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…
1. Mechanical ventilation of a lift station is required to _. a. lower the temperature b. reduce chlorine demand c. eliminate the presence of harmful gases d. increase D.O. in raw wastewater 2. What is the minimum D.O. to prevent formation of hydrogen sulfide in at a treatment plant? a. 2.0 b. 1.0 c. 0.5…
1. Which of these pH readings indicate an acidic wastewater? a. 3 b. 7 c. 9 d. 12 2. The record log of a hydraulic cleaning operation should include _. a. type and amount of material removed from downstream manhole b. feet of rod used c. camera malfunctions d. all the above 3. What type…
DISSOLVED AIR FLOATATION (DAF) THICKENERS Dissolved air floatation thickening relies on a process similar to what happens to sludge during denitrification. Small air bubbles attach themselves to sludge particles and separate them from the remaining liquid by floating them to the surface where they accumulate into a sludge layer. This sludge layer is skimmed off…
Vacuum Sewer Systems Vacuum sewers have become an acceptable alternative in the proper application and are providing efficient and reliable sewer service to communities all around the world. A vacuum sewer system consists of three major components: the valve pit, the vacuum mains, and the vacuum station. Vacuum sewerage is a mechanized system of wastewater…
Operation and Maintenance or Pressure Sewers Routine operation and maintenance requirements for both septic tank effluent pump and grinder pump systems are minimal. Most system maintenance activities involve responding to homeowner service calls usually for electrical control problems or pump blockages. Septic tank effluent pump systems also require pumping every two to three years. The…
Sludge Thickening and Dewatering Even what is considered a “thick” sludge, (5 – 6% total solids), still contains over 90% water. Storing and transporting all the water along with the solids contained within it is not practical. For this reason, there are a number of methods of separating solids from water. These methods include; gravity…
Aerobic Digestion There is not much involved in the operation of aerobic digesters. Sludge feed rates are based on the need to remove solids from the secondary treatment process. Sludge removal rates are determined by the level in the digester and by the availability of sludge dewatering and drying units. Around 1.0 mg/L D.O. should…
