NH3-N and COD Reduction in Endek (Balinese Textile) Wastewater by Activated Sludge under Different DO Condition with Ozone Pretreatment

Abstract

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.