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Biofloc technology is used to improve water quality and fish growth performance of aquaculture. The purpose of this research is to analyse the biological factors on freshwater barramundi in biofloc aquaculture system. Three set of experiments with 3 biological factors were carried out for freshwater barramundi to analyse the water quality and to evaluate the cultivated fish growth performance under the application of biofloc technology for 10 weeks. The biological factors involved are stocking density, carbon-to-nitrogen ratio and feeding rate. The water quality parameters were monitored weekly while the growth indices will be determined at the end of the experiments. The results revealed that stocking density has insignificant effect on the water quality but essential affected the growth rate of the freshwater barramundi. The best growth rate is observed at lowest stocking studied (10 fish/m3). The biofloc technology aquaculture system with C:N ratio of 16:1 and lowest stocking density (10 fish/m3) produced the best water quality and growth performance. Meanwhile the compatible feeding rate for the juvenile freshwater barramundi was identified at rate of 1% of fish body weight with feeding frequency once or twice a day in order to control the water quality and produced good growth performance of the juvenile.

Aquaculture is one of the important food-producing sectors. However, the effluent of the aquaculture system consists of pollutants such as nitrogenous compounds and the ample usage of water for traditional aquaculture systems. Therefore, biofloc technology was developed in the aquaculture industry in the 1980s to improve the water quality of the system and increase the fish production. The purpose of this experimental work is to investigate the effect of biological factors on the growth performance of fish and the water quality of the biofloc technology (BFT) aquaculture system for red hybrid tilapia cultivation. In this study, 3 biological factors such as the carbon-to-nitrogen ratio, stocking density and the feeding rate were studied under BFT. Parallel experiments in thirteen suspended growth tanks were carried out within (10:1-20:1) C/N ratio, (1%-5%) feeding rate and (20-80 fish m-3) stocking density for 10 weeks. Growth rate of fish and water quality data such as ammonia, nitrite and nitrate concentrations were collected weekly during the study. The results revealed that the 20:1 C/N ratio gave the best water quality. Feeding rate at 4% of body weight produced good growth performance of the tilapia species and the higher stocking densities lead to lower water quality and survival rate.

Interaction between the microwave heating rate and dielectric properties of agricultural wastes is important in identifying suitable microwave operating conditions. This work focuses on the interaction between microwave heating rate (power intensity) and dielectric properties of selected agricultural wastes, namely castor shell, empty fruit bunch and palm kernel shell. Heating rate was recorded every 30 s for 10 min in a 2.45 GHz microwave at power intensities of 100, 300, 450, 600, 700 and 800 W. All materials tested display an increase in heating rate with increasing power intensity. Castor shell and empty fruit bunch at 800 W, and palm kernel shell at 600 W exhibit high heating rates of 0.134, 0.165, 0.247 °C/s, respectively. For dielectric properties, palm kernel shell series shows a high value of loss tangent compared to the other counterparts, indicating its effectiveness to be heated via microwave. [ABSTRACT FROM AUTHOR]

This research was conducted to investigate the effect of intermittent water pump operation on nutrient uptakes and plant growth yield in an aquaponics system. Four backyard size aquaponic units were build using the same type of hydroponics grower known as media grow bed. Four different types of water circulation system which are, (a) 2 h on and off (2HWC), (b) 4 h on and off (4HWC), (c) 8 h on and 16 h off (8HWC) and (d) 24 h on (24HWC) of the pump were implemented on the aquaponic units. Cocopeat was used as the substrate. A compact water filtration system containing mechanical and biological filtration units was used in this study. Water quality (ammonia, nitrite, and nitrate), plant yield, and fish growth were all measured weekly during the twelveweek experiment. Other parameters measured include pH, water temperature, dissolved oxygen (DO) concentration and total suspended solids (TSS). The result revealed that pH, water temperature, TSS and DO values remain within the acceptable range for growing Gynura procumbens (G.procumbens) and culturing of Oreochromis spp.. A good conversion rate of ammonia into nitrate was obtained using a compact water filtration system. The highest increment in plants height and leaves production could be seen in 2HWC where the percentage of G.procumbens growth was 377 % (height) and 960 % (leaves) throughout the cultivation period. The highest yield of fish growth was also found to be in 2HWC (211 %). 31.5 kW (50 %) energy could be saved using 2HWC as compared to the control (24HWC). This result could be used in conserving the energy of aquaponic farm growing herbs and tilapia. Future research needs to be conducted to determine its suitability in conserving the energy of aquaponic farm growing other types of plants and aquatic animals. Lower energy consumption in aquaponics system reduces the high cost associated with small aquaponic farm and increase profit in the long-term run. [ABSTRACT FROM AUTHOR]

The capture and storage of CO2 have been suggested as an effective strategy to reduce the global emissions of greenhouse gases. Hence, many studies have been carried out to develop highly efficient materials for capturing CO2. Herein, the CO2 capture performance of mesoporous ceria nanoparticle (MCN) was described. The MCN was synthesized under mild conditions through a sol-gel method using hexadecyltrimethylammonium bromide (CTAB) as a surfactant and further undergone a calcination process at 673 K for 3 h. The prepared MCN possess high surface area (76.0 m² g-1) which is around 9-fold higher than that of commercial CeO2 (8.7 m² g-1), indicating that the organic modification using CTAB is an effective way of preparing a porous structure. The MCN exhibited high CO2 uptake of 213.8 µmol g-1 at 298 K and 1 bar. The prepared MCN using sol gel has shown a rapid and cost-effective method compared to the hydrothermal method. [ABSTRACT FROM AUTHOR]

In any new chemical process development and design, process safety is a critical aspect to be considered besides economic and technical feasibility of the manufacture of the product. A lack of proper hazard assessment during the design phase may later result in accidents with disastrous consequences to workers, the public as well as the environment. Many methods have been introduced to qualitatively and quantitatively assess the safety level of processes. Despite the availability of a large amount of methods, a systematic framework that details guidelines for hazard identification, risk assessment, safety measure design, and safe critical decision-making is still missing. To address this issue, the main objective of this study was to propose a systematic framework that outlines comprehensive guidelines for assessing the safety performance of processes based on information from the piping and instrumentation diagram (P&ID). Apart from proposing the framework, appropriate strategies for minimizing safety hazards and risks are also recommended. In addition, the user is assisted in selecting the most appropriate assessment method according to his or her needs and the scope and constraints of the assessment. A case study is presented to illustrate the application of the proposed framework. [ABSTRACT FROM AUTHOR]

This work was aimed to evaluate the adsorptive nature of palm oil mill effluent sludge ash for methylene blue dye removal in aqueous solution. Two types of palm oil mill effluent sludge collected from different treatment ponds, i.e. anaerobic and biopolishing were burnt to ash, and treated with 5 M HCl. The treated and untreated adsorbents were characterized for surface area and morphology. Methylene blue dye adsorption was carried out in laboratory at room temperature, and the adsorption data were analyzed based on equilibrium isotherm and kinetic models. The surface area of ash-adsorbents was found to increase more than 12 times after HCl treatment. The highest surface area recorded was 218 m²/g. Equilibrium data of ash-adsorbents obeyed Langmuir isotherm to linear approximation suggesting the monolayer uptake of methylene blue dye. The highest maximum uptake of 50.7 mg/g methylene blue dye (50% removal) was demonstrated by HCl-treated biopolishing ash-adsorbent at initial concentration of 200 mg/L and pH 5.8 ± 0.1. The kinetic data for selected HCl-treated ash-adsorbent were fitted to Ho's pseudo-second-order model, indicating chemisorption process. Results showed that ash obtained from palm oil mill effluent sludge after simple treatment with HCl could be employed as effective adsorbent for the removal of methylene blue dye. [ABSTRACT FROM AUTHOR]