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In wastewater treatment plant, an aerobic approach is adopted in the system which utilize the ability of bacteria in the wastewater to reduce biochemical oxygen demand (BOD) and other organic pollutants. High molecular weight of polycyclic aromatic hydrocarbons (HMW-PAHs) are type of organic persistence and insoluble pollutants which hard to be removed from wastewater by bacteria. Owing to the HMW-PAHs tolerant characteristic and abundancy of fungi in wastewater, the bacteria and fungi interaction is anticipated to degrade the HMW-PAHs in wastewater. Thus, this study is carried out as a preliminary study to understand the interaction by optimized the bacterial and fungal growth in the presence of benzo[a]pyrene (BaP). Bacteria and fungi used in this study were Sphingobacterium spiritovorum and Aspergillus brasiliensis ATCC 16404. The response surface methodology (RSM) in Design-Expert® Version 7.0.0 software was used to analysed two factors which are pH and temperature on the bacterial and fungal growth. The growth of bacteria and fungi in co-culture and existence of BaP also been studied. The optimization study showed the growth of S. spiritovorum and A. brasiliensis was optimized at pH 6.2, temperature of 32 °C, and pH 6.5 and temperature of 33 °C, respectively. Synergy interaction was observed in the co-culture condition and with the existence of BaP. The present study provides beneficial information about the bacteria and fungi interaction which has the potential to be applied in the wastewater treatment plant.

The proper maintenance strategy is significant in extending assets and equipment, thus saving maintenance within an organization. Currently, there are three types of maintenance strategies implemented in the Royal Malaysian Air Force (RMAF), namely Reactive Maintenance (RM), Preventive Maintenance (PM), and Condition Based Maintenance (CBM). Due to the constraints in terms of maintenance costs by RMAF, choosing the right maintenance strategy is important to ensure that the maintenance provision can be optimized. In this research study, the Fuzzy Delphi Method has been used as a tool in determining the most effective maintenance strategies to be adopted by the RMAF. The output of agreement and opinion from experts in the related field has been used to select the appropriate maintenance strategy. In choosing this maintenance strategy, goals are set first in line with RMAF maintenance’s objectives. The specified maintenance goals are as follows; low maintenance cost, reducing the chance of a breakdown, safety, feasibility on the acceptance by labor, and response time starting from failure. Later, the result showed that the fuzzy score for RM, PM, and CBM was 0.747, 0.789, and 0.767, respectively. The highest fuzzy score showed the most accepted method chosen by the expert. Based on the result and maintenance goals that have been outlined, experts have agreed to choose PM as a maintenance method that should be given priority to be implemented in RMAF compared to other maintenance methods due to the highest fuzzy score.