Combinatorial optimization of construction waste collection and transportation: A case study of Hong Kong

Although construction waste consistently contributes the highest proportion of all solid waste landfilled, its collection and transportation has received little attention. This research conducts a case study of Hong Kong with the aim of unraveling the causes of ineffective construction waste management from a logistics perspective and developing strategies to improve efficiency of waste collection and transportation. We analyze 112,892 individual trips undertaken by 2,563 construction waste hauling trucks and find three critical issues, namely irrational facility choice, disorganized trip chains, and serious underloading. We design an order-to-order distance matrix, based on which we develop a combinatorial approach to optimizing construction waste collection and transportation through (1) optimal facility choice, (2) proper order sequencing, and (3) increased loading ratio. Simulation results indicate that optimal facility choice is most effective of the three strategies, reducing travel distance by 15.2% (15,256 km) and saving 15.3% (21,467 kg) in CO2-eq emissions. Combining the three strategies creates the best optimization effects, saving 20.3% of travel distance (20,346 km) and 18.2% of CO(2-eq )emissions (25,544 kg). Our findings provide valuable insights for construction waste management and suggest strategies (e.g., developing a work dispatch system like Uber or proper vehicle routing algorithms) for improving waste collection efficiency and reducing carbon emissions.

Automated summary

This research analyzes the issues in construction waste management and proposes strategies to optimize waste collection and transportation. The simulation results show that optimal facility choice is the most effective strategy, and combining the three strategies achieves the best optimization effects.