Physical profile and chemical composition of a novel fabricated Kaolina as alternative growing media in aquaponics.

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 < 0.05. The addition of 25% w/w Musa paradisiaca peel in the fabrication of Kaolina gives an added value of 88.0% of K and 100% of P elements, which show a significant difference (p < 0.05) compared to LECA. The results obtained reveal a better daily growth rate (DGR) and relative growth rate (RGR) of L. sativa at 0.57 ± 0.02 cm day-1 and 0.21 ± 0.00 g day-1, respectively. Results indicated that the porous structure of growing media could contribute to the high-water retention capability and slow the water desorption process. Hence, it could increase the ability of the growing media to hold nutrients for plant intake, resulting in higher removal percentage of nutrients in aquaponics system. Kaolina gives the highest nutrient removal percentage of TAN (96.86 ± 1.50%), NO2- (83.56 ± 1.27%), NO3-(77.55 ± 0.48%), and PO43- (79.46 ± 0.42%). The results also shown growing media has considerable impacts on nutrient removal, which contribute to the aquaponic productions.

Treatment of African catfish, Clarias gariepinus wastewater utilizing phytoremediation of microalgae, Chlorella sp. with Aspergillus niger bio-harvesting.

This study focuses on the evaluation of the performance of Chlorella sp. in removing nutrient in aquaculture wastewater and its correlation with the kinetic growth of Chlorella sp. The treatment was applied with various Chlorella sp. inoculation dosage ranging from 0% to 60% (v/v) of wastewater. The optimum inoculation dosage was recorded at 30% (v/v) with effluent concentration of ammonia and orthophosphate recording at 0.012mgL(-1) and 0.647mgL(-1), respectively on Day 11. The optimum dosage for bio-flocculation process was obtained at 30mgL(-1) of Aspergillus niger with a harvesting efficiency of 97%. This type of development of phytoremediation with continuous bio-harvesting could promote the use of sustainable green technology for effective wastewater treatment.