Solid waste composition and the properties of biodegradable fractions in Izmir City, Turkey: an investigation on the influencing factors.

Background: Waste composition and characteristics are determinative in selecting technological alternatives to develop waste management strategies that can meet legislative requirements. The aim of this study is to identify the major factors influencing the municipal solid waste (MSW) composition and the properties of its biodegradable fraction in İzmir city, Turkey.

Methods: MSW composition was determined in samples collected from different income level areas of the city. Water and organic matter contents, calorific value, and the total chlorine levels in seven biodegradable waste (Bio-MSW) size fractions (between >120 mm and > 10 mm) and in the fine fraction (<10 mm) were analyzed. The data on waste components and Bio-MSW properties were statistically investigated.

Results: The average shares of biodegradables and recyclables in MSW were found as 50.2 and 40.3%, respectively. The organic matter content of Bio-MSW increased with waste size ( r  = 0.313, p  < 0.05) and its calorific value were in the range of 2310-3686 kcal/kg. A link between the plastics' share in MSW and the Bio-MSW chlorine levels was recognized (r: 0.666, p  < 0.1). PCA analysis identified the main factors degrading the Bio-MSW quality as the cross contamination due to the mixed collection (30.8%), compaction applied in waste trucks (27.5%), and the inert broken materials trapped in larger fractions (21.3%).

Conclusion: Strong negative impact of mixed collection on Bio-MSW quality indicated that implementation of source separated collection of MSW is crucial for Izmir city in order to develop an integrated waste management system that meets the legal requirements by means of end product quality.