3 results about "Nitrite concentration" patented technology

This invention relates to the field of wastewater biological treatment technology, specifically to a device and method for improving the autotrophic denitrification performance of a MABR reactor. It employs a composite membrane module combining a curtain-type silica gel filament membrane with excellent oxygen permeability with a spatial three-dimensional mesh packing material that facilitates the attachment of anaerobic ammonia-oxidizing bacteria, thereby coupling part of the nitrification reaction with the anaerobic ammonia oxidation reaction. Through the circulating reaction zone and membrane reaction zone within the reactor, nitrate nitrogen generated by anaerobic ammonia oxidation and excess nitrite nitrogen during instability adjustment are circulated and removed, thus improving the total nitrogen removal efficiency of the reactor. By adding appropriate amounts of sodium nitrite solution at appropriate times, the free nitrite concentration in the reactor mixture is increased. Simultaneously, the intermittent aeration ratio of the MABR is controlled to achieve synergistic inhibition of nitrite-oxidizing bacteria activity by low dissolved oxygen and high free nitrite, allowing the unstable short-range nitrification reaction to recover and improving the autotrophic denitrification performance of the reactor.

The present invention provides a water treatment device that can stably treat COD components while suppressing the generation of nitrite to a low level. [Solution] A water treatment apparatus comprising a biological treatment tank containing activated sludge containing bacteria capable of decomposing COD components, and into which water to be treated containing ammonia and thiocyanate ions is introduced. This water treatment apparatus comprises an aeration device that performs aeration in the biological treatment tank, and a measuring unit that measures at least one concentration value selected from the group consisting of ammonium concentration, nitrite concentration, and nitrate concentration in the treated water obtained by treating the water to be treated in the biological treatment tank. Furthermore, this water treatment apparatus comprises a control unit that adjusts the aeration airflow rate based on the difference between the ammonium concentration in the water to be treated and the ammonium concentration in the treated water measured by the measuring unit, and at least one index value selected from the group consisting of nitrite concentration, nitrate concentration, and the sum of nitrite concentration and nitrate concentration in the treated water measured by the measuring unit.

The application discloses an artificial compound feed for reducing nitrogen pollution of seawater fish culture water, which comprises an animal protein source and a feeding attractant, wherein the animal protein source is composed of fish meal and pork meal, the fish meal accounts for 60-80% of the mass of the animal protein source, and the pork meal accounts for 20-40% of the mass of the animal protein source; and the feeding attractant is fishy odor, and accounts for 0.5-2.0% of the total weight of the artificial compound feed. Compared with the artificial compound feed using fish meal as the animal protein source, the artificial compound feed not only has the same performance of maintaining normal growth of the cultured fish, but also reduces the feed cost, and more importantly, can significantly reduce the ammonia nitrogen and nitrite concentration in the cultured water, thereby providing an effective method for controlling nitrogen pollution from the feed source.