Abstract

The methods to improve the energy balance of a wastewater treatment plant (WWTP) by optimization of aeration process control and application of innovative nitrogen removal technologies were overviewed in the study. The control of aeration based on the ABAC (Ammonia-Based Aeration Control) system allows not only for significant savings in electricity consumption, but it can also increase the efficiency of the denitrification process. In addition to obtaining a shortened nitrification path, the use of the AVN (Ammonia vs. Nitrate/Nitrite) system can provide even more efficient nitrogen removal when controlling the process of conventional nitrificationdenitrification. It is expected that the future of the control systems in WWTPs belongs to smart process control systems cooperating with simulation models. The innovative technologies for nitrogen removal are based on the shortcut nitrogen removal pathways. Compared to the conventional nitrification-denitrification, the advantage of the deammonification (partial nitritation/anammox) process is the reduction of both electrical energy demand for aeration and the production of the sludge, as well as no need for the organic carbon source. The significance of pH, temperature, dissolved oxygen concentration, as well as the aeration patterns were emphasized and investigated in details by numerous researchers. The implementation of the innovative nitrogen removal technologies allows to separate organic and nitrogen waste streams and thus maximize energy capture. A study on the implementation of both the chemically enhanced primary treatment and the deammonification process in the sidestream treatment line revealed the potential for an increased biogas production in the anaerobic digester and reduction in the electric energy demand for aeration, while still maintaining the required total nitrogen effluent standard. The proposed upgrades can lead a WWTP from the energy deficit to the energy neutrality. A few WWTPs have already achieved almost 100% (or higher) electricity self-sufficiency using combined approaches and proved the usability of the innovative nitrogen removal technologies.

Authors (7)