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This paper presents a new approach of optimization technique in the controller parameter tuning for waste-water treatment process (WWTP) application. In the case study of WWTP, PID controller is used to control substrate (S) and dissolved oxygen (DO) concentration level. Too many parameters that need to be controlled make the system becomes complicated. Gravitational Search Algorithm (GSA) is used as the main method for PID controller tuning process. GSA is based on Newton's Law of Gravity and mass interaction. In this algorithm, the searcher agents survey the masses that interact with each other using law of gravity and law of motion. For WWTP system, the activated sludge reactor is used and this system is multi-input multi-output (MIMO) process. MATLAB is used as the platform to perform the simulation, where this optimization is compared to other established optimization method such as the Particle Swarm Optimization (PSO) to determine whether GSA has better features compared to PSO or vice-versa. Based on this case-study, the results show that transient response of GSA-PID was 20%-30% better compared to transient response of the PSO-PID controller.

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In the past decades, research about energy consumption reduction has become a trend due to concern of energy wastage that leads to the negative impact on the environment. Commercial sector produces higher energy consumption compared to other sectors in Malaysia and hospital building is one of the highest energy consumptions in the commercial sector. Continuous operation time and complexity of engineering system are some of the reasons for high energy consumptions in hospital buildings that leads to high energy costs. This study examines the electricity load apportioning for a hospital building in Selangor, Malaysia through a detailed energy audit. From the energy audit, several Energy Efficiency Initiatives (EEI) were identified in reducing the energy usage in hospital: room temperature control, efficient lighting system, efficient unit for Air-Conditioning Split Unit (ACSU) and Variable Speed Drive (VSD) installation. The EEIs is expected to produce a total electricity saving of 1,250,692 kWh/year, equivalent to a cost saving of RM 421, 706/year and total emission reduction of 869 tonnes CO2 per year.