Simulation of organic matter and nitrogen removal performance in the treatment of low-strength domestic wastewater using the modified Ludzack-Ettinger process with the ASM1 model

In this paper, a system with low-strength domestic wastewater characteristics was modeled. The system, which was structured according to the continuous flow Modified Ludzack-Ettinger (MLE) process, was simulated using LYNX software based on ASM1 (Activated Sludge Model No. 1). During the modeling process, soluble and particulate biodegradable organic matter (Ss, Xs), nitrogen components (SNH, SND, SNO, XND), inert substances (SI, XI), microbial biomass (XBH, XBA, XP), alkalinity, and COD changes were monitored and evaluated over a 24-hour operating period. According to the results obtained, the system was able to remove 96% of soluble COD and 99.9% of particulate COD. NH₄⁺-N removal was quite high (>95%), but total nitrogen removal remained limited. The results demonstrated that the ASM1 model is an effective tool for simulating biological process behavior and that the MLE process has high potential for organic matter and nitrogen removal in the treatment of low-strength wastewater.