Method for treating water within a sequential biological reactor including an in-line measurement of the nitrite concentration inside said reactor

A method treating water to reduce ammonium pollution in the water, comprising:

• a. performing a series of treatment cycles in a reactor, each cycle comprising an aerated nitritation phase followed by a subsequent phase and including:
• i. starting a flow of water to be treated into the reactor;
• ii. commencing the aerated nitritation phase by starting aeration of the water;
• iii. continuously or at intervals determining nitrite concentration in the water;
• iv. continuously or at intervals determining elemental nitrogen concentration in the water;
• v. upon elemental nitrogen concentration in the water becoming greater than a first threshold value, stopping the flow of water to be treated;
• vi. upon the nitrite concentration in the water becoming greater than a second threshold value, ending the aerated nitritation phase by stopping the aeration of the water.

A system for treating water to reduce ammonium pollution in the water, comprising:

• a. an incoming water buffer device for receiving, holding, and discharging water to be treated;
• b. a reactor in fluid communication with the buffer device for receiving water discharged from the buffer device;
• c. an aeration device for aerating water held in the reactor;
• d. a carbon injection device in fluid communication with the reactor for injecting carbonaceous substrate into the reactor;
• e. a series of sensors, each sensor for sensing a particular process variable, the series of sensors including:
• i) an ammonium probe configured to sense ammonium in the water held in the reactor and to produce a signal from which ammonium concentration in the water can be computed,
• ii) a nitrite probe configured to sense nitrite in the water held in the reactor and to produce a signal from which nitrite concentration in the water can be computed,
• iii) a water level sensor configured to sense a water level in the reactor;
• f. a controller for:
• i) receiving signals from the sensors,
• ii) performing computations of at least ammonium and nitrite concentrations, and
• iii) selectively producing control signals for controlling the:
• (1) flow of water from the buffer device to the reactor,
• (2) injection of carbonaceous substrate into the reactor from the carbon injection device, and
• (3) aeration of water in the reactor by the aeration device.

A method of treating water, comprising:

• a. feeding water to be treated into a reactor;
• b. treating the water by sequential processes that include nitritation and denitritation;
• c. sensing one or more process variables, including nitrite concentration in the water;
• d. based, at least, on the nitrite concentration in the water and on a comparision of the nitrite concentration with one or more of a plurality of threshold values of nitrate concentration, adjusting one or more of:
• i. the amount of water in the reactor;
• ii. an amount of oxygen in the water;
• iii. an amount of carbon in the water
• to control whether the process is nitritation or denitritation;
• and
• e. aerating the water in the reactor until the nitrite concentration exceeds one of the pluralilty of threshold values.

A method for treating water having ammonium, comprising:

• a. a water treatment process with at least two process steps selected from the group of process steps including:
• i) performing aerated nitritation,
• ii) performing denitritation,
• iii) performing deammonification, and
• b. a measurement process that includes in-line determination of at least one process variable selected from the group of process variables that includes:
• i) nitrite concentration in the water,
• ii) ammonium concentration in the water
• iii) a ratio of the ammonium and nitrite concentrations;
• c. at least one control step selected from the group of control steps that includes:
• i) feeding water to be treated into the reactor,
• ii) stopping the feeding of water to be treated into the reactor,
• iii) aerating the water,
• iv) stopping the aeration of the water,
• v) injecting carbon into the water, and
• vi) stopping the injection of carbon in the water;
• d. extracting treated water from the reactor;
• e. wherein the process step includes nitritation, the measurement process includes determining nitrite concentration and ammonium concentration, and wherein the control steps include feeding water to be treated into the reactor, aerating the water, and stopping the feeding of water in response to the sum of nitrate and ammonium concentrations exceeding a first threshold value;
• and
• f. wherein the process steps include denitritation beginning after nitritation ends, and wherein the control steps include stopping aeration and injecting carbon in response to the nitrite concentration exceeding a second threshold value.