cost were identi?ed with reference to corresponding prices in 2003by Chongqing Price Information Center (an authorized website for various price searches).Most of the data were collected between May and December 2007.3.1.Scope of the study
Chongqing is a commercial and industrial center with average increase rate of the GDP of around 10%per year from 1978to 2006.Average growth rate of investment in construction activ-ities is about 25.4%from 1997to 2006.Chongqing municipality was established on March 14,1997.Covering an urban area of 631.35km 2,there were a total of 15districts and 13.11million urban inhabitants in Chongqing in 2006(Chongqing Municipal Bureau of Statistics,2007).
Generally,the aspect of recycling C&D waste mainly depends on the following factors of a district:the scarce of natural aggregates resource,the industrialization level and the population density (Li,2008).Table 3shows that the higher population density in Chongqing and the Netherlands compared with China indicates boom of potential residential buildings demand in Chongqing and the Netherlands.The comparison of the ratio of industrial added
W.Zhao et al./Resources,Conservation and Recycling 54 (2010) 377–389
381
Table 3
Similarities and differences between the Netherlands and Chongqing in regional factors in?uencing recycling C&D waste in 2006.Factors
China
Chongqing
Netherlands
Population density (people/km 2)256a 390a 483b Natural aggregates resources
?Sand
?Sand
?Sand
?Gravel:sea and riverbeds ?Gravel:riverbeds
?Gravel:northsea and riverbeds ?Rock/mining/mountains ?Rock/mining/mountains ?No rock/mining/mountains Industrialisation level (%)43c
26.8d
16.79b
Current situation of recycling
?Mixed collection e ?Mixed collection f ?Separation at source g
?Manual separation
?Manual separation
?A healthy market for recycled products
?High scrap value materials like steel recycled
?High scrap value materials like steel recycled
?Simple land?ll (dumping)
?Simple land?ll (dumping)
?Financial incentives,such as land?ll tax introduced by the Environmental Taxes Act
?Encouraging utilization of energy-saving,recycling and environmental technologies in construction materials
?Quantitative limitation and quality control of quarry
?The ban on land?ll
a Data source :Population density of the China,Chongqing and the Netherlands from National Statistic Agency of China (2007b).
b Data source :Population density of the China,Chongqing and the Netherlands from Statistics Netherlands (2007).
c Data source :Building industry level of the China,Chongqing an
d th
e Netherlands from National Statistic Agency o
f China (2007a).
d Data sourc
e :Building industry level o
f the China,Chongqin
g and the Netherlands from Chongqing Municipal Bureau of Statistics (2007).e Data source :Current situation of recycling of the China from Zhao and Rotter (2008)and China Academy of Building Researc
h (2005).
f Data source :Current situation of recyclin
g of the Chongqing from investigation on construction sites and Chongqing Construction Commission (2002).g
Data source :Current situation of recycling of the Netherlands from Ministry of Housing,Spatial Planning and Environment (2001).
value to regional GDP,i.e.the regional industrialisation level (Lin et al.,2009),implies that although there is no great
potential demand for non-residential buildings compared with nationwide,this demand is higher than the demand of the mature recycling market in the Netherlands.For the scarce of natural aggregates resource,although there are abundant natural aggregates resources in Chongqing and China compared with no rock in the Nether-lands,national and regional regulations have began to encourage recycling and limit amount of quarry.Considering the above three factors,it can be concluded that for Chongqing,a promising prospect for recycling of C&D waste can be achieved (Fig.2).
C&D waste generation and potential demand of recycled mate-rials (aggregates,brick,wood and metal)were calculated based on the data collected in Chongqing.To evaluate the economic fea-sibility of recycling centers based on different scenarios (plant type,equipment and land),cost estimation (including ?xed costs and variable costs)and investment analysis (IRR,PP and BP)
Fig.2.Location of Chongqing city in China.
were applied.Obstacles of economic feasibility were discussed by comparison of costs and revenues between Chongqing and the Netherlands.
3.2.C&D waste composition and generation rate
There are no data available about the average composition and quantity of C&D waste in Chongqing,since the construc-tion companies until now are not obliged to record and report the qualitative and quantitative characteristics of the waste they generate.In the ?rst approach,rough assumptions were attained through indirect analysis.The C&D waste composition was attained by calculating the arithmetic mean of data from 38construc-tion sites and 28demolition sites.All the sites covered different structures (brick–concrete structure means brick wall have the function of bearing load of residential building (Li and Wang,2005);as frame structure reinforced concrete or steel are used as load-bearing beams for high-rise residential and commercial buildings;wall structure is a frame structure with shear wall for anti-earthquake performance of a high-rise building)with a ?oor area of 1.42Mm 2(construction actives of 1.24Mm 2and demolition actives of 0.18Mm 2)and the sites are located in 7districts.
Generation rate is estimated by project managers of construc-tion and demolition sites based on an estimation of the waste production activities by means of calculating the number of trucks to land?ll.The basis to estimate generation of construction waste (Wc )and demolition waste (Wd ),respectively,is the speci?c gen-eration rate per activity as expressed in Eq.(2):Wc =Fb ×Dc Wd =Fd ×Dd
(2)
where Fb means the ?oor area of building from Chongqing Sta-tistical Yearbook;Dc means the generation rate of construction waste;Fd means the ?oor area of demolition from interviews with governors;Dd means the generation rate of demolition waste.3.3.Potential demand of recycled materials
Considering competition of industry solid waste (coal slag and ?y ash of coal-?red power plants)as road base and foundation,their amount should be deducted from the potential demand of recycled
382W.Zhao et al./Resources,Conservation and Recycling54 (2010) 377–389
Table4
Assumption and equation to estimate the demand of recycled aggregates.
Items Equation Assumption and reference
Road construction Volume of aggregates for road
construction(Mm2)R=L×W×T/1000L additional roads,in Km(National Statistic Agency of China,
2002–2006)
W average width,and T thickness of base for II class road work,12and
0.4,in m(Ministry of Communications of the P.R.China,2003)
W and T for below II class road work,6.5and0.15,in m(Ministry of
Communications of the P.R.China,2003)
Recycled aggregates for road work(Mt)Rr=R×D×Sr r D density of base and foundation for road work,2,in ton/m3(dry
weight)(Road Institute of Ministry of Communications of the P.R.
China,2000)
Sr r substitute rate of recycled aggregate for road construction,50%
(Xiao et al.,2005)
Concrete production≤C30concrete production(Mt)C=E/(Pc×Pc c×Pc30)E cement production,in Mt(Chongqing Municipal Bureau of Statistics,
2002–2006)
Pc Percentage of cement in concrete,12%(Shi and Xu,2006)
Pc c percentage of cement used to make concrete,60%(Shi and Xu,
2006)
Pc30percentage of concrete used for≤C30Concrete production,78%
(Anhui Development and Reform Commission,2007)
Recycled aggregates for concrete work
(Mt)
Ra=C×Pa×Sr c Pa percentage of aggregates in concrete,80%(Shi and Xu,2006)
Sr c substitute rate of recycled aggregate in concrete production,
5%(Kartam et al.,2004)
Corrected Rr(Mt)Rr =Rr?Id Id quantity of coal slag and?y ash,in Mt(Chongqing Municipal Bureau
of Statistics,2002–2006)
aggregates for road construction.The potential demand for RA for concrete work after estimating concrete production in Chongqing was calculated.Quantity of RA for road work was estimated by calculating volume of base and foundation and subtracting the quantity of coal slag and?y ash.Eventually,the estimated demand for total recycled aggregates was calculated.Table4shows the detailed equation and reference for estimation of potential demand of recycled aggregates.3.4.Cost estimation for recycling facilities
The design and capacity choice of a recycling facility is deter-mined by capital costs and has to consider the annual waste generation,economy of scale,relative transportation costs,dis-tance of contractors and potential associated tipping fee(disposal fee of land?ll).According to Duran et al.(2006),Nunes et al. (2007)and Symonds(1999),a medium scale recycling facilities
Table5
Assumptions for calculating recycling unit cost for a mobile and?xed recycling centers in this paper.
Component Assumption
Fixed recycling facility Mobile recycling facility Background Capacity:100t/h Capacity:50t/h
Working life of equipment:7years(new);4year (used) Working life of equipment:7years(new);4year (used)
Work day:300days per year(Duran et al.,2006) Work day:220days per year
Work time:8h/day Work time:8h/day
Operating costs increase at3%per year Operating costs increase at3%per year
Capital costs Construction 10,640D No construction cost
Equipments 642,480D(Nunes et al.,2007) 500,000D
Used equipment’s capital cost of1/2of the capital cost of ne equipment(Nunes et al.,2007) Used equipment’s capital cost of1/2of the capital cost of new equipment(Nunes et al.,2007)
“Equipments”including one crushers,one screen set, one loaders “Equipments”including one crushers,one screeners, one loaders
Land cost A land area of4ha(40,000m2)(Symonds,1999) No land costs
A nominal rent of1500D/ha per year(agricultural
rent levels)
Opportunity costs Interest rate:5% Interest rate:5%
Operating costs Labour 6quali?ed workers;12unquali?ed workers;1
manager 4quali?ed workers;8unquali?ed workers;1 manager
Monthly wage(Chongqing price information center) Monthly wage(Chongqing price information center)
Energy Electricity:0.04D/kwh(Chongqing price information
center) Electricity:0.04D/kwh(Chongqing price information center)
Disposal “Disposal”:20%of quantity of input(Nunes et al.,
2007); “Disposal”:20%of quantity of input(Duran et al., 2006);
Average tipping fee of land?ll of0.5D/t(Commodity Prices issued documents)and transportation cost to land?ll of0.5D/t Average tipping fee of land?ll of0.5D/t(Commodity Prices issued documents)and transportation cost to land?ll of0.5D/t
Other “Other”including maintenance with new equipments
(6%of equipment investment),maintenance with used
(1.2times the maintenance cost of new equipment),
insurance(1%of equipment investment) “Other”including maintenance with new equipments(6%of equipment investment), maintenance with used(1.2times the maintenance cost of new equipment),insurance(1%of equipment investment)and transport of facility
W.Zhao et al./Resources,Conservation and Recycling54 (2010) 377–389383
Table6
Methods to analyze the investment of recycling center.
Methods Description Equation
IRR–Eq.(3)
Discounted PP Discounted PP by considering time value of annual cash in?ows based on net present value(NPV)Eq.(4)(Jia,2000) NPV(discounted rate5%)The present value of an investment’s future net cash?ows minus the initial investment–
BP in terms of number of units The minimum point at which total sales revenue and production costs are?nancially equal Eq.(5)
Table7
Mean and standard deviation(SD)of construction waste composition in2006in Chongqing.
Component Proportion(%)Number of
interview
Brick Mortar Concrete Package material Roo?ng material Steel Wood Other Total
Brick–concrete structure Mean2923144 1.5 2.5151110012
SD13.5410.479.02 2.830.62 1.217.467.83
Frame structure Mean261716122415810016
SD13.638.478.847.2 1.34 2.647.87 5.5
Frame-shearwall structure Mean17.51317.5837181610010
SD 6.36 6.9310.11 3.93 2.2 4.669.7510.86
Table8
Mean and standard deviation(SD)of demolition waste composition in2006in Chongqing.
Component Proportion(%)Number of
interview
Brick Mortar Concrete Roo?ng material Steel Wood Other Total
Brick–concrete structure Mean56.510.515645310016
SD19.29 6.22 6.02 3.63 2.52 3.39 2.06
Frame structure Mean24.59.550.5 4.5 6.5 1.5310012
SD13.56 5.9121.07 1.81 5.04 1.33 1.85
(100ton/hour,t/h)service each district to recycle approximate200 thousand ton per year.Another option is three mobile recycling centers(50t/h)in a district.Since the market for used equipment is due to the sound development of the mining sector,used equip-ment was taken into account in the analysis in order to consider an option with the decrease of the capital costs and more important, more positive cash?ow opportunities.The technology adapted to the Chinese circumstance for the recycling of C&D waste is sim-ple and labour intensive.In those projects,the required equipment processed only the mineral fractions and a magnetic separator removed the ferrous fraction.The other fractions,excluding the mineral and ferrous ones,were removed by hand prior to the crush-ing process and then sold or transported to land?lls.
Six scenarios are developed for the cost estimation of a future recycling facility,based on the following three options:
?Type of the recycling facility:?xed center with100t/h or mobile center with50t/h.
?Equipment:used or new.
?Land cost:included or excluded.
Table5shows assumptions for a mobile and?xed recycling cen-ter in Chongqing,the recycling cost of which was calculated based on the equipments data and related speci?cations from recycling facilities in the Netherlands as discussed by Duran et al.(2006) and Nunes et al.(2007)as well as the unit cost for land,energy, labour from Chongqing Price Information Center.More workers were assigned to do hand sorting of metal and pre-sorting in recy-cling facilities because of low labour cost and improvement in quality of recycled materials.
3.5.Investment analysis of recycling center
Table6shows various methods of investment analysis.IRR,dis-counted PP and breakeven point(BP)with alternating scenario were induced in the analysis of investment.
n
t=0
(CI?CO)t(1+IRR)?t=0(3)
where IRR is the internal rate of return,CIt is the cash income of the t th year,COt is the cash expenditure of the t th year and n is the life time of recycling facility.
T?p
t=1
(CI?CO)t(1+i0)?t=0(4)
where T?p is the dynamic investment payback period(year),CIt is the cash income of the t th year,COt is the cash expenditure of the t th year and i0is the discount rate.
Annual output at BP=
annual?x costs
Uunit sales price?unit variable cost
(5)
where annual?xed costs(including costs of maintenance, depreciation,insurance,?nancing per year);annual unit variable cost(including labour,energy,disposal costs divided by out-put per year).Currency exchange rate of D1=￥10(September 2007).
4.Results—a case study of Chongqing
4.1.C&D waste composition and generation in Chongqing
Data source:Floor area of building from the Chongqing Municipal Bureau of Statistics(2003–2007);Floor area of demo-lition from the Chongqing Ministry of Construction website; Construction waste per m2of?oor area in Chongqing,0.03,in
384W.Zhao et al./Resources,Conservation and Recycling54 (2010) 377–389
Table9
Estimation of the potential demand for recycled aggregates for road construction in Chongqing.
Year II class road Below II class road Total(Mt) Road length(km)Road volume(Mm3)RA for road work(Mt)Road length(km)Road volume(Mm3)RA for road work(Mt)
2001256 1.23 1.23530.050.05 1.28 2002241 1.16 1.16?8900.00 1.16 2003542 2.60 2.602420.240.24 2.84 2004510 2.45 2.455208 5.08 5.087.53 20051264 6.07 6.076072759.2159.2165.28
Table10
Recycled aggregates demand in Chongqing.
Year Total cement production(Mt)≤C30concrete production(Mt)Recycled aggregates for
concrete work(Mt)Rr(Mt)Quantity of coal slag
and?y ash(Mt)
Corrected
Rr(Mt)
Total(Mt)
200115.1158.93 2.36 1.28 4.100 2.36 200216.8065.52 2.62 1.16 4.350 2.62 200319.2775.15 3.01 2.84 4.610 3.01 200419.0674.33 2.977.53 6.06 1.47 4.44 200521.0181.94 3.2865.28 6.9858.3061.57
ton/m2(interviews with project managers);Demolition waste per m2of?oor area in Chongqing,1.01,in ton/m2(interviews with project managers).
The average C&D waste generation in Chongqing between2002 and2006is estimated to be approximate4.2Mt per year(exclud-ing excavated soil).The percentage of construction waste is36%, while construction waste and demolition waste contribute to1.5 and2.7Mt per year,respectively.In2003,a regulation to prevent the overheated investment in building by limiting the?oor area of demolition was issued by the Ministry of Construction.Thus in the following3years,the average amount of waste did not increase anymore.
Based on the66interviews,the average composition in weight can be estimated according to Tables7and8.Inert materials account for more than50%of the total C&D waste among different structures.There is a little difference in composition of construction waste between different structure types,however in the composi-tion of demolition waste,brick and concrete account for a large proportion.4.2.Potential demand for recycled materials
Tables9and10indicate that the potential demand for recy-cled aggregates for road construction and concrete production per year is exceeding the actual generation rates especially in2005. Meanwhile,with increase in substitute rate of recycled aggre-gates and aggregates demand resulted from boom of real estate and infrastructure,the demand for recycled aggregates will further increase.
In Chongqing,an incineration plant with energy recovery was built in2005.It can deal with about0.38Mt of MSW per year. Since the caloric value of MSW is only800kcal/kg,proportion of mixture between MSW and coal is4:1for the combustion process (Newenergy,2008).If coal is entirely substituted by waste wood, the minimum demand for waste wood will be95,000t per year. The second incineration plant with a capacity of0.6Mt per year is planned.Total demand of about0.25Mt per year for incinera-tion can be covered by output of waste wood such as0.27Mt after recycling in2006.
Table11
Example cost calculation for the recycling cost in potential recycling centers in Chongqing in2003.
Concept Fixed center with100t/h Mobile center with50t/h
Used equip.New https://www.sodocs.net/doc/5d2879099.html,ed equip.New equip.
Capital costs00 Construction works(D)10,64010,640250,000500,000 Cost for equipments(D)317,280642,48000 Land costs(D)30,00052,50030,000105,000 Opportunity costs(D)42,950148,180
Operational costs
Labour(D)16,80016,80012,00012,000 Energy(D)28,80028,80014,08014,080 Disposal(D)48,00048,00017,60017,600
Other(D)49,43144,97452,00048,500 Total(1st year)(D)143,031138,57495,68092,180 Total(2nd year)(D)147,322142,73198,55094,945 Total(3rd year)(D)151,742147,013101,50797,794 Total(4th year)(D)156,294151,423104,552100,728 Total(5th year)(D)155,966103,749 Total(6th year)(D)160,645106,862 Total(7th year)(D)165,464110,068 Total cost(D)999,2601,915,615680,2891,311,326 Unit cost(D/t) 1.04 1.14 1.93 2.13 Unit cost excluding land(D/t) 1.03 1.13
W.Zhao et al./Resources,Conservation and Recycling 54 (2010) 377–389
385
Table 12
Internal rate of return,payback period and breakeven point of different recycling centers.Concept
Mobile center with 50t/h Fixed center with 100t/h and revenue of 2.1D /t 3.8D /t 2.1D /t Including land cost Excluding land cost Used equip.
New equip Used equip.New equip Used equip New https://www.sodocs.net/doc/5d2879099.html,ed equip New equip.Annual ?xed costs (D )
113,500
131,430
113,500
131,430
153,275
176,400
147,275
170,400
Unit variable cost per year (D /t)0.500.500.500.500.390.390.390.39IRR (%)
174591752237123774PP excluding sales tax (year) 1.91 3.36 3.69>7.5 1.46 2.43
1.43
2.38Output in BP excluding sales tax (t per year)
34,356
39,783
70,777
81,966
89,635
103,158
86,126
99,649
There is no brick factory making use of C&D waste in Chongqing.Experiences of the brick factory built in 2004in Handan showed that 0.4Mt of C&D waste can produce 0.15billion bricks per year (Construction in Hebei province,2006).It is estimated that 1.09Mt of used bricks from C&D waste can be used,based on the output of approximate17billion bricks in 2003in Chongqing and paving tile accounting for 2.4%of total output in 2003in China (Zhou,2004).
In Chongqing,steel scrap recycled from C&D waste made a little contribution to the total recycling rate due to its low percentage in C&D waste,which is about 5%.Nevertheless,the material recycling rate is over 90%in Chongqing according to questionnaires.Accord-ing to the generation rate,the waste composition and an assumed recycling rate of 90%,about 0.19and 0.2Mt of steel are supposed to be recycled in 2003and 2005,based on the waste generation illustrated in Fig.3and the steel proportion in C&D waste shown in Tables 7and 8.The amount of steel scrap is 2.35and 2.95Mt,cor-responding to only 8%and 7%of total steel production of in 2003and 2005,respectively (Chongqing Municipal Bureau of Statistics,2004,2006).
4.3.Cost estimation for C&D waste recycling centers
Table 11illustrates a summarised form in the capital costs and operational costs necessary
for 50and 100t/h recycling centers,according to the production volumes and option of new or used equipments.It shows that unit cost with different capacity is the great difference because of scale economics.Advantage of the total cost of mobile facility is weakened by low output annually,since it takes time to complete the work of equipment installation and transportation of recycling facility.The contribution of used equip-ments costs on unit cost is about 10%lower than that with new equipments.Although the impact of land cost of ?xed facility on unit cost is only 0.01D /t,it can further enlarge the cost advantage of a ?xed facility compared to a mobile facility.Unit cost for a recy-
Fig.3.Estimation of the quantity of C&D waste generation in Chongqing between 2002and 2006.
cling center with a capacity of 100t/h is about 46%lower than that with a capacity of 50t/h due to the economy of scale.4.4.Investment analysis for recycling centers
The study assumed that only recycled aggregates were produced in the recycling center,since the responses in the questionnaires showed that 90%of steel and about 50%of wood had been either sold on construction and demolition site or collected by waste picker before land?ll.It took about half a year to complete the work of construction and the installation of equipments.The price for recycled aggregates was suggested with reference to the price of quarried stone from quarries that was 2D /t in 2003in Chongqing,since there was no existing price of recycled aggregates in Chongqing.Considering the percentage of rejects in C&D waste processing (20%for recycling facility),RCp should be 1.7D /t.Assum-ing gate fee (Gf )was the same of land?ll fee that was 0.5D /t,the total revenue (Gf +RCp )should be 2.1D /t.It was also assumed that the mobile facility can attain extra revenue of about 1.7D /t from the location advantage of 5km with a transportation cost of 0.34D /t/km from questionnaires compared with ?xed recycling center.Annual unit variable cost,annual ?xed costs,IRR,PP and BP are described through different scenarios listed in cost estimation (Table 12).
If a
residual value is zero at the end of equipment’s life time and the payback time is longer than the equipment’s life time,the investor cannot get his capital cost back during the operation period of a recycling center.Table 12shows that these payback periods (excluding sales tax)are acceptable except a mobile cen-ter with new equipment and revenue of 2.1D /t.The IRR surpasses the annual interest rate of 5%.Especially,?xed centers have abso-lute advantages on investment decision due to unit cost advantage from economy of scale.If recycling centers expect to make prof-its,their output must be more than the capacity based on BP.For instance,by charging 2.1D /t,recycling centers with used equip-
Fig.4.Gap between the supply and demand of recycled aggregates.
386W.Zhao et al./Resources,Conservation and Recycling54 (2010) 377–389
Table13
Composition of unit cost and revenue of recycling center with new equipments(D/t).
Item The?xed center with
100t/h in Chongqing The mobile center with
50t/h in Chongqing
The mobile center with
50t/h in Netherlands
Fixed costs Depreciation0.380.810.81 Insurance and opportunity cost0.110.230.06
Maintenance0.160.340.34
Variable costs Labour0.070.14 2.99 Energy0.120.160.32
Disposal and transportation0.20.20.92
Revenues Gate fee0.50.55 Product price 1.6 1.6 6.45
Extra revenue from location 1.7
ments and land cost reaches its BP with a production of103,158t per year(production obtained from43%of days worked per year in Table12).
https://www.sodocs.net/doc/5d2879099.html,parison between recycling centers in Chongqing and in
the Netherlands
Table13indicates that?xed costs of recycling centers account for about70%of total costs in Chongqing.Disposal costs are a main part of variable costs due to acceptance of mixed waste and simple separation technologies.The comparison on unit cost and revenue indicates that dominating?xed costs and a low revenue range restrict the?exibility of cost control and pro?t margins in Chongqing(Table13).Although the costs of mobile centers in the Netherlands,especially the variable costs(accounting for about78%of total costs)are higher than the costs of two recy-cling centers in Chongqing,it has enough pro?t margin to avoid bankruptcy because of much higher revenues.Dominating labour costs in the Netherlands can be overcome by replacement of equip-ments,depending on cost consideration and quality insurance.On the contrary,decrease in cost by economics of scale is more and more dif?cult on the basis of small range restricted by low rev-enues in Chongqing.Moreover,mobile centers under the scale of economy are also limited by required option to transport the facil-ity.Recycling centers in Chongqing cannot handle cost competition from rivals by managing variable costs like labour cost,since dom-inated?xed costs do not vary depending on output in the short term.
5.Discussion
5.1.Supply of recyclable materials and potential demand of recycled materials
There is a huge gap between the supply of recyclable aggre-gates from waste generation and the potential demand of recycled aggregates in2005(Fig.4).Factors that might enlarge the gap are:?Limitation by the government of the?oor area to be demolished, a main contributor,accounting for about70%of total C&D waste generation,stops the growth of waste generation.
?The boom of construction activity which results in a large demand of construction materials in the case of growth of population and GDP.
?Actual demand for recycled production is not high in the absence of environmental awareness,recycling technology and quality assurance of recycled materials,especially for recycled aggre-gates for concrete as a main part of demand.
?Demolition of low-rise buildings produce a small amount of C&D waste related to the high-rise buildings that will replace them.?A large quantity of virgin land is used as construction site due to high-speed urbanization.
In future,with saturation of building demand like the situa-tion in the developed countries,demand for construction materials will gradually decrease,although even in developed countries the production of RCA can only replace maximum20%of the needed amount.At the same time,more and more C&D waste will be pro-duced with life time of buildings expiring.Waste generation will be closer to the demand of recycled aggregates.
In addition,this gap is also an opportunity to meet potential demand of recycled aggregates as a main production of recycling centers,since inert materials as raw materials of recycled aggre-gates account for more than50%of the total C&D waste.Analysis of the potential demand also indicates that other recycled materi-als like wood,brick and steel are not worried about sale.To meet the demand,C&D waste in land?ll can be used as raw materials by recycling centers,once market access has been secured and recycled aggregates have gained wide acceptance in the market. In addition,actual demand for recycled production is not as high as the potential demand in the case of absence of environmental awareness,recycling technology and quality assurance of recycled materials especially for recycled aggregates for concrete as a main part of demand.The market of recycled products can be successfully created depend on the establishment of recycling centers,price, quality and norms of recycling productions as well as acceptance of the construction industry.
5.2.Design of recycling centers
Tables11and12indicate that recycling centers with used equip-ments have absolute advantages on cost estimation and investment analysis,compared with recycling centers with new equipments. Cost estimation and investment analysis showed that the recycling cost was decreasing with the economy of scale and the revenue was increasing due to the location advantage,respectively.In con-sequence,both contribute to the economic feasibility of recycling center.However,mobile centers lack capacity?exibility due to the transportation of the facility and?nally lose cost advantage from economy of scale.Meanwhile,advantages on the location of mobile recycling centers can weaken the disadvantages of recycling cost by attaining higher gate fees,if a mobile plant is temporarily located at a large construction site.On the contrary,processing capacity of a?xed center is easy to enlarge in the design stage,depending on requirements of the region and recycling costs.However,con-sidering noise,dust pollution and zoning restrictions,?xed center site is expected to be located further away from the city center.It results in increased transportation cost leading to lower gate fees due to loss of location advantage.Thus,the type of recycling center is determined based on which factor can bring more pro?t.As a
W.Zhao et al./Resources,Conservation and Recycling54 (2010) 377–389387
result,a mobile recycling center is chosen when the extra revenue
from location advantage of this mobile center exceeds the differ-
ence between recycling cost of a?xed center and the mobile center
as follows:
|Rc f?Rc m| cost of mobile recycling center;Ut unit transportation cost;La dis- tance of location advantage. As a result,a mobile center with50t/h with unit cost of1.93D/t is chosen if its location advantage is at least2.6km compared with a?xed center with100t/h with unit cost of1.04D/t,mobile center and unit transportation cost is0.34D/t/km. 5.3.Potential risks of investment in a recycling center in Chongqing Results in Table12are static and do not consider interaction of actors in the waste management system.For a recycling facility, there are two main rivals in waste management in Chongqing:(1) owners of legal dumping or back?ll sites(sites where?lling with minerals is needed before building can take place)competing with the gate fee;(2)suppliers of raw materials and other secondary materials like coal slag competing with the sale of construction material.Each rival will execute a price strategy based on his own cost,with reference to other rivals’prices and feedback on his price at the same time.Generally,disposal fee of land?ll is established by comparing Gf to land?ll cost.Owners of land?lls may implement lower prices if their land?ll costs allow this and even more if they need the material for back?ll.The cost of land?ll is rather low in Chongqing,since the C&D land?ll is an authorized dump location operated by the Municipal Administration Commission.It will push recyclers reducing their gate fee to encourage waste producers to bring C&D waste to the recycling facility.On the side of sales of aggregates,the price of recycled aggregates for blocks and bricks is lower than price of utilization in concrete(reinforced and plain). Kartam et al.(2004)suggested that the prices of recycled aggregates for concrete and for blocks and bricks should be about1/2and1/5 of the price of natural aggregates to encourage the construction industry to utilize recycled products.Assuming that revenue is1 D/t(assuming no gate fee and half of the price of natural aggre-gates),all kinds of recycling centers will go bankrupt.The high risk of investment of a recycling center that competes with other rivals and other waste treatment chains,is exposed.The comparison on unit cost and revenue in Table13indicates that revenue range must be increased,because its quite dif?cult to decrease recycling cost to avoid potential investment risk. To provide a broader revenue range for recycling center, demands a rise in the tipping fees of land?lls caused by rapidly declining availability of sanitary land?ll sites,increasing costs for managing land?lls.Also an increase in the prices of primary raw materials contributes to economic feasibility for C&D waste recycle center.For a structural and stable development of material recov- ery,the following instruments in?uencing the waste market are necessary(Leeftink,2007). ?Technical regulations. ?Treatment regulations. ?Economic measurements:subsidies,taxes and their combination. The government should constitute technical regulations such as IPCC Directive(EU directive on integrated pollution prevention and control)to prevent pollution from unregulated land?lls and back- ?ll activities.A second kind of technical regulations involves the establishment of standards and norms for secondary and recycled materials. Concerning treatment regulations,a land?ll ban for unsorted waste and recycled materials should be conducted with the reg-ulation as reference in the Netherlands and Germany.However, execution of a land?ll ban is unadvisable in a short term,since there are few ways to dispose waste in the case of no effective recycling system with recycling centers is available.Recycling will bene?t in future from regulation about“mono”land?ll(for possi-ble future recovery of inert materials),as it acts as“reservoir”of recycled materials(Symonds,1999). As a result more space at sanitary land?lls is left for?nal waste deposit.To avoid“?y tipping”(the practice of illegally dump-ing waste),regulations including punishment for illegal dumping should be strictly enforced under supervision of Municipal Admin-istration Commission of P.R.China. Economic instruments are expected to provide the possibility to establish gate fees at the recycling centers and establish higher sales prices for recycled products to withstand various risks in the waste market competition.Many economic instruments can be chosen including tax on land?lls or raw construction materi-als,subsidy for recycling centers or for the utilization of recycled materials. A combination of measurements,starting with technical regu-lations will create a sustainable market for recycling. 6.Conclusion and recommendations In China,related to the growth of population in par-ticular urban population and the growth of the GDP after the1980s,the huge quantity of C&D waste is not only a continuous challenge for the treatment,but also an opportunity to meet an enormous potential demand of recycled construction materials.The costs for recycling as a key issue of economic feasibility of recycling C&D waste are estimated under different scenarios for the layout of recycling centers.Investment analysis shows that?xed and mobile recycling centers with used equipment are viable considering the annual?xed cost,unit variable cost,IRR,PP with discounted rate of5%and BP in terms of number of units.Recycling center with new equipment is hardly viable due to the limited pro?t margin caused by high?xed costs and from the results it could be concluded: ?Two key factors can contribute to economic feasibility of recycling centers:(a)decrease in cost caused by the economy of scale of ?xed plants and(b)increase in revenue caused by the location advantage of mobile plants. ?The limited pro?t margin is caused by the competition with cheap land?lls with limited quality regulations on the front side and competition with cheap raw materials and secondary materials such as coal slag on the back side.These circumstances contribute to?nancial vulnerability of recycling centers in Chongqing.?Cost estimation and investment analysis and Eq.(6)indicated that type,number and capacity of recycling centers will be deter-mined by related transportation cost and distance,quantity of waste generation,economy of scale,price of raw materials and tipping fee. To achieve economic feasibility of recycling centers in China,it could be recommended that: ?Taking the cost advantage of a?xed plant and the location advan-tage of a mobile plant,semi-mobile crushing plants(with a ?exible capacity of100–600t/h consisting of movable modules and can be shifted to follow disposal at construction sites.)into consideration might be an appropriate option.After that,inter-mediate products might be carried to the?xed plants for a further 388W.Zhao et al./Resources,Conservation and Recycling54 (2010) 377–389 sorting and production of recycled materials with higher value like blocks. ?To minimize investment risks for investors,economic and polit-ical instruments must be established in advance to provide ?nancial support for recycling centers and a regulated recycling market as a whole.A land?ll ban for unsorted waste and“mono”land?lls for recyclable materials should be executed in order to prevent untreated waste from being carried to legal dumping and back?ll sites.In addition,implementation of standards for recycled materials is important to establish a market for recycled materials.To foster the recycling industry,economical feasibility of recycling centers can be improved by government initiatives through indirect impact of tax on land?lling or on primary raw materials as well as through direct in?uence by subsidizing recy-cling centers or recycled secondary raw materials. Acknowledgements Authors are thankful to the European Commission(Asia-Link-Project“Human resources development for the improvement and protection of environment in Asia”.Project https://www.sodocs.net/doc/5d2879099.html,/ASIA-LINK/025 (110-744)for providing?nancial support to this research. References Anhui Development and Reform Commission[Internet].Anhui(CN):Structural adjustment era of cement industry coming.c2004-[cited2007May6](in Chi-nese);2007.Available from:https://www.sodocs.net/doc/5d2879099.html,/info.jsp?xxnr id=193. Brunner PH,Ernst WR.Alternative methods for the analysis of Municipal Solid Waste.Waste Management&Research1986;4:147–60. Chen ZL.Physics,chemical and pollution property of C&D waste in Beijing[master thesis].Beijing(CN):Jiaotong University;2005(in Chinese). Chui D,Yang Z.C&D waste recycled for development of Circular Economy.Industry Technologic Economy2006;10:35–52,in Chinese. Construction in Hebei province[Internet].Handan(CN):Establishment of perma-nent mechanism management,farewell of construction and demolition waste around city.c2006-[cited2007May5](in Chinese).Available from:http:// https://www.sodocs.net/doc/5d2879099.html,/csjs/gsdt/200601/t2006011855838.htm. China Academy of Building Research(CN).Technical Guide of green building.Beijing: Ministry of Construction and Department of Science and Technology;2005(in Chinese). Chongqing price information center[Internet].Chongqing(CN):Chongqing Price Bureau;c2000[updated2007Jul1;cited2007Jul9](in Chinese).Available from:https://www.sodocs.net/doc/5d2879099.html,/. Chongqing Municipal Bureau of Statistics[CD-ROM].Beijing:Chongqing Statistical Yearbook;2003–2007. Chongqing Construction Commission[Internet].Chongqing(CN):Layout Scheme of New Quarry in Developed Economic Circle in Chongqing. c2002-[cited2009August8];2002(in Chinese).Available from: http://china.?https://www.sodocs.net/doc/5d2879099.html,/fagui/jj/25/112563.html. Dean EB.Parametric Cost Deployment.ISQFD1995:Proceedings of the Seventh Sym-posium on Quality Function Deployment;1995June12–13;Novi,USA.QFD.p. 27–34. Dolan PJ,Lampo RG,Dearborn JC.Concepts for Reuse and Recycling of Construction and Demolition Waste.Washington:US Army Corps of Engineers Construction Engineering Research Laboratories;1999[cited2007Aug15].Available from: https://www.sodocs.net/doc/5d2879099.html,/TechReports/lam rere/lam rere.?m.post.pdf. Duran X,Lenihan H,O’Regan B.A model for assessing the economic viability of construction and demolition waste recycling—the case of Ireland.Resources, Conservation and Recycling2006;46:302–20. Feuerborn HJ.Coal ash utilisation over the world and in Europe.Work-shop on Environmental and Health Aspects of Coal Ash Utilization,1–5 November2005,Tel-Aviv,the Israel;2005.Available from:http://www.coal-ash.co.il/sadna/Abstract Feuerborn.pdf. Franklin Associates.Characterization of building-related construction and demo-lition debris in the United States.Washington:The U.S.Environmen-tal Protection Agency Municipal and Industrial Solid Waste Division Of?ce of Solid Waste;1998[cited2007September10].Available from: https://www.sodocs.net/doc/5d2879099.html,/epaoswer/hazwaste/sqg/c&d-rpt.pdf. General Administration of Quality Supervision,Inspection and Quarantine of the P.R.China.National Standard of Sand Utilization(GB/T14684),Beijing;2001a (in Chinese). General Administration of Quality Supervision,Inspection and Quarantine of the P.R.China.National Standard of Crushed Stone(GB/T14685),Beijing;2001b(in Chinese). Hsiao TY,Huang YT,Yu YH,Wernick IK.Modelling materials?ow of waste con-crete from construction and demolition wastes in Taiwan.Resources Policy 2002;28:39–47.Huang WL,Lin DH,Chang NB,Lin KS.Recycling of construction and demolition waste via a mechanical sorting process.Resources,Conservation and Recycling 2002;37:23–7. ICF Incorporated.Construction and demolition waste land?lls.Washing-ton:U.S.Environmental Protection Agency Of?ce of Solid Waste,USA; 1995[cited2007September16].Available from:www.recyclecddebris. com/rCDd/Resources/Documents/CSNWasteLand?lls.pdf. Ji G.The application of advanced technology adjusting based on waste incineration in China.China Environment News2003,in Chinese. Jia HJ.Investment evaluation of civil engineering project.Systems Science and Sys-tems Engineering2000;9:341–5,in Chinese. Jong TPR,Kuilman W.Separation and Sorting of Construction and Demolition Waste. TNO Kringbouw Phase2project Delft(NL):Delft University of Technology;2008 May.Report No.:22.1.08.1. Kartam N,Al-Mutairi N,Al-Ghusain I,Al-Humoud J.Environmental manage-ment of construction and demolition waste in Kuwait.Waste Management 2004;24:1049–59. Klang A,Vikman PA,Bratteb?H.Sustainable management of demolition waste—an integrated model for the evaluation of environmental,economic and social aspects.Resources,Conservation and Recycling2003;38:317– 34. Kohler G.Recyclingspraxis Baustoffe(practice of recycling:construction materials). 3rd ed.Koln:TUV Rheinland;1997. Leeftink RB.Money in the Waste-Inverse Economics in Arti?cial Arenas. ISWA World Congress2007.In:Proceeding of the International Confer-ence on Sustainable Solid Waste Management;2007September5–7;2007. p.543–51. Li ZM,Wang J.Analysis on and preventive measures for the common faults of con-structional column of brick–concrete residential building.Sci/tech Information Development&Economy2005;8:156–61,in Chinese. Li XP.Recycling and reuse of waste concrete in China—Part I.Material behaviour of recycled aggregate concrete Resources.Conservation and Recycling 2008;53:36–44. Li XP.Recycling and reuse of waste concrete in China—Part II.Structural behaviour of recycled aggregate concrete and engineering applications.Resources,Conser-vation and Recycling2009;53:107–12. Lin SF,Zhao DT,Marinova D.Analysis of the environmental impact of China based on STIRPAT model.Environmental Impact Assessment Review2009;29(6):341–7. Lu KA.Application technology and solution of C&D waste.China Academic Journal Electronic Publishing House2006:86–96,in Chinese. Ministry of Communications of the P.R.China.Technical standard of highway engi-neering(JTG B01),Beijing;2003(in Chinese). Ministry of Communications of the P.R.China.Regulation on Urban Construction and Demolition Waste Management.Beijing:the Regulation;2005. Ministry of Construction and Administration for Quality Supervision and Inspec-tion and Quarantine of the P.R.China Code for Design of Concrete Structures (GB50010),Beijing;2002(in Chinese). Ministry of Housing,Spatial Planning and Environment.Construction and Demolition Waste–Waste In the Netherlands[Internet].2001 June[cited2009August10];2001.Available from:www.vrom.nl/ Docs/internationaal/14281174conanddem.pdf. MACREDO.(Mid-Atlantic Consortium of Recycling and Economic Development Of?cials).Philadelphia:Recycling and Reuse in the Residential Construction Industry;2006.Available from:https://www.sodocs.net/doc/5d2879099.html,/maredo/recost.htm. National Statistic Agency of China[CD-ROM].Beijing:China Statistical Yearbook; 2002–2007a. National Statistic Agency of China[CD-ROM].Beijing:China City Statistical Year-book;2007b. Newenergy[Internet].Beijing:Waste to energy in Chongqing.c2008-[cited2008Jan 5](in Chinese).Available from:https://www.sodocs.net/doc/5d2879099.html,/newenergy/html/newenergy-0915091579154755.html. Nunes KRA,Mahler CF,Valle R,Neves C.Evaluation of investments in recycling cen-ters for construction and demolition wastes in Brazilian municipalities.Waste Management2007;27(11):1531–40. Paranavithana S,Abbas M.Effects of recycled concrete aggregates on properties of asphalt concrete.Resources,Conservation and Recycling2006;48:1–12. Poon CS,Qiao XC,Chan D.The cause and in?uence of self-cementing properties of?ne recycled concrete aggregates on the properties of unbound foundation. Waste Management2006;26:1166–72. Poon CS,Chan D.The use of recycled aggregate in concrete in Hong Kong.Resources. Conservation and Recycling2007;50(3):293–305. Reinhart D,Townsend TG,Eun S,Xu QY.Control of Odors from Construc-tion and Demolition(C&D)Debris Land?lls.FL:Florida Center for Solid and Hazardous Waste Management.2004.Available from:http://www. https://www.sodocs.net/doc/5d2879099.html,/publications.htm. Rijpkema LPM.Working document biomass classi?cation,Organisation and Ini-tial breakdown.Amsterdam(NL):Novem/EWAB;1999November.Report No.: 9904. Road Institute of Ministry of Communications of the P.R.China.Technical speci?ca-tion for construction of highway roadbases(JTJ034),Beijing;2000(in Chinese). Shi JG,Xu YZ.Estimation and forecasting of concrete debris amount in China. Resources,Conservation and Recycling2006;49:147–58. Statistics Netherlands.Statistical Yearbook2007.Voorburg:Statistics Netherlands; 2007. Symonds Group Report to DGXI.Construction and Demolition Waste Man-agement Practices and their Economic Impacts.London:European W.Zhao et al./Resources,Conservation and Recycling54 (2010) 377–389389 Commission;1999.Available from:http://ec.europa.eu/environment/ waste/studies/cdw/cdw chapter1-6.pdf. TIFAC(Technology Information Forecasting&Assessment).New Delhi:Utilisation of Waste from Construction Industry:Executive Summary;2006.Availably from: https://www.sodocs.net/doc/5d2879099.html,.in. Tam VWY,Tam CM.Evaluations of existing waste recycling methods:a Hong Kong study.Building and Environment2006;41(12):1649–60. Wu XM.Application of pulverized powder waste of concrete and brick as mineral admixture for cement and concrete[master thesis].Zhengzhou(CN):Zhengzhou University;2004(in Chinese). Xing WH,Charles H.Decontamination of granular wastes by mining separation techniques.Journal of Cleaner Production2006;14:748–53. Xiao J,Wang J,Sun Z,Li J.Investigation on application of recycled concrete aggre-gate in concrete pavement.Journal of Highway and Transportation Research and Development2005;22:52–5(in Chinese).You GH.Research on the Price Forming Mechanism of Iron&Steel Mechanism of China[master thesis].Wuhan(CN):Wuhan University of Technology;2005(in Chinese). Zhang CS,Qi F.Experimental research on construction debris used for admixture. Techniques and Equipment for Environmental Pollution Control2004;5:40–3, in Chinese. Zhao W,Rotter S.The Current situation of construction&demolition waste management in China.ICBBE2008.In:Proceedings of Second International Environment and Public Health Track;2008May16–18;2008.p.4747– 50. Zhou X.The problems of internal and external wall materials industry based on nationwide spot check of quality in2003.Walling Material Innovation and Energy Conservation of Buildings2004;1:16–7.