Two water treatment issues (with supplements)
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This post was last edited by zxan8q on 2009-12-14 22:51. I’m very grateful for the replies from the two people below; I have two additional questions (3, 4, 5, 6). 1. For treating wastewater using the air flotation method, how are the dissolved air efficiency F and the solubility of air in water determined in the formula for calculating the amount of air to be released under reduced pressure? It’s like in the question where you’re given three options: 1. No temperature, only F and solubility in air? 2, 20 degrees F and solubility in air; 3, 40 degrees F and solubility in air. I’m not sure if I expressed this clearly – how should I make a choice? 2. What are the differences in the design parameters for hydraulic retention time, hydraulic load, and solid load in primary sedimentation tanks and secondary sedimentation tanks? 3. Zinc-containing wastewater: How is zinc recovered from it in industry? 4. How should such wastewater be treated when PVA (with poor biodegradability) and starch (with good biodegradability) are mixed to form a slurry? 5. Biochemical reactions take place under the catalysis of enzymes. What are the characteristics of enzymes? 6. Among the physical treatment methods, there is filter bed treatment; I’m not very familiar with it. Could you provide me with detailed information (basic knowledge) on topics such as the principles, water distribution systems, and filter media selection? . zxan8q.love@163.com
I don’t know the answer to the first question. Regarding the second question, the Outdoor Water Supply and Drainage Code of 2006 specifies the following design parameters for the primary sedimentation tank: sedimentation time of 0.5~2 hours； Surface hydraulic load: 1.5~4.5 m3/(m2•h) ； Sludge amount per person per day: 16–36 g/person•day ； Sludge moisture content (%) 95~97 ； Solid load —— kg/(m2•d) Secondary sedimentation tank (activated sludge process): Sedimentation time of 1.5~4.0 hours ； Surface hydraulic load: 0.6~1.5 m3/(m2•h) ； Sludge amount per person per day: 12–32 g/person•day ； Sludge moisture content (%) 99.2~99.6 ； Solid load – 150 kg/(m2•d). This design takes into account the fact that the substances to be settled in the primary sedimentation tank and the secondary sedimentation tank are different. The substances settled in the primary tank are mainly sediment and sludge that are denser than water, while in the secondary tank it is activated sludge, whose density is similar to that of water. Therefore, the settling time and the surface hydraulic load need to be higher accordingly.
This post was last edited by 20036820 on 2009-12-14 at 18:39. The first question should be the second option, as it generally refers to the solubility at room temperature, such as 20 degrees Celsius. The second question was explained quite clearly upstairs; to add something, for these parameters, one sets a value first, and then formulas can be used to calculate or verify the values of the others.