Although nutrient needs for bacteria in aerobic and anaerobic biological treatment processes may be grouped as macronutrients and micronutrients, there are significant differences in nutrient requirements between these two treatment processes.These differences are due to the unique needs of methane-forming bacteria and the
lower cell (sludge) yield of fermentative bacteria as compared to aerobic bacteria. Macronutrients, for example, nitrogen and phosphorus, are nutrients that are required in relatively large quantities by all bacteria. Micronutrients, for example, cobalt and nickel, are nutrients that are required in relatively small quantities by most bacteria.The inorganic nutrients critical in the conversion of acetate to methane—the rate-limiting reaction in an anaerobic digester—are the macronutrients nitrogen and phosphorus and the micronutrients cobalt, iron, nickel, and sulfur.
MACRONUTRIENTS
Macronutrient requirements for anaerobic biological treatment processes are much lower than the requirements for aerobic biological treatment processes such as activated sludge and trickling filter processes. The reduced requirement for macronutrients in anaerobic processes is due to lower cell (sludge) yield compared with aerobic processes from the degradation of equal quantities of substrate. The two macronutrients of concern in any biological treatment process are nitrogen and phosphorus. These nutrients are made available to anaerobic bacteria, including methane-forming bacteria, as ammonical-nitrogen (NH
4+–N) and ortho phosphate-phosphorus (HPO4––P). These nutrients, like all nutrients, are available to bacteria only in a soluble form.
MACRONUTRIENTS
Macronutrient requirements for anaerobic biological treatment processes are much lower than the requirements for aerobic biological treatment processes such as activated sludge and trickling filter processes. The reduced requirement for macronutrients in anaerobic processes is due to lower cell (sludge) yield compared with aerobic processes from the degradation of equal quantities of substrate. The two macronutrients of concern in any biological treatment process are nitrogen and phosphorus. These nutrients are made available to anaerobic bacteria, including methane-forming bacteria, as ammonical-nitrogen (NH
4+–N) and ortho phosphate-phosphorus (HPO4––P). These nutrients, like all nutrients, are available to bacteria only in a soluble form.significant decrease in the rate of methane production, that is, decreased enzymatic ability to convert acetate to methane
SULFIDE
Sulfide is the principle source of sulfur for methane-forming bacteria. For sulfide to enter a bacterial cell, it must exist as nonionized hydrogen sulfide (H2S). This form of sulfide occurs in a relatively high concentration within the pH range of 6.8 to 6.9,which is also near the pH of normal anaerobic digester operation
lower cell (sludge) yield of fermentative bacteria as compared to aerobic bacteria. Macronutrients, for example, nitrogen and phosphorus, are nutrients that are required in relatively large quantities by all bacteria. Micronutrients, for example, cobalt and nickel, are nutrients that are required in relatively small quantities by most bacteria.The inorganic nutrients critical in the conversion of acetate to methane—the rate-limiting reaction in an anaerobic digester—are the macronutrients nitrogen and phosphorus and the micronutrients cobalt, iron, nickel, and sulfur.
MACRONUTRIENTS
Macronutrient requirements for anaerobic biological treatment processes are much lower than the requirements for aerobic biological treatment processes such as activated sludge and trickling filter processes. The reduced requirement for macronutrients in anaerobic processes is due to lower cell (sludge) yield compared with aerobic processes from the degradation of equal quantities of substrate. The two macronutrients of concern in any biological treatment process are nitrogen and phosphorus. These nutrients are made available to anaerobic bacteria, including methane-forming bacteria, as ammonical-nitrogen (NH
4+–N) and ortho phosphate-phosphorus (HPO4––P). These nutrients, like all nutrients, are available to bacteria only in a soluble form.
MACRONUTRIENTS
Macronutrient requirements for anaerobic biological treatment processes are much lower than the requirements for aerobic biological treatment processes such as activated sludge and trickling filter processes. The reduced requirement for macronutrients in anaerobic processes is due to lower cell (sludge) yield compared with aerobic processes from the degradation of equal quantities of substrate. The two macronutrients of concern in any biological treatment process are nitrogen and phosphorus. These nutrients are made available to anaerobic bacteria, including methane-forming bacteria, as ammonical-nitrogen (NH
4+–N) and ortho phosphate-phosphorus (HPO4––P). These nutrients, like all nutrients, are available to bacteria only in a soluble form.significant decrease in the rate of methane production, that is, decreased enzymatic ability to convert acetate to methane
SULFIDE
Sulfide is the principle source of sulfur for methane-forming bacteria. For sulfide to enter a bacterial cell, it must exist as nonionized hydrogen sulfide (H2S). This form of sulfide occurs in a relatively high concentration within the pH range of 6.8 to 6.9,which is also near the pH of normal anaerobic digester operation
