## 1 Introduction  
Wastewater treatment, management, and reuse are promising solutions to the water crisis, especially in semi-arid countries such as South Africa [1]. To protect the environment, it is necessary to treat wastewater before discharging it into freshwater sources [2]. Various methods, such as physical, mechanical, chemical, and biological, can be used depending on the wastewater type and the constituents to be removed [3]. Poultry slaughterhouse wastewater (PSW) is toxic and decreases dissolved oxygen concentrations, leading to eutrophication if discharged untreated into the environment [4]. It contains high chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN), total phosphorous (TP), pathogenic microorganisms, blood, fecal matter, soluble proteins, fats, oil, and grease (FOG), including total suspended solids (TSS). These characteristics make PSWamenable to biological treatment [5]. Overall, biological treatment systems are considered environmentally friendly and are thus preferred over other treatment technologies. Amongst biological wastewater treatment systems are aerobic, anaerobic, and wetland systems. These systems use biological cells to remediate pollutants from wastewater [6]. The anaerobic systems require the use of simple systems, require less energy, have high BOD removal efficiency, and produce biogas; however, high-strength wastewater (which contains a high concentration of FOG, proteins, TSS, and COD) reduces its treatment efficiency and those of other systems; moreover, it requires an aerobic post-treatment system to enhance microbial community contact time to improve COD and BOD removal by >90%, as well as to remove residual TP, TN, and pathogenic microorganisms [7; 8; 9]. Additionally, high concentrations of TP and TN are detrimental to the aquatic ecological system as they result in algal blooms that result in oxygen depletion in the water, which leads to a loss of aquatic life [10]. To decrease the concentration of TN, ammonia oxidizing microorganisms play a huge role. Aerobic ammonia oxidizing microorganisms (AOMs) such as ammonia-oxidizing bacteria (AOB) as well as ammonia-oxidizing archaea (AOA) and complete ammonia oxidizers (Commamox) oxidize NH\({}_{4}\) (ammonium) to NO\({}_{2}\) (nitrite) in a process called nitrification. Furthermore, anaerobic ammonia-oxidizing bacteria convert NH\({}_{4}\)+-N to NO\({}_{2}\) and N\({}_{2}\) under the anaerobic system in a process called denitrification [11]. [PERSON] et al. [12] discovered a novel _Thuarea_ sp. strain SND5 that enhances simultaneous nitrification and denitrification as well as the removal of TP under microoxic conditions, and such strains can be used to enhance the existing conventional wastewater treatment systems. FOG in aerobic systems decreases the DO concentration, and the filamentous bacteria use it as their carbon and nitrogen to enhance their growth, and during their growth, they solubilize it to produce biosurfactants that stabilize biofoam [13]. PSW contains a high lipid content that leads to biofoamation and excessive growth of filamentous bacteria, which leads to sludge floatation and biofoam [14]. To treat such wastewater, both aerobic and anaerobic systems can be integrated to improve the performance of a wastewater treatment system. Examples include integrated aerobic/anaerobic sequential batch reactor (IAASBR) and anaerobic fluid bed reactor (AFBR) systems, among others [15; 16]. However, aerobic systems such as sequential batch reactors, granular aerobic sludge (GAS), activated sludge (AS), and defoamer-supported dissolved air flotation use aerobic microorganisms to flocculate the microbial cells and improve the flocculation of suspended solids as well as FOG [3; 17; 18]. The oxygen concentration can be adjusted depending on the wastewater's strength. This system improves ammonia oxidation and reduces TP, TN, COD, BOD, suspended solids (SS), and recycled biomass, increasing microbial density.