Sludge Drying of Waste Water & Potable Water

 

Dade County Municipal WWTP - Miami, FL

With an in-flow rate of 200 plus million gallons per day, this WWTP had to find an effective method for sludge disposal, and it has with four Brown Bear paddle aerators. Each aerator unit breaks up and turns up to 3,000 cubic yards of windrowed sludge per hour, greatly reducing drying time over other handling methods. The 66 tons of dried sludge produced daily has been approved by the Florida Dept. of Agriculture as a soil conditioner.

The Bears are used to aerate and dry sludge from 20% solids to 85% solids in about a week's time during hot summer months.

In order to cease occasional odor complaints, two Bears with liquid application systems apply an oxidizer – potassium permanganate – directly to the biosolids as they are aerated.

 

Municipal WWTP - Phoenix, AZ

Keith Greenberg, assistant WWTP supervisor for the city of Phoenix states, "Bed space is always limited. We needed to dry our sludge to 40% solids to meet our contract with the sludge haulers for easier spreadability." The dried sludge is applied to cotton fields as fertilizer. The city is paying this contractor a hauling fee of $14 per dry ton; significant savings compared to the $100/ton landfill dumping fees found in Phoenix.

 

Denver Water Company - Denver, CO

Denver Water Company trucks a Brown Bear Model 400 aerator between two of their potable water plants, utilizing it to speed air drying of alum sludge in the summer and to facilitate freeze drying of the alum sludge in the winter. It is possible to take the alum sludge from a solids content of less than 10% to a solids content of over 70% in only a few days using the freeze dry method and the Brown Bear paddle aerator.

Manatee County Public Service – Bradenton, FL

The Manatee County Public Service Dept. operates the potable water plant, serving the city of Bradenton, Florida and all of Manatee County. Alum sludge is a residual material left from the water treatment process and is a problem for most potable plants to dispose of. In the past, landfills would accept the wet alum sludge, but due to landfill space confinements wet sludges are no longer acceptable in most landfills. Additionally, the cost of transportation of wet sludge is very substantial. Manatee's potable water plant was experiencing problems in drying the alum sludge to a landfill acceptable state. The potable water plant now utilizes a Brown Bear Model SC4912 paddle auger which is mounted on a JD 644E articulating front-end loader. The aerator is used to accelerate the drying process, as much as four times faster than non aerated drying, drying the alum sludge to 70% solids. Transportation costs to the landfill are substantially reduced and the dried material is used as daily cover at the landfill.

Ogallala, Nebraska WWTP

Many smaller cities are learning that their present lagoons, perfuming systems, wet-hauling operations, and chemical alteration procedures are too expensive, ineffective, and are still the cause of numerous citizens' complaints. We believe the Brown Bear Model 24 series is the ideal solution for smaller municipalities' waste water treatment plants' problems.

By stirring the sludge, fly-egg infested crust is broken, exposing wet solids to sun and wind, killing the eggs. As the material dries, water-shedding windrows are formed, increasing the exposed surface area which speeds drying.