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Uptake of phosphorus from dairy wastewater by heterotrophic cultures of cyanobacteria, Desalination and Water Treatment, 40:1-3, 224-230, A B S T R AC TThe dynamic removal of different forms of dissolved and suspended phosphorus (reactive phosphorus, acid-hydrolyzable phosphorus, organic phosphorus and total phosphorus) by the cyanobacteria Aphanothece microscopica Nägeli cultivated heterotrophically in dairy processing wastewater was investigated. Bioreactor performance was highly dependent on operation temperature (10-30°C). Aphanothece microscopica Nägeli was able to uptake not only simple phosphorus species (reactive and acid-hydrolyzable phosphorus), but also complex fractions of organically bound phosphorus. Low bioreactor performance was evidenced by the suspended fractions. The conversion of suspended reactive phosphorus and suspended acid-hydrolyzable phosphorus varied between 50.3% and 93.3%. Suspended organic phosphorus and suspended total phosphorus became erratic, with peaks of phosphorus appearing after 8 h of hydraulic detention time and slightly impacting the global phosphorus balance. In addition to phosphorus removal, a good degree of organic matter and total nitrogen (N-TKN) removal occurred simultaneously. The resulting conversions varied from 64.6% to 96.9% and from 47.2% to 72.8% for chemical oxygen demand and N-TKN, respectively. Rapid biomass growth was verifi ed and the resulting biomass production rates were 0.81-3.85 g l −1 d −1 . These results indicate that heterotrophic bioreactors with cyanobacteria have a good potential for phosphorus removal from wastewater.

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RESUMOAs elevadas concentrações de fósforo em águas residuárias industriais é uma das principais causas da eutrofização de corpos hídricos receptores, havendo em virtude disto, uma crescente preocupação com o gerenciamento das cargas de fósforo dos efluentes industriais. Além dos aspectos de contenção ambiental, é estrategicamente desejável que os processos de tratamento permitam a recuperação e o reúso deste elemento que é considerado de elevada demanda biológica. Neste sentido, esta revisão objetiva descrever e analisar criticamente o estado atual das tecnologias de gerenciamento de fósforo em águas residuais industriais, com ênfase no reúso do elemento. As tecnologias consideradas incluem abordagens químicas (precipitação química e adsorção), biológicas (sistemas bacterianos, uso macroalgas e microalgas) além de técnicas de fertirrigação.Palavras-chave: espécies fosforadas, eutrofização, tecnologias de tratamento, reuso. Phosphorus removal technology: Management of the element in industrial waste ABSTRACTHigh phosphorus concentrations in industrial wastewaters is one of the main causes of the eutrophication of water bodies, leading to a growing concern with the management of phosphorus loads from industrial wastewaters. In addition to the environmental aspects of containment, it is strategically desirable that the treatment processes enable the recovery and reuse of this element, which is considered to be of high biological demand. For these reasons, this review describes and critically analyzes the current state of phosphorus management technologies for industrial wastewaters, with emphasis on the reuse of the element. The

RESUMONeste trabalho, a eficiência da cianobactéria Aphanothece microscopica Nägeli em remover heterotroficamente fosfato total dissolvido do efluente do processamento de laticínios foi avaliada. Os experimentos foram conduzidos em biorreatores operados descontinuamente, alimentados com 4,5 L de efluente. As condições experimentais foram: concentração celular inicial de 0,2 g/L, pH ajustado a 7,6, reator isotérmico operando em temperaturas de 10, 20 e 30ºC, ausência de luminosidade e aeração contínua de 1 VVM. Os resultados mostraram que a remoção de fosfato é fortemente dependente da temperatura do processo. A cianobactéria A. microscopica Nägeli foi efetiva na remoção de fosfato, alcançando taxas de remoção de 3,77 mg/L.h, que refletiram em conversões de 98,4% em tempos de detenção hidráulica de 24 h.Palavras-chave: microalgas, biorreator heterotrófico, fosfato, efluente de laticínios. Influence of temperature in phosphate removal by microalgae in heterotrophic bioreactors ABSTRACTThe removal of total dissolved phosphate by the cyanobacteria Aphanothece microscopica Nägeli cultivated heterotrophically in dairy processing wastewater was investigated in this work. The experiments were carried out in bioreactors operating in a batch mode, fed with 4.5 L of wastewater. The experimental conditions were as follows: initial cell concentration of 0.2 g/L, pH adjusted to 7.6, isothermal reactor operating at temperatures of 10, 20 and 30ºC with absence of light and continuous aeration of 1 VVM. The results showed that phosphate removal is strongly dependent on process temperature. A. microscopica Nägeli was effective in the removal phosphate achieving removal rates of 3.77 mg/L.h, which reflected in the conversion of 98.4% in hydraulic detention times of 24 h.