In 1999, one American generated approximately 4.6 pounds of solid waste materials each day, twice the daily amount of waste generated by an individual (2.7 pounds) in 1960 [9]. In 2003 the net per capita discard rate after recycling and composting was 3.09 pounds per person per day, a little below the 3.14 pounds per person per day in 2002. In 2008, the US generated 250 million tons of solid waste and only 83 million tons (33.2%) were recycled. In 2012 an individual still generated nearly the same amount of waste (4.38 lbs) per day and recycled only 1.5 pounds [3]. The US EPA MSW report shows that MSW generation rate has remained relatively constant since the 1990s at 4.4 pounds per individual per day. Americans generated 251 million tons of trash in 2012 compared to 236.2 million tons in 2003 and 250.4 in 2010. Of the 251 million tons generated in 2012, 55% to 65% of total MSW came from residential sources including apartment houses, and 35% to 45% from school and commercial locations such as hospitals and businesses [3]. This estimate does not include industrial, hazardous, or construction waste [3]. In the same year (2012), Americans recovered over 65 million tons of MSW through recycling and nearly 29 million tons through composting. The Americans recycling rate in 2012 was 34.5% compared to 31.4% in 2005 and 34.0% in 2008 [3]. The total MSW generated in 2015 was 262.4 million tons. Of those, nearly 52.5% went to landfills, 25.8 recycled and 8.9% composted [3]. Paper and paperboard was the largest part of the MSW (25.9%) followed by food (15.1%) yard trimmings (13.2%) and plastics (13.1%). A survey among Americans in 2017 on recycling indicated more than half of participants had curbside pick-up of recyclable materials [9]. According to the Pew Research Center FACTANK report on perceptions and realities of recycling, 28% of Americans stated their local community’s social norms strongly encourage recycling and re-use, while 22% stated they do not. Fifty percent reported their communities were in neither side regarding recycling [10]. Nation-wide, there are approximately 9800 curbside recycling programs somewhat up from 9700 curbside programs in 2001 and 8660 in 2006 [10]. However, the US EPA states that household waste remains a constant concern because trends indicate that the overall tonnage we create continues to increase [3] [9].

It is obvious that households possess the key to sustainable management of solid waste. Waste minimization, reuse, and recycling rates vary substantially among individual households for various reasons, which include; personal variables (attitude toward the environment, knowledge, demographic variable, and personality) or situational issues (removal of recycling barriers, prompting, obtaining commitment to recycle, use of social norms, rewards, and providing feedback) [11]. Hence, only changes in individual attitudes, beliefs, norms towards the environment, and the consequential shift in personal behavior, will have the lasting and significant impact on the environment that is badly needed [12].

After obtain research approval from the Institutional Review Board (IRB), households to participate in the study were identified. This residential area was one that yielded the lowest recyclable setouts. The intervention approach at the intrapersonal level adopted from HBM was applied in the intervention process. The intrapersonal approach focused on individuals by influencing their knowledge values, beliefs, and attitudes about recycling through innovative provision of educational messages. This innovative educational approach also empowered people to take control of their recycling behavior. Attention was paid to the design of the educational materials and to their delivery with the intention of catching people’s attention. The appeal of the materials delivered and the persistence of the intervention approach were considered key to getting people interested in partaking in the recycling process and programs. Education materials such as brochures, posters, and fliers were used. This was accomplished by both house-to-house visits and mailing of additional useful materials. In addition, follow-up telephone calls, feedback on recycling progress, and direct mailing were used to remind people about recycling. The following combinations of educational intervention strategies were applied.

The Knowledge, Skills, and Ability (KSA) scale was used to both establish a baseline and to measure changes of knowledge, awareness, attitude, and behaviors toward recycling following educational interventions. The KSA scale which uses a Likert Scale was adopted from Barr (2002) and modified in order to fit the needs of this study [25]. Barr (2002) designed the scale and utilized it to study knowledge, values, attitudes, and behaviors toward recycling household waste in Exeter, Devon UK. The scale measured environmental attitudes, knowledge, values, and behaviors affecting recycling participation. The modified scale was tested for internal reliability in each of its subscales. A Cronbach’s Alpha reliability test for internal consistency of subscale items (recycling activity, knowledge, attitude, and behavior) was calculated using JMP8.SAS Institute [26]. The Cronbach’s Alpha reliability test was chosen as the best approach due to the fact that it tends to provide a high estimate of reliability. An Alpha coefficient score of α = 0.7 or better suggests a satisfactory degree of reliability [27]. For highly correlated items the coefficient can approach α = 1.0. The Cronbach’s Alpha for activity subscale was α = 0.870; knowledge subscale α = 0.630; attitude subscale α = 0.760; skills subscale α = 0.949; and behavior subscale α = 0.833. The data sets were for the actual recyclable weights that were collected from the curb. One set of weight data was gathered before the educational interventions, while two other weight data sets were gathered during the intervention period, and the final weight data set was collected after interventions. These data sets helped to evaluate the progress of the effectiveness of interventions both in the short and long-term.

Data was coded and entered into the JMP8; SAS Institute statistical package. Various quantitative statistical approaches in analyzing data for this study were employed to determine the impact of interventions on recycling activity, knowledge, behavior, skills, and attitude of participants. The following statistical tests were performed: univariate statistics such as descriptive statistics. Descriptive statistics were performed to generate percentages, frequencies, means, and case and group summaries. Descriptive statistics provided a description of the samples or distribution characteristics of the variables in recycling activity, knowledge, behavior, skills, attitude, and waste management strategies.

Before interventions residents in the study area were surveyed to find out which materials they were likely recycle. Figure 1 indicates percentages of individual materials they were likely to recycle in the study area. These included: glass

(GLS; 67%), newspaper (NPR; 75.2%), food cans (FC; 65.2%), drink cans (DC; 73.03%), and plastic bottles (PB; 75.1%). Other solid wastes recycled were junk mail (JM; 58.2%), cardboard (CRDB; 63.4%), and magazines (MGZ; 69.4%). Foils (56.8%) and textiles (TX; 76.5%) were rarely or never recycled.

Figure 2 shows the average amount of solid waste setouts in pounds per household before and after intervention in a biweekly basis. A significant increase in recyclable output was observed after interventions.

As indicated in Figure 2, there was a steady increase in recyclable set-out rates from baseline to the final intervention. Under the HBM intervention approach participants responded to educational interventions by setting out more recyclables (59.3 lbs.) biweekly by the end of the intervention period. These innovative educational interventions were delivered constantly and were consistently on recycling message.

In responding a questionnaire item related to how participants managed recyclable before interventions a Likert scale of (1 = never, 2 = rarely, 3 = sometimes, 4 = usually, 5 = always) for subscale questionnaire items about recycling activity and waste management was used. Participants reported they never or rarely bought items with little packaging (m = 1.8, sd = 0.990), used their own fabric shopping bags rather than the ones provided by the store (m = 1.7, sd = 0.802), looked for easily reusable packaging (m = 1.9, sd = 1.215), and/or reused papers (m = 1.9, sd = 0.956).

However, the post-test results indicated a change in participants’ waste management behaviors. See Table 1.

Note. 1 = never, 2 = rarely, 3 = sometimes, 4 = usually, 5 = always.

Questions in the knowledge subscale tested participants’ knowledge on issues related to the environment (Ev), solid waste (SW), Sustainable Development (SD), and Local Agenda 21(LA). Responses were “True” and “False”. Figure 3 represents the percentage of correct answers to knowledge questions before and after interventions for the participants where HBM intervention method was applied. During post-test, participants improved their scores of correct answers. Under the HBM intervention approach educational materials such as brochures, posters, and fliers were consistently delivery to residents that participated in the

study. These materials were considered key in increased knowledge as well as motivating them in partaking in the recycling process.

To determine attitude and value for the environment, participants in the study were asked questions (1 = Strongly Agree and 5 = Strongly Disagree) about their attitude and concerns towards natural resources, and waste management issues. Participants were asked about policy development (PD), their attitude towards natural resources (NR), personal concerns (PC), and waste issues (W). Participants indicated they were neutral both during pre-test and post-test regarding a statement suggesting the environment was often forgotten when decisions are made (PD) (m = 3.2, sd = 0.975), or humans should not develop any resources or land, in order to protect the natural environment (NR4) (m = 3.2, sd = 1.209). During pre-test, participants disagreed or strongly disagreed that the problem of waste posed a threat to their well-being and health (m = 3.7, sd = 1.317). However, after the interventions, a majority of participants reported they agreed or strongly agreed that the problem of waste posed a threat to their well-being and health (m = 1.6, sd = 0.776). In addition, during pre-test participants reported they agreed or strongly agreed (m = 1.8, sd = 0.786) that their personal well-being was not affected by problems of waste disposal. The post-intervention responses, however, indicated they disagreed or strongly disagreed (m = 4.4, sd = 1.203) that their personal well-being was not affected by the problem of waste disposal.

In terms of Waste Minimization Skills or Willingness to Reduce Waste subscale (1 = Very Willing, 5 = Very Unwilling), participants were asked about whether or not they were willing to reduce waste. A majority of respondents both during pre-test and post-test reported they were neutral or somehow unwilling to adopt waste minimization skills (Ms) such as buying fewer disposable items (m = 3.4, sd =1.225), looking for products with less wrappings (m = 3.0, sd = 1.208) and/or taking old plastic bags for shopping rather than getting new ones at the store (m = 3.3, sd = 1.116). However, the post-test responses indicated a majority of them were willing or strongly willing to wash and reuse certain items before disposing of them (m = 1.5, sd = 0.604).

The behavior subscale sought to obtain responses regarding participants’ recycling behavior in order to determine participants’ intentions reflecting the need to help the environment (1 = Strongly Agree, 5 = Strongly Disagree). The pre-test responses indicated participants were neutral in reporting whether their behavior to recycle was influenced by seeing neighbors and friends reuse and recycle things (m = 3.1, sd = 0.820) or whether they needed financial incentives in order to recycle (m = 3.3, sd = 1.235). However, during post-test participants reported they were motivated to recycle when they saw others recycle (m = 1.3, sd = 0.756). Participants also reported they felt guilty for not recycling (m = 2.1, sd = 0.887). Other responses that indicated behavioral change after interventions were that participants agreed or strongly agreed that they were very concerned with waste issues or problems (m = 1.6, sd = 1.078) and realized that participating in recycling and managing waste was simple (m = 1.6, sd = 0.963).