1. What is the loading rate in gpm/sq ft if a flow of 1,000,000 gal/day flows into a clarifier measuring 20 ft by 25 ft? Loading rate, gpm/sq ft = (GPM / Area, sqft) 2. What is the flow through a trickling filter in gpm if flow = 135 cu ft/min? 3. What is the…
SLUDGE RE-USE AND DISPOSAL Because sludge consists of nutrients, organic molecules and trace metals that are needed by plants for growth, it makes an excellent soil conditioner. In fact, in countries such as China, various forms of sludge have been used as a soil conditioner for thousands of years. The general public often expresses concern…
Vacuum Sewer Systems (cont) Calculate Flow Rates A 2 feet wide rectangular channel is flowing 30 inches deep with an average velocity of 0.8 feet per second. What is the approximate flow rate? To find the flow rate use a variation of the velocity equation. First calculate the area of the channel, and we have…
Vacuum Sewer Systems (cont) Operation and Maintenance Vacuum stations function as transfer facilities between a central collection point for all vacuum sewer lines and a pressurized line leading directly or indirectly to a treatment facility. Vacuum pumps are needed to produce the vacuum necessary for liquid/air transport. They may be either the liquid-ring or sliding-vane…
Sludge Drying Beds The use of sludge drying beds is usually limited to small to medium sized (< 5.0 MGD) plants due to land and manpower requirements. In the southern states, the abundance of warm weather, sunshine, wind and land makes drying beds a good sludge drying process for many treatment plants. In the northern…
Centrifuge Centrifugal thickening of wastewater sludge is accomplished by subjecting the sludge to high centrifugal forces. Sludge is fed into a rotating bowl. Solids separation occurs due to centrifugal force impelling the solids to the bowl wall where they are compacted. The liquid and fine solids (centrate) exit the unit through the effluent line. Thickened…
Vacuum Sewer Systems (cont) The advantage of vacuum collection systems may include substantial reductions in water use, material costs, excavation costs, and treatment expenses. In short, there is a potential for overall cost effectiveness. Specifically, the following advantages are evident: • Small pipe sizes, usually 4”, 6”, 8” and 10” are used. • No manholes…
Vacuum Sewer Systems (cont) The resulting pressure differential between the positive pressure of atmosphere air and the negative pressure in the vacuum main becomes the driving force that propels the sewage towards the vacuum station. The pressure differential that exists at the normal operating vacuum levels provides the energy to propel the sewage at velocities…
Belt Filter Press Belt filter presses consist of two endless belts that travel over a series of rollers assembled on a galvanized steel frame. Sludge is conditioned with polymer and allowed to dewater in a drainage area before it is fed into the area between the two belts. As sludge travels between the belts, it…
Math Problems Checklist: Do not be tempted to look at a problem and start punching numbers into a calculator. Using your calculator like this only ensures you will get the wrong answer QUICKLY. Instead, follow this checklist to help ensure success: 1. Read the problem carefully (you may need to read it twice). 2. Draw…
