Determination of efficiency indicators of various solid waste collection systems of Dhaka city corporation

Abstract

The efficiencies of various methods of solid waste collection systems are determined and compared in this thesis. The efficiency indicators of compactor truck based station collection, open truck based station collection, container based collection and open truck based traditional collection system are determined and compared. DCC does not have sufficient waste collection and transportation equipments to carry its daily generated waste. The scattering of waste in unspecified places and manner creates serious environmental degradation. It is very much necessary to understand how effectively and efficiently DCC's existing collection systems are functioning and identify how it can be improved. Several field visits, interviews of key informants and field staff are taken. A checklist for interview is prepared incorporating the ideas of Engineer and field staff of waste management department of DCC. Time and Motion Surveys have been carried out for four different collection systems. Different efficiency indicators with time fractions of total trip time were measured for different systems and behaviours of waste workers are observed to find possible improvement options. The results show that all types' secondary collection vehicles can make at least 2 trips and container carriers can make 4 trips per day while the round trip haul distances are 12 to 15 kilometres. The average trip times for this distance are 3.5 h, 2.75 h, 4.20 hand 1.33 h for compactor truck, open truck based station collection, morning open truck and container collection respectively. The actual trips and the trips for which fuel is allocated are not always same. The findings show that time ratio for compactor truck collection is about 21%, 6% and 72% for pickup, unloading and travelling respectively. Morning open truck (traditional) collection takes about 58%, 9% and 31% time of total trip for pickup, unloading and travelling respectively. The average pickup rates as ton/hour are 2.56, 1.54, and 1.35 for compactor, open truck based station collection and traditional open truck collection respectively. The ranges of capacity usage of the vehicles for these three systems are 83% to 97%, 78 % to 113%, 95% to 132% respectively and 70 to 91% for arm-roll container based collection system. Different efficiency indicators vary with collection time, method of collection, crew-size and cooperation of community. Collection systems' improvement is possible considering these issues in planning process and enhancing monitoring of DCC.