Saturday, August 8, 2015

Clean Water Services

One of my goals for Jasper's education is to give him a basic working knowledge of the infrastructure that our cities depend upon.  A couple years ago we visited Gresham's wastewater treatment plant, which was really interesting.  I noticed that Clean Water Services was offering tours of their facilities in Hillsboro and Tigard, and decided to take advantage of a tour in Hillsboro. It was interesting to compare the two.

There are many things that we lack the technology to filter from the sewage. Most pharmaceuticals, legal or otherwise, pass right through our bodies and make it right into our sewer systems, mingling with the many chemicals, heavy metals, bacteria and viruses that make it into our sewers. Our Gresham guide had mentioned that at the time they were finding a noticeable amount of cocaine in the sewage. Our Hillsboro guide explained that Intel's fabrication plant is by far their biggest customer, and works with them to monitor the impact of chemicals released in their sewage.   In the wastewater treatment process, sewage is separated into water and solids. Treated water is released to be diluted by our rivers. 

Solids, formerly known as "toxic sludge", now have been given the cute name of "biosolids". On our Gresham tour, our guide was frank about the fact that both the solids and liquids contain toxins, since it is impossible to remove them. He explained that Gresham was giving their toxic sludge to farmers who were legally allowed to use it only on crops not intended for direct human consumption (although crops intended to be eaten by livestock would be fine).  For obvious reasons, food produced with toxic sludge cannot be certified as "organic". Hillsboro turns their toxic sludge into "crystal green" pellets which are sold to farmers and home gardeners, and they were eager to promote its use and give away sample bags.  

This tour definitely reinforced for us the lesson that everything we put down the drain matters.  It definitely helps to use environmentally friendly household cleaners, soap, shampoo, etc., and to think twice about what chemicals we put into our homes and our bodies. It's definitely possible we'll be eating them later.

In this section of the plant, Jasper discovered that under the walkway we stood upon was a
colony of bats! He could just barely see them through a crack.
Methane is a far more powerful greenhouse gas than carbon dioxide. While Hillsboro burns the methane produced in their treatment plant, to lower its environmental impact, Gresham goes a step further and generates electricity with burning methane.  Gresham also has a bank of solar panels to power their facility.  

Methane produced by the bacteria is burned.

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