Abstract: Disclosed is a method of denitrifying a solution including introducing into the solution an amount of a carbon source within a duration and at a frequency so that indigenous heterotrophic bacteria deplete dissolved oxygen in the solution and obtain oxygen from nitrate in the solution. Related apparatuses and compounds also are disclosed.

Abstract: Disclosed is an apparatus for denitrifying a solution that includes a denitrification tank configured to receive a portion of the solution for a period of time. Controlling an amount, duration and frequency of introduction of polyethylene glycol into the solution promotes indigenous heterotrophic bacteria depleting dissolved oxygen in the solution and obtaining oxygen from nitrate in the solution.

Abstract: Disclosed is an apparatus for denitrifying a solution that includes a denitrification tank configured to receive a portion of the solution for a period of time. Controlling an amount, duration and frequency of introduction of polyethylene glycol into the solution promotes indigenous heterotrophic bacteria depleting dissolved oxygen in the solution and obtaining oxygen from nitrate in the solution.

Abstract: Disclosed is a method of denitrifying a solution including introducing into the solution an amount of a carbon source within a duration and at a frequency so that indigenous heterotrophic bacteria deplete dissolved oxygen in the solution and obtain oxygen from nitrate in the solution. Related apparatuses and compounds also are disclosed.

Abstract: An apparatus for associating a solution at an infinitely-variable level and/or flow rate with respect to an agent including an agent amount indicator that promotes agent-solution association adaptable for use in a chlorinator, or comparable component, of a fluid treatment plant. An embodiment configured according to the invention includes a chamber with an inlet and a vertically-inferior outlet. The level and flow of fluid in the chamber is regulated by a weir mounted on the outlet. Fluid in the chamber passes through an agent the retainer maintained in the chamber and washes over the agent, dissolving and depleting the agent. A magnetic follower on top of the agent urges the agent toward the bottom of the retainer. As the agent becomes depleted, the follower approaches the bottom of the retainer until it attains a predetermined distance from a sensor which activates a low-agent-supply alarm. If the alarm remains activated for a predetermined amount of time, a second alarm is activated.