A study on the carbon footprint contributions from a large wastewater treatment plant

Carbon Emission Prediction and Emission Reduction Analysis of Wastewater Treatment Plant Based on Machine Learning and Deep Learning

“…The chemicals are mainly flocculants, coagulants, phosphorus removers, disinfectants and so on. The specific calculation formula is as follows: −20 Where: 𝑚 𝐶𝑂 2 is the fossil source emissions from wastewater treatment, in terms of emission equivalents produced by treating each cubic meter of wastewater,𝑘𝑔𝐶𝑂 2 / 𝑚 3 ; ; Q is the daily volume of water treated in the wastewater treatment plant,m 3 ; 𝑀𝐹𝐶𝐹 is the proportion of fossil sources discharged; SRT is the mean biosolids retention time, d; 1.947 is the yield of microorganisms corresponding to the consumption of synthetic cellular material per 1 kg of endogenous respiration, 𝑘𝑔𝐶𝑂 2 /𝑘𝑔 [22]; and HRT is the hydraulic retention time of the bioreactor, d; MLVSS is the mean mass concentration of volatile suspended solids in the mixed liquor of the bioreactor, mg/L;4.49 is the mass fixed per unit mass of ammonia nitrogen nitrification, 𝑘𝑔𝐶𝑂 2 /𝑘𝑔 ; 𝑇𝑁 𝑖𝑛 is the mass concentration of total nitrogen in the influent of the wastewater treatment plant, mg/L，𝑇𝑁 𝑒𝑓𝑓 is the mass concentration of total nitrogen in the effluent of the wastewater treatment plant, mg/L，0.124 is the mass ratio of the microorganisms (C5H7O2N) body with N mass ratio; FCF is the proportion of fossil source organic matter in the influent water of the sewage treatment plant, taking the value of 10% [23];1.1 is the yield of microbial degradation of organic matter; 𝐵 𝑖𝑛 is the mass concentration of BOD in the influent water of the wastewater treatment plant, mg/l; 𝐵 𝑒𝑥 is the additional carbon source artificially added during the operation, mg/l; 𝐵 𝑒𝑓𝑓 is the effluent BOD of the sewage treatment plant, mg/l;1.47is the ratio of total BOD to BOD5 of the influent water of the sewage treatment plant; 1.42 is the BOD5 equivalence of the microbial cells, 𝑘𝑔𝐶𝑂 2 /𝑘𝑔; 0.67is the absolute yield coefficient, 𝑘𝑔𝐶𝑂 2 /𝑘𝑔; 𝐾 𝑑 is the decay coefficient, d; 0.05 is the reaction rate constant,d -1 ;1.047 is the temperature coefficient.…”

Life Cycle Assessment Methodology Applied to a Wastewater Treatment Plant

“…where N Eff is the nitrogen output load, EF Eff is the N 2 O emission factor for outlet flow, and the factor (44/28) is a conversion from kg of N 2 O-N to kg of N 2 O. The nitrogen output load is calculated as follows [41], whose terms are defined in Table 5: Once the amount of N 2 O produced has been calculated and transformed in g/d, it is then converted to CO 2 via the equivalence factor (Ecoinvent CML, 2001).…”

Carbon Footprint and Energy Recovery Potential of Primary Wastewater Treatment in Decentralized Areas: A Critical Review on Septic and Imhoff Tanks

“…In conventional anaerobic digesters, torches are normally installed to burn the produced biogas, thereby avoiding the direct venting of methane and recovering energy to partly heat up the digestion reactors and obtaining stabilized sludge [102,103]. Nevertheless, in the case of Imhoff tanks, it is important to consider that the produced methane is not always used for energy production, and when it is exploited, the carbon footprint is reduced but not zeroed since the burning process simply converts methane into carbon dioxide, as expressed in Equation (1).…”