Tuesday, March 26, 2013

Water Treatment

Bacterial mass.
I set up a tour  of the Gresham Wastewater Treatment Plant  for our homeschool group which took place serendipitously on World Water Day.  Our guide, Paul Proctor, graciously showed us each of the steps taken to clean up to 20 million gallons of water daily.  It was illuminating both for the capabilities of their facility and its limitations.  They use a combination of physical and biological methods for most of the treatment process.  They physically separate out debris and allow oil to float to the surface.  But Mr. Proctor warned that this is a major challenge, and our pipes are no place to dump any kind of trash or chemical.  Many chemicals simply do not have a process for removal.  He said that they have found traces of cocaine in the water, as well as tons of cooking oil every Thanksgiving from families that deep-fry their turkeys and dump the used oil down the drain.  Bacteria do much of the work to break down contaminants in the water, so toxic chemicals dumped down the drain do double damage by killing this helpful bacteria.  

Bacteria at work.
Methane power generation facility.

Paul Proctor with one of the huge solar panels.
The plant has recently installed a bank of large solar panels, which even on cloudy days generate electricity.  And most impressively they have a facility that takes the methane generated by the bacteria and burns it to generate heat and electricity to power the plant.  He said that when he started working there in 2005, the plant's electric bill was around $45,000 per month, and these measures have lowered their bill to $11,000.  He says they are hoping to increase their methane processing capacity with a goal of 100% heat and electrical self-generation. 
A truck being filled with sludge.
The plant also takes the final sludge and dehydrates it to create a solid that is given away as a fertilizer. This is quite a controversial practice, because sludge contains varying amounts of toxins.  The sludge produced in Gresham is not considered safe for growing food for humans, but it is used for growing crops to be eaten by livestock. So an important way we can all help to keep our food and water supply safe, and keep the Columbia River clean, is to avoid dumping chemicals down the drain. 

The stormwater treatment facility.
We also took a self-guided tour of the Columbia Slough Regional Stormwater Treatment Facility, which looks like a nature park but is designed to filter storm water runoff of contaminants before they reach the river.  They kindly supplied us with a key to the gate and a backpack of interesting educational materials that the kids enjoyed.  

No comments: