WWT in Cromwell, Connecticut, USA The Mattabassett district wastewater treatment facility. By Stephen Schneider December 11, 2007

Located half way between New York City and Boston, on the Connecticut river. Location

It is located 40km from the Long Island Sound. Location

It is still close enough to the shore to still be tidal, but is fresh water. 17 billion gallon per day flow. (750 m 3 /s). The effluent from the plant is 40m from the shore 3m below the surface. C.T. river information:

Treatment plant specifications What goes in: 18 million gallons per day (0.8 m 3 /s) from 120,000 residents in: New Britain, Berlin, and Cromwell. $6.4 million USD per year = 115 million kc per year The plant can also accept and treat septage from septic tank cleaning trucks and liquid biosolids from other waste water treatment plants. What goes out: 8 to 10 mg/L total nitrogen resulting in a yearly nitrogen credit bill of only $5000 USD.

Main W.W. path: 1)Bar racks 2)Detritors 3)Primary clarifiers 4)Aeration tanks 5)Secondary clarifiers 6)Chlorine disinfection Sludge paths: From step 3: (Sludge removal)‏ Storage Belt press Fluidized bed incinerator From step 5: (Sludge recirculation)‏ Added back in before the primary clarifiers

Layout Primary clarifiers Aeration tanks

Primary Clarifiers Four P.C.s hold the water for 2.5 hours.

Odor control The air from the liquid treatment processes is sent through a biofilter that consists of a 1 meter thick layer of wood chips. To date 4.5 million has been spent on odor control. The odor controls were installed in 1991 to I can personally attest to it appearing to have worked having not noticed any smells coming from the plant in recent years, while driving by.

Sludge disposal After the belt press removes 75% of the water, sludge is incinerated in a fluidized bed incinerator that contains 19 tons of sand at 760°C. In addition to the sludge the incinerator also uses air from near the belt press to reduce odor. The ash is blown out the top of the incinerator with the exhaust gases. To remove the ash from the air water is used. This resulting water/ash mix is then left in a lagoon to dry and then is sent to a landfill.

Questions? Resources: mattabassettdistrict.org Images: mattabassettdistrict.org Maps.google.com