J

J

Jackson Turbidity Unit (JTU)

A formerly-used measurement of the turbidity in a water sample. This has been replaced by the nephelometric turbidity unit.

Jar Test

A laboratory procedure that simulates a water treatment plant's coagulation/flocculation units with differing chemical doses and also energy of rapid mix, energy of slow mix, and settling time.     The purpose of this procedure is to estimate the minimum or ideal coagulant dose required to achieve certain water quality goals.     Samples of water to be treated are commonly placed in six jars.     Various amounts of chemicals are added to each jar, stirred, and the settling of solids is observed. The dose of chemicals that provides satisfactory settling removal of turbidity and/or color is the dose used to treat the water being taken into the plant at that time.     When evaluating the results of a jar test, the operator should also consider the floc quality in the flocculation area and the floc loading on the filter.

Jet (Ejector) Pump

A combined centrifugal and ejector pump.     In a jet pump, a portion of the discharge water from the centrifugal pump is diverted through a nozzle and venturi tube. A pressure zone lower than that of the surrounding area is created by the velocity of water flowing through the venturi tube; therefore, water from the source (the well) flows into this area of reduced pressure. The velocity of the water from the nozzle pushes the water through the pipe toward the surface where the centrifugal pump can lift it by suction. The centrifugal pump then forces the water into the water plumbing system.

Jetted Well

A shallow well constructed by a high-velocity stream of water directed downward into the ground.

Jogging

The frequent starting and stopping of an electric motor.

Joule

A measure of energy, work, or quantity of heat. One joule is the work done when the point of application of a force of one newton is displaced a distance of one meter in the direction of force.  The absolute unit of work-energy equal to 10<sup>7</sup> ergs or about 0.7736 foot-pounds or 0.2389 calories.    One joule is the work done when the point of application of a force of one newton is displaced a distance of one meter in the direction of force.     The absolute unit of work-energy equal to 10<sup>7</sup> ergs or about 0.7736 foot-pounds or 0.2389 calories.

Glad we could be helpful. Thanks for the feedback.

Sorry we couldn't be helpful. Your feedback will help us improve this article.

How helpful was this page?

  
Updated on Mon, 22 Jun 2020 by Jonathan

In this section