A low-cost method for purification of agricultural wastewater based on S. platensis

The contamination of water bodies by untreated agricultural wastewater is a major global issue. Traditional centralized treatment methods, including sedimentation tanks and photocatalytic degradation modules, which are commonly employed in economically developed areas such as Shanghai, present significant challenges for implementation in remote regions due to cost and technological limitations. Consequently, there is a pressing need for cost-effective alternatives in these less accessible areas. In this study, we hypothesized that Spirulina platensis, a species of cyanobacterial microalgae, has the potential to thrive in and purify agricultural wastewater, as has been previously reported for other cyanobacterial microalgae. Firstly, we conducted a comparative analysis of S. platensis growth in simulated agricultural wastewater (SAW) and a standard medium, Zarrouk’s medium, to assess its adaptability to the growth conditions of SAW. Subsequently, utilizing total nitrogen, total phosphorus, and chemical oxygen demand as indicators for the purification of agricultural wastewater, we examined the efficacy of S. platensis in treating SAW. Our findings indicate that S. platensis is capable of reducing the concentration of each pollutant. However, the S. platensis–based treatment methods may be constrained by the potential toxicity of SAW with elevated nitrogen levels, necessitating additional research and development. This research offers a novel approach to cost-effective agricultural wastewater purification.