Advanced methods of designing biological treatment facilities

Summary

The data of the analytical reviews and practical results of calculating and designing advanced wastewater treatment facilities are presented. The analysis of the methods of designing biological wastewater treatment facilities (construction rules and regulations SNiP, ATV) and the software for mathematical simulation of the facilities operation («EcoSim», GPS-X etc.) is made together with the hydrodynamic continuum mechanics software as applied to calculating the flow conditions at the treatment facilities. The mathematical model of biological wastewater treatment process is based on the analysis of the relationships of enzyme kinetics of the wastewater pollutant transformation and makes a connection between the parameters of the raw waste and effluent, dissolved oxygen concentration and activated sludge. The principles of designing and calculating the facilities for biological treatment of municipal and industrial wastewater including the use of nitri-denitrification and biological phosphorus removal processes have been developed. The practical experience of using the mentioned methods in front end and design works.

Key words

biological treatment , nitri-denitrification , mathematic modelling , energy efficiency of equipment , wastewater composition , biological phosphorus removal

The technology of step-feed nitri-denitrification in municipal wastewater treatment: the analysis of options and case record

Summary

The experience of MY PROJECT JSC in designing biological treatment facilities (aeration tanks) at the municipal treatment facilities of the Russian Federation with the use of step-feed nitri-denitrification is considered. Over the past 10 years more than 20 treatment facilities have been upgraded and built with the introduction of a step-feed scheme; the author of the article made a personal commitment in commissioning of more than 10 biological treatment facilities for municipal and industrial wastewater processing. In order to observe the data confidentiality, no data is provided on the chemical analysis of the operation of structures; however, with the help of mathematical modeling, the specific features of the implementation of step-feed denitrification are shown. The key process engineering aspects of the implementation of the schemes of a step-feed process with a different number of stages (two and three), cases of the need to use or reject nitrate recycling, as well as using, where applicable, an additional substrate (methanol) with particularly stringent requirements to the nitrogen concentration at the effluent discharge are considered. Traditionally, it is believed that the scheme of step-feed denitrification is designed for nitrogen removal; however, additional positive modifications of step-feed denitrification have been also considered that provide for arranging biological removal of phosphorus. The design of an anaerobic zone upstream the first denitrification cascade (D1), the use of step-feed denitrification in the implementation of the process scheme of the University of Johannesburg (JHB), as well as the arrangement of step-feed of return sludge are considered.

Key words

biological treatment , nitrification , denitrification , aeration tank , biological phosphorus removal , step-feed technology