Kinetic study of compost liquor nitrification
J Gagnaire1, X Y Wang, L Chapon
1Université Paul Cézanne Aix Marseille III, Laboratoire de Mécanique, Modélisation et Procédés Propres, M2P2 UMR-CNRS 6181, Europôle de l'Arbois, BP 80, Bâtiment Laennec, Hall C, 13545 Aix-en-Provence Cedex 4, France.
Summary
Compost liquor, a wastewater high in organic and nitrogen compounds, inhibits ammonia oxidation in non-acclimated activated sludge. A dedicated wastewater treatment plant with acclimation is recommended for effective treatment.
Area of Science:
- Environmental Microbiology
- Wastewater Engineering
- Biochemical Kinetics
Background:
- Compost liquor presents a significant challenge for wastewater treatment due to high organic (COD) and ammonia nitrogen loads.
- Urban Wastewater Treatment Plants (WWTPs) may struggle with such industrial effluents without specific adaptations.
- Understanding the kinetic behavior of activated sludge is crucial for designing effective treatment processes.
Purpose of the Study:
- To investigate the kinetic approach for treating compost liquor using activated sludge.
- To assess the inhibitory effects of compost liquor on ammonia oxidation by non-acclimated sludge.
- To determine the feasibility of treating compost liquor in conventional urban WWTPs.
Main Methods:
- Kinetic modeling of ammonia oxidation rates using Haldane and Monod models.
- Comparison of sludge performance with real compost liquor and a synthetic substrate.
- Measurement of ammonia oxidation rates and nitrate production.
Main Results:
- Compost liquor acts as an inhibitory substrate for ammonia oxidation, best described by the Haldane model (K(I)=26.0 mgN.L(-1)).
- Ammonia oxidation of a synthetic substrate with similar pollutant load followed the Monod model, indicating inhibition by real wastewater.
- Nitrite oxidizing bacteria were also inhibited, suggesting a broader impact on nitrification.
Conclusions:
- Treatment of compost liquor in standard urban WWTPs (<50,000 p.e.) is not feasible due to substrate inhibition.
- A dedicated WWTP is recommended for compost liquor treatment.
- An essential acclimation step for activated sludge is required for effective treatment of this industrial effluent.
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