Gate to Gate
Identity ID
f6434137-3a90-4eb2-9ca4-22664de99c96
Process class
Associated ID
4052893c-81f5-4b12-a3f6-a0930edefd9a
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Included activities ends
Description
Representing the mainstream hybrid technologies currently used in wastewater treatment plants, these technologies have been widely applied and optimized in China, mainly including oxidation ditch, A2/O (also known as AAO), AO, MBR (membrane bioreactor), MBBR (moving bed biofilm reactor), CASS (cyclic activated sludge system), CAST (cyclic activated sludge technology), among others. Below is an introduction to the application of these processes in China:
Oxidation Ditch Process: As a well-established activated sludge wastewater treatment technology, the oxidation ditch process has been widely implemented nationwide. Its aeration tank has a closed channel shape, forming a circulating flow aeration ditch with connected ends, where wastewater is purified. The oxidation ditch process exhibits plug flow characteristics and can create aerobic, anoxic, and anaerobic conditions, thereby achieving effective nitrogen and phosphorus removal.
A2/O (AAO) process: This is an abbreviation for the anaerobic-anoxic-aerobic biological nitrogen and phosphorus removal process, used in as many as 60% of wastewater treatment plants in China. The A2/O process can simultaneously remove organic matter, nitrogen, and phosphorus, and it operates stably with strong resistance to load shocks. However, the conventional A2/O process has some drawbacks, such as the placement of the anaerobic zone at the front, which allows nitrate from the returned sludge to negatively affect the anaerobic zone. Therefore, in practical applications, modified A2/O processes are often adopted to optimize treatment performance.
AO process: Developed in the 1970s, this process is capable of organic matter degradation and nitrogen removal, with convenient operation and management. In China, the AO process is commonly used in small- and medium-sized municipal wastewater treatment plants, achieving high removal efficiencies for organic pollutants, ammonia nitrogen, and other contaminants in wastewater. MBR Process: MBR is a highly efficient wastewater treatment process that combines biological treatment with membrane separation technology. In China, MBR is commonly used in wastewater treatment projects with stringent discharge requirements, such as those meeting Class I-A or higher standards. The MBR process offers advantages including high-quality effluent, small footprint, and low sludge production, although its construction and operational costs are relatively high.
MBBR Process: The MBBR process combines the advantages of the activated sludge process and the biofilm process, achieving efficient wastewater treatment through a moving bed biofilm reactor. In China, the MBBR process is commonly used in industrial wastewater treatment and municipal sewage treatment projects, offering advantages such as high treatment efficiency, stable operation, and convenient maintenance.
CASS/CAST process: Both CASS and CAST are variants of the sequencing batch reactor (SBR) activated sludge process and are widely applied in China. These processes achieve organic matter removal as well as nitrogen and phosphorus removal by periodically changing operating conditions in the reaction tank. The CASS and CAST processes offer advantages such as excellent effluent quality and strong resistance to shock loads, although their operation and management are relatively complex.
Activity Description
The wastewater treatment process includes: an accident equalization tank for stabilizing the quality and flow rate of sewage; a primary clarifier to remove large suspended solids from the wastewater; iron-carbon reduction technology that enhances wastewater biodegradability through micro-electrolysis; a hydrolysis and acidification process that converts refractory organic compounds into biodegradable small-molecule organics; an A/O reactor (utilizing MBBR technology) that effectively removes organic matter and nitrogen under anaerobic and aerobic conditions; a secondary clarifier for further water clarification through solid-liquid separation; a high-efficiency sedimentation tank that removes suspended solids via chemical coagulation; an ozone oxidation unit to enhance organic matter removal; and a biological aerated filter (BAF) that combines biological degradation with physical filtration to improve effluent quality. quality; denitrification filter removes nitrate nitrogen; activated carbon filtration adsorbs residual organic matter; finally, effluent disinfection ensures safe and compliant discharge of water quality.
Process Description
Wastewater treatment services typically include four main aspects: pretreatment, primary treatment, secondary treatment, and tertiary treatment, ensuring the stable operation of the wastewater treatment system and compliance of the effluent water quality with regulatory standards.
Time period
2022
2026
Geography
China
Macroeconomic value
Business-as-Usual
Data validation
Yes
Technology
Current Technology
Technology comment
This activity represents the treatment of wastewater mixing technology in the WWTP