1. The machine that tears debris after the bar screen is called a _. a. barometer b. concubine c. comminutor d. blender 2. The principle function of the zoogleal mass on the trickling filter is to _. a. filter the suspended solids b. reduce the organic content c. reduce the nitrogenous BOD d. control the…
Rearranging a Formula Sometimes the way a formula is written, the item you are trying to find does not stand alone. You must rearrange or transpose the formula to solve for the unknown. When rearranging a formulas, think of a formula as a balanced scale – the quantity on the left has to equal the…
LUBRICATION Pumps, motors, and drives should be oiled and greased in strict accordance with the recommendations of the manufacturer. PUMP CHARACTERISTIC CURVES Every pump has certain characteristics under which it will operate efficiently. These conditions can be illustrated with pump characteristic curves. The graph of the pump curve should show: 1. The head capacity curve…
SOLIDS HANDLING PROCESSES When a wastewater treatment plant is operating properly, most of the solids in the wastewater will be removed at the plant while the water itself will be discharged as effluent to the receiving waters. These solids, known as sludge, must be stabilized and reduced in volume before they can be reused or…
Slope Sewer pipes must be adequately sloped to reduce solids deposition and production of hydrogen sulfide and methane. Table 4-2 presents a list of minimum slopes for various pipe sizes. If a sewer slope of less than the recommended value must be provided, the responsible review agencies may require depth and velocity computations at minimum,…
Design Flow Sanitary sewers are designed to carry peak residential, commercial, institutional, and industrial flows, as well as infiltration and inflow. Gravity sewers are designed to flow full at the design peak flow. Design flows are based on various types of developments. If it is assumed that the average velocity of the wastewater in the…
Changes in Sampling Program Data on system performance can be greatly affected by changes in a sampling program. If improper sampling locations or laboratory procedures are used, lab results could vary considerably. When the lab data varies widely from one day to the next, check sampling location, time, and lab procedures for errors. Remember that…
CENTRIFUGAL PUMP COMPONENTS (continued) Pumps that do not have packing in the stuffing box will be equipped with a mechanical seal. Mechanical seals are comprised of two highly polished seal faces. One seal face is inserted in a gland ring that replaces the packing gland on the stuffing box. The other seal face is attached…
CENTRIFUGAL PUMP COMPONENTS (continued) Now that the casing is assembled and the piping is in place, we can spin the impeller and begin moving water. Water will enter from the suction side of the volute and will be slung out of the impeller into the discharge side of the volute. Unfortunately, the water will try…
Storm Events Many treatment facilities experience increased influent flows during storm events due to the inflow of storm water from streets and low lying areas. Storm flows often sweep excessive dirt and silt into the plant. This can result in a rapid increase in the MLSS concentration in the aeration basin, but the concentration of…
