PROPELLER PUMPS There are two basic types of propeller pumps, axial-flow and mixed-flow impellers. The axial-flow propeller pump is one having a flow parallel to the axis of the impeller. The mixed-flow propeller pump is one having a flow that is both axial and radial to the impeller. VERTICAL WET WELL PUMPS A vertical wet…
Foaming Problems Operators of activated sludge systems may encounter a variety of foam and scum problems. Non-degradable detergents, grease, oil and other unknown substances can all create foam and scum. Most types of foams that are caused by detergents can be controlled by simply hosing them down regularly. Other foams can be extraordinarily persistent and…
Aerobic Bacteria Water, the home of most bacteria, contains oxygen in two forms. The first form, free oxygen, is the most readily available form. Free oxygen is basically the same as dissolved oxygen oxygen from the atmosphere that has become dissolved in water. Aerobic bacteria require free oxygen in order to survive. Bacteria may be…
1. Hazards that may damage a TV camera going through a sewer include _. a. deep water that submerges the camera b. fogging of optical lens c. offset joints d. all the above 2. Centrifugal pump parts include _. a. diaphragm b. piston c. rotor d. volute 3. When packing a centrifugal pump, the packing…
1. Possible techniques for controlling filamentous organisms in an activated sludge process include _. a. dosage of return sludge with oxidants such as hydrogen peroxide or chlorine b. lower D.O. levels in aeration basins so filamentous organisms cannot breath c. lower F/M level to starve filamentous organisms d. reduce nutrients essential for filamentous organisms e….
Decimals Decimal numbers are used when you need more precision than whole numbers provide. Decimals are based on units of ten (tenths) and multiples of tenths. The value of a digit in a decimal depends on the place of the digit. Examples: 1.234567 – the 1 is in the whole number position 1.234567 – the…
BOD Biochemical oxygen demand or BOD is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. It is not a precise quantitative test, although it…
RAS Chlorination When filamentous bulking problems reach the extent that large amounts of solids are washing out of the secondary clarifier, it is time for drastic measures to be taken to regain control of the situation. One way of doing this is through the introduction of a toxic substance, such as chlorine, into the mixed…
A centrifugal pump moves water by the use of centrifugal force. Any time an object moves in a circular motion there is a force exerted against the object in the direction opposite the center of the circle. This would be easier to explain if we use an example consisting of a person with a bucket…
Pumps serve many purposes in wastewater collection systems and treatment plants. They are classified by the character of the material handled; raw wastewater, grit, effluent, activated sludge, raw sludge, or digested sludge. Or, they may relate to the conditions of pumping: high lift, low lift, recirculation, or high capacity. They may be further classified by…
