Water Wednesday - Putting Wastewater into Perspective
Written By: Keith Rutherford
Date: March 24, 2021
Keith Rutherford, PE, is a Principal and a Senior Project Manager for Parkhill’s Treatment Practice. As an expert in hydraulics, pipelines, and pumping systems, he publishes a series of Water Wednesday blogs for Parkhill employees. He has served as president of the local chapter for the American Society of Civil Engineers (ASCE), vice president – technical for the Texas section of ASCE, and as a project advisory committee member for the Water Reuse Foundation.
Yuck, nasty, ew… Just a few of the words people use to describe wastewater. Let’s put wastewater into perspective!
Lean ground beef contains anywhere from three to six percent fat. This fat is the waste of ground beef since it cooks down and is for the most part gone by the time you eat it.
In comparison, wastewater is usually one percent or less waste and 99+ percent water. That means that wastewater is purer than lean ground beef!
Cooking (treating) wastewater through a conventional wastewater treatment plant takes steps to remove the waste through primary sedimentation, aeration, secondary clarification, and in the case of reclaimed water, filtration. The smaller photo shows a great comparison of the start and end products.
At this stage, the water could be chlorinated or disinfected with ultraviolet light and sent out for irrigation, power generation, dust control and other non-potable use. It can also be taken to another treatment process like what is used at the Fred Hervey Water Reclamation Plant (Parkhill 1985) or the Advanced Water Purification Facility (AWPF) that we are working on now.
These plants treat the water to potable quality, meeting or exceeding the drinking water parameters set forth by the Texas Commission on Environmental Quality (TCEQ) and the Environmental Protection Agency (EPA).
The treatment process diagram for the Fred Hervey plant shows the wastewater treatment processes on the left, labeled PACT®, and the purification process on the right. By the time the water leaves the plant, it is ready for human consumption and there is a tasting station at the end of the plant tour so you can appreciate the taste or lack of taste of highly purified water.
The AWPF uses modern membrane treatment in a much smaller footprint to achieve high-quality purified water in place of the more conventional treatment process found at the Fred Hervey plant.
Obviously, the water treatment processes are much more involved when compared to throwing a burger on the grill!
If your community is faced with using reclaimed wastewater to provide drinking water, rest assured the treated water will be purer and safer than the other water sources in your community.
Hopefully this takes the ew out of wast(ew)ater!