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.
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.
Thiourea is a typical nitrification inhibitor that shows a strong inhibitory effect against the biological nitrification process. The 50% inhibitory concentration (IC50) of thiourea on nitrification was determined to be 0.088 mg g VSS−1, and nitrifiers recovered from the thiourea inhibition after it was completely degraded. The thiourea-degrading ability of the sludge system was improved to 3.06 mg gVSS−1 h−1 through cultivation of thiourea-degrading bacteria by stepwise increasing the influent thiourea concentrati...
The potential for integrated fixed film activated sludge (IFAS) processes to achieve enhanced transformation of pharmaceuticals relative to conventional activated sludge (CAS) processes was assessed. Previous studies have focused on direct comparisons of parallel reactors with and without fixed film carriers and little information is available on the impacts of how varying operating parameters impact the differences in observed pharmaceutical compound (PC) transformation capabilities between CAS reactors and...
The aim of the present work was to evaluate the effects of carbon sources and chemical oxygen demand (COD)/NO2−-N ratios on the anammox–denitrification coupling process of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm. Also, the anammox activities of the SNAD biofilm were investigated under different temperature. Kaldnes rings taken from the SNAD biofilm reactor were operated in batch tests to determine the nitrogen removal rates. As a result, with the carbon source of sodium...
This study evaluates the removal of nitrogen compounds from wastewater in modified, small diameter gravity slope (SDGS) pipes during its conveyance. A 13-meter long, closed loop, wastewater collection network was designed and built at laboratory scale. The modified SDGS consists of Polyvinyl Chloride (PVC) tubes with perforated plastic netting fixed to the inner surfaces, to enhance biofilm attachment and growth under gravity flow. The system was operated at constant temperature using synthetic wastewater similar...