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.

The alumina nanoparticles (NPs) have been synthesized from reaction between alum with ammonia and then calcined the precipitate at 1200 °C for 4 h. Its surface was modified by oleic acid (OA) and trimethoxyvinylsilane (TMVS) in o-xylene at 50 °C. The alumina NPs and its modified were characterized by XRD, FT-IR, SEM, EDX and TGA. The TGA analysis indicated that the grafting amount of OA and TMVS were 10.5 and 8.0% respectively. The dispersion of modified NPs was determined in monomers such as methyl methacrylate (MMA), butyl acrylate (BuA) and styrene (St) and in solvents such as ethanol, hexane and acetone. The experimental results showed that the highest dispersion was happened NPs modified by oleic acid in n-hexane, while the highest dispersion was observed NPs modified by TMVS in acetone. The results indicate that NPs modified by oleic acid formed a stable dispersion in MMA and BuA. The highest amount of dispersion happened NPs modified by oleic acid in MMA and BuA in initial weight of 5 and 2.5% respectively, while stable dispersion is formed in styrene when TMVS is used as modifier. The highest amount of dispersion was happened NPs modified by TMVS in styrene in initial weight of 2.5%.

Biosurfactants are amphiphilic compound, having hydrophilic and hydrophobic moieties enabling them to reduce surface and interfacial tension at the surface. Their unique properties are applied in various industries such as foaming and wetting agents, emulsifiers, detergents and bioremediation. A total of 98 isolates showed biosurfactant activity using hemolytic activity, drop collapse test and oil spreading assay. All isolates were rod-shaped, Gram positive and majority of them were non-endospore former. Only the isolates showing the highest percentage of emulsification index (E24) and ability to reduce tension were used for species identification using 16S rDNA gene sequencing which were isolates A1(6) and A2(1). Both isolates were identified as Bacillus sp. cp-h50 and Bacillus sp. XT-24 respectively, rod-shaped, endospore former and Gram positive. The biosurfactant produced by both species showed high emulsification index (E24) (A1(6), 63.3% and A2(1), 46.7%) and good surfactant capacity. The size of amplified gene of 16S rDNA gene was approximately 1.5 kb. These features provide evidence that both species could be a potential biosurfactant producer with proper optimization for the production of biosurfactant. The biosurfactant produced by both bacterial species were identified as surfactin using Fourier Transform Infrared Spectroscopy (FTIR).

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