The current teaching approach of the undergraduate subjects is very dependent on conventional methods, without any participation and contribution of the students during the learning process. Active learning refers to any approach to instruction in which all students are required to involve in the learning process. The purpose of the manuscript is to evaluate the application of active learning in teaching the compulsory course in the environmental engineering department, Curtin University Malaysia. Green engineering is a compulsory unit in 3rd year of Department of Environmental Engineering, that approach of the design, process, product and commercialization that following environmentally conscious attitude, principles and values combined with multidisciplinary engineering science to minimize pollutants and promote local and global sustainability. A simple approach that combining the classical lecture-presentation and active engagement of the students with the course materials through Problem-Based Learning, Interactive Class Learning and Project-Based Learning has been developed. Introducing the active learning to the students on solving any problems improve the students' ability in achieving the course outcome and thus the program outcome of the Department of Environmental Engineering, Curtin University Malaysia. The attainment of each assessment by the students and student evaluations indicated that the students' achievement, and retention of information have greatly improved. This can be judged by high student attendance and participation, high grades, and large student satisfaction.