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Abstract. Increasing textile industries in Indonesia resulted in increasing the utilization of dyes. The use of synthetic dyes are still dominating because they have many advantages. But, synthetic dyes are difficult to decompose in nature so they can cause potential pollution if discharged directly into the environment. In this study, Procion Red was used as a model of synthetic dye wastewater. The objective of this research is to study the effect of TiO2 catalyst concentration and irradiation time on the degradation of Procion Red under solar irradiation. Photo degradation takes place by using TiO2 catalyst powder in the various concentration of Procion Red of 150-300 ppm. The various concentrations of TiO2 catalyst of 0.5-8 g/l were used. The color and COD degradation of Procion Red for 12 hours of solar irradiation were investigated. Color degradation was measured by using a spectrophotometer. While COD degradation was measured by using Ferrous Ammonium Sulfate (FAS) analysis method. The result showed when using Procion Red of 150 ppm, the highest color degradation of 100% was achieved by using TiO2 catalyst of 6 g/l and the highest COD degradation of 62% was obtained by using TiO2 catalyst of 8 g/l, under 12 hours of solar irradiation

The development of textile factories has had a significant impact on the environment because dye wastewater is difficult to degrade. The handling of textile wastewater usually involves the adsorption method, in which pollutants only transfer to another phase. As an alternative solution, a photodegradation method was developed using photocatalyst material assisted by ultraviolet irradiation. In this photodegradation method, dye substances are broken down into components that are simpler and safer for the environment. The possibility of using sunlight as a radiation source makes this a particularly promising method for countries such as Indonesia. Procion red, one of the most commonly utilized synthetic dyes in the home textile or Batik industry, was used as a model pollutant in this study. The objectives of the present research were to synthesize and characterize a nano-photocatalyst of ZnO-natural zeolite with the capacity to degrade Procion red. This nano-photocatalyst was synthesized using the sol-gel method, by which Zn(CH3COO)2 2H2O was used as a precursor and combined with natural zeolite to increase its photocatalytic ability. The nano-photocatalyst was characterized using X-ray diffraction (XRD), scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDX), and Brunauer-Emmett-Teller (BET). The activity of nano-photocatalyst ZnO-natural zeolite was compared to ZnO alone and natural zeolite alone in terms of its ability to degrade Procion red. An average photocatalyst crystallite diameter of 82 nm was achieved, proving that a nano-sized photocatalyst of ZnO-natural zeolite was successfully synthesized. BET characterization showed that nanophotocatalyst ZnO-natural zeolite had a specific surface area of 14.84 m 2 /g, a pore size of 32.71 nm, and a pore volume of 0.12 cm 2 /g. A peak Procion red degradation percentage of 96.23% was obtained using nano-photocatalyst ZnO-natural zeolite after 120 minutes of irradiation under sunlight applied to a Procion red concentration of 50 ppm.

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Abstract. In this research, an algae cultivation strategy was studied. Integrating algae cultivation with wastewater treatment is currently seen as one of the most economical ways of producing algae biomass. A combination of an anaerobic baffled reactor (ABR) and a constructed wetland (CW) was applied for treating domestic wastewater with an additional collection tank for improving effluent quality. The effluent produced from the three stages was used as algae cultivation media and suplemented with 10% bold basal medium (BBM). The results showed both micro-and macro-algae growth and their lipid contents were higher when they were grown in effluent-BBM (9:1 v/v) media. The lipid content of the micro-algae mixed culture was 16.5% while for macro-algae Oedogonium sp and Cladophora sp it was 6.90% and 6.75% respectively.

Rice husks contain cellulose as a raw material for manufacturing second-generation bioethanol. Cellulose from pre-treated rice husks was converted into reducing sugars through enzymatic hydrolysis using enzymes derived from Aspergillus niger. This study aims to determine the kinetics of enzymatic hydrolysis at enzyme concentrations of 10, 15, and 20% (v/w) and hydrolysis times of 5, 10, 15, 20, and 25 h. The results showed that cellulose was hydrolyzed to form reducing sugars. The CMCase activity and FPase activity reached 548.940 and 314.892 U mL−1, respectively, much higher than most previous reports on this genus. From the calculation of the reaction rate using the Michaelis–Menten kinetic model, the value of the Michaelis constant ranges from 0.001 to 0.0007, and the maximum rate is 1.3 × 10−7 to 2.7 × 10−7 Mol L−1 s−1. The highest reducing sugar concentration was obtained (1.80 g L−1) at an enzyme concentration of 20% (v/w) and a hydrolysis time of 25 h.