Selecting the most suitable microalgae species to treat the effluent from an anaerobic membrane bioreactor

Abstract

Conventional treatments for nutrient removal in wastewater are shifting to Anaerobic Membrane Bioreactors, which produce a high-quality effluent with minimum sludge production. The effluent resulting contains high nitrogen and phosphorus load that can be eliminated by microalgae culture. The aim of this study is to evaluate the ammonium and phosphorus removal rate of different microalgae species in the effluent of an anaerobic treatment. For that, 4 different microalgae species have been tested (Chlamydomonas reinhardtii, Scenedesmus obliquus, Chlorella vulgaris and Monoraphidium braunii) in batch monoculture and mixed conditions. Results indicate that all species are able to eliminate both P and N in the medium with high removal rates. However, a slight interspecies competition may boost these removal rates and productivity values ensuring, the success of the process.

Continuous 3-year outdoor operation of a flat-panel membrane photobioreactor to treat effluent from an anaerobic membrane bioreactor

“…When the system is nutrient-limited, 24 N t , NH 4 and P can also have a significant effect in MPBR performance. In this respect, other authors have reported microalgae limitation when ammonium and phosphorus are under 10 and 1 mg•L -1 , respectively(Pachés et al, 2018). Since these effluent variables are also related to microalgae nutrient uptake, it is therefore reasonable to expect that P, NH 4 and N t presented a relatively high inverse correlation with microalgae performance(Figure 6a).…”

Effect of ambient temperature variations on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella

“…However, at this time, the non-nitrification-inhibited PBR had nitrogen concentrations under 10 mg N•L -1 (Figure 4a). It has previously been reported that microalgae activity is significantly reduced at nitrogen concentrations below 10 mg N•L -1 (Pachés et al, 2018). Under these conditions, the microalgae growth rate in the non-nitrification-inhibited PBR was therefore reduced because of limiting nitrogen, and AOB activity was favoured when the ammonium load increased after day 65, reaching negligible AOB activity was seen below 32 ºC.…”

Effect of light intensity, light duration and photoperiods in the performance of an outdoor photobioreactor for urban wastewater treatment

“…It must be highlighted that factors which influence microalgae growth such as solar irradiance [24;39], temperature [54,55], nutrient loading rates [8,53] and culture mixing [17,30] were the same for PBR-A and PBR-B in each experiment, only differing in the artificial lighting regime. In addition, nutrients were maintained in replete conditions (i.e., nitrogen higher than 10 mg N•L -1 and phosphorus above negligible concentration as explained in Pachés et al [62]) during all the Experiments except for 1 and 2A (Figure 2a). Hence, microalgae were only considered to be nutrient-limited in PBR-A…”