Are active sludge processes basically used in all wastewater treatment plants in the country?

I did a search and found that there are indeed many methods using activated sludge? Which method is commonly used in domestic wastewater treatment plants?   1 Traditional (conventional) activated sludge process: 1. The aeration tank is of the plug-flow type; wastewater and returned sludge enter from the same end, allowing for thorough contact between organic matter and sludge as they move downward in the direction of operation. 2. The sludge goes through a process from the logarithmic phase to the stationary phase, and even to the senescence phase, during which adsorption and metabolism take place. Advantages: 1. Good treatment effect. 2. The degree of wastewater treatment can be adjusted flexibly, to be either high or low. Disadvantages: The effluent concentration So cannot be high, and it is not suitable for shock loads. 1. The oxygen demand is high at the beginning and low later on, resulting in oxygen deficiency in the early stage and excess oxygen in the later stage. 2. To avoid oxygen deficiency in the early stage, the inlet concentration cannot be high. If V rises, Nr falls and infrastructure costs increase.  Ns: 0.2~0.9 kgBOD5/kgMLSS·d; dNr: 0.3~0.6 kgBOD5/m3·x; X: 1500~3000 mg/L; Xv: 1200~2400 mg/L; Θc: 5~15; dt: 4~8 h; R: 0.25~0.5; E: 85~95%. 2. Gradual aeration – there is a mismatch between oxygen demand and oxygen supply; the aeration system is not well-designed. It is necessary to arrange the aeration system in such a way that it varies along its length, while keeping the total amount of air supplied constant.  Advantages: 1. Improved oxygen utilization, avoiding waste. 2. It needs to be synchronized with the supply, addressing the issues of oxygen deficiency in the early stage and insufficient supply in the later stage, thereby improving processing efficiency. Disadvantages: It is very difficult to achieve a balance between the oxygen supply and the oxygen demand; the situation remains unchanged. Three-stage aeration with multiple water inlets along the length of the tank. Advantages: 1. The organic load is more evenly distributed, which helps to resolve the imbalance between supply and demand and thus reduces energy consumption. 2. It facilitates the full utilization of microorganisms’ oxidative decomposition capabilities. 3. The sludge concentration (suspended solids concentration) gradually decreases throughout the tank, reaching 2.0 in the later sections, where there are primarily highly active bacteria. Class B: Low load, Ns: 0.15~0.3 ； Dwell time: 2~4h, Qc5~1.5d. Advanced microorganisms (protozoa and a few metazoans) are present. 2. Both stage A and stage B are equipped with their own sedimentation tanks, with independent recirculation systems. 3. No primary sedimentation tank is provided. 1. Stage A: Bacteria possess extremely high reproductive and adaptive capabilities, which enhances their resistance to shocks. 2. Stage B: 0.5, 60% BOD; reaction time of 2–4 hours; V value decreases over time. 3. Stable operation. 15 Phosphorus and nitrogen removal: A/O, A2/O, A/A/O. Nitrification: NH3 + 3/2 O2 (denitrifying bacteria, nitrifying bacteria) → NO2 + H2O + H+; NO2 + 1/2 O2 → NO3-. Denitrification: NO3- (anaerobic bacteria) → N2. 16 Sequential Batch Reactor (SBR) method. The core of this method is the SBR reactor, which operates in an intermittent, sequential, periodic manner. Inlet water ； reaction ； precipitation ； Drainage and sludge removal, idle. This article is from: Environmental Technology Network (www.cnjlc.com). For the full source, see: http://www.cnjlc.com/plus/view.php?aid=7612

The activated sludge process should be used whenever possible, as it is cost-effective. For wastewater that is difficult to treat, physical and chemical treatment methods such as advanced oxidation and membrane treatment are also required

The activated sludge process is the foundation; other wastewater treatment processes that involve aeration and activated sludge are all extensions and improvements of the activated sludge process

Industrial wastewater treatment varies depending on the water quality and the treatment processes used. Biological treatment is generally used as the main method, but pretreatment is often carried out (adjustment, air flotation for oil removal, neutralization); post-treatment such as coagulation, filtration, and activated carbon adsorption may be applied as needed

:victory: :victory: Yes, that’s basically the case – it’s because of the low prices and the large volume of work to be handled. Most importantly, we **don’t have high standards regarding drainage**.

The activated sludge process in our plant follows an anaerobic phase, followed by an aerobic phase, and then an anaerobico-aerobic phase (biofilm-type activated sludge process). Enter the regulation tank 500, outlet 80

The most commonly used processes are CASS, A/A/O, oxidation ditches, SBR, etc. MBR is used very little.

BAF process for the retrofitting of processes such as CASS, A/A/O, oxidation ditches, and SBRs