Organic and nutrient removal in domestic wastewater from commercial building using onsite wastewater treatment of anoxic fixed bed-MBBR system with variation of resirculation ratio and intermittent aeration

• Main Author: Subroto, Michael
• Format: Theses
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/45878
• Institution: Institut Teknologi Bandung

Commercial bulding of domestic wastewater has the significant difference with the individual domestic wastewater based on amount, employee activities, and its facilities. Generally, these wastewater has nutrient content especially ammonia which is higher than household domestic wastewater. This unique characteristics need to be treated by using modified septic tank (MST) so that it can comply with the domestic wastewater quality based on Ministry of Environment Law number 68 year 2016 especially ammonia parameter with the maximum value of 10 mg/liter. The determination of optimum condition in resirculation ratio and aeration frequency is applied based on artificial wastewater with the C:N:P ratio of 83,85:28,38:1. The modified septic tank of anoxic-aerobic systems is first applied on the artificial domestic wastewater, then applied to the real domestic wastewater which come from sewage treatment plant (STP) of Telkom Indonesia Bandung city. The application of sponge media inside MBBR to the performance and also organic and nutrient degradation kinetics will be discussed in this research. In the pre-experimental stage consist of seeding and acclimatization stage has been done until it reached attached biomass of 2478,575 mg/liter in sponge media. The artificial wastewater that is used has the chemical composition of gluccose (C6H12O6) , NH4Cl, K2HPO4.6H2O, KNO3, and NaNO2 as the sources of nitrate and nitrite in nitrogen cycle. Based on the study that is conducted in this research, the optimum resirculation ratio is R1= 5/1 (26,4 liter/hour) and the oxygen aeration frequency in moving bed biofilm reactor (MBBR) is 12 hour (3,24 lbm O2/ day). This factor is generally based on the highest degradation efficiency of organic and ammonia which are 76,1% and 30,6% with decreased effectivity related to denitrification reaction beacus of nitrate (NO3-) as chemical inhibitor to ammonia oxidizing bacteria (AOB). The application of real domestic wastewater from STP Telkom as case study generally has the organic degradation efficiency of 83,1 %, ammonia of 32,5%, total nitrogen (TN) of 51,3%, nitrite 94,8%, nitrite 46%, total phosphate (TP) of 72,4%, TSS liquid 15,9%, BOD5 27,5%, and also oil grease content of 88,2% that mostly is higher compared to its artificial wastewater counterparts. Based on statistical analysis result, in the organic loading rate (OLR) of 2,007 g COD/ liter.day it has been found that aeration frequency in MBBR is significant with the organic, ammonia, and total phosphate (P< 0,05). Meanwhile, the variation of flow resirculation ratio does not have significant effect with the degradation ability of organic and nutrient (P < 0,05). The Stover-Kincannon model is the most suitable to describe the organic and ammonia degradation processes with determination coefficient of 0,862 and 0,831. The degradation kinetics of organic and ammonia in this research are 38,121 day-1 and 5,088 day-1. Grau (second order kinetics) model is the most suitable to explain the total phosphate (TP) degradation process with k2(s) value of 0,004962 day-1 and R2 value of 0,57. The sponge media used in MBBR compartment has the higher organic degradation efficiency (83%) compared to biochips media (58%) but has lesser efficiency compared to kaldness media (88%) with the lower ammonia removal efficiency compared to kaldness media with the largest specific surface area (SSA). The periodic aeration frequency treatment (intermittent aeration) with the modified septic tank systems can save the electricity energy of 0,624 kJ for one day treatment operation and also could comply well with the baseline standard of Ministry of Environment Law number 68 year 2016 especially related to the total organic concentration.