pH-Based Control Strategies for the Nitrification of High-Ammonium Wastewaters

Abstract

Aquatic nitrogen pollution is one of the most urgent environmental issues requiring prevention and mitigation. Large quantities of high-ammonium wastewaters are generated by several industrial sectors, such as fertilizer and anaerobic-digestion plants. Nitrification of these wastewaters is commonly carried out, either to remove nitrogen or produce liquid fertilizers. Standard control methodologies for the efficient nitrification of high-ammonium wastewaters to produce liquid fertilizers have not yet been established and are still within their early stages of development. In this paper, novel pH-based control algorithms are presented that maintain operation at the microbial maximum reaction rate (υmax) in batch and continuous reactors. Complete conversion of ammonium to nitrate was achieved in a batch setup, and a conversion of 93% (±1%) was achieved in a continuously-stirred-tank-reactor. The unparalleled performance and affordability of the control schemes proposed offer a steppingstone to the future of sustainable fertilizer production.

Dynamic Modelling, Process Control, and Monitoring of Selected Biological and Advanced Oxidation Processes for Wastewater Treatment: A Review of Recent Developments

“…The results of that study have encouraged industries to implement SBRs for treating high-ammonia wastewater. Furthermore, in controlling the nitrification process in a lab-scale bioreactor, van Rooyen et al [137] kept the biological reaction rate at its maximum amount by monitoring and controlling the pH of the process. The pH-based control system was used because of the importance of pH in nitrification.…”