Fungal biomass is increasingly considered as a practical material for supporting the treatment of contaminated water and other industrial streams. In this context, the term refers to fungal material that can interact with dissolved pollutants and hold them on its surface or within its structure. The biomass may be living, but many treatment concepts use inactive or dead material because it can be easier to store, handle, and control.
Fungal biosorption is not a universal replacement for established treatment technologies. It is a treatment option that may be useful for particular contaminants and operating conditions, especially when a suitable source of biomass is available and the material can be managed responsibly after use.
What is fungal biomass?
Fungi grow as networks of fine filaments known as hyphae. Together, these filaments form a larger structure called mycelium. Fungal biomass can be collected from cultivation processes, recovered as a by-product of fermentation, or produced specifically for treatment applications. It may be used in forms such as loose material, dried particles, pellets, mats, or incorporated into a treatment column.
The chemical groups present in fungal cell walls can interact with certain substances in water. Depending on the fungal species, the preparation method, and the pollutant, these interactions may attract and retain metals, dyes, or other dissolved compounds. Different fungal materials have different surface properties, so results from one type of biomass should not automatically be applied to another.
What does biosorption mean?
Biosorption is the passive capture of a substance by biological material. In fungal treatment, a pollutant may attach to the biomass through surface interactions rather than being broken down or consumed by the organism. This is different from biodegradation, in which microorganisms transform a contaminant into other substances. It is also different from bioaccumulation, which generally involves living organisms taking substances into their cells.
Because biosorption often concentrates a pollutant onto a solid material, the process does not make the contaminant disappear. It transfers the contaminant from a liquid or industrial stream to the fungal biomass. That spent material must therefore be tested, stored, regenerated, reused, or disposed of through an appropriate route.
How a fungal biosorption system generally works
A practical project normally begins with characterising the industrial stream. Important information includes the contaminants present, their concentrations, flow rate, temperature, acidity or alkalinity, suspended solids, and the presence of substances that could interfere with treatment. The target pollutant and the required discharge or reuse standard should be defined before selecting biomass or equipment.
1. Preparing the biomass
Biomass may be washed, dried, milled, sieved, chemically treated, or formed into a more manageable shape. These steps can alter its surface properties and improve handling, but they also add cost and may create additional waste streams. In some applications, untreated biomass may be sufficient. In others, preparation is needed to provide consistent particle size, strength, or contact performance.
Where possible, a reliable and traceable source should be selected. Biomass that has already been exposed to chemicals or contaminants needs careful assessment before it is used. Its composition, moisture content, storage stability, and potential to introduce new contaminants should be understood.
2. Bringing biomass into contact with the stream
The prepared material can be mixed with contaminated water in a tank or placed in a fixed-bed, packed-bed, or other contact system. Batch treatment may be suitable for intermittent flows, while continuous systems may be considered for more consistent industrial streams. Contact time, biomass dose, flow rate, particle size, pH, and temperature can all affect performance.
A change in one operating condition may improve capture of one pollutant while reducing capture of another. Competing ions, organic matter, suspended solids, and fluctuating pollutant concentrations may also affect the outcome. For this reason, laboratory results should be treated as an indication of potential rather than a guarantee of full-scale performance.
3. Separating treated water from the biomass
After contact, the biomass must be separated from the treated stream. Depending on the system, this may involve screening, settling, filtration, clarification, or retaining the biomass within a treatment column. Fine particles can be difficult to recover and may require a support material or a more durable pellet or composite form.
Monitoring should confirm both the pollutant concentration in the treated stream and any release of fungal particles or other substances from the treatment unit. Flow, pressure, pH, temperature, and signs of clogging or channeling may also need to be tracked during operation.
Potential industrial applications
Fungal biomass may be considered where a process produces contaminated water containing substances that interact favourably with the selected biomass. Possible areas of interest include polishing steps for industrial wastewater, removal of selected dissolved metals, and treatment of some coloured or otherwise persistent compounds. It may also have a role as one stage in a wider system rather than as a complete treatment process.
For example, a biosorption step might be evaluated after larger solids have been removed and before final polishing or discharge. It could also support recovery of a valuable substance if the pollutant can be released from the biomass in a controlled way. Whether recovery is practical depends on the contaminant, the biomass, the regeneration method, and the quality requirements for the recovered material.
Advantages and limitations
The main attraction of fungal biomass is that it can provide a relatively simple biological material for capturing particular pollutants. Depending on the source and preparation method, it may be available as a low-cost by-product. It can also offer flexibility in system design and may complement physical, chemical, or biological treatment processes.
However, apparent low material cost does not represent the full cost of treatment. Drying, transport, preparation, storage, pumping, separation, monitoring, replacement, and spent biomass management all affect the economics. Performance may decline as available binding sites become occupied, and the biomass may swell, break down, clog equipment, or become difficult to handle.
Other limitations include variable composition between batches, sensitivity to water chemistry, competition from multiple pollutants, and uncertainty about long-term stability. A material that captures a contaminant in a controlled test may perform differently in a complex industrial stream. Some pollutants may not bind effectively at all, and biosorption does not necessarily destroy hazardous substances.
Reuse, regeneration, and spent biomass
In some systems, the biomass may be regenerated by washing or using a chemical solution that releases the captured pollutant. Regeneration can reduce material consumption, but it creates a concentrated liquid that must be treated or recovered. Repeated cycles may also reduce the biomass’s capacity or physical strength.
If reuse or regeneration is not suitable, spent biomass should be classified according to the contaminants it contains and managed under applicable waste requirements. It should not be composted, spread on land, burned, or sent to ordinary waste collection without confirming that the route is safe and legally permitted. Storage should prevent leaks, dust, and uncontrolled contact with people, animals, or the environment.
Testing before full implementation
A responsible evaluation normally progresses from screening tests to more realistic pilot work. Testing should use representative biomass and, where possible, samples that reflect normal variation in the industrial stream. Useful questions include:
- Which pollutants are captured, and at what concentrations?
- How do pH, temperature, flow, contact time, and competing substances affect treatment?
- How quickly does the biomass reach its working capacity?
- Can the material be separated reliably without creating a secondary problem?
- Can it be regenerated, reused, or disposed of safely?
- What monitoring and maintenance are needed during operation?
Pilot testing can reveal practical problems such as clogging, inconsistent biomass quality, pressure loss, or changes in performance over time. It also helps establish realistic replacement schedules and operating costs. Full-scale installation should proceed only when treatment performance, safety, waste handling, regulatory obligations, and total cost have been assessed for the specific site.
Where fungal biosorption fits in remediation
Fungal biomass is best viewed as a potential component of a broader remediation strategy. It may be useful for a defined treatment objective, particularly where conventional methods are expensive, produce difficult residues, or need an additional polishing step. It should be selected based on evidence from the actual contaminant mixture and operating conditions, not simply because the material is biological or appears inexpensive.
With site-specific testing, appropriate monitoring, and responsible management of spent material, fungal biosorption can support practical industrial remediation. Its value depends on matching the right biomass to the right pollutant and treatment system, while recognising that expert oversight and conventional treatment methods may still be necessary.