Microalgae biotechnology is of increasing importance and a central application concerns the treatment of wastewater. Here, its implementation in a recirculating aquaculture system (RAS) to lower the discharge of wastewater is studied. To better cope with external variations in culture conditions, a co-cultivation of two species of microalgae, Chlorella vulgaris and Tetradesmus obliquus, was used to obtain a more reliable and robust culture and was compared to monocultures. This approach was tested using RAS water both under sterile and non-sterile conditions at laboratory scale and then compared to a co-culture at pilot-scale in an open thin-layer photobioreactor. Performance of cultures was tested in terms of microalgae growth and nutrient removal efficiency. Furthermore, to better understand the interaction between environmental variables and each microalgae species, their relative frequencies in co-cultures as well as the presence of protozoa and bacteria were monitored. All growth experiments were carried out successfully and, unlike in a previous study, no crashes were observed. However, shifts in species frequency in co-cultures indicated that the two species were differentially affected by cultivation conditions. Despite nutrient limitation, the pilot-scale cultivation had a high productivity (13.3 g m⁻² d⁻¹) and final dry weight (11.1 g l⁻¹) after 29 days and demonstrated its suitability for RAS water treatment.

微藻生物技术的重要性日益提高，其主要应用涉及废水的处理。在此，研究了其在循环水产养殖系统（RAS）中的实施以降低废水排放。为了更好地应对培养条件的外部变化，共培养了两种微藻，小球藻和斜生小球藻，用于获得更可靠和健壮的文化，并与单一文化进行了比较。使用RAS水在实验室规模的无菌和非无菌条件下对该方法进行了测试，然后与开放式薄层光生物反应器中试规模的共培养进行了比较。根据微藻生长和营养去除效率对培养物的性能进行了测试。此外，为了更好地理解环境变量与每种微藻物种之间的相互作用，对它们在共培养物中的相对频率以及原生动物和细菌的存在进行了监测。所有生长实验均成功进行，与先前的研究不同，未观察到任何崩溃。但是，共培养中物种频率的变化表明，这两种物种受栽培条件的影响不同。^-2 d ^-1）和29天后的最终干重（11.1 g l ^-1），证明其适用于RAS水处理。