## 1 Introduction  
Aquaculture holds significant importance in the fisheries sector and serves as a vital source of nutrition for large populations globally. The industry experienced an average annual growth rate of 9.8% between 1980 and 2000 and 5.8% between 2000 and 2016 [1]. In 2022, global aquaculture production reached a record high of 130.9 million tons, comprising 94.4 million tons of aquatic animals and 36.5 million tons of algae (including seaweed and microalgae) [2, 3]. The estimated farm-gate value of this production in 2022 was USD 312.8 billion, with aquatic animals accounting for USD 295.7 billion and algae for USD 17 billion [3]. However, this growth comes at a cost. A comprehensive report from the Food and Agriculture Organization highlights the ongoing depletion of marine fish stocks [4], being necessary to promote awareness about preserving global fishery resources. Measures such as fishing regulations and marine conservation efforts aim to achieve a balance between sustaining the environment and meeting food demands. Since the 1990s, wild-capture fisheries have reached a production plateau [5], making aquaculture a promising alternative to address the growing demand for seafood. Aquaculture has emerged as one of the most rapidly expanding industries in global food production [6], contributing 46% of the total aquatic food output in 2018 and providing 52% of the fish consumed worldwide [2]. Although aquaculture is widely regarded as a potential solution to meet global food demands, some researchers caution that its future growth may be hindered by several challenges, particularly the limited availability of high-quality water resources [7]. In this context, it is crucial to implement advanced monitoring strategies capable of detecting pollutants at very low concentrations. Biomonitoring approaches using living organisms have shown great promise for continuous environmental surveillance [8]. Additionally, emerging single-molecule detection tools offer ultrasensitive alternatives for identifying trace levels of toxic compounds, enabling more proactive and precise management of aquaculture systems [9]. Nevertheless, there is still a lack of comprehensive scientific research on the environmental implications of aquaculture practices. Key areas of concern include waste management, the use of growth-enhancing substances such as antibiotics and hormones, their impact on ecosystems, and the effectiveness of wastewater treatment techniques within the industry [7]. Aquaculture effluents are increasingly recognized as a significant source of pollution, releasing suspended solids, dissolved organic matter, nitrogen, phosphorus, and other harmful compounds into water bodies, which can pose serious environmental risks [10]. Among existing technologies, recirculating aquaculture systems (RASs) have become increasingly popular in modern aquaculture as they offer a more sustainable solution by continuously treating and reusing water through several purification stages. This process significantly reduces the need for fresh water inputs and minimizes pollutant concentrations in the effluents discharged. As the industry expands, regulatory requirements for effluent treatment are expected to become more stringent. For example, to produce 1000 tons of fish annually, approximately 3 tons of feed are required daily. Assuming a feed conversion ratio of 1.1 and a feed loss of 1%, the system could discharge roughly 35 kg of total phosphorus and 877 kg of total chemical oxygen demand (COD) each day [11]. Given the production of effluent with high pollutant charges and serious environmental risks [10], it is necessary to treat this water efficiently so it can be recycled into the system. Effluent streams in RASs typically fall into two categories: one with high suspended solids, originating from drum filter and biofiliter backwash, and another with lower solids content, resulting from water exchange overflow.