Abstract
Surface water eutrophication is one of the major ecological problems that the world faces today. The need for clean water for domestic utilization is growing faster than the world population. However, the amount of clean water sources available is shrinking, and the need to reclaim previous clean sources that human activities have fouled is increasing daily. Many of these reclamation projects involve the elimination or the treatment of a contaminant from a specific point source. The overarching goal of this study is to find or develop an economical and sustainable method for removing either nitrogen or phosphorus or both from the effluent waters of aquaculture facilities, principally phosphorous, as it has been identified as the major contributor to the eutrophication process in the downstream waters of the Snake River. Such method or process must be capable of being adjusted to fit the effluent conditions for a specific facility, including major differences in the volume of discharge between facilities, available space for construction, simplicity of design and operation, secondary product recovery and reuse, environmentally friendly and sustainable. The research objectives are to produce engineered biochars (i.e., non-modified and modified) and develop pathways to remove nitrogen and phosphorus, or both from the effluent waters of aquaculture facilities. The results indicate that the proposed approach can improve downstream fish farm waters by adsorbing micronutrients (e.g., nitrogen-ammonia, nitrate-n + nitrite-n, and total phosphorus). Water treatment time and biochar pH are the key parameters that had relatively strong associations with adsorbed compounds. Overall, the results appear more promising as a solution to reduce micronutrients from fish farm effluent. Longer residence times should be applied to identify the optimal treatment time for the adsorption of phosphorus and nitrogen compounds.