How Rain Affects Wastewater Treatment

Dry vs. Rainy Weather Performance

A big plant that cleans water, called an aerobic granular sludge (AGS) plant, is really good at taking out nutrients and organic stuff. But what about tiny pollutants, like medicine and chemicals? That's what scientists wanted to find out.

They looked at 19 medicines and 2 industrial chemicals in this plant over a year. They checked how well the plant cleaned these pollutants in both dry and rainy weather.

Dry Weather Performance

• Good job: The plant took out more than 20% of 14 different pollutants.
• Pollutants stuck to sludge: Some pollutants adhered to the sludge, which is like a thick layer of bacteria and dirt that helps clean the water.

Rainy Weather Performance

• Water got dirtier: Rain made the water dirtier with some pollutants.
• Cleaning power went down: The plant's ability to remove pollutants decreased.
• Pollutants in cleaned water: Some pollutants ended up in the cleaned water.

Scientific Findings

• Less time to clean: When it rains, the plant has less time to clean the water.
• Harder to break down pollutants: This made it harder for the plant to break down some pollutants.
• Sticky pollutants unaffected: For pollutants that stick to stuff, rain didn't make much difference.

Comparison with Regular Plants

• Dry weather: The AGS plant did better than regular plants.
• Rainy weather: It's hard to say which plant performs better.

Conclusion

This study is the first to look at how rain affects these plants, showing that rain can make it harder for the plant to clean water.