The water quality index standards of circulating water are usually determined according to the specific purpose and industry standards. Here are some common circulating water quality indicators and their standards:
PH value: Generally, the pH value of circulating water is between 6.5-8.5 to ensure that the pH in the water body is moderate.
Suspension: Suspension refers to solid granules in the water, such as sand and granular pollutants. The concentration of suspended objects should be controlled within a reasonable range, and it is generally required to be less than 20 mg/L.
Total solubility solid (TDS): The total dissolved solid in circulating water includes inorganic salts and organic substances dissolved in water. Specific standards will be different due to the use of circulating water, and generally requires between 1000-3000 mg/L.
Ammonia nitrogen (NH3-N): Amino nitrogen is an important water quality index. Excessive ammonia nitrogen content may cause harm to the biological system and environment. The standards will be different according to the requirements of specific industries and application, and generally requires less than 1 mg/L.
Total colon flora: The total colon flora in circulating water is a microbial indicator for evaluating the hygiene of the water body. Specific standards will be different due to the industry and applications, and generally requires less than 100 CFU/ml.
Chemical oxygen demand (COD): Chemical oxygen demand is an indicator for measuring the concentration of organic pollutants in the water body. Generally, it is required to be between 50-200 mg/L. The specific standard varies from the industry.
Please note that the above only lists some common circulating water quality indicators and its standards. In practical applications, there may also be other specific indicators and corresponding standards. Therefore, under the specific circumstances, the applicable water quality indicators and standards need to be determined according to local regulations, industry standards, and recycling water.