Method of combined treatment of air terminal wastewater and liquid wastes from dry closets of aircrafts

Summary

The composition of the wastewater of air terminals includes sewage and industrial wastewater from the technological equipment of the food unit. Process flow schemes for wastewater treatment of air terminals do not provide for the reception and treatment of liquid wastes from water closets of aircrafts, that are highly concentrated in terms of COD, ammonium nitrogen, phosphorus. In addition, they contain high concentrations of disinfectants with quaternary ammonium salts (QAS) as an active ingredient toxic to microorganisms. As a result of liquid waste discharge to the operating treatment facilities of the air terminal, the quality indicators of biological wastewater treatment have significantly deteriorated, and the properties of the biocenosis of the biofilm have also changed. The aim of the research was to determine a method for reducing the concentration of QAS to the level where the toxic effect on the biofilm biocenosis ceased, and to develop an appropriate process flow scheme. An analysis of the literature data on the impact of QAS on activated sludge microorganisms is presented; on this basis laboratory studies were carried out and a method was developed for the pre-treatment of liquid waste from aircraft water closets for the subsequent combined treatment with the air terminal sewage. In the course of the tests, the efficiency of pollution sorption, including QAS, by the preliminary regenerated excess activated sludge was determined. The technological parameters of the processes were determined; an efficient, reliable, easy-to-use process flow scheme for the combined treatment of sewage of the air terminal and liquid waste of water closets of aircrafts was developed and implemented.

Key words

biological treatment , surplus active silt , adsorption , air terminal wastewater , liquid waste of water closets of aircrafts , quaternary ammonium salts , pre-treatment