Use of stratified cluster sampling for efficient estimation of solid waste generation at household level

Abstract

Relatively few studies have been performed to characterize municipal solid waste (MSW) at household level. This is due in part to the difficulties involved with collecting the data and selecting an appropriate statistical sample size. The previous studies identified in this paper have used statistical tools appropriate for analysing data collected at a material recovery facility or landfill site. This study demonstrates a statistically sound and efficient approach for characterizing MSW at the household level. Moreover, a household approach also allowed for consideration of the socio-economic conditions, level of waste generation, geography, and demography. The study utilized two-stage cluster sampling within strata in Kathmandu Metropolitan City (KMC) to measure MSW for 2 weeks. In KMC, the average household solid waste generation was 161.2 g capita( -1) day(- 1)with an average generation rate between 137.7 and 184.6 g capita(-1) day(-1) for a 95% confidence interval and 14.5% relative margin of error. The results show a positive relation between income and waste production rate. Organic waste was the biggest portion of MSW, and hazardous waste was the smallest of the total. Sample size considerations suggest that 273 households are required in KMC to attain a 10% relative margin of error with a 95% confidence interval.

Municipal solid waste generation in Kathmandu, Nepal

“…Also, given the time period these studies were conducted, the methods used, the assumptions made and the statistical limitation in designing the studies, only further investigation will determine the accurate numbers for household solid waste generation. The pilot study for this research documented the lack of accurate information in this area (Dangi et al, 2008). The pilot study provided some comparative results of household waste generation in KMC, but this waste stream should be examined concomitantly with other sources of MSW.…”

“…Sharma and McBean (2007) seemed most promising in demonstrating standard sample size calculations based on simple random sampling; however, that study is more suited for waste sampling in the field. ASTM (1998) and Dangi et al (2008) identified appropriate techniques to derive statistically defensible sample sizes at waste disposal sites and sources of generation, respectively. Having derived the socioeconomic information of households across a geographic area with the proper sample size called for by the above studies, this manuscript bases its methods on Dangi et al (2008).…”

“…ASTM (1998) and Dangi et al (2008) identified appropriate techniques to derive statistically defensible sample sizes at waste disposal sites and sources of generation, respectively. Having derived the socioeconomic information of households across a geographic area with the proper sample size called for by the above studies, this manuscript bases its methods on Dangi et al (2008). Tchobanoglous et al (1993) and Vesilind et al (2002) showed that waste generation rates could vary depending on the season, month and day of the week.…”

“…The pilot study provided some comparative results of household waste generation in KMC, but this waste stream should be examined concomitantly with other sources of MSW. The basis of the methodology used in this research is cluster sampling of strata, identified as a useful, statistically sound tool for estimating household waste generation at the source by Dangi et al (2008).…”

“…However, this paper utilized a one-day sampling of waste based upon the findings of Nippon Koei Co. Ltd. and Yachiyo Engineering Co. Ltd. (2005) and Dangi et al (2008 Dangi et al (2008). Also, the survey and sampling of waste was conducted in the shortest duration possible to minimize the effect of the rapidly changing political and physical environmental conditions in Nepal in the summer of 2007 (Bieber, 2007) as well as the difficulty of handling waste from 336 households with limited resources.…”