Our city is actually quite a beautiful place. At 6300 ft above sea level with tall mountains to the west, it kind of reminded me of Denver on my first visit. The south side of our town is bordered by the sixth largest freshwater lake in China (Dianchi Lake):
On a recent trip to Haigeng park, we strolled and watched as some fishermen labored for a very small catch:
However, it’s amazing that anything lives in this heavily polluted lake. Photos of the lake may look nice with the right combination of sun and camera angles, but a direct shot shows the green, soupy reality:
As the city has grown, the wastewater loading has exceeded the old axiom that “the solution to pollution is dillution.” People used to swim here 20 years ago, but now the lake is rated “grade five” (unsafe for human contact). In addition to runoff from nearby phosphate mines, ditches full of stinking grey water pour into the lake from the city.
Since it seems unlikely that people will stop dumping their wastewater into the ditches, the city has been working to convert the ditches into mini-treatment facilities. A few months ago, I watched as teams of workers shoveled, bagged, and removed the sludge from the bottom of the ditch in front of our school:
A truck of water hyacinths arrived:
They built wooden frames, hooked them to the sides of the ditch, and “planted” the hyacinths:
A botanist friend told me that water hyacinths are extremely good at absorbing heavy metals. Since the hyacinths are alive and spreading, I suppose they do OK with basic sewerage as well. While I doubt that this process will be sufficient to clean up the lake, at least it keeps the ditch from smelling so bad. I only hope that they don’t incinerate the hyacinths each year and dump the ashes in the lake…
Further down the ditch (near our apartment) is the construction site of a new hospital. Over the winter, they spent a few months building rock structures and dikes in this section of ditch, making me wonder if they were trying to make a staged pollution control reactor. Unfortunately, the chemical engineer in me was disappointed when they filled all of their structures with dirt and stuffed dead-looking plants into them:
But this is China, and they seem to have an uncanny ability to make things grow. A month or so later, the dead things started to show signs of life:
Now that summer is here, the old sewer ditch is starting to look pretty good:
OK – I know that it’s not Longwood gardens or anything. But for a wastewater ditch, it doesn’t look too bad. At least until the hospital opens up and the medical waste starts to flow…
Update for October: Here is the latest photo of the ditch garden, looking better every month:
I wonder what the fishermen are going to use that small catch for…dinner? I wonder how much of that lake is used to water your vegetables.
These freshwater shrimp and small catfish usually end up in our market out back (or nearby restaurants). The lakewater would actually be an improvement over the irrigation currently used on our roadside vegetation, which is pumped directly from the sewers (it stinks, but it works).
I guess this is their version of a wetlands – it looks a little smaller than the Victoria wetlands. I must ask – what is the source of your potable water at the apartment?
Enjoy your upcoming time with your family and grandson during your US visit. You have a reserved room in Texas if you come by for a visit.
Imagine combining the biotreatment plant, separation, and wetlands into a single system of many miles of ditches. No Terragators for landfarming the sludge, just an army of workers with shovels to spread it on top of gardens.
Our fresh water here is very high quality (for China). It originates with groundwater, passes through sand filters, and is chlorinated. According to a water engineer that I’ve met, you could almost drink it (almost).