Purification of inorganic nitrogen from the mariculture tail water by anaerobic/anoxic/oxic (A2O) process.

This study aims to address the suboptimal performance of conventional denitrifying strains in treating mariculture tail water (MTW) containing inorganic nitrogen (IN). The concentration of inorganic nitrogen in the mariculture tail water is about 5-20 mg·L-1. A biofilm treatment process was developed and evaluated using an anoxic-anoxic-aerobic biofilter composite system inoculated with the denitrifying strain Meyerozyma guilliermondii Y8. The removal effect of total nitrogen (TN), IN, and Chemical Oxygen Demand (CODMn) from MTW was investigated. The results indicate that the A2O composite biological filter has excellent pollutant removal efficiency within 25 days of operation, after the acclimation of the denitrifying microorganisms. The initial concentrations of TN, IN, and CODMn ranged between 10.24 and 12.89 mg·L-1, 7.84-10.49 mg·L-1, and 9.44-11.52 mg·L-1, respectively, and the removal rates of these indexes reached 38-68 %, 45-70 %, and 55-70 %, respectively. The experiments with different hydraulic retention times (HRT = 6 h, 8 h, 10 h) demonstrated that longer HRT was more conducive to the removal of inorganic nitrogen. Moreover, scanning electron microscopy observations revealed that the target strain successfully grew and attached to the filler in large quantities. The findings of this study provide practical guidance for the development of efficient biofilm processes for the treatment of MTW.

Rapid screening of edible oils for phthalates using phase-transfer catalyst-assisted hydrolysis and liquid phase microextraction coupled to high performance liquid chromatography-tandem mass spectrometry.

Edible oil is easily contaminated with phthalic acid esters (PAEs). Conventional procedures to analyze individual PAEs require very rigorous experimental conditions that are extremely labor-intensive due to significant procedural contaminations generated by the ubiquitous presence of PAEs in the laboratory environment. In this study, a rapid screening method for PAEs in edible oil was successfully developed. Using a phase-transfer catalyst (terabutylammonium bromide) during oil/water biphasic base hydrolysis of PAEs, the hydrolysis time was decreased from a previously reported time of 20 h to 10 min (80 °C). The resulting phthalic acid in the acidified hydrolysate was extracted with 600 µL of tributyl phosphate and then analyzed by high performance liquid chromatography-tandem mass spectrometry in 6 min. Parameters affecting the hydrolysis of PAEs and the extraction of phthalic acid were optimized, and the analytical method was validated. No obvious matrix effect existed in the edible oils whether an external or internal standard method was used. The detection limit was 1.0 µmol kg(-1), and the quantification limit was 1.3 µmol kg(-1). The recovery rates varied from 86 to 107% with relative standard deviations equal to or lower than 9.9% in all of the tested conditions. Twenty-six samples were analyzed, and the background corrected total PAE content was found to be in the range of