To begin with, guided by professional tour guides, the students, filled with curiosity, closely observed key water purification processes such as sedimentation tanks and biological treatment tanks along the wastewater treatment workflow.

What's more, when everyone saw murky wastewater with foamy scum, first intercepted by coarse screens to remove debris, then separated in sand settling tanks, and finally broken down by countless microorganisms in biological treatment tanks—transforming into clear, transparent recycled water—they were all amazed at the miraculous power of modern technology to turn waste into something valuable. Through glass walls, watching each precisely operated stage of the treatment process, students deeply appreciated just how precious every drop of clean water truly was.

In addition, not only did this visit broaden everyone's horizons and unveil the mystery of the city's underground water supply network and water treatment systems, but also planted the seeds of water conservation and environmental protection in the hearts of each student.

Specifically, 'it turns out that the dirty water we usually pour away can go through so many complicated processes before it becomes clean!' Many students exclaimed after the observation. In the meantime, everyone agreed that in their future daily lives, they must start from small things like turning off the tap tightly and reducing the use of detergents, striving to be the 'environmental protection little guards' for water conservation.

In conclusion, beautiful China, I am an active participant. Let's walk hand in hand and take concrete actions to protect our green mountains and clear waters. More remarkably, let the sky be bluer, the mountains greener, and the water clearer!