5.B 2020 Residential Waste Composition Final Report
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#5.b January 21, 2021 Ms. Nancy Plunkett Director of Special Projects Chittenden Solid Waste District 1021 Redmond Rd Williston, VT 05495 Subject: Residential Waste Composition Study Results Dear Ms. Plunkett: MSW Consultants is pleased to submit this letter report to the Chittenden Solid Waste District (CSWD) to summarize the characterization of residential waste at the Casella Waste Systems Transfer Station in Williston during August and November of 2020. The objective of the study was to complete two seasons of sample collection and sorting that proportionally reflected the residential waste produced by representative communities in Chittenden County. Methodology In order to develop a Sample Plan for this study, CSWD reviewed detailed route and material quantity data from waste haulers, truck types, and sources of waste deliveries to Casella Transfer Station in Williston. The Sample Plan was developed in order to capture representative samples from communities in proportion to the volume each community contributed to the District’s overall residential waste stream. Community and/or hauler weight data was then used to proportionally allocate samples across the list of communities. MSW Consultants reviewed the Sample Plan, which was then executed during two seasonal field data collection events at the Casella Transfer Station. Prior to conducting the field work for this project, MSW Consultants and the District determined three consecutive days of the week that would have the greatest number of representative trucks from which to collect samples. To be most representative across both sorting seasons planned for this project, it was necessary to collect samples on Monday through Wednesday during Season 1, and on Wednesday through Friday during Season 2, as shown in Table 1 below. Table 1 Sample Collection Plan and Schedule Field Data Collection Sample Collection Days Total Samples Season 1 – August 3-5, 2020 M-T-W 15 Season 2 – November 18-20, 2020 W-Th-F 15 Total Samples 30 Based upon community waste weight and volumetric data, CSWD compiled a Sample Plan determined to be most representative in allocating the 30 samples for this project. Table 2 below summarizes the Sample Plan, while also providing the number of samples actually collected from each community during the study. 11875 High Tech Ave, Suite 150, Orlando, FL 32817 (800) 679-9220 CSWD Residential Waste Composition Study January 21, 2021 Page 2 of 6 Table 2 Sample Plan Targeted Actual Loads Community Loads Sampled Burlington 8 7 Colchester 1 1 Colchester/Winooski 2 2 Essex/Essex Junction/Williston 2 3 Hinesburg 1 1 Jericho 1 1 Milton 1 1 Richmond/Bolton 1 1 Shelburne 1 1 Shelburne/South Burlington 1 1 So. Burlington 3 3 Williston 1 1 Drop-Off Centers (serve multiple communities) Essex 2 2 Milton 1 1 South Burlington 2 2 Williston 2 2 Totals 30 30 As can be seen in the table above, slight variations to the Sample Plan were encountered, mostly attributable to truck schedule variations. MSW Consultants believes the slight differences between the targeted and actual sample distribution would not be expected to adversely impact the study results. Sample Collection At the transfer facility, MSW Consultants personnel identified incoming truck loads for sample collection, as targeted in the Sample Plan. Selected loads of waste were then tipped in a designated area. A bucket loader and operator were available to assist with sample collection. From each selected load, one sample of waste was collected based on systematic “grabs” from the perimeter of the load. The sample was then loaded into 30-gallon trash barrels and pre-weighed to achieve the targeted sample weight of 200 to 250 lbs. Each refuse sample was labeled by a unique sample number, community(ies) of origin, truck number, hauler name, and sample weight. Digital photographs of each load were also obtained. Sorting Each sample was then sorted by a field-trained sort crew into open bins or barrels representing 28 material categories. Sorters were trained to specialize in certain material groups, with someone handling the paper categories, another the plastics, another the glass and metals, and so on. In this way, sorters become highly knowledgeable in a short period of time as to the definitions of CSWD Residential Waste Composition Study January 21, 2021 Page 3 of 6 individual material categories. A sorting crew chief monitored the bins as each sample was sorted, ensuring items were properly classified. The material categories and definitions are included as Exhibit 1. The sorting crew chief utilized a tablet computer synched to the cloud via cellular service to record material composition weights for each sample. After sorting, the total weight of each sample was cross-referenced against the collected sample data to assure accurate tracking of the samples each day. Please refer to Exhibit 1 at the end of this letter report for the list of Material Categories and Definitions used for this study. Data Analysis The following statistical calculations were performed to determine the overall composition of each waste generator sector: Sample Mean: The sample mean, or average composition is considered the “most likely” fraction for each material category in the waste stream. Confidence Intervals: A confidence interval is a statistical concept that attempts to indicate the likely range within which the true value lies. The confidence intervals reflect the upper and lower range within which the population mean can be expected to fall. Confidence intervals were calculated at a 90 percent level of confidence, meaning that we can be 90 percent sure that the mean falls within the upper and lower confidence intervals shown. Results MSW Consultants sorted a total of 6,386 pounds of refuse from 30 samples over the course of the two seasons. Table 3 on the following page summarizes the Seasonal results and the Aggregate composition percentages obtained for this study. Please refer to Exhibit 2 at the end of this letter report for complete seasonal data. In addition, the individual sample composition results have been added as an addendum. CSWD Residential Waste Composition Study January 21, 2021 Page 4 of 6 Table 3 Seasonal and Aggregate Composition Results Season 1 Season 2 Aggregate Recyclable Est. Est. Est. Material Category Class Percent Percent Percent Paper 14.5% 17.1% 15.8% MFUntreated OCC and Kraft Paper RF 2.0% 1.9% 2.0% MFUntreated Recyclable Paper RF 2.0% 2.9% 2.5% MFChemically-Treated Boxboard RF 0.3% 0.4% 0.4% Aseptic Beverage Containers & Cartons 0.5% 0.5% 0.5% O Compostable Paper 8.4% 6.9% 7.7% Hardcover Books 0.3% 0.2% 0.2% O Remainder/Composite Paper 1.0% 4.4% 2.7% Plastic 9.8% 14.1% 11.9% MCRecyclable Plastic Bottles RC 0.8% 1.2% 1.0% Black Plastic Bottles, Trays, and Lids 0.2% 0.2% 0.2% MC#1 - #7 Other Plastic Non-Bottle Rigid Containers - RC 0.8% 1.3% 1.0% (Tubs, Trays, and Thermoforms) Bulky Rigid Plastics 0.6% 2.2% 1.4% Styrofoam Packaging (not for food) 0.7% 0.3% 0.5% Recyclable Film Plastics 0.1% 0.1% 0.1% O Non-Recyclable Film Plastics 5.2% 7.1% 6.1% O Remainder/Composite Plastics 1.4% 1.8% 1.6% Metals 4.5% 2.5% 3.5% MCAluminum Cans, Tins, and Foils RC 0.6% 0.5% 0.5% MCSteel Cans RC 0.6% 0.7% 0.6% Remainder/Composite (Scrap) Metal 3.3% 1.3% 2.3% Glass 1.0% 1.6% 1.3% MCGlass Bottles & Jars RC 0.8% 1.2% 1.0% O Remainder/Composite Glass 0.2% 0.4% 0.3% Organics 23.9% 31.7% 27.8% Food Scraps & Soiled Paper 20.7% 29.3% 25.0% Yard Trimmings 3.3% 2.4% 2.8% Other 46.3% 33.0% 39.7% Clean Wood & Natural Wood (logs, branches) 8.9% 3.5% 6.2% Textiles 8.0% 7.2% 7.6% O Bulky Materials (itemized & weighed) 7.5% 2.0% 4.8% Hazardous Waste & Electronics (itemized & weighed) 1.0% 0.4% 0.7% O Residue 20.5% 19.7% 20.1% O PPE 0.4% 0.3% 0.3% Grand Total 100% 100% 100% No. of Samples 15 15 30 Recoverable Fiber (RF) 4.4% 5.2% 4.8% Recoverable Containers (RC) 3.6% 4.9% 4.2% CSWD Residential Waste Composition Study January 21, 2021 Page 5 of 6 Per the Scope of Work for this project, Table 4 below summarizes the Electronics and Household Hazardous Materials (HHW) encountered during the sorting process. Table 4 Electronics and HHW Summary Item Type Item Total (lbs.) Electronics Light Fixtures 12.44 Electronics Circuit boards (2) 5.53 Electronics Camera and headphones 3.20 Electronics Laptop Computer 3.12 Electronics 8 mm movie projector 2.45 Electronics Remote Controls (2) 1.44 Electronics Palm Pilot 0.26 Electronics iPod 0.25 Electronics Lithium Battery 0.90 Electronics Ear Thermometer 0.14 Electronics 1 mini dehumidifier 0.08 Subtotal Electronics 29.81 HHW Bag of Insecticide 3.60 HHW Motor Oil 1.98 HHW CFL Bulbs (6) 0.66 HHW CFL Tubes (2) 1.50 HHW Liquid Insecticide 0.94 HHW Liquid Disinfectant 0.50 HHW Cleaning Product 0.32 Subtotal HHW 9.50 Unidentified Unidentified Items* 1.96 Grand Total 41.27 *Descriptive data from two items was unintentionally not recorded due to severe weather conditions during Season 1. In addition, MSW Consultants recorded itemized data from Bulky Materials during the sorting process, summarized in Table 5 as follows: CSWD Residential Waste Composition Study January 21, 2021 Page 6 of 6 Table 5 Bulky Materials Summary Bulky Item(s) Total (lbs.) Carpet (wet) - 8 pcs 227.28 Furniture 37.40 Tire 24.25 Partial Toilet 12.80 Foldable Chair 4.74 Child’s Suitcase 2.94 Total 309.41 Conclusion This study successfully collected and analyzed samples of residential waste that were representative of residential waste routinely collected with the CSWD.