Effect of alginate structure and microalgae immobilization method on orthophosphate removal from wastewater

Abstract

Microalgae play an important role during the tertiary treatment of municipal wastewater. Cell immobilization techniques have been developed in order to improve the quality of the treated wastewater and avoid wash out of the biomass. Since cell immobilization method may affect the nutrient removal efficiency, ten strains of microalgae were immobilized in sodium alginate gel in differentdiameter circular screens, and orthophosphate removal efficiency from municipal wastewater was studied. Results indicate that the alginate immobilization screen size and contact surface with wastewater affects the microalgae synthesis activity and thus orthophosphate removal efficiency. Increasing the contact surface by making smaller alginate screens will increase the cation exchange rate and reduce the orthophosphate concentration in the medium. Among all microalgae treatments, Scenedesmus rubescens MCCS 018, Chlamydomonas sp. MCCS 026, and Chroococcus dispersus MCCS 006 had the highest PO 4 3--P removal efficiency of 68.8%, 71.9%, and 72.3% within 12 days.

Removal of nitrogen and phosphorus from wastewater using microalgae free cells in bath culture system

“…The supernatant was transferred to BG-11 solid culture medium [5], and Petri dishes were stored in a culture room under constant illumination (4150 lux) with white fluorescent lamps at 25±2°C. After colonization, the isolation and purification were performed using plate agar method to obtain unialgal cultures [5]. The microalgal cells were grown at room temperature in liquid BG-11 medium with shaking at 130 rpm.…”

“…Using microalgae in wastewater treatment has been studied widely and indicated to have positive effect in nutrient removal [5]. Microalgae are widespread in different locations such as soil, air and fresh water [6].…”

“…Microalgae are widespread in different locations such as soil, air and fresh water [6]. The technology of using microalgae in wastewater treatment is based on natural ecosystems; therefore there is no danger for environment and even if the biomass produced is reused, causes no secondary pollution [5]. Nitrogen (N) and phosphorus (P) removal by microalgae in batch cultures of wastewater can be done using immobilized and free-cells techniques.…”

“…Nitrogen (N) and phosphorus (P) removal by microalgae in batch cultures of wastewater can be done using immobilized and free-cells techniques. In case the latter technique is used, harvesting free cells in effluent is necessary to improve the quality of the treated wastewater and avoid wash out of the biomass which potentially can be used in food and pharmacy industries and/or as biogas [5].…”

Nutrient Removal Efficiencies of <i>Chlorella vulgaris</i> from Urban Wastewater for Reduced Eutrophication

“…In addition to biomass and lipid productivities, microalgae are reported to have potential environmental benefits through removing nutrients from waste water [7] [8] [9] [10]. Integrating nutrient removal from wastewater with microalgae cultivation is one effective method to reduce the cost of large scale biofuel production [11] [12] and it would not cause secondary pollution [13].…”