Promoting sustainable wastewater treatment operations: The role of lean practices and lean six sigma enablers

This study investigates the influence of Lean Six Sigma enablers (LSS_En), comprising strategy, environment, culture, resource, and linkage based on Sustainable Performance (Sus_Perf) in wastewater treatment plants of Malaysian and Multi-national Companies (MNCs), using data from 276 respondents. Additionally, the study examines the intervening impact of lean practices (LPs), specifically statistical process control, human resource management, and total productive maintenance, on this relationship. Employing partial least squares structural equation modelling, the analysis demonstrates a positive and significant impact of LSS_En on Sus_Perf, with β = 0.406, p = 0.001 for Malaysian companies, and β = 0.608, p = 0.001 for MNCs. Furthermore, the impact of LSS_En on LPs is also significantly positive in both types of companies, with β = 0.544, p = 0.001 for locals, and β = 0.546, p = 0.001 for MNCs, respectively. However, the relationship between LPs and Sus_Perf is insignificant in MNCs, with β = 0.126, p > 0.05, while Malaysian companies show a stronger impact with β = 0.418, p = 0.001. Multi-group analysis confirms that local companies excel in H3 with a significant difference of 0.289, p = 0.043. However, the intervening role of LPs in H4 shows no significant difference between the two company types in the LSS_En and Sus_Perf relationship when p > 0.05. This research highlights the scarcity of studies exploring the impact of LSS enablers on sustainable performance in Malaysian wastewater treatment plants and emphasizes the role of LPs by focusing on ownership contributions.