Combined zeolite-based ammonia slow-release and algae-yeast consortia to treat piggery wastewater: Improved nitrogen and carbon migration

Cultivation of microalgae in food processing effluent for pollution attenuation and astaxanthin production: a review of technological innovation and downstream application

“…Thirdly, high concentration of ammonia in some FPEs could negatively impact the growth of microalgae or even cause the failure of microalgae cultivation. To attenuate ammonia toxicity and utilize FPEs as the substrate for algae production, dilution and ammonia stripping were widely applied by previous studies ( Fernando et al, 2021 ; Lu et al, 2023a ). Nevertheless, due to the high consumption of freshwater and intensive emission of ammonia, the aforementioned two methods could not be regarded as an eco-friendly or sustainable way for microalgae-based FPE remediation.…”

“…As a result, the ratio of C/N in FPEs may not be improved obviously and the astaxanthin synthesis in microalgae will not be positively impacted. Besides, dilution, which consumes a large volume of freshwater, can not be regarded as an eco-friendly and sustainable method for the pretreatment of FPEs ( Lu et al, 2023a ). Secondly, as a process releasing dissolved ammonia into atmosphere, ammonia stripping can effectively reduce the concentrations of TN and TAN in FPEs while have no obvious effect on the concentration of TOC.…”

“…As reported by previous study, when zeolite was added in wastewater (960–1,080 mg L -1 TAN) at a density of 125 g L -1 , after 15-h, 71.27% of TAN was transferred into zeolite, resulting in a low concentration of TAN (285 mg L -1 ). Accordingly, the ratio of TOC to TAN in wastewater was remarkably increased from 4.83 to 16.77 ( Lu et al, 2023a ). Hence, with the addition of zeolite, ammonia toxicity could be attenuated and FPE with high C/N ratio is more favorable to the astaxanthin synthesis in algal cells.…”

“…Up to now, dynamics of zeolite-based ammonium adsorption and desorption have been intensively studied and this novel strategy has been successfully implemented to regulate the C/N ratio for Arthrospira platensis , Amphidinium carterae , and C. vulgaris cultivation in waste streams ( Markou et al, 2014 ; López-Rosales et al, 2022 ; Lu et al, 2023a ). It was reported that due to the improvement of C/N ratio in wastewater, oil yield and oil content of C. vulgaris were improved to 1.24 g L -1 and 34.6%, respectively ( Lu et al, 2023a ). These results fully confirmed the practical feasibility of enhancing the biosynthesis of certain algal compounds by zeolite-based ammonium adsorption and C/N adjustment.…”

“…For example, mechanisms associated with the microalgae immobilization on biofilm for wastewater remediation have been revealed in the lab research, but only a few studied conducted the pilot-scale experiments to evaluate the practical feasibility of RAB for algal astaxanthin production. Also, the concept of zeolite-based ammonium adsorption and desorption was mainly studied in the lab research while pilot-scale experiments were rarely conducted to use this innovative method for astaxanthin-rich microalgae cultivation ( Lu et al, 2019 ; Lu et al, 2023a ). Due to the lack of pilot-scale experiments, it is too hard to find out the weaknesses of these innovative methods developed in lab research and making them to be more applicable in the industry.…”