Food Scraps Diversion Cart Tag Study

Transcription

1 Food Scraps Diversion Cart Tag Study On behalf of King County Solid Waste Division June 23, 2017 Cascadia Consulting Group

2 EXECUTIVE SUMMARY Table of Contents Table of Contents... 2 Executive Summary... 4 Introduction... 9 Project Background and Goals... 9 Project Scope... 9 Tactics Used... 9 Tools and Communication Used Project Location and Audience Project Timeline Evaluation Methods Activities Completed Cart Tag Placement Cart-Based Audits Resident Engagement Baseline Analysis Findings Baseline Household Food Waste Generation Baseline Household Food Scraps Diversion Behavior Baseline Food Capture Rates Study Results: Midpoint and Final Analysis Findings Household Food Scraps Diversion Behavior Food Capture Rates Organics Contamination Household Food Waste Generation Conclusions and Recommendations Conclusions Household Food Scraps Diversion Behavior Food Capture Rates

3 EXECUTIVE SUMMARY Organics Contamination Rates Effects of Tagging Frequency Other Findings Recommendations for Next Steps Appendix A Study Maps and Tagging Frequency Assignments Kenmore (Republic Services) Burien (Recology Cleanscapes) Unincorporated North King County (Waste Management) Appendix B Cart Tag Designs Appendix C Evaluation Audits Material List and Category Descriptions Material Categories Category Descriptions Appendix D Composition Tables Baseline Audit Composition Tables Overall Kenmore Burien North King County Midpoint Audit Composition Tables Overall Kenmore Burien North King County Final Audit Composition Tables Overall Kenmore Burien North King County

4 EXECUTIVE SUMMARY Executive Summary Overview The Food Scraps Diversion Cart Tag Study was designed to help the King County Solid Waste Division (KCSWD) assess whether and how educational cart tags, when applied to residential curbside garbage carts, affect resident behavior. This project was conducted in support of KCSWD s comprehensive plan development and identification of strategies for achieving 70 percent diversion by Specifically, the study aimed to answer the following questions: To what extent does cart tagging prompt households to put their food scraps in their organics carts? To what extent does the frequency of cart tagging affect the durability of behavior change over time? The study s central question had two parts: First, can cart tag prompts successfully activate that is, prompting households that are not currently diverting food scraps to start participating in food scraps diversion? Second, can cart tag prompts increase diversion among households already participating? The comparison of audit results from baseline to final indicates that the answer to both is yes. The study was conducted on nine residential organics routes in three study areas: three routes in Kenmore (serviced by Republic Services), three routes in Burien (serviced by Recology Cleanscapes), and three routes in unincorporated North King County (serviced by Waste Management), including one route each in the Redmond Ridge, Sammamish, and Woodinville areas. Each of the study areas represents a unique set of demographics and organics collection service arrangements. Over the course of the study s 14-month tagging timeframe, households on study routes received either two or four cart tags depending on the frequency assigned to their address. Only households already subscribed to organics collection service and with either a garbage or organics cart set out on the day tagging occurred received tags. Overall, 90 percent of all organics-subscribing households in the study area received at least one tag between the baseline and final audits (conducted approximately one year apart in each study area). Impacts of the cart tagging were evaluated using three rounds of waste audits in each study area. During each audit, random samples were collected from households on each route. Samples were only collected from households with both garbage and organics carts placed at the curb on the day of the audit (considered set-out households ). The entire contents of the garbage and organics carts were collected from sampled households. 4

5 EXECUTIVE SUMMARY The contents of each cart sample collected was hand-sorted into five material categories (food, compostable paper and packaging, non-compostable paper and packaging, yard debris, and all other) and each component was weighed and the data were recorded and analyzed. Key Findings Findings from the baseline, midpoint, and final audits, which each included samples collected from at least 150 households in each of the three study areas (over 450 households total), revealed important information about food waste generation and food scraps diversion behavior among households included in the study. Key findings from the analysis include the following: HOUSEHOLD PARTICIPATION Household participation rates that is, the percentage of households participating in food scraps diversion by placing food in their organics cart among study households participation increased by twenty percent (from 61% to 73% of households with organics carts set out on collection day) during the study. The increase in participation rate was statistically significant and observed at similar levels in both tagging frequency groups Household participation in food scraps diversion increased by 20 percent. (T2: 2x/year, T4: 4x/year) in all three study areas except the T2 group in the Burien study area. DIVERSION EFFICIENCY The study revealed that food scraps diversion is largely an all or nothing behavior, meaning that most households participating in food scraps diversion divert a majority of the food scraps generated by their households. From the baseline audit, more than half (56%) of households participating in food scraps diversion at the start of the study were diverting more than 80 percent of the food scraps they generated. Over the study period, the number of households participating in food scraps diversion increased, and households already participating in food scraps diversion at baseline diverted a larger portion of generated food scraps. Overall, the percentage of all study households diverting more than 80 percent of food scraps generated increased from 35 to 40 percent. At the same time, the percentage of households diverting less than 20 percent of food scraps fell from 43 to 30 percent. 5

6 EXECUTIVE SUMMARY FOOD CAPTURE RATES Average food capture rates (the percentage of all food scraps in a household s waste that is placed in the organics cart) among households sampled increased in all study areas between baseline and final audits. Overall, average household food capture rates increased by 20 percent (increased from 45% to 54%). The increase in food capture rate was found to be statistically significant in all study areas except in Burien, where the observed increase in food capture rates was smallest (increased from 61% to 65%). The largest increase in food capture rates from baseline to the final audit was among households in North King County (increased from 40% to 55%). ORGANICS CONTAMINATION RATES Overall, organics contamination rates increased from 2.0% to 2.3% between the baseline and final audit, but the increase was not found to be statistically significant. Both the baseline and final rates are comparable to the countywide contamination rate measured in 2014 (2.4%). Although overall changes in contamination rates were not significant, the number of households participating in food scraps diversion with contamination rates greater than 5 percent increased sharply. At the final audit, one-fifth of participating households had more than 5 percent contamination in their organics carts. This finding suggests that increasing participation in food scraps diversion may result in slightly higher levels of contamination, although it is possible that additional education and outreach specifically focused on reducing contamination could counteract this effect. EFFECTS OF TAGGING FREQUENCY The effect of cart tagging on participation and diversion efficiency was stronger among households tagged quarterly, indicating that repetition may successfully reinforce desired behavior change. However, the differences in participation and diversion observed between T2 and T4 groups were not statistically significant. Because many households in the T4 group did not have carts set out during all rounds of tagging, only 38 percent actually received tags in all four rounds of tagging in their study areas. Consequently, the study results should be interpreted as representative of a minimum of two rounds of tagging over the course of the year. 6

7 EXECUTIVE SUMMARY Conclusions and Recommendations The increase in both household participation and average food capture rates observed in this study suggests that cart tags can activate new households, prompting Overall, food capture rates increased by 20 percent. households that are not currently diverting food scraps to start participating, and also prompt households already participating in food scraps diversion to increase their diversion rates. The results of the study indicate that cart tag prompts can successfully increase residential food scraps diversion. It is also noteworthy that Burien, where the change in participation was lowest because baseline participation was already very high (increasing from 77% to 81%), is the only study area where organics service is embedded (universal) and weekly. These findings suggest that implementation of this service arrangement alone may have a strong positive effect on participation in food scraps diversion programs. Based on our analysis, recommendations for next steps include the following: Because the majority of food scraps remaining in the garbage are from households not participating at all in food scraps diversion, future efforts should prioritize outreach and education activities aimed to activate new households over those that aim to increase diversion rates among households already participating in food scraps diversion. Provide educational messaging via cart tagging at least twice per year to reach households not currently diverting food scraps and increase food scraps diversion among households already participating. Additional audience testing should be conducted to tailor the message and tag design, but keep the cart tags focused on: Placing food in the organics cart. Keeping contaminants out of the organics cart. Keep the message about contamination reduction separate from the message about participation, and consider which audience you are trying to reach (e.g., participating or nonparticipating households) when prioritizing messaging. Carefully consider the language demographics at the route level to ensure you are making your best efforts to communicate with households with limited English proficiency or who do not speak English at home. We recommend integrating cart tagging into broader County outreach campaigns to change social norms and promote desired behavior change around organics diversion. 7

8 EXECUTIVE SUMMARY The study findings also highlight areas where additional research may be needed to inform outreach messages and strategies going forward. KCSWD may want to consider additional research in the following areas: Audience research to better understand the demographic attributes, behaviors, and attitudes of households that do not participate in food scraps diversion, including reasons for the differences in household food waste generation between participating and non-participating households. Characterization of contamination at a greater level of detail than provided in studies to-date and with a focus on more clearly identifying the types of items and contaminant materials most commonly found in household organics carts. Gaining greater insight into the make-up and prevalence of specific contaminants (e.g., the percent of households with plastic bags found in organics carts, not just the relative weight of plastic bags relative to all other materials in the cart) could guide more effective outreach and communication intended to address organics contamination issues. 8

9 PROJECT BACKGROUND AND GOALS Introduction Project Background and Goals The was designed to: 1. Assess the extent to which the placement of educational tags on residential curbside garbage carts ( cart tagging ) acts as a prompt to increase residential food scrap diversion. 2. Assess the extent to which the frequency of cart tagging affects the durability of behavior change over time. 3. Assess the extent to which cart tagging has different effects on residents under different service arrangements. Past cart tagging studies conducted in the King County region have tested the use of cart tagging to increase curbside recycling participation, improve the quality of collected recycling, and increase solid waste diversion overall. However, we are not aware of any previous study that has tested the use of cart tagging designed specifically to increase diversion of food scraps from the garbage. Further, we are not aware of any previous study that has examined the optimal frequency of tagging for achieving sustained behavior change. This study was a collaboration between KCSWD, Republic Services, Waste Management, and Recology Cleanscapes, and was carried out by C+C and Cascadia Consulting Group. Project Scope TACTICS USED Diversity of Study Areas To detect differences in behavior change between different service level arrangements, the study included three different study areas, each with a unique set of demographics, organics collection service arrangements, and history of resident participation in organics collection. Organics collection service arrangements vary by frequency of collection and whether service is embedded (universal) or subscription-based. In embedded service, the cost of organics collection is bundled with the collection rate for garbage, appearing free to the resident. 9

10 PROJECT SCOPE Because embedded service makes organics program participation opt-out rather than opt-in, residents with embedded service are more likely to participate in organics collection programs than residents where service is available by subscription, which is structured as an opt-in program with a separate cost. Additionally, residents with weekly service (instead of every-otherweek) are also thought to be more likely to participate in organics collection programs because weekly collection reduces the ick factor associated with how long material remains in the bin and the potential for smells over time. 1 Figure 1: Organics collection service arrangements in the three study areas Cart Tagging Cascadia placed cart tags on curbside carts along residential collection routes in three study areas according to the tagging frequency assignments described below. Over the course of 14 months (December 2015 January 2017), staff placed tags on carts set out on study routes either two or four times depending on their assigned treatment group. Households received tags if they were already subscribed to organics collection service and had either a garbage or organics cart set out on the day tagging occurred. 1 Belcher, Sherly. Overcoming the Ick Factor: Increasing participation in food scrap recycling in King County, WA. June,

11 PROJECT SCOPE Cart Tagging Frequency Assignments To detect differences in the influence of different cart tagging frequencies on behavior change, study households were divided into two treatment groups: Treatment Group T2 received tags two times over the course of one year. Treatment Group T4 received tags four times (once per quarter) over the course of one year. Study households were assigned to treatment groups following analysis of baseline audit data to create comparable starting points there were no statistically significant differences between groups within each study area in per-household food scrap generation (the total amount of food set out at the curb for collection, including both garbage and organics cart contents) and food capture rates (the percent of all food scraps in a household s waste that is placed in the organics cart). See Appendix A Study Maps and Tagging Frequency Assignments for maps of each study area, including tagging frequency assignments. Suspension of Non-Study Education Tactics Because the study was intended to assess the effectiveness and optimal frequency of cart tag placement in isolation, with no other tactics or specific communication promoting food scraps diversion used to encourage participation, the County and participating haulers agreed to suspend all non-study education tactics related to food scraps diversion for the study audience during the study timeframe, with the exception of standard contamination notification tags used by the haulers as part of regular collection service. To the knowledge of the study team, this practice was followed in all study areas. TOOLS AND COMMUNICATION USED The central communication tool used in this study was a custom cart tag designed to educate and remind residents in each study area to place food scraps and food-soiled paper in their organics, or yard debris, cart. The tags used in each hauler s service area were slightly different; the tags used in Burien and North King County contained the same words and images but different hauler logos, while the tag used in Kenmore contained slightly different words and images as well as a different hauler logo. See Appendix B for the cart tag designs used in each study area. PROJECT LOCATION AND AUDIENCE The study was conducted on nine residential organics routes in three study areas located in King County: three routes in Kenmore (serviced by Republic Services), three routes in Burien (serviced by Recology Cleanscapes), and three routes in unincorporated North King County (serviced by 11

12 PROJECT SCOPE Waste Management), including one route each in the Redmond Ridge, Sammamish, and Woodinville areas. Each of the study areas represents a unique set of demographics, organics collection service arrangements, and level of resident participation in organics collection. The County completed a demographics analysis for each of the study areas. Overall, households in the Burien study area were more likely to speak a language other than English at home, have lower levels of education, and earn less than households in the North King County and Kenmore study areas. Key findings included the following: Nearly one-quarter of households in the Burien study area speak a language other than English at home (16 percent speak Spanish and 6 percent speak Vietnamese). In contrast, less than 10 percent of households in the North King County and Kenmore study areas speak a language other than English at home (primarily Spanish or Chinese). Households on routes in the Burien study area have lower education levels than households in the North King County or Kenmore study areas. On average, less than one-third (31%) of adult residents on Burien routes have earned a college degree or higher. In contrast, more than 60 percent of adults on routes in the North King County or Kenmore study areas have earned college degree or higher. Fewer households in the Burien study area report annual incomes over $100,000 than in other study areas. Less than one-quarter of households (23%) on studied routes in Burien earn over $100,000 per year. In contrast, in Kenmore, nearly half (45%) earn more than $100,000 per year, and in North King County, 70% of households earn more than $100,000. In Burien, less than 3 percent of households earn over $200,000 per year, in contrast to nearly one-quarter (23%) of households in North King County. Table 1. Organics collection service arrangements and customers, by study area Study Area (Hauler) Kenmore (Republic Services) Burien (Recology Cleanscapes) North King County (Waste Management) * Every other week Organics Collection Service Arrangements Service Collection Type Schedule Study Area Customers # Garbage Customers # Organics Customers Subscription EOW* 2,019 1,384 Embedded Weekly 3,179 3,080 Subscription Weekly Not reported 2,487 During the study, the residents of Klahanie and several adjacent neighborhoods voted to annex to the City of Sammamish. The annexation became official on January 1, This resulted in 12

13 EVALUATION METHODS 629 households (36%) from one route in the previously unincorporated WM study area becoming part of the Sammamish city limits, which is serviced by Republic Services (although not near the Republic study area). This change occurred before the final round of tagging and final audit in the WM study areas. For these final events in the WM study areas, we tagged only the carts that were outside of the newly annexed area and collected extra samples during the audit from another North KC route serviced by WM to compensate for the reduction in households remaining on the Sammamish area route included in the WM study area. PROJECT TIMELINE This study was implemented over the course of one year in each study area but on two different timelines, beginning in the Kenmore area in November 2015 and in the two other study areas in March The table below shows the audit and tagging intervals for the study. Table 2. Study Timeline Study Area Nov '15 Dec '15 Jan '16 Feb '16 Mar '16 Apr '16 May '16 Jun '16 Jul '16 Aug '16 Sep '16 Oct 16 Nov 16 Dec 16 Jan 17 Feb 17 Mar 17 Kenmore (Republic) Burien (Recology) North KC (WM) Audit B Tag T2 T4 Tag T4 Audit B Audit B Tag T2 T4 Tag T2 T4 Audit M Tag T2 T4 Tag T4 Tag T4 Audit M Audit M Tag T4 Tag T2 T4 Tag T2 T4 Audit F Tag T4 Tag T4 Audit F Audit F Evaluation Methods Impacts of the cart tagging were evaluated using waste audits (hand sorting and weight-based measurement of random samples of waste collected from households on selected routes in the study areas). Three rounds of audits were completed in each study area: 1) Baseline, conducted prior to the start of cart tag placement. 2) Midpoint, conducted halfway through the one-year cycle of cart tagging. 3) Final, conducted after completion of the one-year cycle of cart tagging. During each audit, samples were collected using random systematic selection (using a set interval to randomly select households with paired carts set out) from a minimum of 50 households on each route (representing at least 75 samples from each group in each study area). Overall, 13

14 ACTIVITIES COMPLETED sampled households represented 7 percent of households with organics service in the study area. Samples were only collected from households with both garbage and organics carts placed ( set out ) at the curb on the day of the audit. The entire contents of the garbage and organics carts were collected from sampled households, resulting in two samples collected from each household sampled in each study area for each of the three audit rounds. Collected samples were sorted into five categories: 1. Food 2. Compostable paper, plastic, and food-related wood items 3. Non-compostable paper and plastic foodservice items and packaging 4. Yard debris 5. Other material More detail about each category, including descriptions of items defined within each category, is provided in Appendix C Evaluation Audits Material List and Category Descriptions. Activities Completed CART TAG PLACEMENT In each study area, cart tags were placed in four rounds over the course of one year. Across study areas, 62 percent of households assigned to the biannual frequency (T2) received two tags over the course of the one-year tagging cycle. Another 30 percent received at least one tag as part of the study, and 8 percent of organics-subscribing households in the T2 group did not receive a cart tag at all due to not having a cart set out during either round of tagging conducted in their area. Among organics-subscribing households assigned to the quarterly frequency (T4), 98 percent received at least one tag during the first half of the study timeframe. However, fewer than half (32%-43%) actually received all four tags because many households did not have carts set out during each round of tagging. The table below provides more detail on tagging activity and reach. 14

15 ACTIVITIES COMPLETED Table 3. Tag placement among study households Study Area # T2 HHs in study Not Tagged % T2 HHs % T4 HH Tagged 1x Tagged 2x # T4 HHs in study Not Tagged Tagged 1x Tagged 2x Tagged 3x Tagged 4x Kenmore 695 7% 25% 68% 680 1% 10% 21% 37% 32% Burien 1,542 11% 34% 55% 1,538 3% 8% 19% 33% 37% North KC 1,219 4% 28% 68% 1,267 2% 5% 14% 35% 43% Total 3,456 8% 30% 62% 3,485 2% 7% 18% 34% 38% CART-BASED AUDITS Over the course of the study, Cascadia conducted nine audits (baseline, midpoint, and final in each of the three study areas) of study households garbage and organics carts. Each round of audits included collection and sorting of samples from at least 450 households (at least 150 households from each study area). 2 Sampling rates ranged between 5 and 12 percent of all organics-subscribing households included in each frequency group throughout the study area. The table below provides more detail on the number and percent of households sampled during each round of audits. Table 4. Audit sampling rates among study households Study Area # of T2 HHs # of T4 HHs Kenmore (Republic) Burien (Recology) North KC (WM) ,542 1,538 1,220 1,267* # T2 HHs sampled (%) Baseline # T4 HHs sampled (%) # T2 HHs sampled (%) Final # T4 HHs sampled (%) % 11% 11% 12% % 5% 5% 5% % 6% 6% 6% *The number of T4 households in the final audit was reduced to 632 due to the annexation of Klahanie by the City of Sammamish and the transfer of waste collection service from Waste Management to Republic Services on January 1, Additional samples were collected during each audit as contingency to ensure minimum sample counts were achieved. Samples found to contain no food waste in either cart were dropped from the data set. The number of contingency samples collected during each audit and used in the analysis varied. 15

16 BASELINE ANALYSIS FINDINGS RESIDENT ENGAGEMENT During each of the three rounds of three audits, study field staff collected samples on routes serving approximately 7,000 households. By the completion of the final round of audits, field staff had collected samples from 1,388 households and had the potential of interacting with up to 21,000 households. Throughout this process, field staff documented 109 resident interactions, 92 percent of which were positive or neutral in tone and content. Resident interactions characterized as negative in tone or content comprised 8 percent of total interactions, representing less than one percent (0.6%) of households sampled and less than 0.1 percent (0.04%) of all households on sampled routes in study areas. Resident concerns came up in Kenmore during the first audit, prompted in part by the fact that the neighborhood in which we were sampling had recently experienced a series of break-ins, which had the neighborhood watch group on high alert. This, coupled with the fact that our trucks did not have signs and that it was quite dark when we conducted sampling, created concern among several residents, prompting a call to the local police department and to a local news network. For subsequent audits, the study team took several steps to proactively increase resident awareness and effectively address concerns as they arose. These steps included: Placing Study in Progress magnets and signs on trucks when conducting sampling in neighborhoods. Sending a letter to residents explaining the study and offering them the opportunity to opt out of the study. Notifying local police stations when we were going to be in the area. Providing hauler, city partner, and King County customer service staff with reminders prior to field activities and providing FAQs for answering customer questions. Providing residents with a handout explaining the study when they approached the field team. Establishing direct lines of communication and staying in close contact with all project stakeholders, including field crew, customer service staff, and project managers when field activities were happening. Baseline Analysis Findings Analysis of the baseline audit data collected for the study revealed some important information about food waste generation and diversion behavior among households included in the study. These insights, presented in detail below, are helpful for understanding the trends and patterns 16

17 BASELINE ANALYSIS FINDINGS of household food scraps diversion in King County overall and interpreting the results observed in the subsequent midpoint and final audits. BASELINE HOUSEHOLD FOOD WASTE GENERATION Households sampled during baseline audits generated an average of 41.7 pounds of food scraps deposited in garbage and organics collection carts per household per month. Food waste generation patterns among participating households (households with any food found in the organics cart) were statistically different from non-participating households, with participating households generating significantly more food waste than non-participating households (48.7 pounds compared to 31.8 pounds per month). In addition, households in Burien generated more food waste than households in the other study areas (49.3 pounds per month compared to 32.9 pounds in Kenmore and 42.9 pounds in North King County). In both cases, the differences in food waste generation could be due to a number of factors including demographic characteristics such as household size or presence of children at home or household behavior such as frequency of meals at home and type of food used in cooking, participation in backyard composting or poultry keeping, or use of an in-sink disposal. Figure 2. Household food waste generation rates among households with organics cart set-outs food waste generation (lbs/hh/mo) Overall Kenmore Burien North King County Participating Non-Participating BASELINE HOUSEHOLD FOOD SCRAPS DIVERSION BEHAVIOR Baseline Household Participation Rates The household food scraps diversion participation rate that is, the percentage of households in a given area participating in food scraps diversion by placing food in their organics cart is one of two major determinants of the overall capture rate achieved in that area. The other factor is participation efficiency, discussed below. 17

18 BASELINE ANALYSIS FINDINGS Overall, households included in this study participated in food scraps diversion at the baseline at higher rates than the countywide average last estimated in In the 2014 King County Organics Characterization Study, approximately 52 percent of organics cart set-outs contained food. In this study, the participation rate was higher 61 percent overall at baseline but with wide variation between study areas. The food scraps diversion participation rate at baseline was significantly lower in Kenmore than the 2014 countywide average (47%), much higher in Burien (77%), and also higher in North King County (59%). Figure 3. Household food scraps diversion participation rates among households with organics cart set-outs 100% 80% 60% 40% 52% 61% 47% 77% 59% 20% 0% King County 2014 Overall Kenmore Burien North King County Baseline Diversion Efficiency Diversion efficiency that is, the rate at which participating households place food scraps available for diversion into organics collection carts is the other major determinant of overall food capture rates. Relatively little information about food scraps diversion efficiency in the county was available prior to this study because no previous audit had involved sampling paired garbage and organics carts from residential households. The baseline audit results found that diversion efficiency did not follow a normal distribution pattern throughout the population but rather a bimodal ( all or nothing ) distribution, as illustrated in the histogram of household food capture rates below, presented overall and by study area. 18

19 BASELINE ANALYSIS FINDINGS Figure 4: Household-level food scraps diversion efficiency distribution (Overall Baseline) Figure 5: Household-level food scraps diversion efficiency distribution (Kenmore Baseline) % 200 Households Sampled % 9% 7% 5% Food Capture Rate (% range) Households Sampled % 28% 3% 4% 6% Food Capture Rate (% range) Figure 6: Household-level food scraps diversion efficiency distribution (Burien Baseline) 200 Figure 7: Household-level food scraps diversion efficiency distribution (North King County Baseline) 200 Households Sampled % 25% 5% 11% 12% Households Sampled % 29% 9% 8% 10% Food Capture Rate (% range) Food Capture Rate (% range) BASELINE FOOD CAPTURE RATES The food capture rate is the measure of the percent of all food scraps in a household s waste that is captured for composting (i.e., it is placed in the organics cart). For this study, the average food capture rate was calculated as an average of the household-level capture rates among all households sampled as well as among participating households only. Among all households sampled, the average food capture rate is influenced by the participation rate and the diversion efficiency of those participating households; among participating households, the capture rate is influenced by diversion efficiency only. 19

20 BASELINE ANALYSIS FINDINGS In the King County 2014 Organics Characterization Study, the average capture rate among organics subscribers with set-outs was 39.5 percent. 3 Results from the baseline audits for this study showed that food capture rates among households sampled overall and among participants in the study area were slightly higher than the 2014 countywide average, but varied significantly among study areas: In Kenmore, the average food capture rate was lower among all households with garbage and organics carts set out compared to the two other study areas (35% in Kenmore compared to 61% in Burien and 40% in North King County). However, Kenmore households already participating in food scraps diversion at the start of the study achieved capture rates similar to those in the other study areas (74% in Kenmore compared to 78% in Burien and 66% in North King County). Burien had exceptionally high average food capture rates among households with garbage and organics carts set out. The combination of strong household participation and high diversion efficiency among participating households has resulted in very high food capture rates overall. Figure 8 shows the average baseline household food capture rates of all households sampled and of households participating in food scraps diversion. Figure 8. Average baseline food capture rates for all households with set-outs (left) v. households participating in food scraps diversion (right) King County 2014 (includes FSP) Overall 40% 45% 67% 73% Kenmore 35% 74% Burien 61% 78% North King County 40% Set Out Food Capture Rates 66% Participant Food Capture Rates 3 Household-level capture rates developed for the King County 2014 Organics Characterization Study included both food and food-soiled paper (FSP) combined, so are not directly comparable to the food capture rates calculated for this study, which calculated food capture rate only (not including FSP). 20

21 STUDY RESULTS: MIDPOINT AND FINAL ANALYSIS FINDINGS Study Results: Midpoint and Final Analysis Findings Analysis of the data collected via the midpoint and final audits provide additional insights about food waste generation and average food capture rates among households included in the study and offer information about the effects of promotional messaging related to food scraps diversion and household food scraps diversion behavior. HOUSEHOLD FOOD SCRAPS DIVERSION BEHAVIOR Household Participation Rates Household participation rates among households sampled increased across all study areas and frequency groups between the baseline and final audits except among T2 households in Burien. In Kenmore and North King County, the increase in household participation in food scraps diversion for both frequency groups (T2 and T4) was statistically significant, with the largest observed increase among households in Kenmore (24 percentage point increase in participation). The observed increase in participation among T4 residents in Burien (where participation rates were already high at baseline) was also statistically significant, leading to a statistically significant increase in household participation in food scraps diversion for the Burien study area overall. Overall, we observed higher participation from T4 households across all study areas, but this difference is not statistically significant, meaning that the apparent difference between T2 and T4 group outcomes could be the result of random variance in selected samples and not representative of actually different outcomes between groups. Table 5 shows baseline and final household participation rates for each study area and treatment group. Table 5: Baseline and final household participation rates by study area and treatment Study Area Baseline Participation Rate Overall HHs (%) T2 HHs (%) T4 HHs (%) Overall HHs (%) Final Participation Rate T2 HHs (%) T4 HHs (%) Kenmore 47% 50% 44% 65% 62% 68% Burien 77% 77% 78% 81% 77% 85% North King County 59% 61% 58% 73% 71% 74% Overall 61% 63% 60% 73% 70% 75% Figure 9 shows the baseline, midpoint, and final participation rates by treatment group, and Figure 10 shows the same data by study area. 21

22 STUDY RESULTS: MIDPOINT AND FINAL ANALYSIS FINDINGS Figure 9: Baseline, midpoint, and final household participation rates by treatment Baseline Midpoint Final Household Participation Rate 100% 80% 60% 40% 20% 0% 73%* 75%* 70%* 61% 62% 63% 67% 57% 60% Overall Overall - T2 HHs Overall - T4 HHs Figure 10: Baseline, midpoint, and final household participation rates by study area Baseline Midpoint Final Household Participation Rate 100% 80% 60% 40% 20% 0% 77% 81%* 73%* 63%* 65%* 68% 59% 55% 47% Kenmore Burien North King County * Midpoint and final participation rates marked with an asterisk indicate increases in participation from the baseline found to be statistically significant. Diversion Efficiency Over the study period, the number of households participating in food scraps diversion increased, and households already participating in food scraps diversion at baseline diverted a larger portion of generated food scraps. Overall, the percentage of all study households diverting more than 80 percent of food scraps generated increased from 35 to 40 percent. At the same time, the percentage of households diverting less than 20 percent of food scraps fell from 43 to 30 percent (Figure 11). 22

23 STUDY RESULTS: MIDPOINT AND FINAL ANALYSIS FINDINGS Figure 11. Overall household-level food scraps diversion efficiency distribution, baseline vs. final 43% % 30% Households Sampled % 7% 9% Household-level food capture rate (baseline) In Kenmore, the percentage of households participating in curbside food scraps diversion significantly increased; the percentage of households diverting less than 20 percent of their food scraps fell from 59 to 41 percent. In Kenmore, it appears that households new to food scraps diversion diverted a smaller portion of their generated food than households that were already participating at the start of the study, but the diversion efficiency of new participating households increased over time. Figure 12 shows the change in household-level food scraps diversion efficiency in Kenmore from the start to end of the study. Figure 12. Kenmore household-level food scraps diversion efficiency distribution, baseline vs. final Households Sampled % 3% 4% 6% 28% Household-level food capture rate (baseline) % 9% 14% 40% % Household-level food capture rate (final) 9% 12% 8% 31% Household-level food capture rate (final) In Burien, resident participation and food scrap diversion efficiency was already high at the beginning of the study (baseline) prior to pilot tagging. Even with the high baseline, food scrap diversion efficiency increased over the course of the study; the percentage of households diverting less than 20 percent of their food scraps decreased from 25 to 20 percent. By the end of the study period, half of all households were diverting more than 80 percent of their food scraps. Figure 13 shows the change in household-level food scraps diversion efficiency in Burien from the start to end of the study. 23

24 STUDY RESULTS: MIDPOINT AND FINAL ANALYSIS FINDINGS Figure 13. Burien household-level food scraps diversion efficiency distribution, baseline vs. final Households Sampled % 5% 11% 12% 48% Household-level food capture rate (baseline) % 7% 7% 16% 50% Household-level food capture rate (final) In North King County, more households began diverting food scraps and shifted up the ladder of diversion efficiency over the course of the study. The percentage of households diverting less than 20 percent of their food scraps decreased from 45 to 30 percent. Figure 14 shows the change in household-level food scraps diversion efficiency in North King County from the start to end of the study. Figure 14. North King County household-level food scraps diversion efficiency distribution, baseline vs. final Households Sampled % FOOD CAPTURE RATES 9% 8% 10% 29% Household-level food capture rate (baseline) Average food capture rates among households sampled increased in all study areas between baseline and final audits. Overall, average food capture rates increased by 20 percent (9 percentage points). The increase in food capture rate was found to be statistically significant in all study areas except in Burien, where the observed increase in food capture rates was smallest (8 percent change; 4 percentage points). The largest increase in food capture rates from baseline to the final audit was among households in North King County, with a 37 percent increase (15 percentage points). Figure 15 shows the change in average household food capture rates from the start to the end of the study % 5% 9% 17% 38% Household-level food capture rate (final) 24

25 STUDY RESULTS: MIDPOINT AND FINAL ANALYSIS FINDINGS Figure 15. Average food capture rates, baseline vs. final 100% Food Capture Rate 80% 60% 40% 20% 0% 61% 65% 54%* 55%* 45% 43%* 40% 35% Overall Kenmore Burien North KC Baseline Final * Final food capture rates marked with an asterisk indicate increases from the baseline found to be statistically significant. Figure 16 shows the average food capture rates specifically among households participating in food scraps diversion (households that diverted any amount of food scraps). Overall, though the number of participating households increased (see Figure 9), the food capture rate among participating households did not change over the course of the study. The small changes observed in food capture rates among participating households in Kenmore and North King County are not statistically significant but the results nonetheless reinforce the trends identified in the diversion efficiency analysis. In Kenmore, many households began participating in food scraps diversion during the study period and these new participants diverted a smaller portion of their overall food generated, leading to a slight decrease in average capture rates among participating households. In North King County, diversion efficiency among participating households increased over the course of the study, leading to a slight increase in average capture rates among participating households. Figure 16. Average food capture rates among households diverting food scraps, baseline vs. final Food Capture Rate 100% 80% 60% 40% 20% 0% 73% 74% 78% 78% 73% 72% 65% 66% Overall Kenmore Burien North KC Baseline Final 25

26 STUDY RESULTS: MIDPOINT AND FINAL ANALYSIS FINDINGS ORGANICS CONTAMINATION Figure 17 shows organics contamination rates at the baseline and final audit overall and by study area. Overall, organics contamination rates increased between the baseline and final audit from 2.0% to 2.3%; this rate is comparable to the countywide contamination rate measured in 2014 (2.4%). Contamination rates among all set-outs increased in Kenmore and North King County but decreased in Burien. However, no observed changes in contamination rates were statistically significant. In Burien and North King County, organics contamination among participating households (households that diverted any amount of food scraps) had higher contamination rates than non-participating households in the final audit, but the differences were not statistically significant. Figure 17. Overall organics contamination rates by study area, baseline vs. final (all households) 6.0% Percent of Organics Collected 5.0% 5.2% 5.0% 4.0% 3.3% 3.4% 2.9% 3.0% 3.0% 2.3% 2.6% 2.4% 2.0% 2.1% 2.0% 1.1% 0.8% 1.0% 0.9% 0.8% 1.0% 0.0% Overall Kenmore Burien North KC Baseline (all set-outs) Final (all set-outs) Baseline (participating HHs) Final (participating HHs) Figure 18 shows the distribution of contamination rates among households participating in food scraps diversion at baseline and at the final audit. Although changes in contamination rates were not significant, the number of households participating in food scraps diversion with contamination rates greater than 5 percent increased sharply. At the final audit, one-fifth of participating households had more than 5 percent contamination in their organics carts. A household s degree of participation (that is, their capture rate of food in the organics cart), however, did not have bearing on its contamination rate. In other words, no statistically significant trend was observed between a household s food capture rate and its contamination rate. Participating households with low rates of food scraps diversion were equally likely to have high levels of contamination as households with high rates of food scraps diversion. 26

27 STUDY RESULTS: MIDPOINT AND FINAL ANALYSIS FINDINGS Figure 18. Organics contamination rates, baseline vs. final (households participating in food scraps diversion) Households % 10% 3% 3% 2% 12% <1% 1%-2% 2%-3% 3%-4% 4%-5% >5% Contamination Rate (baseline) % 7% 6% 3% 1% 20% <1% 1%-2% 2%-3% 3%-4% 4%-5% >5% Contamination Rate (final) HOUSEHOLD FOOD WASTE GENERATION Average household food waste generation was slightly higher across all households in the final audits compared to the baseline, but this result was not found to be statistically significant. Figure 19 shows the estimated average pounds of food scraps generated per household per month based on data collected through the baseline, midpoint, and final audits. Figure 19. Average household food waste generation rates at baseline, midpoint, and final audits Lbs Food Waste Generated Per Month Baseline Midpoint Final Non-participating HHs Participating HHs 52.9 As in the baseline audit, food waste generation patterns among participating households were significantly different from non-participating households, with participating households generating significantly more food waste than non-participating households (52.9 pounds compared to 35.2 pounds per month in the final audit). Lower food waste generation among non-participating households may indicate underlying demographic differences and associated food consumption patterns, such as household size or resident age, or it may indicate behavioral differences such as participation in backyard composting, poultry keeping, or use of an in-sink disposal. Complete generation and composition estimates for food and the other four material categories used in this study are provided in Appendix D Composition Tables. 27

28 CONCLUSIONS Conclusions and Recommendations Conclusions The Food Scraps Diversion Cart Tag Study was designed to help KCSWD assess whether placement of cart tag prompts increases residential food scraps diversion, and, if so, which of the two tagging frequencies tested supports sustained behavior change. The study s central question had two parts: First, can cart tag prompts successfully activate new households to participate in food scraps diversion? Second, can cart tag prompts increase diversion among households already participating? The comparison of audit results from baseline to final indicates that the answer to both is yes. HOUSEHOLD FOOD SCRAPS DIVERSION BEHAVIOR Overall, household participation rates increased by 20 percent during the study, with statistically significant increases in participation in all three study areas. The study findings suggest that these cart tags can activate new households, prompting households that are not currently diverting food scraps to start participating. The increase in participation was largest in the Kenmore study area, which also had the lowest baseline participation rate (47% participating at baseline; 65% participating at end of study). Conversely, the change in participation was lowest in Burien, where baseline participation was already high (77% participating at baseline; 81% participating at end of study). It is noteworthy that Burien is the only study area where organics service is embedded (universal) and weekly, suggesting that implementation of this service arrangement alone may have a strong positive effect on participation in food scraps diversion programs. We observed that participation in food scraps diversion programs was virtually an all or nothing behavior more than half (56%) of participating households diverted more than 80 percent of the food scraps they generated. It appears that once a household begins participating in food scraps diversion, they are likely to participate at a high rate. Still, the study found that cart tagging can also prompt households already participating in food scraps diversion to increase their diversion rates. FOOD CAPTURE RATES Average food capture rates among households sampled increased in all study areas between baseline and final audits. Overall, average household food capture rates increased by 20 percent. 28

29 CONCLUSIONS The increase in food capture rate was found to be statistically significant in all study areas except in Burien, where the observed increase in food capture rates was smallest and where the baseline capture rate was highest. These results indicate that cart tag prompts can successfully increase residential food scraps diversion. ORGANICS CONTAMINATION RATES Although overall changes in contamination rates were not significant, the number of households participating in food scraps diversion with contamination rates greater than 5 percent increased substantially. This finding suggests that increasing participation in food scraps diversion may result in slightly higher levels of contamination. The tag used in this study focused primarily on encouraging participation and not on addressing contamination. It is possible that a different tag design or additional education and outreach specifically focused on reducing contamination could counteract this effect, especially for households identified as being heavy contaminators. EFFECTS OF TAGGING FREQUENCY The effect of cart tagging on participation and diversion efficiency was stronger among households tagged quarterly, indicating that repetition may successfully reinforce desired behavior change. However, the differences in participation and diversion observed between T2 and T4 groups were not statistically significant. Because many households in the T4 group did not have carts set out during all rounds of tagging, only 38 percent actually received tags in all four rounds of tagging in their study areas. Consequently, the study results should be interpreted as representative of a minimum of two rounds of tagging over the course of the year. OTHER FINDINGS Other takeaways from this study include the following: Overall, participation in food scraps diversion programs is highest where organics service is embedded (universal) and weekly. Households that generate less food waste may be less likely to participate in food scraps diversion; overall, non-participating households generated two-thirds the amount of food scraps relative to participating households. The potential reasons for this disparity are numerous and may involve demographic differences and associated food consumption patterns (e.g., household size or resident age) or may indicate behavioral differences (e.g., participation in backyard composting, poultry keeping, or use of an in-sink disposal). 29

30 RECOMMENDATIONS FOR NEXT STEPS Recommendations for Next Steps In reviewing the analysis findings and considering the implications for next steps, it is important to keep in mind that the cart tag was designed before the diversion efficiency pattern among participating households was understood. Therefore, the message presented on the cart tag was not designed specifically to reach non-participating households and the intervention as a whole was not designed specifically to address the (perceived or real) barriers to participation among non-participating households or to speak to benefits of food scraps diversion relevant to those households. Even so, the cart tags as designed were successful in activating new households to participate in food scrap diversion programs, increasing participation rates and food capture rates by 20 percent overall during the course of the study. Based on our analysis, recommendations for next steps include the following: Because the majority of food scraps remaining in the garbage are from households not participating at all in food scraps diversion, future efforts should prioritize outreach and education activities aimed to activate new households over those that aim to increase diversion rates among households already participating in food scraps diversion. Provide educational messaging via cart tagging at least twice per year to reach households not currently diverting food scraps and increase food scraps diversion among households already participating. Additional audience testing should be conducted to tailor the message and tag design, but keep the cart tags focused on: Placing food in the organics cart. Keeping contaminants out of the organics cart. Keep the message about contamination reduction separate from the message about participation, and consider which audience you are trying to reach (e.g. participating or nonparticipating households) when prioritizing messaging. Carefully consider the language demographics at the route level to ensure you are making your best efforts to communicate with households with limited English proficiency or who do not speak English at home. We recommend integrating cart tagging into broader County outreach campaigns to change social norms and promote desired behavior change around organics diversion. The table below illustrates strategies and accompanying outreach tactics, illustrating how cart tagging can fit into an integrated and comprehensive campaign. 30

31 RECOMMENDATIONS FOR NEXT STEPS Strategy Raise awareness that you can compost at curb Provide tools and education to make it easy Prompt to start behavior or modify behavior (contamination) Tactics Traditional media Social media Direct mail Through grassroots outreach efforts: events, outreach, one-to-one If possible, at point of YW service signup or service level change Collect commitments to take part Curbside cart tags Collect commitments to take part Provide feedback E-communications Social media Direct mail The study findings also highlight areas where additional research may be needed to inform outreach messages and strategies going forward. KCSWD may want to consider additional research in the following areas: Audience research to better understand the demographic attributes, behaviors, and attitudes of households that do not participate in food scraps diversion, including reasons for the differences in household food waste generation between participating and non-participating households. Characterization of contamination at a greater level of detail than provided in studies to-date and with a focus on more clearly identifying the types of items and contaminant materials most commonly found in household organics carts. Gaining greater insight into the make-up and prevalence of specific contaminants (e.g., the percent of households with plastic bags found in organics carts, not just the relative weight of plastic bags relative to all other materials in the cart) could guide more effective outreach and communication intended to address organics contamination issues. 31

32 KENMORE (REPUBLIC SERVICES) Appendix A Study Maps and Tagging Frequency Assignments Kenmore (Republic Services) 32

33 BURIEN (RECOLOGY CLEANSCAPES) Burien (Recology Cleanscapes) 33

34 UNINCORPORATED NORTH KING COUNTY (WASTE MANAGEMENT) Unincorporated North King County (Waste Management) 34

35 KENMORE (REPUBLIC SERVICES) Appendix B Cart Tag Designs Kenmore (Republic Services) Burien (Recology Cleanscapes) and Unincorporated North King County (Waste Management) 35