Discharge requirements for COD
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Dear sea industry peers, the new sewage discharge standards in Liaoning Province require that COD levels be below 50 mg/l before discharge is allowed. Can your companies meet this requirement?
We can basically keep the online monitoring values between 30 and 40; there are very rare instances when they exceed this range. As those in the chemical industry, our standard is 100. [This post was last edited by lyhh9024 on 2009-2-16 at 11:32]
Depending on the type of wastewater, treating ordinary domestic sewage or organic wastewater with good biodegradability is relatively easy. For industrial wastewater, high-concentration organic wastewater, pharmaceutical wastewater, etc., it may be difficult to achieve a concentration of 50 ppm using simple secondary biological treatment processes; technical upgrades are necessary in such cases. As for industrial wastewater, a CDO concentration of 100 ppm is generally sufficient. If this is necessary, the company will have to carry out significant technical upgrades.
The COD level in my company reaches 120 mg/l.
We are also in the chemical industry; the COD emission standard is below 40. If this value exceeds that limit, the liquid either needs to be diluted with water, sent to a wastewater treatment plant, or reused. The standard distance of one hundred is too far for us.
The water quality here is far from meeting the standards; to allow discharge in compliance with regulations, it has to be diluted first. A huge amount of water resources is being wasted. I think COD should be below 50 g/l; it’s probably difficult even for domestic wastewater to reach that level.
Diluted emissions? No control on the total COD emissions?
At present, the water used in our company is recycled cooling water, which does not increase the COD level in the water. Without this indicator, water is reused.
Our factory recycles industrial water, and it is said that zero-emission levels have been nearly achieved.