The present study aimed to optimize the production of Scenedesmus sp. biomass during the phycoremediation process. The biomass productivity was optimized using face centred central composite design (FCCCD) in response surface methodology (RSM) as a function of two independent variables that included wet market wastewater concentrations (A) with a range of 10% to 75% and aeration rate (B) with a range of 0.02 to 4.0 L/min. The results revealed that the highest biomass productivity (73 mg/L/d) and maximum growth rate (1.19 day⁻¹) was achieved with the 64.26% of (A) and 3.08 L/min of (B). The GC-MS composition analysis of the biomass yield extract revealed that the major compounds are hexadecane (25%), glaucine (16.2%), and phytol (8.33%). The presence of these compounds suggests that WMW has the potential to be used as a production medium for Scenedesmus sp. Biomass, which has several applications in the pharmaceutical and chemical industry.

The high level of organic elements and nutrients in wet market wastewater (WMW) has raised public concerns. The phycoremediation method, which utilizes microalgae, can be further valorized by converting it into various valuable potential bioproducts. The production of Scenedesmus sp. in WMW was investigated as an ingredient for fish feeds in this study. The potential of two natural plant-based coagulants, Cajanus cajan (pigeon pea) and Cicer arietinum (chickpea), for harvesting microalgae Scenedesmus sp. were compared. Statistical analysis and response surface methodology were used to investigate the flocculant dosage and pH effect on harvesting efficiency. It was found that Cajanus cajan (CC) and Cicer arietinum (CA) both had a harvesting efficiency of 89.29% and 88.56%, respectively. The optimal dosage and pH for CC were 178.75 mg/L and 11.72, and for CA, they were 137.77 mg/L and 9.15. This study indicated that Scenedesmus sp. can remove heavy metals cadmium (87.24%), chromium (85.55%), and ferum (90.35%), respectively. The level of heavy metals content (μg/kg in ppb) in dry biomass was found ultimately low and did not exceed the maximum concentration set up by the European Commission Regulation. The Fourier Transform Infrared (FTIR) analysis of microalgae biomass displayed O-H, N-H and C-H functional groups. The protein–lipid for the potential application as fish feed in the sample was 45.8–43.6% and 15–13%. Moreover, the biomass contained 53% to 40% oleic acid, which is high concentration of fatty acid methyl ester (FAME). As a result, there is high potential of Scenedesmus sp. in wastewater treatment; both natural coagulants give the possibilities for efficient microalgae biomass recovery as fish feed and are applicable for improving the quality of Scenedesmus sp. cultivated in WMW.

Indoor air pollution by airborne fungi has risen to become a common issue all over the world and it is hazardous to indoor occupants' health as it is associated with a series of respiratory-related and skin-related diseases. Selected bioactive compounds from the food industry have been suggested to be effective against individual fungus isolated from indoor environment. However, the techniques used to evaluate these compounds were lengthy and unsuitable against total airborne fungi. Therefore, this paper describes an assay to assess the effectiveness of a bioactive compound to inhibit growth of total airborne fungi.•A combination and modification of previous methods and the NIOSH Manual Analytical Standard Method (NMAM 0800) is proposed.•This method concurrently samples the total airborne fungi and evaluates the ability of bioactive compounds (potassium sorbate in this paper), as a biocide, to treat these indoor airborne fungi.•The current method shortens the time of evaluation from 30 days to only 5 days and employs the counting of colony forming units (CFUs) to ease the measurement of the growth of fungi.

This study investigates the potential of a hybrid process combining sand filtration column with activated banana peels macrocomposite (ABPM) adsorbent for river water treatment. Scanning electron microscopy (SEM) analysis displayed an irregular structure and high cavities of the banana peel adsorbent surface that caters to the deposition of contaminants, while energy-dispersive X-ray analysis detected major elements of the adsorbent, such as calcium, oxygen, silicon, and carbon. Fourier-transform infrared analysis of the banana peels adsorbent showed the presence of hydroxyl, acyl, amine, and alkene groups that were responsible for the adsorption process. The sand filtration column experiment was investigated to find out the removal of turbidity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and ammonia nitrogen (AN) where it resulted in the highest removal efficiency operated at a flowrate of 1.15 ml/s with >90% turbidity, 44% COD, 87% BOD, 75% TSS, and 54% AN removal. The adsorption isotherm was best described by the Langmuir model (R2 > 0.98) compared to the Freundlich model (R2 > 0.95). The pseudo-first-order kinetic model was the best fit for all the experimental data. The combination of sand filtration column with ABPM adsorbent is an efficient treatment solution for improving river water quality.

This research aimed to investigate the potential of chemically modified banana blossom peels (BBP) as an adsorbent for removing manganese (Mn) from water. Zeta potential, field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Brunauer–Emmet–Teller (BET) were used to characterise the BBP adsorbent. Batch adsorption studies were used to assess the effects of the solution pH, adsorbent dosage, initial manganese concentration, and contact time of the adsorption process. Zeta potential of BBP with a value of −9.87 to −21.1 mV and FESEM analysis revealed deeper dents and rough internal surfaces conducive to Mn deposition, whereas EDX analysis revealed the presence of C, O, and Na elements (before adsorption); C, O, and Mn (after adsorption). The presence of hydroxyl, carboxylic, and amino groups, which are responsible for the adsorption process, was discovered using FTIR analysis. Furthermore, XRD analysis revealed that the BBP adsorbent structure is amorphous. The BBP adsorbent has a BET surface area of 2.12 m²/g, a total pore volume of 0.0139 cm³/g, and an average pore diameter of 64.35 nm. The BBP adsorbent demonstrated remarkable results of 98% Mn removal under the optimum pH 7, 0.5 g (adsorbent dosage), and 10 mg/L of Mn initial concentration in 150 min of contact time. The linear Langmuir and Freundlich isotherm models best fit the adsorption isotherm data with the R² > 0.98. In contrast, the adsorption process occurs as a function of the chemisorption as determined by linear pseudo-second-order kinetics. Using 0.1 M HCI, the maximal desorption rate of Mn was 92% in the first cycle, with a recovery rate of 94.18% Mn removal in 30 min. These findings support the use of BBP as a natural adsorbent for Mn removal as a treatment option for improving wastewater quality.