overview of the results of the first three-week waste sort activity orga- nized and managed by GBB staff and conducted from July 12 to July 30, 1993. It is the first of a two season sort to be conducted in the

Debris the municipal waste Stream es- Town, with the second sort planned to be conducted in October, 1993.

The article describes the type of construction and demoli- tion projects that were se- lected for sorting and a re- view of the data and results from this July 1993 activity.

Data on the Composition Analysis of Construction

Waste & Demolition

(C&D waste) generated in the Long Island Community of 225,000 people. Altho%hC&Ddebriscom- Prises a relatively Small Portion of

h a t e d by the EPA to be 10 to Prepared By Gershman, Bnckner & Bratton, Inc. Falls Church, VA

One of the largest areas of concern for the nation’s demolition contractors is what to do with their waste stream. Gone are the days DESCRIPTION OF of cheap landfill space and SORT PROCEDURES low transportation costs. AND SELECTED What was once a minor bid PROJECTS item has become a major cost component of any The sorting was conducted demolition project. As the inside the Construction and NADC, the demolition in- Demolition Processing dustry and government Wood Fraction of Sample regulatory agencies wrestle with this problem it is important to develop a clear understanding of what is be- ing disposed of and what can be recycled. The following study per- formed by GBB, a solid waste man- agement consultant from Falls Church, VA for the New York State Energy Research and Development Agency oflers some insight into the problems the industry faces and the methods available to deal with them.

The New York State En- ergy Research and Development Authority (Energy Authority) has provided funding to the Town of Babylon, NY in the form of cost sharing for the investigation of re- cycling and tracking of construc- tion waste and demolition debris

20 % of total Municipal Solid Waste [MSW]), it is difficult to manage through traditional waste manage- ment methods due to its bulky na- ture. Therefore, in order to develop efficient C&D debris management/ recovery systems, accurate methods to quantify its presence and compo- sition must be developed. As part of the overall study, which includes the development and demonstration of a municipal tracking program and gathering data on existing disposal and recycling practices in the town for C&D waste, the project includes a composition analysis of waste ma- terials generated from construction & demolition projects. This refine- ment of data will help ensure that recovery systems and associated market development efforts can be

Building (C&D Building) at the Commercial and residential Re- cycling Facility (CRRF) located in Babylon. The CRRF is a privately owned recycling and waste transfer facility built and operated under a 20-year Service Agreement with the Town. Based on a separate CRRF utilization agreement entered into between the Town and the private owner/operator, the GBB project team used a portion of the C&D Building for the waste sort.

Approximately 5,000 sq. ft. of floor space was used inside the C&D Building for both the stock- piling of the C&D waste and con- ducting the actual sort. Approxi- mately six to seven sorters were used each day to pick through the mate- rial, weigh each of the sorted com- ponents, perform screening and siz- ing functions on certain loads, and

1 O*DEMOLITION AGE*9/93

conduct other sort related operations. A small slud steer and forklift were used periodically to move the C&D waste for sorting access as well as to load and unload the larger con- tainers for weighing and ultimate materials deposition.

Three 20 cu. yd. roll-offs were provided by the CRRF operator to hold certain categories of sorted material; these were for wood, ferrous and non-ferrous met- als, and all other sorted waste. Ad- ditionally, for two of the delivered C&D waste loads, a fourth roll-off container was provided for handsorted cinder blocks, concrete and bricks.

Due to the higher C&D debris tipping fees charged by Babylon at the CRRF versus locally available C&D debris land- fills, the CRRF is not cur- rently receiving regular com- mercial deliveries of C&D waste. However, deliveries were coordinated by the Town of Babylon for the C&D waste brought in dur- ing the three-week sort pe- riod. Extensive efforts were made by the GBB Project Team prior to the field work to identify construction and demolition projects for inclusion in the sorting project. This identification included a review of recently approved construction permits in the Town, current prop- erty inspections then being con- ducted by the Town’s Building De- partment, site visits, if possible, and conversations with the local con- tractors and haulers.

The actual waste deliveries and sorting was done from 7:OO a.m. to 3:30 p.m., Monday through Fri- day for three consecutive weeks. In summary, samples from five project categories were included in the July sorting program and more than one source of each of five project cat- egories were sampled. This data is summarized in Table 1.

A total of 16 projects were sorted from 8 residential and 8 com- mercial projects, comprising a total of 161.5 tons. On average, about 1 1 tons were sorted each day. Given an average crew size of six laborers and an eight hour day, the sorting rate averaged 1.3 tons per hour i.e. about 450 pounds per sorter per hour. If the demolition projects were excluded, which consisted of rela- tively dense material, the average sorting rate was about 350 pounds per sorter per hour. For the four demolition projects which com- prised 58.6 tons, the average sorting

house was completely demolished and a pre-demolition audit to esti- mate the quantity of C&D waste materials was conducted by GBB staff on this structure.

REVIEW OF SORTED PROJECTS FROM PERMITS AND VISUAL INSPECTIONS

G55 Sampling Team rate was about 600 pounds per hour.

Commercial building reno- vations were the most common type of construction activity in the Town at the time of the July sort and be- came the most frequently sampled category. Six such projects were analyzed comprising 68.9 tons, or about 43% of the total quantity sorted. These commercial renova- tions ranged from interior retail space upgrading to exterior remod- eling and refurbishment. Four resi- dential renovations were sorted and consisted of 20.1 tons.

Two residential demolition projects were sorted, totalling over 38 tons of material. This category had the greatest density of material and consisted of a lot of concrete from basement flooring and cinder block walls. One single family

The GBB project team tried to make a site visit, take photographs and/or gather construction permit in- formation of the various projects in- cluded in the sort. This was accom- plished for a majority of the projects

and found to be useful in assessing the resultant com- position data. Table 2 presents a summary of the sorted projects and the Sample Number Identifica- tions assigned to each. The residential construction con- sisted of single-family homes and one multi-fam- ily building. The four resi- dential renovations ranged from small add-ons to exist- ing single-family homes to interior upgrading and re- modeling. The type of spe-

cific renovation conducted dictated the type of waste being generated. For example, a new addition would include many typical components of a new home construction (dimen- sional lumber, plywood, drywall, in- sulation, etc.) whereas, a project in- volving the installation of a new roof or addition of new siding would generate only limited variety of ma- terials. The one house demolition project that was included in the waste sort consisted of a one story single-family “cottage frame” house. For the 8 commercial sector projects, six were renovations and two demo- litions. Much like the residential renovations, a variety of projects were included which generated spe- cific waste types and materials. They varied from retail interior reno- vations (e.g., to accommodate a new

11. DEMOLITION AGE 9/93

loading it into the roll-off contain- ers. The bulldozer's steel tracks shredded the C&D waste into small fragments making manual sorting difficult. Given the large percent- age of miscellaneous fines (32%), the GBB Project Team decided that some additional analysis of this com- ponent should be made to assist in later related activities.

After all the large compo- nents of Sample 16 were sorted off the tipping floor and weighed, two separate manual screening methods were undertaken on the remaining "miscellaneous fines" component. The first involved the field construc- tion of a nominal 3'x3' wood frame doubEdeck screen constructed with support legs to discharge at a height compatible with the field bins. The screen was constructed with a top deck of 1/2" square hole screen cloth and a bottom deck with 1/4" square holes. Material was manually loaded (by shovels) onto the top screen such that three products were produced - greater than 1/2", a mid- dlings fraction of 1/4" -1/2", and a fines fraction less than 1/4". The results from the first screening of over 4,000 lbs. of the Sample 16 "miscellaneous fines" were as fol- lows:

Size Weieht % Den.

>112" 1,090 25 650 114" - 112" 411 11 1,350

< 1/4" 2.745 642.900

Total 4,312 100 1,450

A sample of the oversized (i.e., that greater than 1/2") material from the screening operation was then sorted a second time by two GBB Project Team Staff on a flat 4' x 8' sorting table to get a general sense of this smaller sized material, i.e., typically 1/2" - 3" in size. The results of this additional hand pick- ing activity were as follows:

ComDonent Composition %

Concrete/rocks 32 wood 15 Roofing Material 7 Drywall 2 Metals - 2

Subtotal 58 Misc. Leftovers 42

Total 100

The miscellaneous leftovers were mostly shredded wood, dry- wall, paper and small stones that were greater than 1/2" but, because of their volume, could not easily be further sorted (by hand) within a reasonable time frame.

In order to attempt to in- crease the hourly manual screening capacity of the sorters, a second larger deck screen was constructed in the field. The screen deck was approximately 12' long and 3' wide and was constructed with miscella- neous on-site materials of the CRRF operator consisting of nominal 3" x 3" angle iron used for the horizontal bracing and two higher quality (Le., thicker and stronger) but slightly dif- ferent shaped screen cloth. Approxi- mately 7,500 lbs. of miscellaneous fines was screened and, as it turned out, the second screening program presented similar results to the ini- tial smaller-sized screen. The ma- jority of the material in the "miscel- laneous fines" category were in fact small dirt-like fines, less than 1/4" material, with about 75% of the to- tal material screened being less than 1/2 inches. For Sample Number 16, these fines consisted mainly of dirt and small rocks dug up by the bulldozer during the demolition.

Visually, these materials appeared relatively clean and pend- ing chemical analysis (which is not part of the contract scope) could possibly be reused as a soil amend- ment, landfill cover, road construc- tion, or some other uses for soil.

2. Commercial

Within the commercial sec- tor, 6 building renovations and 2 building demolition were sorted and analyzed. Like the residential sec- tor, the demolition projects had a high percentage of miscellaneous fines, (55%), along with wood (17%) and pressboard/chipboard (12%). The largest components in the renovation projects were con- crete (22%) and cinder blocks (19%).

Commercial renovations were the most common type of con- struction activity in Babylon in July of 1993. Given that the town has very little undeveloped land for com- mercial projects, commercial reno- vations are expected to continue to be a predominant form of commer- cial construction activity in the town. In summary, the Babylon project involves several seasonal C&D de- bris waste sorts and the establish- ment of a new construction waste and demolition debris (C&D waste) waste audit and tracking system within the town. Figure 2 presents the summary of the major waste components from the July 1993 sort. Over 160 tons of C&D waste were sorted in July, 1993 and an addi- tional three week sort will also be conducted by GBB in October, 1993. The refinement of such C&D debris data will help ensure that pro- posed recovery systems and asso- ciated material and/or energy mar- ket development efforts are tailored to best meet the needs of the com- munity.

The data presented in this article was provided by Robert H. Brickner, Vice President of GBB with the permission of the New York State Energy Research and Devel- opment Authority and the Town of Babylon, New York. It presents an in-depth look at the type of waste the demolition industry handles in an typical American city and is use- ful as part of the industry's ongoing program to develop recycling op- tions for its waste. It also provides regulatory agencies with additional information on the true nature of the demolition industry's waste.

13. DEMOLITION AGE 9/93

tenant or space use) to a major roof- ing job. Table 2 presents a brief description of each project by Project Type. The density of certain mate- rial delivered loads was calculated for some of the samples and is shown in Table 3. Generally, the materials from the demolition projects were found to be of greater density than the renovations.

ANALYSIS OF RESULTS

The data from the sorting of the 16 projects were analyzed in a variety of ways including:

Composition by Compo- nent in Each Sector

Combined Composition of All Samples

Combined Composition of All Residential Samples

Combined Composition of All Commercial Samples

Table 4, which reflects over 40 individual components sorted, provided the results for all samples. The largest component by weight was miscellaneous fines (29%), fol- lowed by concrete without rebar (14%), untreated and unpainted wood (13%), and cinder block (12%). The component “miscella- neous fines” dominates because nearly every sample had some fines and small fragments that could not be easily sorted and the four demo- lition projects had a large fraction of such fines (e.g., dirt, crushed con- crete, etc.). The GBB Project Team was careful not to casually lump materials into this component.

It is worth noting that Sample 16 alone had nearly ten tons of miscellaneous fines. This demo- lition project employed a dozer that ran over the material to increase ma- terial densities prior to loading into the contractor’s roll-off boxes. The nature and size of the miscellaneous fines was analyzed, in part, during the waste sort and is discussed later in this article.

The second most common component, by weight, is concrete without rebar followed closely by cinder blocks. These are fairly dense materials contributing their high per- centages and were found frequently in various types of renovations and demolitions. No project generating reinforced concrete was hand sorted during the three week July sort. Visually,- wood was clearly the dominant waste component. Oftentimes an entire load would be dumped on the floor and appear to be all wood, when in fact the heavier materials had settled to the bottom of the pile. If all of the six wood categories are combined, the total overall wood composition, by weight, is 19.8%, Standard 2x4s were the most common type of wood, followed by 4x4s and other dimensional lumber sizes. Plywood comprised about 3% of the total composition by weight, but visually seemed to be a more predominant material type than the actual weight indicated.

The ferrous and nonferrous metals (3.1%) consisted mostly of interior framing, shelves, and small structural members. Electrical wir- ing, electrical fixtures and metal drums were sorted as separate cat- egories. All metal-related compo- nents comprised 4.5% of the total material sorted.

COMPOSITION DATA BY SECTOR AND PROJECT TYPE

In looking at the composi- tion results by sector - residential and commercial - one can see sev- eral key differences. Miscellaneous fines and wood made up a larger fraction of the residential projects (59%) than commercial projects (39%) and reflects the large contri- bution from the residential demoli- tions. Concrete was more prevalent in the commercial loads as was cin- der blocks. Most of these differ-

ences can be attributed to the mix of project types e.g. 6 commercial reno- vations were sorted versus 4 resi- dential renovations and 2 new home constructions.

1. Residential

Within the residential sec- tor, several distinctions can be made between the three project types - construction, renovation and demo- lition. The demolition jobs were found to have much more concrete and cinder blocks than the other two groups - a combined 32% for the demolition jobs versus an average of only 3% for renovations and con- struction. This is because the demo- litions involved the removal of the structure’s entire foundation and basement walls, whereas new resi- dential construction and renovation jobs typically generate only leftover pieces of block for example, and unused materials left at the jobsite.

The total wood fraction var- ied from 24% in residential demoli- tions to 33% in residential renova- tions. The composition of drywall was almost identical at about 12% for both residential construction and renovation. Roofing shingles were 11% of the residential renovation composition versus less than 2% for the other categories. This was be- cause one of the samples (#14) was a major roofing job. This points out again the difficulty in making broad conclusions about the overall results - they are highly dependent on the specific construction and demolition activity in the sort.

For the one major home demolition project - Sample Num- ber 16 - some special sorting tech- niques were used to better charac- terize the large quantity of miscella- neous fines. As noted earlier, a large amount of fines were produced from this job because the demolition con- tractor used a bulldozer not only in tearing down the house but also in grinding up the C&D waste prior to

12=DEMOLITION AGE=9/93

I I I 1

Not To Scale

20 yd3

Other Roll-Off

20 yd’

Metals Roll-Off

Roll-Up Doors Truck Entrance for Sort Materials

n 90-Gallon 0 0 0 0

Toters 0 Bins

0 Sorting Area 0 (2 yd3) Material Staging Area for Non-Sort Debris

200 f t L

Town of Babylon, New York

CONSULTANTS

Figure 2

Summary of Major Components

Project Type

\ Met a I-F e r ro us (3.7 Yo Drvwal I/S heet roc k (4.6 YO \

Sample Weight Volume . v.04 (Cu.Yd.)

Misc. Fines (29.0%)

Commercial Renovation

Residential Renovation

Commercial Demolition

Residential Demolition

cot

15 2.43 20 243

6 4.57 20 457

13 5.52 30 368

11 8.65 50 346

12 11.57 30 77 1

16 30.7 90 920

icrete wi l

8

9

Cinder

Commercial Renovation 5.5

Residential Construction 7.1

:hout Rebar (1 4.(

~

Table 1. rhmrmaay of Project Typea pnd Weights

A d Numbex of Total Weight Percent of project cptegory Project Sorted CTOns) Tdal

Residential New Construction 2 13.9 8.6

. Block (1 2.4%)

Brick (1.3

12

13 _ _

3oofing

11'5 5.5 I Commercial Demolition Residential Renovation

Table 2. Sample I d e d f h t b md Weight

W Commercial Renovation

Commercial Renovation

Commercial Renovation

3 I Commercial Renovation I 10.6 11

Residential Renovation

Residential Demolition

Commercial Building Renovation

4 I Residential Construction I 6.8 11 I 1

4 20.1 12.4

2 38.7 24.0

6 68.9 42.7

5 I Residential Renovation 6 I Residential Renovation 4.6

TOTAL 161.5

7 I Commercial Renovation I 10.5 11

Total

Material-S hir

-d/Chip boa rd

16 161.5 100.0

igles (2.

(3.0 yo)

1 Yo)

Table 3. Comparison of Delivered Weight and Roll-Off Containex Size

I I Deliwered I Contaiueds) I

11 I Commercial Demolition I 8.4 11

14 I Residential Renovation I 2.4 11

Composition by Category in Each Sector

Table 4. Composition by Category in Each Sector (For 16 Projects Sor ted )

1 1