Toxic Effect of Ammonium Nitrogen on the Nitrification Process and Acclimatisation of Nitrifying Bacteria to High Concentrations of NH4-N in Wastewater

Iwona Beata Paśmionka,Karol Bulski,Piotr Herbut,Marina Celant De Prá,Marcelo Bortoli,Frederico Márcio C Vieira,Gabriela Bonassa,Elżbieta Boligłowa

doi:10.3390/en14175329

Abstract

The aim of the conducted research was to assess the effectiveness of the nitrification process, at different concentrations of ammonium nitrogen, in biologically treated wastewater in one of the largest municipal and industrial wastewater treatment plants in Poland. The studies also attempted to acclimate nitrifying bacteria to the limited concentration of ammonium nitrogen and determined the efficiency of nitrification under the influence of acclimated activated sludge in the biological wastewater treatment system. The obtained results indicate that the concentration of ammonium nitrogen above 60.00 mg·dm−3 inhibits nitrification, even after increasing the biomass of nitrifiers. The increase in the efficiency of the nitrification process in the tested system can be obtained by using the activated sludge inoculated with nitrifiers. For this purpose, nitrifiers should be preacclimated, at least for a period of time, allowing them to colonize the activated sludge. The acclimated activated sludge allows reducing the amount of ammonium nitrogen in treated sewage by approx. 35.0%. The process of stable nitrification in the biological treatment system was observed nine days after introducing the acclimated activated sludge into the aeration chamber.

Highlights

Nitrogen is the basic building element that regulates biological productivity in the aquatic environment
In the first series of tests, the limit concentration of total ammonium nitrogen (TAN) was determined in wastewater directed to biological treatment, above which the nitrification process is inhibited
The results obtained in the first test series (Table 3) indicate a low efficiency of NH4-N oxidation both in the samples containing cultures of nitrifying bacteria, with a biomass of 0.25 mg, and in the control samples, only when the concentration of ammonium nitrogen did not exceed 60.00 mg·dm−3 (Figure 2)

Summary

Introduction

Nitrogen is the basic building element that regulates biological productivity in the aquatic environment. This element, like other biogeochemical elements, has its own circulation cycle. The main source of nitrogen in wastewater is proteins and other organic compounds, including urea. As a result of hydrolysis and ammonification processes, part of the nitrogen present in the organic form (especially urea) is converted into the ammonium or ammonia form. Total ammonium nitrogen (TAN) represents the sum of these two forms. The major part of the non-oxidized forms of nitrogen is TAN, while the rest is bound in the form of various organic compounds [2,3]

Objectives

Methods

Results

Conclusion