PERFORMANCE AND ECONOMIC WASTE ASSESSMENT (PEWA) METHODOLOGY

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Performance and Economic Waste Assessment (PEWA) Methodology

Copyright of LabSearch, a working title of Dr Malcolm Sutherland ©2013

BE-AWARE Work Package 3 Deliverable 3.5

PERFORMANCE AND ECONOMIC WASTE ASSESSMENT

(PEWA) METHODOLOGY

Mohamed Osmani, Andrew Price, Malcolm Sutherland

(Loughborough University)

Completed May 2007

REVISED MAY 2013: portions of the original document have been scanned, including original

tables and methodology slides



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EXECUTIVE SUMMARY

A performance and economic waste assessment (PEWA) methodology has been developed

in fulfilment of Deliverable 3.5. This is a culmination of the activities conducted duringprevious deliverables, which is presented in this report as a waste auditing process, and

which can be used to select appropriate waste materials and re-use/recycling routes, prior

to developing re-use/recycling processes. In addition to the PEWA methodology, the results

of the waste mapping and the PEWA survey are also presented and briefly discussed.

The waste mapping and PEWA survey results were collected through interviews with

construction product manufacturers and demolition contractors. 22 waste material streams

were surveyed through the waste mapping exercise, 12 of which were also surveyed

through the PEWA survey interviews. The interviews addressed waste materials occurring

in a variety of sub-sectors, including concrete, clay bricks, timber, plastics, insulation and

plastering. Several of the waste materials surveyed are currently entirely recycled (namely

concrete, clay bricks, PVC profile, sawdust and other off-cuts from timber processing). In

contrast, WESP sludge, cement kiln dust, plastics and plastering from demolition, and

polyethylene packaging are largely disposed of to landfill. GRP (glass reinforced plastic),

timber waste from demolition and plasterboard off-cuts are recycled to a limited extant.

Among the current applications, it was found that hardcore materials (concrete, clay bricks)

are mainly used as bulk fill for roads or landscaping, recycled limber is often used for

chip/panel-board, whilst PVC and plastering can be recycled back into the manufacturing

process.

A literature review was conducted into methodologies (audits) used for sun/eying and

assessing waste materials and the potential re-use/recycling routes. Examples cited from

the literature generally follow a logical plan of data collection and analysis. A waste audit is

initiated by defining the aims and boundaries of the study (i.e. which waste materials will be

examined). Following this, information is then collected on the current status (e.g. waste

sources and quantities). Potential waste re-use/recycling routes may be examined, as well

as the factors which affect the viability of re-use/recycling (e.g. high transportation costs).

Once data has been collected, a decision must be taken as to whether or not the waste can

be re-used or recycled, and if so, which reprocessing route is the most suitable. A decision

may be based using a variety of methods, ranging from consulting stakeholders (e.g.

through Delphi studies), to using advanced techniques such as multi-criteria analysis orcomputer models.

Following a literature review, the PEWA methodology was developed, and was validated

through consultation with BRE, the Construction Products Association, NISP and the

BeAware partners. The PEWA methodology Incorporates a range of ideas extracted from

literature, including gathering data on waste (quantities, types, costs, etc.); and identifying

limiting factors such as economic and technical constraints on recycling viability. In addition,

the PEWA methodology includes some novel concepts (including ranking of waste materials

in terms of recycling potential, as well as short-listing, selecting or rejecting waste materials

at various stages).



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The PEWA methodology is composed of ten stages. Based on the data collected, at the end

of each stage (except for Stage 1), the user decides whether or not to continue examining a

selected waste material or reprocessing route. The ten stages are as follows:

Stage 1: waste targeting (list the waste materials occurring in a sector);

Stage 2: waste composition (describe the physical and chemical composition of the waste

materials, and also Identify hazardous materials);

Stage 3: waste prioritising (list the recycling drivers and barriers for the waste materials, and

rank the wastes in terms of recycling poiential);

Stage 4: waste sources, quantities and value (identifying the causes and proportions of

waste occurring throughout the construction product lifecycle, and identify market values

for recycled materials);

Stage 5: waste costs and current recycling status (examine the proportions (and costs) of

waste being recovered or disposed, the reasons for disposal, and the reprocessing/landfill

locations);

Stage 6: re-use/recycling limiting factors (identify and rate the economic, technical,

environmental and other limiting factors which may restrict re-use/recycling};

Stage 7: addressing the limlSng factors (suggest how the identified limiting factors may be

overcome, and the necessary time period required (e.g. short-term, or under 3 years);

Stage 8: re-use/recycling opportunities (Identify current and alternative re-use and recycling

processes, both onsite and offsite);

Stage 9: re-use/recycling requirements (identify the essential material properties for selling

recycled products on the market (e.g. British Standards)); and,

Stage 10: re-use/recycling costs and markets (the capital and operational costs and payback

period for reprocessing on-site, and the prices of primary and recycled products on the

market).

The PEWA will be applied for selecting waste materials (which will in turn be subjected to

laboratory testing later in the BeAware project).



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Contents

Executive summary pages 2, 3

Contents page 4

1: Introduction page 5

2: Information collected to date pages 6 - 21

3: Literature review of methodologies pages 22 - 32

4: The PEWA Methodology pages 33 - 45

5: Conclusions page 46

Acknowledgements page 46

References pages 47 - 49

Appendices pages 50 - 164

Appendix 1 [confidential]

Appendix 2 pages 51 - 98

Appendix 3 [confidential]





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1: Introduction

The focus of Work Package 3 (Cross-sector Recycling Opportunities) is on identifying suitable

waste materials within the construction sector, for which further research and developmentis required in order to create opportunities for their recycling and/or re-use.

Figure 1 summarises the deliverables and outcomes of Work Package 3, which commenced

at the beginning of 2006, said ts expected to be accomplished by April 2008. As shown, four

of the nine deliverables, as well as the PEWA (Performance and Economic Waste

Assessment) survey, have been accomplished.

Figure 1: Work Packages-progress achieved 10 date

(dark shading Indicates completed stages, tight shading indicates current stage)



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2: Information collected to date

This section reviews the data collection activities conducted so tar under Work Package 3 of

the BeAware project, and reviews the information collected from the waste mapping andPEWA survey interviews.

2.1: Deliverable 3.1: Workshop 1: Waste Targeting and Prioritising

The First BeAware workshop was held at BRE, Watford on 10th May 2006, and comprised

three main activities:

waste targeting, whereby delegates:

o listed waste materials arising in their sector, and,

o indicated where these arise within the construction product lifecycle

(production, distribution, point-of-use, end-of-life);

waste prioritising, whereby delegates,

o listed the benefits and problems associated with recycling identified waste

materials, and,

o ranked the waste materials in terms of their recycling potential;

plenary session (during which delegates summarised and debated on their findings).

The findings of the First BeAware Workshop were published in an earlier report, First

BeAware Workshop Report - Waste Targeting and Priontisation.

2.2: Deliverable 3.2: Industry-reviewed Waste Mapping Process

Introduction and specifications

The waste mapping exercise was conducted through interviews with construction product

manufacturers, and demolition contractors. Following a literature review of waste mapping

techniques, a basic waste mapping flowchart was produced (Appendix 1A), along with

functional specifications of the waste mapping process. These were discussed between BRE,

Loughborough University and the Construction Products Association, and the process was

validated by industry during the first five interviews.

Following discussion and validation, a further 17 interviews were conducted. Information

regarding 22 waste materials was collected through the waste mapping exercise, and the

results are tabled in Appendix 1B. The results summarised in this section are therefore case-



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specific. Details of companies, interviewees and site locations have been kept confidential.

The waste mapping process comprised four sections:

- the sources and causes of waste;

- the quantities and values of waste;

- the costs of waste; and,

- the current recycling status.

Sources and causes of waste

The first stage of the waste mapping focussed on the occurrence of waste materials

throughout the construction product lifecycle. Information was also collected, regarding the

types of waste produced, the causes of waste production, and the relative significance of

each waste produced in different life cycle stages. Interviewees ranked each waste

produced, and/or indicated the quantities (high, medium, low).

Quantities and values of waste

In relation to the construction product lifecycle, information was gathered regarding the

relative quantities of waste arisings, and any market values of waste being reprocessed

and/or sold. Interviewees also stated whether the wastes were segregated or unsegregated.

Costs of waste

The third stage of the waste mapping process involved breaking down the costs of wastemanagement into general categories:

costs of disposal to landfill

o transport costs

o landfill tax

o collection and handling costs

costs of recovery of waste

o transport costs

o reprocessing costso collection and handling costs

Interviewees provided values (e.g. costs per tonne of waste, I.e. £/tonne), indicated what

proportions of total waste management costs were attributed to each category, and/or

indicated the significance of each category (e.g. the costs of transporting waste being

"high").



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Current recycling status

Information was collected regarding the current status of waste disposal and/or recovery.

Interviewees indicated what proportions of waste were disposed or treated on-site or off-

site, provided reasons for disposal of wastes to landfill (where applicable), described the

applications for reprocessed waste, and also provided information on waste destinations.

Data was collected, regarding the proportions of waste being recovered (re-used or

recycled) or disposed to landfill, and the proportions off-site or on-site.

Summary of results

A brief overview of the waste mapping data is provided in Table 1 over-page, and the data

collected is compiled in Appendix 1 B. It was seldom possible to obtain highly accurate

numerical data for all the sections of the waste mapping flowchart- Nevertheless, it was

discovered that several of the waste materials surveyed are currently being recycled.Concrete, bricks and blocks are commonly crushed to produce secondary bulk fill aggregate.

Sawdust and timber off-cuts from timber manufacture/usage are also currently utilised,

mainly as feedstock in chipboard or panel-board manufacture. At the manufacturing stage,

it was also reported that PVC is recycled back into the process; likewise, plasterboard off-

cuts from construction sites are being collected via a take-back scheme, before the

extracted gypsum core is re-introduced back into the plasterboard manufacturing process.

In contrast, it was found that air filter dust (cement kiln dust, WESP sludge), as well as

plastics and plastering (from demolition) and polyethylene packaging are currently disposed

to landfill, in addition, there is limited recovery of GRP, timber waste (from demolition), andfactory containers (IBC, or intermediate bulk containers).

Damaged/unsalable bricks (Appendix 1B, section 1.1)

The main sources of this waste included manufacture, and demolition, and it was indicated

that significant proportions of this waste throughout the lifecycle may end up being sent to

landfill. However, it was also found that waste brick materials are often crushed and used as

bulk fill aggregate, or may be reclaimed for new-build projects. These recycling outlets are

mostly off-site, although transportation distances are limited (25 miles for crushed brick).

Overall, the level of confidence in the information was rated from medium to low.

Cement kiln dust (Appendix 1 B, section 1.2)

Kiln dust (also termed scrubber, or bypass dust) is produced alongside cement manufacture,

and was found to be entirely disposed of to landfill. mainly owing to its hazardous

classification and nature (alkalinity). No recycling opportunities were perceived, and of the

disposal costs, those of collection and handling were reported to be highly dominant,

accounting for about four fifths of the cost. The level of confidence in the information was

rated from medium to high.



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Saw dust (Appendix 1B, section 1.3)

In contrast with cement kiln dust, saw dust produced mainly alongside timber product

manufacture and use onsite was reported to be entirely recycled, worth as much as

£20/tonne (off-set by small reprocessing costs of £2/tonne in total), and used generally as

feedstock for panels and chipboard. The level of confidence in the information was mostly

rated as high.

Roofing PVC (Appendix 1 B, section 1.4)

The main causes of roofing PVC waste include cutting, trimming and de-railing processes,

the main source being use on-site; however, the market values and proportions of PVC

waste arising during the different product lifecycle stages were not determined. Overall it

was speculated that the majority of PVC waste (throughout the Iifecycle) was currently

disposed of to landfill, whilst the remainder was being re-used (possibly re-introduced into

the manufacturing process). However, the level of confidence in information provided wasaccorded a low rating.

Waste IBCs (Intermediate Bulk Containers) (Appendix 1B, section 1.5)

These containers arise alongside concrete manufacture, since they are used for delivering

raw materials. Some of these are recycled (whereby aluminium cages are retrieved), and a

smaller minority are used elsewhere as waste bins. However, it was speculated that around

85% of the containers (being plastic) are sent to landfill. Overall, the level of confidence in

the information provided was rated from low to medium.

Leftover concrete mix (Appendix 1B, section 1.6)

Waste concrete mix arises during the manufacturing process as hardened mix following the

end of a production run. In contrast with the IBC containers, all of the mix was reported to

be recycled, and entirely used on-site as a sand replacement. The main financial costs of

recycling therefore owed to the reprocessing (accounting for -60%). The level of confidence

in information provided ranged from low (for quantities and value - possibly due to lack of

numerical values) to high (current recycling status).

WESP (Wet electrostatic precipitator sludge) (Appendix 1B, section 1.7)

This residue is a particulate by-product of timber panel production, and was reported to be

entirely sent to landfill, mainly owing to its hazardous nature (including high content of

lead). No costs or market values were specified, although the landfill tax was reported to be

£133/tonne (evidently for disposal to hazardous landfill). This information was provided

with a high level of confidence.

Protective film and polyethylene sleeve packaging (Appendix 1 B, section 1.8)

The main source of this waste was reported to arise on construction sites due to packagingremoval and disposal (accounting for around two-thirds of all packaging waste). It was



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reported that the packaging (presumably on construction sites) is entirely sent to landfill,

although perhaps 30% of all waste produced throughout the construction product Iifecycle

may be recycled off-site to produce new packaging.

Unsaleable concrete manhole units (Appendix 1 B, section 1.9)

The causes of man-hole unit waste include defects found in the products during

manufacture, or inadequate storage leading to damage (possibly accounting for a fifth of all

waste). Nearly all waste units were reported to be recycled for use as secondary aggregates

(worth around £1.50/tonne). No ratings were given regarding the level of confidence in the

information.

Glass-reinforced plastic and associated wastes (Appendix 1 B, section 1.10)

The data obtained regarding GRP was unique, in that the waste was only partially recycled,

with a variety of re-use and recycling outlets, and some very high market values for GRPwastes (e.g. £500/tonne for that arising alongside manufacture). In addition to GRP

trimmings, other wastes produced include acetone, wooden pallets, steel/plastic containers,

plastic binding tape and cardboard. Overall, around 56% of all waste (by weight) is

recovered, whereby cardboard and pallets are re-used, and steel/plastic containers are also

re-used. GRP waste may be recycled, although locations are distant (including receptors in

Hong Kong).

Recycled GRP market values for wastes arising further down the lifecycle (point-of-use,

storage) were reported to be considerably lower (around £100/tonne). GRP waste arising

from demolition was deemed to be worthless, mainly because it may be intermingled withinmixed (un-segregated) waste. A high level of confidence was placed on the information

provided.

Plasterboard off-cuts (from construction sites) (Appendix 1B, section 1.11)

The manufacturer currently operates a take-back scheme, retrieving excess plasterboard

arising as off-cuts from sites. (This applies to most types of plasterboard, with the exclusion

of duplex (aluminium foil-backed) and thermal laminated boards.) During reprocessing, the

paper component is retrieved and distributed amongst farmers for animal bedding, whilst

the gypsum core is entirely recycled back into the plasterboard production line. Detailedinformation regarding market values and financial costs were not available, although the

transport costs were said to dominate the total costs of the take-back scheme (approx.

75%), with plasterboard off-cuts being recovered from sites throughout the UK. The level of

confidence in the information provided ranged from low-medium (for costs and quantities)

to high (regarding processes).

Timber waste from demolition (Appendix 1B, section 1.12)

Timber waste comprises a wide range of materials and components occurring in varying

proportions and quantities, depending on the site. As a result, the recycling rate wasreported to be highly variable, with some timber waste arisings being entirely sent to



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landfill, and others fully recovered (sent to reprocessing plants), depending on fees,

transport costs, as well as time constraints within the demolition contract. No market values

were reported, since the contractor currently pays reprocessing contractors to collect

timber. waste which is suitable. Unsuitable timber waste (which is disposed to landfill)

includes treated limber, MDF and particle-board; these types are automatically rejected by

recycling operators.

Concern was expressed over the costs of waste management, whereby the costs of sending

waste to landfill are followed closely by the fees charged by recycling operators; typical

landfill costs ranged from approx. £40 - £50/tonne, whereas recycling fees could be around

£25/tonne (this excluding transport costs). A high level of confidence was accorded to all

information given.

Plastics waste from demolition (Appendix 1B, section 1.13)

Plastics wastes were reported to be entirely disposed of to landfill, often due to being un-segregated, its low quantities, its lightweight density, as well as negligible markets. No

market values were applicable, and limited information was provided regarding the costs of

disposal (it was estimated that landfill tax might account for around half the cost). Estimated

costs were expressed with a low level of confidence, although a high level of confidence was

confided on the rest of the information provided.

Sawdust, chips, bark, etc. from sawmill production (Appendix 1 B, section 1.14)

Around half of all wood wastes was estimated to emerge during timber processing

throughout the timber lifecycle. Within the timber manufacturing process, around half thevolume of the original log ends up as residues, which are currently entirely recycled off-site.

Bark was reported to be used for landscaping, whilst chips and sawdust are sent to paper

mills as feedstock. Other applications for residues include animal bedding. Detailed

information was provided regarding the types of residues and their applications, although a

medium level of confidence was placed on market values and the costs of waste recovery.

Sale values for residues range from approx. £10 to £30, depending on location and

application.

Reject pre-cast concrete units (and wash-out sludge) (Appendix 1B, section 1.15}

Both these wastes arise within the manufacturing stage, although the quantities were

regarded as being too minor for reprocessing off-site. The rejected units (arising due to

over-ordering, or poor production methods) are crushed onsite and used as back-till within

the premises, whilst the wash-out sludge is disposed of onsite (the quantities arising were

considered to be Insignificant). Reprocessing costs for the reject concrete units were rated

as medium, whilst transport and handling costs were rated as low (a speculative figure of

£15k to £20k per annum was provided for total costs of recovery).



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Clay bricks and concrete bricks/blocks from demolition (Appendix 1B, section 1.16)

Approximately a tenth of clay bricks are either reclaimed for re-use, whilst the rest are

crushed to produce bulk fill aggregate. All clay brick materials arising during demolition

were reported to be recovered, and market values were also provided, including ranges of

£250 to £400 per 1000 reclaimed bricks, and approx, £5.5/tonne for crushed brick. For

crushed brick aggregate, approx. A third of recovery costs attribute to reprocessing, with the

rest arising from transportation (around £6/tonne). No crushed brick material was reported

to be used as secondary aggregate in new concrete. The viability of reclaiming clay bricks

was reportad to be determined mainly by the brick mortar, whereby physically weaker lime

mortar from older structures could be more easily removed by hand.

Likewise with clay bricks, all concrete bricks and blocks arising during demolition were

reported to be recovered, being crushed and recycled in their entirety for use as bulk fill

aggregate, and selling for approximately £5.5 per tonne. The recovery costs for crushed

concrete were reported to be similar to those for crushed clay bricks. As with theinformation regarding clay bricks, the information on concrete bricks/blocks was provided

with a high degree of confidence.

Reject pro-cast concrete flooring units (Appendix 1B, section 1.17)

These wastes were said to arise mainly during point-of-use (due to accidents, or poor

specification), as well as during demolition. It was known that nearly all concrete units

waste is currently recycled for use as bulk fill aggregate (with perhaps a small minority being

used for high-grade applications such as aggregate In new concrete). However, much of the

information was provided with a medium or low level of confidence, and the costs of wastereprocessing could not be accurately estimated.

PVC (window frames) (Appendix 1 B, section 1.18)

Polypro currently recycles PVC arising mainly from the manufacturing stage. Although this

interview was not an integral part of the waste mapping survey, the Information provides a

detailed insight into the costs, processes and markets for recycled PVC. Much of the

information provided was confidential, although transport costs were reported to be very

high (around £300/tonne). Another poignant issue raised was the anticipated rise in PVC

from demolition over the next few years.

PVC profile (Appendix 1B, section 1.19)

Profile waste arisings during manufacture were estimated to be high, compared with

rejects/off-cuts arising during transport or point-of-use, perhaps accounting for 60% of all

PVC throughout the lifecycle. Within the manufacturing stage: nearly all PVC resin is

returned (in-house) back into the production line, although the processes described are

confidential. The destinations for PVC arising during point-of-use or transportation were

not fully known, although a majority Is likely to be sent to landfill. High confidence was

confided on the information regarding PVC profile waste arising during manufacture.



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Trimmings from insulation manufacture (Appendix 1B, section 1.20)

Nearly all trimmings and dust were reported to arise during manufacture, whilst boards

were being cut to specified dimensions. These comprised rigid phenolic or urethane core

insulation materials, which are entirely compressed into smaller units and sent to a recycling

depot (details confidential).

Damaged/reject day bricks (Appendix 1B, section 1.21)

The majority of this waste was reported to arise during point-of-use, owing mainly to poor

handling and storage techniques. The proportions of waste being recovered during storage,

transportation and point-of-use were not known, although it was reported that nearly all

reject/damaged clay bricks arising during manufacture are used as road sub-base within the

brickearth quarry beside the plant, whilst a small minority are given away to local farmers

for use as drainage. The costs of recovery could not be estimated, although they were said

to be minor compared with the manufacturing and quarry operation costs. A high level of confidence was confided on the information given.

Plastering from demolition (Appendix 1 B, section 1.22}

It was reported that plastering arises as un-segregated waste, mixed with other "soft-strip"

waste materials such as wallpaper, timber and mortar fragments. Due to comparatively

minor quantities (compared with hardcore materials), the difficulty of mechanically

separating out the plastering, as well as the absence of markets, plastering was reported to

be entirely disposed to landfill in nearly all demolition projects. No market values were

given as a result, and disposal costs were estimated to be around £45/tonne for transport(accounting for perhaps half of all costs). Much of the information was given based on a high

level of confidence.

2.3: Deliverable 3.3: Literature Review on Waste Characterisation

Following development and validation of the waste mapping survey, a literature review was

conducted into waste characterisation techniques. Waste characterisation is an essential

process used for analysing waste streams, and for determining or developing recyclate

markets. The literature review examined these issues in further detail, including approaches(e.g. classification and quantification of waste materials), technologies (e.g. computer

models/databases), and methodologies (e.g. waste material sampling strategies. Further

information can be found in the report, Waste Characterisation Literature Review .



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2.4: Deliverable 3.4: Workshop 2: Performance and Economic Waste

Assessment

Following the waste characterisation literature review, further investigation into the

economic and material performance approaches was put into practice, through the SecondBeAware Workshop. The workshop embraced a wide range of sectors, including drywall

manufacturing, Insulation manufacturing, and demolition and refurbishment. During the

workshop, delegates short-listed waste materials, which were then considered for further

investigation through the PEWA survey. Further reference to the findings of the workshop

can be found in the report: Second BeAware Workshop Report: Performance and Economic

Waste Assessment .

2.5: Performance and Economic Waste Assessment (PEWA) Survey

Following from the Second BeAware Workshop, further investigation was conducted into

other economic and material performance-related issues which were identified in the waste

characterisation literature review, but not addressed during the workshop. Table 2 lists the

waste materials studied through the PEWA survey:

Table 2: waste materials investigated through the PEWA survey

The following issues were addressed through the PEWA survey;

Waste material performance:

o detailed physical and chemical composition of the waste;

o hazardous properties of the waste (if any);

o essential physical/mechanical, chemical and/or other properties for recycling

or re-use; and,

o current or potential re-use or recycling opportunities.



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Economic issues:

o capital costs (including land, hiring staff, purchasing equipment, construction

or alterations to company buildings, etc.);

o operational costs (e.g. labour, operation and maintenance);

o Payback period (of capital and operational costs);

o effects of forthcoming environmental legislation on viability of re-use or

recycling; and,

o market prices and price fluctuations:

virgin products

products with waste (recycled back into manufacture); and,

recycled waste products offsite.

The interview template is provided in Appendix 2, and results are provided in Appendix 3. As

with the waste mapping, interviewees were asked to indicate the level of confidence in theinformation they provided (H (high), M (medium) or L (low). This section summarises the

PEWA survey data collected.

GRP (Appendix 3, section 3.1)

GRP is generally composed of glass fibres encapsulated within a polyester resin, and as

mentioned, is only partially recycled (whereby recycling is conducted abroad). It was

reported that GRP can be ground into powder, and be used as a secondary feedstock in

other industries, namely in automobile manufacturing. The manufacturer is currently

developing its own GRP reprocessing, and acquiring equipment as a result, hence the capitaland operational costs have been examined (predicted to be around £37k and £47k.

respectively). Another financial issue raised was the transportation costs, mainly due to the

rural location of the manufacturing plant. A further economic issue of relevance is the

recent surge in oil prices, which have raised the prices of polyester resin. Other drivers

behind recycling include the End of Life Vehicles Directive, which enforces greater sustain

ability surrounding the materials used in cars, and which may act as an incentive for

increased demand for GRP waste by car manufacturers.

Plasterboard off-cuts from construction sites (Appendix 3, section 3.2)

The company visited for the PEWA survey produces a variety of plasterboard products,

Including standard plasterboard, moisture-board, thermal laminated boards, glass-

reinforced boards, and fire-resistant boards. In addition to gypsum and paper lining, some of

these brands contain additives or supporting boards (e.g. polystyrene in thermal laminate

boards). As mentioned, the thermal laminate and moisture-board types are not currently

recycled. Limited information was provided on required properties for recycling, mainly

since material properties are inspected by the waste contractor which collects the off-cuts

on behalf of the manufacturer. Nor was detailed information regarding capital or

operational costs forthcoming, although these were presumed to be quickly addressed by

plasterboard sales.



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Timber waste from demolition (Appendix 3. section 3.3)

Timber waste was reported to be heterogeneous, containing a wide variety of both timber

and non-timber-based components or materials, including window frames, floorboards,

roofing supports, chipboard, and MDF - which in turn may contain nails, broken glass, glues

and presen/ativas. Of these materials, MDF and particleboard are currently rejected by

recycling contractors, mainly owing to their preservatives content. Reprocessing plants

might also reject timber which is contaminated with soil, stones and plastics. Very minimal

scope for timber re-use was reported, since retrieved items (e.g. timber planks) carry no

market value.

The capital and operational costs of timber reprocessing (for converting Into feedstock tor

particleboard or for mulch) were speculated to be high, due to the use of extensive, high-

energy mechanical processes. The scope for increasing limber recycling from sites was also

perceived to be limited, mainly due to the comparatively small volumes arising from

demolition (a typical example was said to be 2% of all demolition waste), as well as recyclingcontractors charging fees which may approach the level of landfill fees.

Plastics waste from demolition (Appendix 3, section 3.4)

As mentioned, the scope for recycling plastics waste was perceived to be minimal. One of

the reasons for this is the complexity of the plastics waste stream, which may contain PVC, a

range of thermoplastics, and possibly asbestos-laden materials (which are classified as

hazardous). The arisings are comparatively minor (compared with major demolition waste

streams such as hardcore), and since no viable markets or outlets currently exist, neither the

capital or operational costs of recycling plastic wastes could be predicted.

Sawdust, chips, bark, etc. from sawmill production (Appendix 3, section 3.5)

In contrast with plastics from demolition, the recycling outlets for the residues produced

during timber processing are firmly established, with a range of applications reported

(including horticulture, animal bedding, feedstock for paper production, or use in panel-

board production). Limited checks are conducted on the residues, since they arise as pure

timber waste streams. The market values for residues sold to other industries were reported

to be generally stable (except for panel-board feedstock, which varies in price). One concern

raised was the need for increased energy-from-waste (timber residue Incineration), whichcould be more profitable than current recycling routes.

Reject pre-cast concrete units (and wash-out sludge) (Appendix 3, section 3.6)

As mentioned, the volumes of both wastes are considered to be insignificant, and hence

they are currently processed and disposed of onsite. Furthermore, the company reported it

had no facilities for reincorporating the waste back into the pre-cast concrete units, partly

due to the very high purchasing costs. The volumes of these wastes were considered too

insufficient to justify sending the materials to a recycling contractor or client off-site, and

the changes in market prices of primary and crushed concrete were reported to be fairlyminor.



19



Clay bricks, and concrete bricks/blocks from demolition (Appendix 3, section 3.7)

Clay bricks were reported to either be (mostly) crushed to produce secondary aggregate, or

reclaimed. Clay bricks suitable for reclamation were said to be those which are obtainable

without inflicting damage or fracturing, and which could sell (bricks which are not blotched

or multicoloured carry higher market values). The reclamation process is labour-intensive,

whereby the mortar must be hacked off manually; consequently, as much as 75% of

operational costs of clay brick reclamation were said to attribute to employing trained

personnel. In contrast, the operational costs of crushing clay bricks to produce secondary

aggregate mainly attributes to the operation (esp. Fuel consumption) and maintenance of

crushing equipment. At present, crushed aggregate Is used as bulk fill; other potential

recycling outlets are perceived to be economically unviable (e.g. aggregate for new

concrete). Some tests are currently conducted on both crushed clay brick and concrete

using a lab facility near the demolition contractor offices, including physical tests (e.g.

particle size, compressive strength) and chemical tests (e.g. impurities content).

As with most clay bricks, concrete bricks and blocks were reported to be entirely crushed to

produce secondary aggregate, whereby the material is crushed, and also sieved and passed

through magnetic separators (to remove metal components). The crushing process was

reported to generate dust and noise, as well as consuming between 40 to 50 gallons of fuel

on a daily basis. It was therefore highlighted that there is a need to develop more efficient,

quieter onsite hardcore crushing equipment. It was also noted that crushers typically last

about 5 years, and the capital costs are therefore recuperated over this period of time by

passing costs to the client.

Reject precast concrete flooring units (Appendix 3, section 3.8)

Limited information was collected; the capital and operational costs of recycling pre-cast

flooring units could not be speculated, although it was generally noted that several BPCF

members have set up their own in-house concrete recycling operations for returning the

waste back into the original product. Reprocessed material was also said to comply with

certain standards, including BS 8500 and those set by the Highways Agency (for use as bulk

fill). It was also hinted that using recycled concrete aggregate in new concrete might

diminish the appearance of the product, and that the impact of the aggregates levy (£1.60

per tonne until next year) was relatively minor (compared with quarried aggregates often

selling at £7 to £9 per tonne).

PVC (window frames) (Appendix 3, section 3.9)

Information regarding the reprocessing methods used at the recycling plant was treated as

confidential. However, it was noted that PVC profile may be composed of approximately

80% PVC resin, and 20% filler additives (including varying quantities of calcium carbonate,

titanium dioxide, lubricants, and also stabilisers (Including lead-based salts).

The capital costs of the reprocessing equipment were reported to be very high (worth

perhaps £2 million), although on balance, the market values for PVC products Is also high(around £1000 to £1200 per tonne). At present, all PVC reprocesses at the plant is returned



20



as feedstock to PVC product manufacturers. Increasing oil prices and rising landfill taxes are

expected to make the reprocessing of PVC increasingly viable.

PVC profile (Appendix 3, section 3.10)

As previously mentioned, nearly all PVC profile off-cuts generated were reported to be

recycled in-house, using physical processes to produce PVC particles for re-introduction

back into the production line. (Further details were also treated as confidential.) Potential

recycling applications off-site or using other processes (e.g. chemical treatment) were

perceived to be economically unviable. In contrast, the in-house recycling processes were

reported to incur small to medium capital and operational costs, which were quickly

recovered through PVC profile sales. One issue raised was that of increasing landfill costs

leading to increased opportunity for recovering PVC from construction and demolition sites,

although one difficulty needing to be addressed is chemical degradation or contamination

within these PVC waste streams.

Trimmings from insulation manufacture (Appendix 3, section 3.11)

The insulation trimmings produced generally include rigid phenolic or urethane core-based

materials, accompanied with glass-fibres, aluminium foil or bitumen-coverings. Although

these trimmings are classified as Special Waste (due to their phenolic or urethane content),

they are currently mechanically compressed into "brickets" on-site, before being sent to a

recycling contractor (details confidential). The main concern raised was the high

transportation costs involved in recovering the trimming materials, and the limited recycling

options available. Another issue raised was the rising price in MD1 (a raw ingredient used in

insulation material production), as well as declining market values of insulation products atpresent.

Damaged/reject clay bricks (Appendix 3, section 3.12)

Very limited scope for recycling the clay bricks was reported to exist, other than their use as

road sub-base within the quarry beside the manufacturing plant. The estimated costs

(possibly £10 - £15/tonne) for crushing the clay bricks to produce secondary aggregate for

use elsewhere were not expected to be matched by any potential market values. Other than

crushing the material, no other potentially viable recycling routes were known to exist. The

current use of brick waste onsite was said to incur minor financial costs, and does notrequire any materials testing or safety checks.

Plastering From demolition (Appendix 3, section 3.13)

Since it was reported that plastering from demolition sites is currently nearly always sent to

landfill, no capital or operational costs of recovery were reported. It was speculated that

plastering could in theory be sorted onsite and returned to plasterboard manufacturing

plants. However, this was said to be mostly unfeasible, partly due to the small and

contaminated quantities produced during demolition (accounting for under 5% of tola!

demolition waste produced). Two other major factors limiting recovery of plastering includethe "10% Rule" (which currently does not persuade contractors to salvage



21



plastering), and the absence of central C&D waste collection depots throughout the UK,

which (if created) could "bring" recyclate markets closer to demolition sites and thereby

reduce transportation costs.



22



3: Literature review of methodologies and decision-making tools

3.1: Introduction

A review was conducted into reported methods of data collection and decision-making,

which precede implementing a waste reduction or reprocessing programme. Chen et al

(2003) reported that one of the greatest hindrances to effective waste minimisation was the

absence of a logical methodology for waste auditing. John and Zordan (2000) stated that "a

research methodology must be a logical guideline to help research teams carry out their

tasks...", and that, "the methodology must emphasise the important aspects to be

considered and their interconnections". A waste management programme must take into

account (Kiely, 1997):

o the size and nature of waste streams;

o waste sources;

o the potential cost savings generated through reduction or recovery;

o the technical feasibility of proposed solutions:

o required investment for the programme; and,

o feasibility of monitoring the success of the programme.

3.2: Waste treatment routes within the Waste Hierarchy

Waste re-use and recycling opportunities need to be considered alongside other wastemanagement avenues (further up the waste hierarchy), including waste reduction, or waste

elimination at source. There may be scope for eliminating certain waste streams, which

arise due to non-physical causes including (Serpell and Alarcon, 1998; Yahya and

Boussabaine, 2006):

o damage to construction products during transportation;

o ordering errors (e.g. excess materials delivered on-site);

o poor waste management methods;

o off-cuts from over-sized products;

o misuse of materials; or,

o inefficient manufacturing or construction methods.

Figure 2 over-page illustrates the variety of waste re-use, recycling and minimisation routes

which may be pursued, including product re-design, alterations to product manufacturing

equipment, re-use of the waste material within manufacture, or reprocessing of the waste

material (recycling) for use elsewhere (Kiely, 1997):



23



Figure 2: re-use, recycling and waste minimisation routes (taken from Kiely, 1997)

Appendix 4 illustrates examples of methodologies cited in the literature, which have been

used for waste management and assessment. These are presented as flowcharts, andcomprise a series of stages of data collection, materials testing, appraisal and options

selection/rejection. Examples are taken from eleven sources*, and references to these

methodologies are given throughout the rest of this chapter. These flowcharts also indicate

the variety of data collection and processing methods, including literature research, waste

audit surveys, workshops/discussions, interviews, questionnaires, computer databases or

models, and lab testing on waste materials. Methodologies generally encompass the

collection and analysis of background data, following a series of stages, which are described

within sub-sections 3.3 to 3.8.

*Kiely (1997); Envirowise, 1999, SEPA (2000); John and Zordan (2000); Inyang et al (2003); Wie et al (2003);Mamlya el al (2005); DEFRA (2006); Domburg et al (2007); Park and Martin (2007); Uqwu and Haupt (2007)

3.3: Purpose and boundaries of study

A methodology is initiated by establishing initial goals or targets. The target issues, materials

or pollutants need to be defined, as well as anticipated outcomes (e.g. reduced wastage by

5% per year, or increased profits due to waste minimisation) (Kiely, 1997).

One example is Life Cycle Analysis, whereby the researcher must define the goals and scopedefinition. This involves identifying the target audience of the study (e.g. local authorities),



24



defining the study goal (e.g. to examine the environmental impact of various waste

treatment options), and defining the extent of the study (e.g. how many waste treatment

options will be studied; what processes will be considered for each) (Arena et al, 2003).

Undertaking a waste audit study may be triggered by financial or regulatory demands. Wie

et al (2003) indicated in their flowchart (Appendix 4, Figure 4.5) that a waste

characterisation study follows recognition that current disposal of wastes to landfill is

becoming too expensive for the company concerned. There may be regulations which

necessitate undertaking a waste audit, e.g. the Site Waste Management Plans, which are

expected to become mandatory for construction projects valued at £250k and over. For

secondary aggregate producers, the Quality Protocol requires that waste source studies and

laboratory testing is conducted, in order to confirm that the material can be classified as

"inert" (WRAP, 2006).

3.4: Waste arisings and current status

A waste management pian is dependent on the collection of data regarding (1) waste

quantities, (2) financial costs associated with the waste, and (3) the composition and types

of waste (McDonald and Smithers, 1998). Several of the flowcharts provided in Appendix 4

include the examination of waste streams during the earlier stages of a methodology. Data

initially collected can include information regarding:

- waste streams: fractions and flows;

- waste quantities (including percentage of raw materials being wasted);

- waste sources, causes and locations;- energy and waste disposal costs;

- industrial processes and machinery;

- waste disposal destinations;

- legal status (e.g. classification of waste as hazardous; regulations governing waste);

- current recycling routes and rates of recovery;

- emissions from waste streams;

- composition and properties of waste materials; and,

- general drivers and barriers to re-use or recycling.

References: Kie!y, 1997; Envirowise, 1999; SEPA, 2000; John and Zordan, 2000: Inyang (2003); Wie et al, 2003;DEFRA, 2006: Domburg el al, 2007: ParK and Martin, 2007.

Information such as waste disposal destinations, quantities and types Is required under the

Area Waste Management Plans and the Site Waste Management Plans (SEPA, 2000; DEFRA,

2006). Waste "mapping" and auditing tools have been developed, including the Waste

Mapping process (see Appendix 4, Figure 4.2) by Envirowise, or SMARTAudit (benchmarking

and categorisation of waste - based on quantities, causes, sources and costs) (Envirowise,

1999} (Osmani and Li, 2006).



25



3.5: Material testing and characterisation

Detailed information will also be required, regarding the composition of the waste material,

its properties and those of a product (partly) composed of the processed waste material.

The physical and chemical characteristics of waste materials will determine the properties of

the recycled product, including compliance with environmental regulation, product

strength, product durability, as well as health and safety issues (e.g. occupational hazards

associated with using the product on-site) (Inyang, 2003).

Collecting this information may necessitate analysing and conducting some lab testing of

samples, a process included in some methodologies (e.g. Inyang (2003); Park and Martin

(2007)) (Appendix 4, Figures 4.5 and 4.10). Materials testing is a requirement under the

Aggregates Protocol, prior to placing secondary aggregates on the market (WRAP, 2006).

Testing and analysis of waste material samples may be necessary, in order to establish

whether or not it is classified as hazardous (Environment Agency, 2005). However,

laboratory testing of materials is also expensive, and may therefore be limited during a

waste audit.

3.6: Waste treatment routes

In addition to identifying appropriate waste materials, appropriate waste treatment routes

must also be identified and assessed within a methodology. One reason is that reprocessing

techniques are constantly being developed, whereby those currently at an embryonic stage

(e.g. lab testing) may exist on the market in a few years hence (Faber et al, 2007). The

availability, location, requirements and costs of reprocessing routes should also be

examined, as part of a screening process in order to determine (1) which options are

economically or technically unfeasible, and (2) whether or not the waste materials meet the

requirements of the potential option (e.g. sufficient quantities, appropriate composition)

(Kiely, 1997; Willard and Goonan, 1998; Inyang,2003).

Studies into the available waste re-use/recycling opportunities are indicated in several of

the methodologies illustrated in Appendix 4, and necessary for investigating financial issues

such as capital and operational costs. Dornburg et al (2007) (Appendix 4, Figure 4.9) studied

the sizes, locations, costs and energy demands of different waste treatment technologies for

biomass residues; using this data, the authors then selected or rejected identified treatmenttechnologies, depending partly on energy and cost savings.

The identification and assessment of waste treatment alternatives is listed in several other

flowcharts in Appendix 4 (including SEPA, 2000; John and Zordan, 2000; Wie et al, 2003;

Mamiya el al, 2005; and Park and Martin, 2007) (Figures 4.3 - 4.4, 4.6 - 4.7, 4.10). The

identification of appropriate waste treatment options by local authorities is required under

the Waste Strategy 2000, and is also a requirement for contractors under the Site Waste

Management Plans (DEFRA, 2006 - Appendix 4, Figure 4.8).



26



3.7: Assessment and ranking of re-use/recycling opportunities

Once background data regarding waste materials and reprocessing routes has been

assembled, the issues affecting the viability and practicality of re-use or recycling routes

need to be assessed (Park and Martin, 2007). A waste recovery process will only be

conducted if savings or profits can be generated as a result, and only if the method is

determined to be technically feasible and environmentally (and even socially) acceptable

(Aravossis et al, 2003).

Re-use/recycling viability criteria

Most of the flowcharts provided in Appendix 4 include the examination of economic and

technical criteria, as well as environmental, H&S, regulatory and even social criteria. Table 3

over-page lists the criteria, as cited from the literature, which may be examined, in order to

judge the acceptability of re- use/recycling options. These have been classified into general

categories, including economic (financial, market-based), technical (material, equipment-

related), environ mental/H&S and social issues, as well as those relating to regulation and

practicality (i.e. feasibility, flexibility). Financial costs often form the most critical aspects

being considered when evaluating waste management options; however, other aspects such

as legislation or public opposition may overshadow a potential waste treatment route which

could be financially affordable (Aravossis et al, 2003).

Decision-making tools

Several of the illustrated methodologies in Appendix 4 include taking decisions on which

waste materials or waste reprocessing routes should be investigated further or rejected.

This can be a complicated and unenviable task, whereby waste treatment options possess

both benefits and drawbacks, different stakeholders (e.g. managers, consultants) hold

different opinions, and criteria may be contradictory or not equally as important; as a result,

it may not be possible to determine the "optimum" route (Geldemnann and Rentz, 2004;

Mergias et al, 2007). Issues which may lead to decisions being taken include *:

o waste quantities:

o waste materials arising in insufficient quantities may not be worthreprocessing;

o the quantities may determine which reprocessing methods are most appropriate;

waste material properties:

o compliance with environmental regulations;

o compliance with industry or product standards;

o transportation, reprocessing, energy or labour costs; or,

o overall suitability of waste materials/options against identified criteria.

*Kiely, 1997: John and Zordan. 2000; Inyang et al, 2003; Wie el al, 2003; Mamlya et al, 2005; WRAP, 2006:

Dornburg et al, 2007



27



Table 3: criteria which can be used to assess re-use/recycling opportunities



28



Decision-making may also address a comprehensive set of data addressing several different

criteria, including economic, technical and environmental Issues (e.g. Kiely (1997); SEPA

(2000); Park and Martin (2007)). A wide variety of decision-making methods were cited in

the literature; these range from an individual making an intuitive (ad hoc) decision, to using

advanced computer models or multi-criteria-based tools (e.g. outranking software such as

PROMETHEE).

Comparison with regulatory/specified limits or standards

A waste material may be accepted or rejected, depending on requirements such as industry

standards (e.g. British standards), or regulatory limits relating to emissions from the waste

material itself or its reprocessing (Brunner and StarkI, 2004). One example is reference to

the Waste Acceptance Criteria specified under the Aggregates Protocol, whereby wastes

considered for use as secondary aggregate must not "undergo significant physical, chemical

or biological transformations" and must not be corrosive, or “cause potentially damaging

releases of pollutants to surface or groundwater” (WRAP, 2006).

Multiple assessment of criteria

As listed in Table 3, there is potentially an extensive and varying range of criteria which

could be considered prior to undertaking development towards waste re-use or recycling.

Not all data will be quantitative, and potential waste materials cr reprocessing options

might simultaneously perform highly on certain criteria, and poorly against others (SEPA,

2000; Linkov et al, 2003).

Researchers have developed various means of assessing a range of options, which take awide range of criteria into consideration, and which may accommodate both qualitative and

quantitative information. Criteria measured using broad qualitative statements (e.g. "low",

"medium", "high") has been converted into quantitative measurements by some

researchers; Hua et al (2005) reported on the use of "fuzzy logic" to convert statements into

rankings (e.g. "definitely low" = 1; "middle" = 5; "very high" = 9).

The importance (or weighting) of criteria have also been measured, usually by asking

experts to rank criteria (Aravossis et al, 2001; Geldermann and Rentz, 2004; Norese, 2004;

Park and Martin, 2007; Ugwu and Haupt, 2007). Some of the main multi-criteria analysis

techniques are summarised throughout the rest of this sub-section.

Ad Hoc decisions

Linkov et al (2003) noted that the simplest approach to selecting options is for the analyst to

make an intuitive decision, based on limited information, with minimal criteria, and possibly

without consulting stakeholders. This method incurs a high risk of critical factors (which

could make reprocessing unviable) being overlooked or underestimated, and hence the

most promising option being rejected.



29



Delphi technique

The analyst can base his/her decisions on the opinions of panels of experts, who make

anonymous forecasts or comments during two or more rounds of questionnaires or surveys.

The rounds may be repeated over a period of time, and results collected may be averaged

(Boks and Tempelman, 1998). The Delphi technique is a subjective (opinion-based)

approach, although the input by experts and their anonymity Increases the validity of the

data collected.

Comparative risk assessment (CRA)

CRA involves the use of a matrix table, whereby a list of options are tabled, which in turn are

compared against specified criteria. Using such a table (or even charts), the analyst then

makes an informed decision on which option is the most acceptable.

A more advanced version was illustrated by SEPA (2000) within their method for selectingthe Best Practicable Environmental Option (BPEO) for management of waste materials

under Area Waste Management Plans.

According to Brunner and StarkI (2004), determining the BPEO involves ascribing limits (t)

for listed criteria, measuring the performance of options (x) against each criterion, and

identifying the option with the minimum impacts or problems, i.e.

For assessing the BPEO for waste management under the Area Waste Management Plans,

SEPA (2000) detailed two assessment processes:

- ranking of waste management options against specified criteria, from "best" to "worst"

(e.g. from A to F); and,

- qualitative comparisons between options against specified criteria (e.g. "much worse,

slightly worse, similar, slightly better, much better").

Cost Benefit Analysis

CBA is a purely economic, monetary unit-based technique, which essentially is used to

identity an option with the highest surplus of financial benefits against costs (Brunner and

StarkI, 2004). This involves measuring the predicted capital costs, the ongoing operational

and maintenance costs, and the revenues over a set period ot years, in order to measure

the pay-back period, and the profit margins (Wilburn and Goonan, 1998). There are a wide

variety of cost-benefit analysis formulae and equations (Stenis, 2004; Duran et al, 2006).

Nevertheless, in general, a reprocessing operation or route will only be selected if:

- costs are reduced through sending waste to a reprocessing contractor, instead of to

landfill; or,



30



- purchasing recycled materials does not exceed the cost of purchasing primary materials

(Duran et al, 2006); or,

- if the revenues from selling re-used/recycled materials can match the reprocessing costs

(Peng et al, 1997).

Although CBA does not take technical or environmental indicators into account, the

profitability of re-use/recycling opportunities is a prime deciding factor for most companies;

any option which does not lead to decrease in costs or an increase in profits is generally

rejected (NISP, personal communication 2007).

Multi-criteria analysis

Methods have been developed during the past two decades, whereby the performance or

acceptability of options are measured against selected criteria (Linkov et al 2003). From

this, options may be measured in terms of preference, taking a wide variety of criteria into

consideration (Mysiak, 2006). Both qualitative and quantitative data can be converted intoquantitative measurements of the performance of each option against each criterion. The

data generated from this is then used to calculate the total "utility", or measure of

satisfaction gained from each option. A graphical illustration of utility "results" for different

options is provided in Figure 3:

Figure 3: graph of the utility of potential recycling routes (Options A to E)

Within multi-criteria analysis, each criterion is ascribed with a weighting factor, whereby

some criteria are classed as being more important than others. This is strongly subjective,

and weighting factors are often based on experts' own opinions. In general, the utility (U) of

an option relates to the performances against each criterion (c), and is affected by the

weightings (w) ascribed to each criterion:

Table 4 (page 32) summarises the functions of some multi-criteria decision- makingapproaches reported from the literature. These methods can be time-consuming, involving



31



extensive consultation wtth experts and stakeholders. In order to establish realistic

weighting values for criteria; furthermore, results generated using different methods may

vary (Brans and Mareschal, 2002; Unkovetal,2003).

Probability and Consequence

An approach commonly applied within risk assessment studies is to compare the probability

of dangerous occurrences with their predicted severity (or consequence). Probability (p) and

Consequence (c) risk assessments are used In H&S, transportation, civil engineering,

management and also in medical studies. The degree of Risk (R) is represented by; R s cp,

and R values may be presented in a matrix table.

Kingdom Drilling (2001) used this assessment in order to determine the risk of accidents

associated with oil exploration (including the risk of pollution). This assessment was based

on probability metrics (Table 5) and consequence metrics (Table 6). Each potential hazard

was measured using R values listed in the resulting risk matrix table (Table 7).

Models and databases

Highly advanced and intricate assessments of economic, technical, social and/or

environmental data have been conducted using methods such as LCA (Life Cycle

Assessment), pollution dispersion models (i.e. the sources, and movement of pollutants

throughout ihe environment), and GIS (used to study processes across geographical regions,

e.g. transportation routes) (Arena et al, 2003; Kaebernick et al, 2003; Dahlbo el al, 2006;

Schmelev and Powell, 2006).

These may be used for quantifying an extensive list of processes and impacts (e.g. the

quantities of emissions to air generated throughout a manufacturing process, e.g. COa,

methane, nitrous gases) (Arena et al, 2003). Nevertheless, the use of techniques such as LCA

is also time-consuming, as they rely on the provision of highly specific data, which in turn

can be very difficult to obtain or measure (Kaebernick et al, 2003).



32



Table 4: examples of multi-criteria decision-making methods cited from the literature



33



Table 5: definitions of probability used by Kingdom Drilling (2001)

Table 6: definitions of consequence used by Kingdom Drilling (2001)

Table 7: matrix table of probability and consequence (Kingdom Drilling, 2001)



34



4: The PEWA methodology

4.1: Aims and Objectives

The aim behind Deliverable 3.5 was to produce a validated methodology, which can be used

by companies within the construction Industry as an assessment tool for selecting waste

materials which could be tested for potential re-use or recycling. It has been developed by

Loughborough University, and has being validated through consultation with BRE, the

Construction Products Association, NISP (National Industrial Symbiosis Programme), and by

the BeAware partners. The fully validated methodology will be applied for the selection of

waste materials and re-use/recycling outlets for laboratory testing within the BeAware

project.

4.2: Overview of proposed methodology

The PEWA methodology is composed of ten stages, most of which comprise data collection,

followed by decision-making. Each decision involves deciding whether to:

- continue investigating the selected waste material towards possible re-use or recycling; or,

- to reconsider it outside the scope of the project (e.g. ignore the waste temporarily, or

reduce it at source).

The first three stages Involve identifying the waste materials occurring in a sector, obtaininginformation on waste material composition, identifying whether or not any of the waste

materials are classified as hazardous, before prioritising which waste materials should be

investigated further.

Stages 4 and 5 relate to the waste mapping exercise, whereby Information is collected

regarding the sources, quantities and value of waste. Assuming that the waste is segregated,

occurring in significant quantities and may possess good market value, further information

is then collected regarding the financial costs associated with the waste, the revenues (if

any) relating to its recovery, as well as the current recycling status. It is also important to

identify whether the material is "wet waste" or "dry waste" (NISP, personal communication

2007).

Stages 6 and 7 focus on the limiting factors which currently affect, limit or may even prevent

recovery of the waste material, and the potential solutions for addressing these factors.

Once it is established that none of the limiting factors (rated as "critical") currently prevent

the possibility of recovering the waste material (and that a solution may be implemented

through a testing and development programme in the short-term), the analyst can proceed

to Stages 8 and 9, which involve studying the current and potential recycled product

markets, and the demands placed on the design of the product. If the waste material can be

reprocessed in-house, further financial information should be collected within Stage 10 (e.g.

capital, operational costs).



35



4.3: Stage 1 - Waste Targeting (Figure 5)

The waste materials occurring within the sector are identified, and their arising within the

construction product lifecycle is indicated. Wastes can arise alongside manufacture,

distribution, during construction (point of use), and/or during demolition (end of life).

Figure 5: Stage 1 of the PEWA methodology

4.4: Stage 2 - Waste composition

Information regarding the physical and chemical composition of the identified waste

materials are then collected (Figure 6). One important reason tor this is to identify which

materials may be currently classified as hazardous (under the Hazardous Waste Directive

(91/689/EEC)).

Figure 6: data collection for Stage 2: waste composition and disposal status



36



Further information regarding the hazardous nature of the waste material is also produced

during Stage 2 (Figure 7). If hazardous waste materials are identified, and if these are

currently disposed of to landfill, the user is advised to re-consider these materials later, and

focus on the remaining waste materials in Stage 3 (Figure 8).

Figure 7: data collection for Stage 2: hazardous status of waste material

Figure 8: decision-making at end of Stage 2 of the PEWA methodology

4.5: Stage 3 - Waste prioritising

Stage 3 is an initial screening process, whereby the main recycling drivers and barriers are

listed for the identified waste materials. There may be several different waste materials, and

some may occur in minor quantities, or may have minimal scope for re-use/recycling. The

waste materials are ranked in terms of their recycling potential (Figure 9), and higher-

ranked materials are examined further (Figure 10).



37



Figure 9: data collection for Stage 3 of the PEWA methodology

Figure 10: decision-making process at end of Stage 3 of the PEWA methodology

4.6: Stage 4 - Waste source, quantity and value

For each of the selected waste materials, more detailed information is collected regarding

their sources, quantities, and market value. As shown in Figure 11, such information

includes descriptions and causes of the waste during the construction product lifecycle, as

well as ranking the significance of these arisings. The waste is also identified as either a

"wet" or "dry" waste, since the costs and technical issues will contrast between these

categories (NISP, personal communication 2007).



38



Figure 11: waste sources, causes and ranking

Stage 4 requires further examination of the waste material quantities (including the

percentages of the total arisings occurring during each lifecycle stage) (Figure 12). The user

must also indicate whether or not the waste is segregated at source, and what market

values (if any) are carried by the recycled material. The use of the terms "high", "medium"

or "low" may be purely intuitive, and their meaning will vary with regards to the market

price of recycled materials. In this methodology, "medium" quantities occur at between

25% and 50% of total waste occurring within the product lifecycle, whilst "high" quantities

occur at over 50% of total waste.

Figure 12: waste quantities, segregation and market value

At the end of Stage 4, the user selects waste materials which are segregated, since these willbe easier to collect and reprocess (Figure 13, over-page):



39



Figure 13: decision-making process at end of Stage 4 of PEWA survey

4.7: Stage 5 - Waste costs and current recycling status

The proportions of the costs of waste owing to disposal and/or recovery (re- use/recycling)

are examined. These proportions are further divided into categories, including waste

handling, transport, landfill tax, and reprocessing (Figure 14).

Figure 14: costs of disposal and recycling (examples are purely illustrative)

The proportions of waste currently sent to landfill (Disposal), or re-used or recycled

(Recovery) are then examined (Figure 15). For waste which is still sent to landfill, the landfill

locations and reasons for disposal are provided, and the potential recovery applications are

also indicated; the recycling potential is also intuitively measured. For waste materials

currently re-used or recycled, information provided includes whether this is conducted on-



40



site or off-site, the current locations and applications, and an indication as to whether the

application is low-grade or high-grade.

Figure 15: current recycling status (examples are purely illustrative)

Following collection of the above information, waste materials which are entirely recovered

(and incurring minor financial cost in the process) are not considered further in the later

stages of the methodology (Figure 16).

Figure 16



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4.8: Stage 6 - Re-use/recycling limiting factors

The factors which may restrict or even prevent re-use or recycling of the selected waste

materials are examined. These are generally classified under four categories, and examples

are provided in Table 8:

Table 8: examples of limiting factors

An example of listing limiting factors under one of these categories is illustrated in Figure 17.

Each of the Identified limiting factors is rated as:

- low (can be tolerated);

- medium (restricts re-use or recycling); or,

- critical (prevents re-use or recycling).

Figure 17: examples of economic limiting factors

Following the data collection, waste materials which are not affected by critical limiting

factors are then selected for further investigation within the PEWA methodology (Figure

18):



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Figure 18: decision-making process at end of Stage 6 of the PEWA methodology

4.9: Stage 7: Addressing the limiting factors

For the selected waste materials, potential solutions for addressing the limiting factors are

identified, and an indication is given as to how long this may take (Figure 18). The limiting

factors are classified as E (economic), T (technical), Env (environmental), or O (other); the

time-frame may be ST (short-term, or in the next 12 months), MT (or1 -3 years), or LT (long-

term, or over 3 years).


Waste materials, for which technical limiting factors could be addressed over the short-term

(i.e. through testing and development), are then selected for further investigation in Stage 8

(Figure 20).



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Figure 20: decision-making process at end of Stage 7 of PEWA methodology

4.10: Stage 8 - Re-use/recycling opportunities

The re-use and/or recycling routes are investigated for Stage 8, including those currently

being pursued. Reprocessing methods are constantly being developed, and there may be

more profitable, higher-grade applications for waste materials currently reprocessed for

low-grade applications (Faber et al, 2007). As shown in Figure 21, the current and potential

re-use and recycling routes for the selected waste material are identified. These may involve

introducing the waste material back into the company's own product (OP, or Own Product);alternatively, the waste may be reprocessed or used by another company in the

construction sector (SS, or same sector), or outside the construction sector (CS, or cross-

sector).




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4.11: Stage 9 - Re-use/recycling requirements

Information regarding required waste material or recycled product properties is then

collected. Standards (e.g. impurities content, mechanical strength) may be imposed by the

waste recycling contractor, or will be detailed in publications including British standards and

other relevant documents (e.g. Highways Agency specifications for recycled aggregate)

(Figure 22). If the relevant specifications can be met, the user may proceed to Stage 10 -

otherwise, the user should return to Stage 8 and select another reprocessing route (Figure

23).

Figure 22: data collection tor Stage 9 of the PEWA methodology

Figure 23: decision-making process at end of Stage 9 of PEWA methodology



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4.12: Re-use/recycling costs and markets

If reprocessing Is technically feasible, a detailed investigation needs to be conducted into

the potential capital and operational costs (and hence the payback period), as well as

current market prices and their variations. These are taken into account during Stage 10, as

indicated in Figure 24.

Capital costs include purchasing machinery and vehicles (equipment), labour (e.g.

consultants' fees during design and development), buildings (e.g. new, or alterations),

overheads (e.g. administrative, licensing), and possibly land being purchased (Figure 24).

Operational costs include labour, equipment operations (including fuel consumption),

equipment repair (maintenance), overheads (e.g. inspections), and possibly rent paid for use

of the land (Figure 25).

The payback period may be short-term (less than 3 years), medium-term, or long-term (over

10 years), although nowadays, a payback period of more than 3 years is no longer

considered to be attractive (NISP, personal communication 2007); the influence of future

environmental legislation on the viability of reprocessing (e.g. increasing landfill tax) should

also be considered (Figure 26).

The market for primary and recycled materials should also be investigated, including:

current market prices, how these have altered during the past 3 years, and what changes

may occur during the next 3 years (Figure 27):

Figure 24: data regarding the capital costs of a potential onsite reprocessing route



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5: Conclusions and further work

22 waste materials were surveyed during the waste mapping exercise, and of these, 13 were

also surveyed through the PEWA survey interviews- Of these, cement kiln dust, WESP (wetelectrostatic precipitator) sludge, plastics from demolition, and polyethylene packaging

were reported to be currently sent to landfill. GRP (glass reinforced plastic), IBC

(intermediate bulk containers) and timber waste from demolition were reported to be

partially recovered. The other waste materials were reported to be almost entirely

recovered (including the plasterboard off-cuts from construction sites, although these do

not include thermal laminated boards). Information was also collected regarding waste

material quantities, sources, costs, as well as technical and economic Information such as

essential material properties (for re-use/recycling), and current markets.

A methodology (which relates to the data collecting activities described in Section 2) hasbeen developed, and has been validated by BRE, the Construction Products Association. It

will be further validated through communication with the BeAware project partners- Once a

fully validated methodology is developed, it will be applied to the information collected to

date, in order to select waste materials, which will in turn be analysed further through

laboratory testing.

Acknowledgments

The authors are extremely grateful to ail the interviewees who participated in the waste

mapping and PEWA survey interviews, and to the partners (BRE, Construction Products

Association, NISP) who offered their advice regarding the methodology.

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Documents

PERFORMANCE AND ECONOMIC WASTE ASSESSMENT (PEWA) METHODOLOGY