Sewers are wild places. All types of naturally occurring bacteria grow there. The one thing these bacteria have in common is that, for the most part, they cause problems. Filamentous bacteria — specifically sulfate-reducing bacteria — produce hydrogen sulfide, and other odor  causing bacteria dominate the wild microbiology of the collection system.

In fact, the indigenous microbiological growth within the collection system is generally considered detrimental to treatment objectives when it reaches wastewater treatment plants (WWTPs). Long hours of retention time in the collection system can produce situations that hinder treatment. Long retention times also can cause corrosion and odor problems.

But what if the sewers could be tamed? What if those miles of existing pipe could be turned into a meaningful treatment step?   Read full article (login required)  

In Florida, a state that leads the nation in water reuse, the city of Apopka, located near Orlando, is in a class by itself. Its 4.5-mgd (17,000-m³/d) wastewater treatment plant (WWTP), which treats an average flow of 2.6 mgd (9840 m³/d), won the David W. York Water Reuse Award in 1997. Since that time, the plant has more than doubled the amount of reuse water supplied to golf courses, recreation facilities, agricultural  irrigation, and more than 4000 residents, according to water resources manager Kevin Burgess.“In 1997, we provided 3.2 mgd [12,100 m³/d],” Burgess said. “Now the figure is 6.4 mgd [24,200 m³/d], including supplementation with groundwater.”

But 2 years ago, the plant faced an infestation of filamentous bacteria, including Nocardia, which led to poor solids settling. Burgess attributes the plant’s bounce back and continued success to using bioaugmentation to control the filamentous bacteria and improve solids settling.   Read full article (login required)