In our previous articles, we discussed the removal processes for ammonia nitrogen and total phosphorus, and touched upon total nitrogen while talking about carbon sources. It seems we missed the most significant indicator in effluent online monitoring: COD. A netizen from Jiangsu reminded me of this a few days ago, so today let's fill this gap. Let me clarify again: I write these articles to explain wastewater treatment knowledge in plain language. There are bound to be omissions and shortcomings, so please feel free to offer criticism and corrections. Back to the topic. Today, we won't discuss complex theories. We will focus on just one thing:
