Microalgae has emerged as a promising approach for removing substrate and nutrient from wastewater with the concomitant biofuel production. The substrate and nutrient removal are influenced by several factors such as C/N ratio, F/M ratio, pH, and DO. This study aims to determine the efficiency of substrate and nutrient removal with the growth rates of microalgae and biomass by varying the addition of aeration and substrate. Intermittently aerated reactors were used with the flow rate of 14 L/minute. The batch reactors were prepared by adding glucose substrate of 50 mg/L (Ra0A), 100 mg/L (Ra0B), and 150 mg/L (Ra0C) without aeration; 50 mg/L (Ra12A), 100 mg/L (Ra12B), and 150 mg/L (Ra12C) with 12-hour aeration, and 50 mg/L (Ra24A), 100 mg/L (Ra24B), and 150 mg/L (Ra24C) with 24-hour aeration. The substrate removal, expressed as chemical oxygen demand (COD) in the reactor with aeration, showed the efficiency of 73.88% ± 2.05 (12-hour aeration), 75.2% ± 3.97 (24hours aeration), and 69.86% ± 5.69(without aeration). Nutrient removal as ammonia-N (NH3-N) gave high removal value of 98.3% ± 0.11 and the removal of nutrient as phosphate (PO3-4) showed the efficiency of 54.3% ± 0.1. The growth rate of microalgae and biomass exhibited the highest value in Ra24C reactor with the values ??of 0.0229/day and 0.1295/day, respectively. The pH values ??indicated a shift from normal to alkaline while DO values ??increased by the addition of 12 and 24-hour aeration.

Nitrogen and organic matter are part of the pollutant causing eutrophication in freshwater. Textiles industry like Endek is the main source of Nitrogen and organic matter. Tis paper aims to know the degradation process of Ammonia-Nitrogen (NH3-N) and Chemical Oxygen Demand (COD) with ozone pretreatment in operated by different DO level activated sludge. There are 2 scenarios of treatments in this study: with ozone pretreatment (R1) and without ozone pretreatment (R2). Wastewater treatment began with the seeding and acclimatization process. This acclimatization study showed the efficiency degradation of NH3-N and COD by 17.7 and 27.5 %. Biological Oxygen Demand (BOD)/COD level increased with ozone pretreatment, from 0.25 to 0.38, COD/TKN level stated at 3.26. Ozone pretreatment reduced NH3-N and COD by 23.8 and 34.1 %. Wastewater treatment with activated sludge operated by different DO levels showed efficiency of 44.2 % (R1) and 68.2 % (R2). This ammonia elimination was capable of preventing eutrophication in the waterbody. The efficiency of NH3-N and Nitrogen organic degradation was indicated by TKN (Total Kjeldahl Nitrogen) levels: 87 % (R1) and 79 % (R2). The concentration of Nitrate (NO3-N) increased from 2.9 to 5.5 mg/L when DO reached 1 - 3 mg/L. COD reduction levels in this study were 17 % (R1) and 42.5 % (R2). Ozone pretreatment could make the efficiency of wastewater treatment qualified into standard quality.

The endek industry produces low-biodegradable wastewater, which is very difficult to treat using the biological methods. For this reason, this study was aimed at improving the quality of wastewater for endek textile wastewater using the combination of ozone oxidation process as pretreatment and anoxic-aerobic activated sludge. The ozone reactor volume amounted to 3L and the applied ozone dose equaled 0.05 mg/minute. The BOD/COD of endek wastewater increased to 0.38 after ozone treatment and the application of anoxic-aerobic activated sludge treatment. The anoxic-aerobic experiments were conducted in batch process and consisted of activated sludge. Conventional anoxic-aerobic treatment can reach color and COD removal of 30% and 32%, respectively, without pre-treatment. The ozone pretreatment can increase color and COD removal up to 76.6% and 86.9%, respectively. On the basis of the effluent standards of textile wastewater quality, COD, BOD 5 , and total ammonia (NH 3-N) parameters have met the quality standards.

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Aim:The purpose of this study was to determine the efficiency and characteristics of pig wastewater treatment. This was to be achieved using ABR with the addition of effective microorganism4 (EM4) as a bio-activator during the startup process (R1) and without EM4 (R2). Methodology and Results: Piggery wastewater is poured into ABR with 12 hours HRT (hydraulic retention time), though it is reduced to 6 hours after the concentration is stable. The COD removal efficiency at 12 hours HRT was 60% (R1) and 51% (R2). However, the results did not change significantly, since the 6 hours HRT COD efficiency was 57.8% (R1) and 51.3% (R2). The biomass growth rate at R1 is faster than R2 with Food to Microorganism Ratio (F/M) 0.4-0.89 (R1) and 0.68-1.38 (R2) while the yield of methane gas formation was 0.25-0.28 L-CH4/g-COD. Conclusion, significance, and impact study: COD effluent is the total organic material present in the piggery wastewater effluent, which is discharged into water bodies without meeting the set quality standards. This damages the quality of water bodies. The wastewater treatment needs to be prioritized to meet quality standards of COD effluent. Also, the addition of EM4 to the activated sludge reactor improves the COD removal efficiency and biomass growth, though advanced treatment is still needed for piggery wastewater.