Existing municipal effluent treatment plants designed earlier for the BOD removal are usually not suitable for nitrification at low temperatures, because of :
Small plant dimensions and low sludge age, respectively
Consequences are that in the cases of nitrification expensive plant extensions are required.
2. Our problem solution results in
Plants being upgraded into fluidised bed reactors using microorganisms immobilised on adsorbing LEVAPOR-carrier.
Nitrifying bacteria immobilised on adsorbant carriers become more robust and efficient, produce lower quantities of excess sludge and are able to maintain their activity even after a storage over 12 months.
A. Upgrading of a small municipal WWTP with aerated basin of 45 m³, for nitrification in winter, by filling it with 12 vol.% of LEVAPOR carrier
As a possible alternative to plant extension, it was considered to establish the nitrification by a susequent WWTP- upgrading via immobilisation of nitrifying sludge on 12 vol.% of adsorbing LEVAPOR-carrier.
After addition into the basin the carrier cubes became colonised and fluidised directly and despite the low temperatures (November) the nitrification was established at 17°C within two to three weeks and kept efficient achieving 70 to 80% nitrification over several months, despite even the lower temperatures in December (12 °C).
Nitrification performance of the plant at different temperatures
Immobilising the activated sludge, nitrification was established within 2 to 3 weeks.
The nitrification remained stable and efficient, even at lower temperatures, of 8 to 13°C with increased volumetric N-loading rates.
The existing aeration system was proven as sufficient for almost a complete fluidisation of the colonised carrier cubes.
Removal of excess biomass from the surface of the carrier cubes occurred automatically by fluidisation without any additional measure.
B. Nitrification and removal of hazardous pollutants from municipal effluents ( pilot plant trials)
Comparison of immobilised -LEVAPOR-carrier - vs. suspended sludge
In two parallel operated fluidised bed reactors, each of 3,1 m³, nitrification and hazardous pollutant removal of immobilised and suspended biomass have been compared. In addition to higher degree of nitrification and denitrification ( due to inner pores of carrier cubes ), immobilised biomass achieved also a remarkably higher removal of polycondensed aromatic compounds.
Environmental factors control the rate of nitrification. For a determined substrate concentration, the most significant environmental factors are temperature, pH and oxygen availability. The well known critical influence of those factors on the nitrification are here analyzed by making use of a specific software and advanced respirometry based on a dynamic LFS system, where the test conditions can be set in the corresponding test-settings board and their levels modified throughout the test performance....
For a determined substrate concentration, the most significant environmental factors are temperature, pH and oxygen availability. The well known critical influence of those factors on the nitrification are here analyzed by making use of a specific software and advanced respirometry based on a dynamic LFS system, where the test conditions can be set in the corresponding test-settings board and their levels modified throughout the test performance. In this way, it is possible to get and asses the trajectory of the...
Greener Waste Technology is a Process Engineering and Environmental Consultancy specialising in the Municipal sector. Following several years of extensive research Greener Waste Technology has advanced the unique bacteria dosing technology which has been successfully introduced to a number of water companies. The BioCube is being successfully used in wastewater treatment to optimise processes which suffer from excess FOG, BOD overload, poor nitrification, and poor sludge quality.
To improve the efficiency of simultaneous heterotrophic nitrification and aerobic denitrification (SND) at high concentrations of NaCl and ammonia nitrogen (NH4+—N), we investigated the SND characteristics of Halomonas bacteria with the ability to synthesize the compatible solute ectoine. Halomonas sp. strain B01, which was isolated, screened and identified in this study, could simultaneously remove nitrogen (N) by SND and synthesize ectoine under high NaCl conditions. Gene cloning and sequencing analysis indicated...
Accumulated sludge in polishing (maturation) ponds reduces the hydraulic retention time (smaller useful volume), and this could potentially lead to a decrease in performance. However, settled biomass, present in the sediments, can contribute to nitrogen removal by different mechanisms such as nitrification and denitrification. This study investigated the influence of the bottom sludge present in a shallow maturation pond treating the effluent from an anaerobic reactor on the nitrification and denitrification...