Research on the treatment process of non-radioactive production wastewater in nuclear power plant

The sources and components of non-radioactive production wastewater from nuclear power plant is relatively complex. The existing wastewater from nuclear power plant is discharged into the circulating cooling water drainage system and then into the sea through the main discharge outlet of the power plant. The water quality of the discharge outlet meets the discharge requirements of the Comprehensive Wastewater Discharge Standard. With the improvement of domestic environmental protection requirements, some local environmental protection departments require that the content of Class Ⅱ pollutants in the wastewater should meet the discharge requirements of the Comprehensive Wastewater Discharge Standard before being discharged into the circulating cooling water drainage system. The existing wastewater quality cannot meet this requirement. To meet the above requirements, taking the CAP1000 nuclear power plant as an example, by analyzing the composition and current treatment conditions of non-radioactive production wastewater, it was discovered that the unqualified wastewater was mainly the acid and alkali wastewater discharged during the regeneration of the condensate polishing system. The ammonia nitrogen content in the wastewater was much higher than the discharge standard requiremented. Based on the discharge situation and water quality characteristics of the wastewater, high and low salt classification and reduction treatment were first carried out. Then three treatment technological processes were proposed for high salt wastewater in which ammonia nitrogen exceeded the standard, including break point chlorination oxidation treatment, combined treatment of air stripper and electrolytic chlorine oxidation, and membrane treatment. Technical and economic comparisons were made for each technological process, providing reference for the design of non-radioactive production wastewater treatment in nuclear power plant.