Nitrite inhibition of microalgae induced by the competition between microalgae and nitrifying bacteria.

摘要: Abstract Outdoor microalgae cultivation systems treating anaerobic membrane bioreactor (AnMBR) effluents usually present ammonium oxidising bacteria (AOB) competition with for uptake, which can cause nitrite accumulation. In literature, effects over have shown controversial results. The study evaluates the inhibition role in a microalgae-nitrifying culture. For this purpose, pilot- and lab-scale assays were carried out. During continuous outdoor operation of photobioreactor (MPBR) plant, biomass retention time (BRT) 2 d favoured AOB activity, caused This was confirmed to inhibit performance. Specifically, 5-d showed reduction nitrogen recovery efficiency by 32, 42 80% when concentration culture accounted 5, 10 20 mg N·L−1, respectively. On contrary, short 30-min exposure no significant differences photosynthetic activity under concentrations 0, 20 mg N·L−1. other hand, MPBR plant operated at 2.5-d BRT, reduced negligible values due increasing (NOB). allowed obtaining maximum performance; i.e. rate (NRR) productivity 19.7 ± 3.3 mg N·L−1·d−1 139 ± 35 mg VSS·L−1·d−1, respectively; while nitrification (NOxR) reached lowest value (13.5 ± 3.4 mg N·L−1·d−1). Long BRT 4.5 d NOB growth, avoiding inhibition. However, it implied decrease growth accumulation nitrate effluent. Hence, seems that optimum has be within range 2–4.5 d order favour respect NOB.