[Investigation of Initiation and Shock Process of ANAMMOX Based on Color Space]

Anaerobic ammonia oxidation (ANAMMOX) is an efficient and energy-saving denitrification technology, but it still lacks a simple and easy method to characterize its start-up process and stable state. Based on the analysis of water quality, color space was used to monitor the color change of sludge during the start-up of ANAMMOX, and the species and quantity of microbial flora were analyzed by high-throughput sequencing technology. The results were as follows. ① According to water quality characteristics, the whole start-up process can be divided into activity lag phase, activity enhancement period, load increase period, and stable operation period. At the same time, HSV and CIELAB color space indicators decreased first, then increased, and finally remained stable. The change of sludge color was consistent with the change of water quality and the change of dominant bacteria based on the molecular biology testing, which implies correlations among these three. Therefore, color space can be used to characterize the start-up process of ANAMMOX. ② When subjected to shocks caused by high load, H, S, a^*, b^*, C_ab^*, and TIN volume removal rate all decreased, while H_ab suddenly increased. The impact characteristic of the system was accurately expressed by all of the color indicators. This paper proposes a color space-based method for characterizing all phases of the start-up of ANAMMOX and a shock process index system that provides a theoretical basis for applying color space in ANAMMOX systems.