Analysis of Different Methods for Reclamation of Nitrogen and Phosphorus from Sewage Lagoons

Abstract

The need for better nutrient management has spurred efforts towards more comprehensive recycling of nutrients contained in sewage lagoons to agriculture. Research in this direction has intensified throughout the past years, continuously unfolding new knowledge and
technologies. The present review aspires to provide a systematic synthesis of the field by providing an accessible overview of terminology, recovery pathways and treatment options, and products rendered by treatment. Our synthesis suggests that, rather than focusing on a specific recovery pathway or product and on a limited set of nutrients, there is scope for exploring how to maximize nutrient recovery by combining individual pathways and products and including a broader range of nutrients. The research aimed at reclaiming two useful plant nutrients from sewage sludge, which were nitrogen and phosphorus. Nitrogen was reclaimed from sewage sludge through the Kjeldahl method and phosphorus through chemical precipitation and digestion methods. The two were then analyzed for trace metals using X-ray fluorescence spectroscopy (XRF) and their functional groups using Fourier transform infrared spectroscopy (FTIR). The results found the nitrogen sample to contain 57.91% of ammonia which was greater compared to the phosphorus sample which contained 27.44% of phosphoric acid. All the samples were found to contain a lot of impurities as they
had high concentration content of up to more than 80% of compounds such as sulfur trioxide and magnesium oxide. In conclusion, reclamation of both nitrogen and phosphorous from sewage sludge was no pure as expected due to presence of impurities.