Self-regulation strategy of influent dissolved oxygen in ANAMMOX unit of domestic wastewater onsite source-separation and synergistic treatment process

An onsite source-separation and synergistic treatment (O3ST) process has been proposed in a previous study. In the study, it was found that toilet wastewater is characterized by spontaneously realizing and stably maintaining a partial nitritation (PN) without dissolved oxygen (DO) control. On this basis, to realize the goal of practical application of ANAMMOX technology following the PN in the O3ST process, this paper carries out the key research on the self-regulation strategy of DO in the effluent of PN unit to reduce the influent DO of ANAMMOX unit. By adding a buffer unit between the PN and ANAMMOX unit with an effective volume of 50.0 % of the PN unit, an interconnecting area of 0.9 % of the coplanar area of the PN and buffer unit, an overflow length of 35.7 % of the width of the PN unit, the automatic control to reduce the amount of DO diffusion and residual in the buffer unit was realized, and the DO concentration of the influent from the buffer to ANAMMOX unit was guaranteed to be less than 1.00 mg/L. Successful application of ANAMMOX technology can increase the TN removal efficiency of the process from a bottleneck value of 66.0 % to 84.0 %, with 44.0 % of the TN removal occurring in the ANAMMOX unit. This study is expected to apply the ANAMMOX technology in a low-maintenance or even no-maintenance form in the O3ST process, which is both an expansion of the application scope of the ANAMMOX technology and a breakthrough in decentralized wastewater treatment technology.