Study on Startup Strategies for Seawater MBBR Biofilters: Effects on Nitrite Accumulation and Nitrification Performance

This dataset is derived from the study on the start-up strategy of seawater moving bed biofilm reactor (MBBR) biofilter, aiming to compare the effects of different substrate feeding methods on nitrogen conversion, nitrite accumulation, mature biofilm nitrification performance, and microbial community structure during the start-up process of seawater circulating aquaculture system (RAS) biofilter. The study set up three start-up strategies, including a single ammonia nitrogen addition group (Group A), a nitrite nitrogen pre enriched ammonia nitrogen addition group (Group B), and a synchronous ammonia nitrogen and nitrite nitrogen addition group (Group C), with three parallel reactors in each group. The dataset mainly includes four parts: ① Raw monitoring data of seawater MBBR startup phase water quality, covering indicators such as NH ₄⁺ - N, NO ₂⁻ - N, NO ∝⁻ - N, and pH, used to characterize nitrogen transformation and nitrite accumulation processes under different startup strategies; ② Raw data from mature biofilm batch nitrification experiments were collected at 0, 12, 24, 36, 48, 60, and 72 hours under uniform ammonia nitrogen load conditions.

The concentration changes of NH ₄⁺ - N, NO ₂⁻ - N, and NO ∝⁻ - N were recorded to evaluate the subsequent nitrification performance and nitrite control ability of biofilm formation under different start-up strategies; ③ Alpha diversity analysis results of microbial community; ④ OTU relative abundance matrix and related microbial community composition data obtained based on high-throughput sequencing of 16S rRNA gene V3-V4 region. The experiment used MBBR reactors with an effective volume of 50 L, each reactor was filled with 30 L of artificial seawater with a salinity of 35 PSU, and the filling rate of K5 carrier was 40%.