Tagged with 'wastewater'

Fats, oils and grease (FOG) in wastewater are one of the biggest challenges facing wastewater systems around the world. Grease, sometimes along with solids, can build up into a solid mass that can narrow or even block wastewater pipes. When that happens, sewers overflow, pipes break, and local authorities are forced to clean up the mess and make repairs.

In the United States alone, the Environmental Protection Agency estimates that as many as 47 percent of all wastewater system blockages are caused by the buildup of grease. In New York City alone, those annual repairs cost nearly $5 million. Other large cities also rack up multi-million dollar bills for repairs and emergency service.

Cities are adopting a number of tactics to keep grease out of their wastewater systems.

Like many wastewater treatment facilities, the Asheboro Wastewater Treatment Plant, is under constant pressure to do more with less.

Already, the facility has cut in half the amount of electricity it uses to run the blowers in its two aeration tanks.

But the facility is now looking at some additional innovations to save money by reducing energy costs, reducing waste disposal costs and process even more waste from customers.

The Asheboro Wastewater Treatment Plant was built in 1962, during a different era. The Cuban Missile Crisis was right around the corner and America had just launched a space race to put the first man on the moon.

At the time, if you had mentioned “Class A biosolids” or “thermophilic bacteria” to a manager or operator at the plant, chances are they would have looked at you as though you had just come from the moon.

But the Asheboro, N.C. plant — even with some infrastructure that dates back more than 50 years — is on the leading edge of wastewater treatment. And it is the plant’s operators and staff that now talk about biosolids, bacteria and other cutting edge practices.

The damage that grease and other pollutants can inflict on the environment is well documented, but few cases illustrate this as well as Narragansett Bay in Rhode Island.

Narragansett Bay is a prime example of what untreated sewage can do to the environment. However, it’s also a great case study in how pretreatment can help turn around polluted waterways and help reverse the impact of pollution.

The problem began in the 18th century when Rhode Islanders would empty their raw sewage directly into their nearby rivers that flowed into the bay. By the 1970s, nearly 65 million gallons of untreated sewage was flowing into Rhode Island’s waters each day. Grease deposits the size of soccer balls were sometimes seen floating in the bay. The bay’s shellfish beds, which had created a booming industry, were closed.