Biological nitrification and denitrification are key processes to remove nitrogen from wastewater and have become more important due to stringent discharge regulations.Nitrifier’s population (ammonia oxidizing bacteria (AOB) + nitrite oxidizing bacteria (NOB)) should be more than 5–8% of the biomass for good nitrification. However, nitrifiers have slow growth rates and they are also believed to be sensitive to environmental changes such as toxic shocks, pH, and temperature changes. Due to these characteristics, it is difficult to obtain and maintain sufficient nitrifies in wastewater treatment plants (WWTPs), if solids retention time (SRT) gets shorter. And as a consequence, it is difficult to maintain nitrification in municipal and industrial wastewater treatment plants (WWTPs). Organic material in wastewater is removed in order to reduce oxygen consuming substances in the recipient and it is performed by bacteria at wastewater treatment plants (WWTP). In activated sludge the biomass consists of different types of bacteria. The aerobic degradation process of organic material can be determined by measuring the oxygen uptake rate (OUR) for the microorganisms. Oxygen uptake rate measurements can provide much information concerning treatment plant performance, wastewater characteristics, degradability of special concentrated streams as well as parameters needed for mathematical models, in order to predict possible optimizations of a treatment plant. In addition it is useful for daily operation control.

Nitrification is of great importance for nitrogen removal from municipal wastewater in the biological nutrient removal process (BNR) employed in waste water treatment plants (WWTPs). In nitrification, ammonium is firstly oxidized to nitrite via ammonia-oxidizing bacteria (AOB), and then to nitrate by nitrite-oxidizing bacteria (NOB).

Nitrifier's population (ammonia oxidizing bacteria (AOB) + nitrite oxidizing bacteria (NOB)) should be more than 5–8% of the biomass for good nitrification [. However, nitrifiers have slow growth rates and they are also believed to be sensitive to environmental changes such as toxic shocks, pH, and temperature changes. Due to these characteristics, it is difficult to obtain and maintain sufficient nitrifiers in wastewater treatment plants (WWTPs), if solids retention time (SRT) gets shorter . And as a consequence, it is difficult to maintain nitrification in municipal and industrial wastewater treatment plants (WWTPs).In conventional activated sludge processes, a long SRT is necessary to maintain sufficient nitrifiers for nitrification. The long SRT increases the concentration of mixed liquor suspended solids (MLSS) which requires large tanks and clarifiers to accommodate the accumulation of solids inventory .

https://www.researchgate.net/publication/252014875_Modeling_and_simulating_for_enrichment_of_Nitrifying_Bacteria_by_reject_water_to_enhance_nitrification_in_wastewater_treatment?_sg=LYEhanK_hzHYhYp1smTNBB-82m2iNBtRakOx8AGY00oECVrMgK9k8kq9bydxsm7hKaG-GmxChPyNxe5rPMDZD_oNO8lCjMZAPRGRYOUy.ahwP7gV6bh2FuuK7cZ4i4xtALb3dp0-Ur7DQYvNQg563JngS5LOTy85bPDtmkibnX0z5FqSZvK_KW-8mZE8hJQ

https://www.researchgate.net/publication/232611800_Shifts_in_Nitrification_Kinetics_and_Microbial_Community_during_Bioaugmentation_of_Activated_Sludge_with_Nitrifiers_Enriched_on_Sludge_Reject_Water?_sg=LYEhanK_hzHYhYp1smTNBB-82m2iNBtRakOx8AGY00oECVrMgK9k8kq9bydxsm7hKaG-GmxChPyNxe5rPMDZD_oNO8lCjMZAPRGRYOUy.ahwP7gV6bh2FuuK7cZ4i4xtALb3dp0-Ur7DQYvNQg563JngS5LOTy85bPDtmkibnX0z5FqSZvK_KW-8mZE8hJQ

You can also download this really good book:

Book Experimental Methods in Wastewater Treatment

Can anyone help me, I want to calculate the nitrification rate in an SBR process treating landfill leachate. Thank you very much

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