The proliferation of Harmful Algal Blooms (HABs) in freshwater systems has emerged as a pressing environmental concern in recent years. Lake Tegel in Berlin, Germany, serves as a notable case study. This research elucidates the multifaceted drivers behind HABs, including the exacerbating roles of anthropogenic climate change, wastewater intrusion, and eutrophication. Of particular concern are potent toxins like anatoxin-a, which have been linked to neurotoxicity and faunal mortalities. This study proposes adopting a circular economy paradigm to tackle Harmful Algal Blooms (HABs) challenges. By leveraging biotechnological advancements, the research suggests detoxifying affected aquatic systems and converting these toxins into commercially viable byproducts, such as biofertilizers. This investigation underscores the imperative of a holistic understanding of HAB etiology, the potential efficacy of microalgal bioremediation, and the broader socio-economic implications of integrating circular economy principles into environmental remediation strategies.