The city of Phoenix Arizona, in a document called Uniform Standard Specifications, lists down the requirements issued in the city in order to protect the health of its residents and the integrity of its structures. The specifications deal with various aspects of public utility. One of the most important of these is in the area of the sewage systems. The reason for their significance is http://site-not-allowed/wf060F

https://www.cleanwaterservices.org/AboutUs/WastewaterAndStormwater/TreatmentProcess.aspx

http://www.youtube.com/watch?v=3b6oRyfgiAs