In this batch study, the adsorption of malathion by using granular activated carbon with different parameters due to the particle size, dosage of carbons, as well as the initial concentration of malathion was investigated. Batch tests were carried out to determine the potential and the effectiveness of granular activated carbon (GAC) in removal of pesticide in agricultural run off. The granular activated carbon; coconut shell and palm shells were used and analyzed as the adsorbent material. The Langmuir and Freundlich adsorption isotherms models were applied to describe the characteristics of adsorption behavior. Equilibrium data fitted well with the Langmuir model and Freundlich model with maximum adsorption capacity of 909.1mg/g. The results indicate that the GAC could be used to effectively adsorb pesticide (malathion) from agricultural runoff.
The focus of this research is to study the potential of nanofiltration membrane technology in removing ammonia-nitrogen from the aquaculture system. One of the major fabrication parameters that directly affect the separation performance is shear rate or casting rate during membrane fabrication. In this study, asymmetric polyethersulfone (PES) nanofiltration membranes were prepared at five different shear rates within the range of 67-400 s(-1). Membrane productivity and separation performance were assessed via pure water, salt and ammonia-nitrogen permeation experiments, and their structural properties were determined by employing the combination of the irreversible thermodynamic (IT) model, solution diffusion model, steric hindrance pore (SHP) model and Teorell-Meyers (TMS) model. The study reveals that the alteration of shear rate enormously affects the membrane morphology and structural parameters, hence subsequently significantly influencing the membrane performance. It was found that, membrane produced at the shear rate 200 s(-1) or equivalent to 10s of casting speed during membrane fabrications managed to remove about 68% of ammonia-nitrogen, in which its separation performance is the most favourable by means of highest flux and rejection ability towards unwanted solutes. Besides, from the research findings, nano-membrane technology is a potential candidate for the treatment of aquaculture wastewater.
A study was performed to determine the effect of Conway and f/2 media on the growth of microalgae genera. Genera of Chlorella sp., Dunaliella sp., Isochrysis sp., Chaetoceros sp., Pavlova sp. and Tetraselmis sp. were isolated from the South China Sea. During the cultivation period, the density of cells were determined using Syringe Liquid Sampler Particle Measuring System (SLS-PMS) that also generated the population distribution curve based on the size of the cells. The population of the microalgae genera is thought to consist of mother and daughter generations since these microalgae genera reproduce by releasing small non-motile reproductive cells (autospores). It was found that the reproduction of Tetraselmis sp., Dunaliella sp. and Pavlova sp. could be sustained longer in f/2 Medium. Higher cell density was achieved by genus Dunaliella, Chlorella and Isochrysis in Conway Medium. Different genera of microalgae had a preference for different types of cultivation media.
The growths of the African catfish (Clarias gariepinus) and water spinach (Ipomoea aquatica) were evaluated in recirculation aquaponic system (RAS). Fish production performance, plant growth and nutrient removal were measured and their dependence on hydraulic loading rate (HLR) was assessed. Fish production did not differ significantly between hydraulic loading rates. In contrast to the fish production, the water spinach yield was significantly higher in the lower hydraulic loading rate. Fish production, plant growth and percentage nutrient removal were highest at hydraulic loading rate of 1.28 m/day. The ratio of fish to plant production has been calculated to balance nutrient generation from fish with nutrient removal by plants and the optimum ratio was 15-42 gram of fish feed/m(2) of plant growing area. Each unit in RAS was evaluated in terms of oxygen demand. Using specified feeding regime, mass balance equations were applied to quantify the waste discharges from rearing tanks and treatment units. The waste discharged was found to be strongly dependent on hydraulic loading rate.
Mass cultivation of high-value aromatic herbs such as Vietnamese coriander and Persicaria odorata required specific soil, nutrients, and irrigation, mostly found in the limited natural wetland. This study aimed to evaluate the capacity of P. odorata at different densities in nutrient removal and the growth performance of African catfish, Clarias gariepinus in aquaponic systems. P. odorata was cultivated for 40 d with less than 10% water exchange. The effects of increasing crop densities, from zero plants for the control, 0.035 ± 0.003 kg/m2 in Treatment 1, 0.029 ± 0.002 kg/m2 in Treatment 2, and 0.021 ± 0.003 kg/m2 in Treatment 3, were tested on the growth performance of C. gariepinus with an initial density of 3.00 ± 0.50 kg/m3. The specific growth rate (SGR), daily growth rate of fish (DGRf), and survival rate (SR) of the C. gariepinus were monitored. Nutrient removal, daily growth rate of plant (DGRp), relative growth rate (RGR), and the sum of leaf number (Ʃn) of the P. odorata plant were also recorded. It was found that nutrient removal percentage significantly increased with the presence of P. odorata at different densities. The growth performance of C. gariepinus was also affected by P. odorata density in each treatment. However, no significant difference was observed in the DGRp and RGR of the P. odorata (p>0.05), except for Ʃn values. Treatment 1 had the highest Ʃn number compared to Treatment 2 and Treatment 3, showing a significant difference (p<0.05). This study demonstrates that the presence of P. odorata significantly contributes to lower nutrient concentrations, supporting the fundamental idea that plants improve water quality in aquaponic systems.
The aim of this study was to determine the effect of different light sources and media (wastewater and BBM) on the growth of Pseudanabaena mucicola and its phycobiliprotein production. Results showed that P. mucicola grown in white light using wastewater as medium attributed higher biomass (0.55 g L-1) and when extracted with water, also showed significantly higher (P
The physical profile and chemical composition of growing media are vital in evaluating fish waste filtration efficiency and plant growth performance in aquaponics. The present study reported and compared the physical and chemical evaluation of the novel fabricated Kaolina, gravel, and commercially used lightweight expanded clay aggregate (LECA) as growing medias in aquaponics. Field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy (FESEM-EDX) was utilized to analyze the growing media's chemical composition and structural characterization. The resultant effect of these growing medias on water quality and the growth performance of Clarias gariepinus and Lactuca sativa were also reported. Kaolina exhibited an excellent physical profile (42.95 ± 1.39%) in water absorption capacity as compared to LECA (35.90 ± 1.28%) and gravel (1.97 ± 0.25%), showing a significant difference at p