Luxury uptake of phosphorus by microalgae in full-scale waste stabilisation ponds

摘要

Biological phosphorus removal was studied in two full-scale waste stabilisation ponds (WSP).nLuxury uptake by microalgae was confirmed to occur and in one pond the biomass containednalmost four times the phosphorus required by microalgae for normal metabolism. However, thenphosphorus content within the biomass was variable. This finding means that assumptions madenin prior publications on modelling of phosphorus removal in WSP are questionable. Whilenfluctuations in microalgal growth causes variation in many water quality parameters, this furthernvariation in luxury uptake explains the high degree of variability in phosphorus removal commonlynreported in the literature. To achieve effective biological phosphorus removal high levels of bothnluxury uptake and microalgal concentration are needed. The findings of this work show that whilenhigh levels of these parameters did occur at times in the WSP monitored, they did not occurnsimultaneously. This is explained because accumulated phosphorus is subsequently consumednduring rapid growth of biomass resulting in a high biomass concentration with a low phosphorusncontent. Previous laboratory research has allowed a number of key considerations to be proposednto optimise both luxury uptake and biomass concentration. Now that is has been shown that highnlevels of biomass concentration and luxury uptake can occur in the field it may be possible tonredesign WSP to optimise these parameters.