1. Project Introduction Wastewater containing phenol mainly comes from coking, coal gasification, oil refining, and chemical and pharmaceutical production processes that use phenol or phenol-formaldehyde as raw materials. It has a wide range of sources, large quantities, and significant hazards, making it one of the toxic and harmful wastewater issues that are prioritized for control in water pollution management worldwide. In 2011, China's total wastewater discharge was about 65.2 billion tons, with an estimated 51.1 million tons of phenol-containing wastewater. This type of wastewater has the following characteristics: (1) Wide sources: Mainly from the petroleum processing and coal chemical industries, accounting for 68% of the phenol-containing wastewater discharge; Large emissions: For example, a coal gasification station with an annual production capacity of 4 billion Nm3 of natural gas emits about 770 tons/hour of phenol-containing gasification wastewater; approximately 40 cubic meters of wastewater are discharged for every ton of petrochemical product produced; (2) Difficult to treat: High pollutant concentrations, with COD reaching 10,000 mg/L. The wastewater contains up to 7000mg/L of phenol and 5000mg/L of NH3-N; it is complex in composition, including not only phenol but also aliphatic compounds, heterocyclic compounds, and polycyclic aromatic hydrocarbons; the water quality varies greatly, with a COD variation coefficient reaching 2.3; (3) Strong toxicity: teratogenic, carcinogenic, mutagenic. When the phenol concentration exceeds 10mg/L, fish and other aquatic plants cannot survive. This type of wastewater has been listed in the hazardous waste directory. Effective treatment of this kind of wastewater has become a difficult problem for the water treatment industry. Supercritical water oxidation technology (SCWO) is a new type of high-efficiency treatment technology for high-concentration, refractory organic wastewater. Under the conditions of supercritical water (temperature >374°C, pressure >22.2MPa), and with the participation of excess oxygen, organic substances undergo oxidative reactions dominated by free radicals. The technology rapidly and thoroughly oxidizes carbon-containing organic substances in wastewater into carbon dioxide and water, featuring rapid reaction, thoroughness, cleanliness, and environmental protection. In recent years, this technology has received increasing attention in the treatment of high-concentration and refractory organic wastewater. Studies have shown that this technology can reduce the phenol concentration in wastewater from 5000mg/L to below 0.1mg/L without pretreatment, meeting the national GB8978-1996 discharge standards. 2. Technological innovation and leadership: Currently, the main treatment process for phenol-containing wastewater is a combination process centered on biological methods, which includes pre-treatment processes (such as ammonia blowdown, steam stripping for dephenolization, etc.) - biological method - subsequent advanced treatment processes (such as advanced oxidation, chemical precipitation, etc.). Although this combined process can ultimately achieve standard discharge of wastewater, it still has the following issues: The process flow is complex, Strict pretreatment and efficient deep treatment are required; high concentrations of phenol and ammonia are required, with the phenol concentration entering the biochemical treatment section needing to be below 300mg/L and the ammonia concentration below 30mg/L; if not thoroughly treated, the COD degradation rate in the biochemical section is only about 80%; secondary pollution is generated: approximately 3-4 tons of sludge are produced for every 10,000 tons of wastewater treated, which contains harmful substances such as PAHs and heavy metals. The production of hazardous waste sludge is a difficulty brought about by the conventional treatment of phenol-containing wastewater. This technology has the following advantages: (1) By setting up a wastewater concentration tower, the water volume of the wastewater can be reduced by 5 times, and the organic matter concentration increased by 5 times. This effectively achieves self-heating for wastewater with an initial COD of 10,000mg/L, reducing energy consumption; (2) By setting up a urea carbonate recovery device, The CO2 produced by SCWO reacts with the ammonia at the outlet of the ammonia stripping tower, on one hand producing ammonium carbonate, and on the other hand, separating the excess O2 and CO2 from the SCWO outlet, recovering O2 and reducing material consumption. (3) Thorough treatment. Under conditions of 600°C, 25MPa, and an oxidation coefficient of 3, the effluent concentrations of COD, NH3-N, and volatile phenol are 13, 9, and 0.1mg/L, respectively, which can meet the national first-class discharge standards. 3. Market and Benefit Analysis Taking the treatment of 500t/d coal gasification wastewater containing phenol as an example: The actual treatment capacity of the SCWO system in the process is 100t/d. Compared with the traditional process of 'ammonia stripping dephenolization—biochemistry—coagulation', the investment in the processes is 25 million yuan and 15 million yuan, respectively; the cost of treating 1 ton of wastewater by the SCWG-SCWO process is 20 yuan/t. The treatment cost for 'Ammonia Evaporation and Phenol Removal - Biochemical - Coagulation' is 40 yuan/ton. Compared with the 'Ammonia Evaporation and Phenol Removal - Biochemical - Coagulation' process, the 'SCWO-SCWO' process saves 3.65 million yuan per year, and the additional investment cost can be recovered within three years. Phenol-containing wastewater mainly comes from the petrochemical industry and coal chemical industry. Taking the comprehensive processing capacity of 168 million tons per year for Sinopec as an example, the wastewater discharged is about 6.72 billion cubic meters. The operating cost for using the SCWO process is 134.4 billion yuan, while the operating cost for the conventional biochemical method is as high as 268.8 billion yuan. Taking a coal gasification station with an annual production capacity of 4 billion Nm3 of natural gas as an example, the phenol-containing coal gasification wastewater discharged is about 770 tons/hour. Using the SCWO process, the operating cost is 370,000 yuan/day, with an annual operating cost of 135 million yuan. Using the conventional biochemical method, the treatment cost is 40 yuan/ton of wastewater. The operating cost is 740,000 yuan per day, with an annual operating cost of 270 million yuan. The SCWO process saves 135 million yuan per year compared to the conventional biochemical method. During the 12th Five-Year Plan period, it is planned to reach a coal-to-natural gas production capacity of 60 billion Nm3/year. Based on this calculation, the wastewater discharge will increase to 11,550 t/h, with an annual discharge of about 101.16 million tons. Treating wastewater using the SCWO process will save 2 billion yuan per year compared to the conventional biochemical method.