Mutag BioChip vs Kaldnes K1
Mutag BioChip vs Kaldnes K1
In a recent study, Bassin et. al. (2016) assessed the activity of the suspended and attached biomass on two types of moving-bed biofilm carriers under identical conditions. The moving-bed biofilm reactors were loaded with K1 (MBBR1) and white Mutag BioChip™ (MBBR2) and evaluated at different pollutant loads.
They concluded that both biofilm carrier types reached the same performance in COD removal and nitrification, but the Mutag BioChip™ used only one sixth of the volume AnoxKaldnes™ K1 carrier used (factor of 1 : 6). The same findings were achieved in elaborate and numerous laboratory scale tests and pilot trials.
Both systems could completely remove high organic loads (up to 12.8 g COD/m²/d = 6.4 kg COD/m³ of K1 and 38.4 kg COD/m³ of Mutag BioChip™) at simultaneously performed complete ammonium removal.
The trials had been conducted over a period of 700 days in two 1 liter MBBR systems. To ensure reproducible process conditions, a synthetic substrate was produced from sodium acetate and ammonium chloride, together with the required nutrients. The dissolved oxygen concentration varied in the range from 4 to 5 mg/l. The ambient temperature was around 22°C and the pH value was maintained between 6.8 and 7.5.
The MBBR1 was operated with the AnoxKaldnes™ K1 carrier and the MBBR2 with the Mutag BioChip™. Using published carrier surface area values given by the respective suppliers (K1: 500 m²/m³; Mutag BioChip™: 3,000 m²/m³), the MBBR1 was operated with 50% of the K1 and the MBBR2 with 8.3% of the Mutag BioChip™ carrier media. Hence, both systems contained 250 m² [surface area] / m³ [reaction tank volume].
After a start-up period of 20 – 30 days required for the establishing of biofilms on the carriers, the measurements were started. The different loads were similar for both reactors. The increase of the organic load was adjusted by increasing the inlet COD concentrations.
In further tests, the HRT and the COD were reduced to keep the influent loads at a constant level. After 40 days in operation, a nearly complete ammonium removal was observed. Although the organic load of 0.8 kg COD/m³/d (= 1.6 kg COD/m³ K1 and 9.6 kg COD/m³ Mutag BioChip™) was gradually increased to 3.2 kg COD/m³/d (= 6.4 kg COD/m³ K1 and 38.4 kg COD/m³ Mutag BioChip™), a very stable and high ammonium removal was observed throughout the complete observation period.
In both MBBR tanks a nearly complete COD (>95%) and ammonium removal (>90%) was observed up to the maximum test loads of 6.4 kg COD/m³ K1 and 38.4 kg COD/m³ Mutag BioChip™.
Biomass: The total quantity or weight of living organisms in a system, area or volume.
Biofilm: A thin but robust layer of slime or glue-like substance (mucilage) adhering to a solid surface (ie the media) and containing a community of bacteria and other microorganisms.
COD: Chemical oxygen demand is a measure of the capacity of water to consume oxygen during the decomposition of organic matter and the oxidation of inorganic chemicals such as ammonia and nitrite.
COD: Chemical oxygen demand is the total measurement of all chemicals in the water that can be oxidized. TOC or Total Organic Carbon is the measurement of organic carbons. BOD- Biochemical Oxygen Demand is supposed to measure the amount of food (or organic carbons) that bacteria can oxidize.
HRT The Hydraulic retention time (HRT) or t (tau) is a measure of the average length of time that a soluble compound remains in a constructed bioreactor. The volume of the aeration tank divided by the influent flowrate is τ (tau), the hydraulic retention time.
Chemical Oxygen Demand or COD is a measurement of the oxygen required to oxidize soluble and particulate organic matter in water.
The standard method for indirect measurement of the amount of pollution (that cannot be oxidized biologically) in a sample of water.
The chemical oxygen demand test procedure is based on the chemical decomposition of organic and inorganic contaminants, dissolved or suspended in water. The result of a chemical oxygen demand test indicates the amount of water-dissolved oxygen (expressed as parts per million or milligrams per liter of water) consumed by the contaminants, during two hours of decomposition from a solution of boiling potassium dichromate. The higher the chemical oxygen demand, the higher the amount of pollution in the test sample.
SDK: If we then extrapolate, the new blue Mutag BioChip-25 with its specified area of 4000 m2/m3 will use one eighth of the volume of K1 for the same application. A significant cost reduction in transport, vessel construction, plant footprint and plant overheads.