In Situ Aerobic Biodegradation In Soil Contact Using The Standard Test Method of ASTM D 5988-12

Abstract

With an over growing problem of plastic waste accumulation, Kuwait faces a serious threat to its natural resources. Latest estimates show that plastic solid waste (PSW) is generated at an alarming rate of over 200 ktpa, making up over 16% of the total municipal waste load. In this paper, the standards test method of ASTM D 5988-12 for determining the degree and rate of biodegradation of plastics in contact with soil was applied to three commercial plastic products sourced locally. The plastic samples are claimed to be of biodegradable nature by the manufacturer and the converter. The test method was applied in situ using analytical desiccators and have proven to be a good indicator to biodegradable measurements. In addition to technical control and reference tests, the test method was also applied on the natural soil secured from the field simulating the largest operating landfill site. The test has proven to be reliable and has produced repeatable results. The biodegradation extent was noted to be very rapid and can be described by comparison to other works as accelerated. This was attributed to both what is described by this work as external and internal factors of the polymer-soil matrix. The former can be noted as environment and soil characteristics, pH level and presence of contaminants in the biota. On the other hand, the latter can be described as type of soil (mixture) ratio, polymer surface area and carbon dioxide (CO2) evolution kinetics which were noted to be of a first order with respect to biodegradation time and dissolution.