Wastewater treatment: the pH value keeps changing, how to deal with it? Thank you very much
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Our industrial wastewater has a pH of around 12–13; after acid neutralization, its pH is maintained within the 6–9 range. The problem is that the water flow is continuous and constantly changing, and the remote valve controls in the control room need to be adjusted continuously, resulting in ongoing fluctuations in the pH values. Almost the whole class is looking at it; it’s really annoying! I’m really looking for a good way to keep the pH stable. My vague idea is to carry out segmented treatment – that is, to process part of the water and release the rest. The problem is that the water volume and pH level are unstable; therefore I need to control the amount of waste water and ensure it is properly treated before proceeding with the rest of the process. I’m really wondering if there’s any established process; it would definitely be extremely difficult to implement such a method for my own homemade pastries. Thank you very much.
How should it be understood? As a buffering effect? Could you talk about the manufacturing process? Thank you very much; it would be great to have pictures.
First of all, I’m not sure how acids and bases are mixed – is a pipeline mixer used for that? Still stir it in the equipment? Is the system’s PH response fast? If PH can respond quickly, it can be linked to a control valve; acids and bases are mixed using a pipeline mixer, and PID can be used for control. The valve operation should not be focused on a single value but rather within a range, such as 6.5–8.5.
This involves two issues: first, the wastewater flow rate is unstable, with no room for buffering and neutralization; second, the current control methods are not suitable for the operating conditions. It is recommended that, 1) based on the experimental results regarding the acid-base neutralization of wastewater, the time required for this process be analyzed first to understand the underlying mechanisms, after which it should be considered whether to use two buffer tanks to alternate between neutralization processes, with each tank being emptied once it has completed its function, thereby enabling continuous operation. 2. Based on the neutralization time in the process, determine the automatic pH control strategy. An automatic pH meter combined with a neutralization flow meter can be used, or an online pH meter along with a control valve or metering pump can form a PID control loop; this should solve the problem. If neutralization takes place within the pipeline, it is advisable to install a static mixer to ensure uniformity. For reference only
You can sell this alkaline water to companies that need desulfurization; it can be used to neutralize their acidic water.