Here are some other sites that you may find of interest*:
Learner.org – Annenberg/CPB education website has a presentation on garbage and sewage.
Sewage.net – A site of links to water treatment plants around the world.
Pennsylvania Municipal Authorities Association – A site all about various muncipal authorities throughout Pennsylvania. Representing the interests of public water, wastewater, solid waste, recreation, and community projects.
PIX, Inc. ~ Pretreatment Information Exhange bringing Lehigh Valley municipalities, discharging businesses, regulators, environmentalists and concerned citizens together for pretreatment information sharing.