Pilot-scale struvite recovery from anaerobic digester supernatant at an enhanced biological phosphorus removal wastewater treatment plant

摘要

Pilot testing of a fluidized bed reactor used to recover phosphate, in the form of struvite, from anaerobic digester supernatant was conducted at the Advanced Wastewater Treatment Plant, City of Penticton, British Columbia. The main objective of this study was to demonstrate the ability of the reactor to remove at least 70% of the phosphate in the supernatant from a digester fed with a combination of primary and secondary sludge. It was found that the operation of the reactor could be controlled to achieve any desired level of phosphorus removal up to 90%. Analysis of the recovered struvite crystals showed essentially pure struvite (>99% by weight) with small amounts of calcium (99 % poids) avec de petites quantités de calcium (<0,5 % poids) et des traces de potassium et de fer. Les cristaux récupérés avaient des diamètres moyens augmentant de 0,5 à 1,8 mm durant l'étude. Cette augmentation de diamètre est probablement causée par des changements dans la structure cristalline, solidifiant les cristaux au fur et à mesure de la progression de l'étude.Mots clés : cristallisation, retrait des nutriments, récupération du phosphore, struvite, traitement des boues, eaux usées.[Traduit par la rédaction]