Efficient nutrients & trace elements for biological water and wastewater treatment

In biological wastewater treatment, microorganisms - bacteria, fungi, protozoa - perform the main work of breaking down organic and inorganic pollutants.
Three key requirements must be met for these organisms to work optimally:

1. Energy source (organic substances, e.g. carbohydrates, fats, proteins)

2. Macronutrients (nitrogen, phosphorus, potassium) for building cell structures

3. Trace elements (e.g. iron, copper, zinc, cobalt, molybdenum) for enzymatic metabolic reactions

If just one of these components is missing, the metabolic chain of the microbes can be interrupted - comparable to a production line in which a missing component stops the entire production process.
The results are:

• Lower COD and BOD₅ degradation

• Unstable process values (pH, dissolved oxygen, redox potential)

• Visible operating problems such as foaming, flake decay or filament growth

Practical example:
In a dairy wastewater treatment plant, a lack of phosphorus led to unstable nitrification and increased ammonium in the effluent despite a high COD load. Nitrification was only restored within 48 hours after the targeted addition of an ALMA AQUA nutrient mix.

A defect can be detected both directly through laboratory analyses and indirectly through process observations.

Typical indicators in operation:

• Chemical-analytical:

  • Elevated discharge values for COD, BOD₅, ammonium or nitrate

  • Unfavorable N/P ratio in the inlet

  • Very low concentrations of certain metals (Fe, Cu, Co, Mo) in the sludge phase

• Process biology:

  • Reduced oxygen uptake rate (OUR)

  • Extended start-up times after peak loads

  • Lower gas production in anaerobic plants

• Visual cues:

  • Foaming or unstable sludge flakes

  • Filamentous sludge (filamentous bacteria)

  • Dark or very light sludge coloration (false colonization)

Practical tip:
A microscopic examination in combination with a nutrient balance is the safest way to detect a deficiency at an early stage - before limit values are exceeded.

This is determined by means of a nutrient balance:

1. Analysis of the inflow values (COD, BOD₅, total N, total P, trace element content)

2. Calculation of the N/P ratio - for aerobically operated systems, the ideal value is usually approx. 100:5:1 (COD:N:P)

3. Process monitoring - reaction times, degree of degradation, sludge properties

4. Laboratory tests with targeted addition of nutrients for efficacy testing

Tip: ALMA AQUA offers a complete nutrient analysis including dosing recommendations for every system size.

Key elements for stable biological water and wastewater treatment:

• Iron (Fe):

  • Involved in electron transport in the respiratory chain

  • Important for the formation of stable flake structures

  • If iron is missing, flocs disintegrate and the settling properties deteriorate

• Copper (Cu):

  • Activates oxidation and reduction enzymes

  • Important for denitrifying bacteria

  • However, overdosing can have a toxic effect

• Cobalt (Co):

  • Essential for vitamin B₁₂ synthesis in methanogens

  • Particularly critical in anaerobic processes, e.g. biogas plants

• Zinc (Zn):

  • Co-factor of numerous enzymes

  • Supports cell wall and membrane stability

• Molybdenum (Mo):

  • Necessary for nitrification and nitrate reduction

  • Deficiency leads to nitrogen degradation problems

Practical example:
In an industrial wastewater treatment plant in the chemical industry, a lack of cobalt and nickel led to a drastic drop in biogas production. After adding an ALMA AQUA trace element mix, the methane yield was increased by 30 %.

An overdose can be just as problematic as a deficiency - only less obvious.

Possible risks:

• Increased operating costs due to unnecessary chemical consumption

• Precipitation of nutrients in the effluent → Exceeding the limit values for total N or total P

• Toxic effects on sensitive microorganisms with trace elements such as copper, nickel or zinc

• Secondary effects:

  • Formation of interfering solids (e.g. iron phosphate sludge)

  • Inhibition of certain metabolic pathways (e.g. nitrification)

Prevention:

• Automated dosing systems with flow or load-dependent control

• Regular monitoring of the concentrations in the reactor and outlet

• Combination with process monitoring (OUR measurement, microscopy, nutrient balance)

• ontinuous dosing: via a dosing pump directly into the inlet or aeration tank

• Impulse dosing: For acute deficiency states or process disorders

• Multi-point dosing: For large systems or several reactor lines

We offer complete dosing systems with storage tanks, controls and remote monitoring.

Yes - ALMA AQUA nutrients and trace elements are formulated to be widely applicable and process compatible:

• Aerobic processes:

  • Activated sludge (conventional)

  • Membrane bioreactors (MBR)

  • Trickling filter systems

• Anaerobic processes:

  • Digestion (municipal & industrial)

  • UASB/EGSB reactors

  • Co-fermentation in biogas plants

• Combined procedures:

  • Nitrification / denitrification

  • Sequencing Batch Reactors (SBR)

Important:
The exact composition (macronutrients, trace elements, chelates) is adapted to the process type, the wastewater characteristics and the load.
This ensures that the microorganisms are optimally supplied without burdening the process by overdosing.

The N/P ratio (ratio of nitrogen to phosphorus) is a key indicator of the nutrient supply in biological purification processes.

• Standard values for aerobic processes: approx. 100:5:1 (COD:N:P)

• Standard values for anaerobic processes: vary depending on the substrate, often lower P requirement

optimization strategy:

1. Analyze inlet characteristics - measurement of COD, total N, total P

2. Take daily and weekly fluctuations into account

3. Fine-tuning the dosing based on discharge values and microscopy results

4. Load-dependent control with automatic adjustment of nutrient addition

Practical example:
In a dairy wastewater treatment plant, precise adjustment of the N/P ratio from 100:3:0.8 to 100:5:1 increased the nitrification performance by 20 % and kept the ammonium values in the effluent permanently below 2 mg/l.

Anaerobic processes - especially methane formation stages - react very sensitively to trace element deficiencies. These are particularly important:

• Cobalt (Co): essential for vitamin B₁₂, indispensable for methanogens

• Nickel (Ni): Co-factor for enzymes in methanogenesis

• Selenium (Se): for enzymes in acetate degradation

• Iron (Fe): Electron transport, hydrogen sulphide binding

Typical problems with deficiency:

• Decrease in methane production

• Increase in volatile fatty acids (VFA) → pH drop

• Unstable gas quality (CO₂ increase)

Solution:
Targeted addition of ALMA AQUA trace element mixtures with chelated stabilization to prevent precipitation in the event of excess sulphide or carbonate.

Early detection is crucial in order to avoid process faults and limit value violations.

Recommended methods:

1. Regular laboratory analyses of biomass and water (total and dissolved trace elements)

2. Microscopic control: decline in species diversity, occurrence of filamentous bacteria or lack of protozoa

3. Online process monitoring: changes in gas production (anaerobic), OUR/respiration rate (aerobic)

4. Bioassays: Laboratory scale tests with targeted nutrient addition → Measure reaction speed

Practical tip:
Trace element deficiencies often occur first in sub-processes, e.g. inhibition of nitrification or reduced biogas yield. Continuous process data evaluation in combination with a proactive nutrient strategy prevents critical faults from occurring in the first place.