A socio-economic based survey of household waste characteristics in the city of Dublin, Ireland. I. Waste composition

Abstract The importance of reliable information on both the quantity and composition of municipal solid waste for the effective planning of waste handling infrastructure has long been recognised. Much of the data currently available in Ireland, and specifically the Dublin region, is either old or unreliable. The present study sought to address the problem of unreliable waste composition data with regard to the city of Dublin. In late 1992 a representative sample of 1500 households was generated at random from the computerised record of the Electoral Register for the city. Each household was visited by trained interviewers and key demographic and socio-economic data was obtained on the 1036 households that agreed to participate in a survey of waste arisings. Waste was subsequently collected in uncompacted form from 857 of these households and hand-sorted into 12 main categories and 36 categories in total including all sub-divisions. Both total waste and individual waste fractions for each household were weighed. An overall total of 12 tonnes of waste was analysed in this manner over a 5-week period in October/November 1992. The physical data revealed substantial differences in the relative composition of the waste stream as compared with both previous studies undertaken in Dublin in the late 1970s. In particular the proportion of organic waste was found to be in excess of 45% by wt. in the 1992 study as compared with 34% in 1977/78. However, the present findings were supported by the results of a more limited survey of waste composition carried out separately in 1993/94 for the Dublin green-box recycling service. The physical weight data and the corresponding social, economic and demographic data for all households were amalgamated in electronic format. Statistical techniques were used to test the relationship between socio-economic factors and the composition of generated waste. The results indicated a clear divide between the more prosperous section of the city's population and the less prosperous in relation to overall waste generation and the generation of individual components of the waste stream.