**16. Commercialization and adoption of biosorption as waste treatment technology**

In spite of the advantages over other conventional techniques, there is a glaring lack of adoption of biosorption as a waste treatment technology. Few commercial ventures offering


AlgaSorb in each column. Equipment for operating at higher flow rates has been designed. Both metal cations and oxyanions can be bound while Ca, Mg, Na, and K ions do not interfere

Bioclaim by Vistatech Partnership Pvt. Ltd. developed *B. subtilis* biomass obtained by treating with NaOH and immobilizing in binders like polyetheimine and glutaraldehyde. The biosor-

US Bureau of Mines devised bio-fix beads by immobilizing biomass in porous polysulfone beads. Immobilized *Sphagnum* biomass has 4-5-5.0 meq cations per gram capacity comparable to ion exchange resin, with an operational pH range of 3.0–8.0, and metal affinity in the order of Al > Cd > Cu > Zn > Fe > Mn > Ca > Mg. Majority of equilibrium sorption occurred in 20 min. Bio-fix was used for four onsite field trials. The regeneration by sulfuric acid and subsequent

deterioration and displayed over 95% removal over 250 cycles of regeneration. The source of wastewater and the presence of organic matter below 50 mg/L did not inhibit metal removal.

A three column-circuit (lead, scavenger and elution) was used to remove metals from wastewater from taconite operation. Several metals (Ni, Co, Cu, Zn) were removed (98%) with 20 min residence time and 40–50BV of solution at low temperatures of water (1–3°C) or air (<=0°C). The metals were precipitated by treating the elute with MgO and evaporating to

Employing a similar setup, 90–95% of removal was obtained for Zn, Fe, and Mn. However, the

In a low maintenance circuit, beads filled in bags made of Polymax B material were placed in troughs or in buckets in the flow of wastewater discharge. Over a 11-month period, Fe concentration of wastewater from an abandoned silver mine was reduced to below 1 ppm level from 20 to 60 ppm levels. This involved 2300 L of beads placed in troughs. Both bucket and trough circuits were used to treat discharge for abandoned mine containing Cd, Cu, Fe, Pb, and Zn. Drinking water standards were (85–89% removal) met with either system at flow rates of 0.3–0.5 L/min with weekly replacement of 50% of beads. Operating cost with bio-fix

beads compared well with lime precipitation treatment for similar wastewaters [223].

BIOS process by the Noranda technology center utilized a bed of sawdust, algae and sphagnum moss near seepage. The metal-saturated biomass is later disposed of (as tailings or sent to smelter) or washed for recovery of metals. The bed contained bark (20 years old), wood pulp, and sawdust. Total void volume was 7 L. A Plexiglas reactor was used in 30 L capacity to treat acid mine drainage (AMD). Over a 7-day residence time at room temperature, pH was not effected but Cu (100%) and Zn (65%) were removed.Better metal removal (95–100% for Al, Cu, Zn, Fe) was achieved for a 14-day residence time. The pH did not increase and stabilized

of metal (except for Cu) ions was reduced. The process compared well with lime organic mixture (LOM) and the anoxic lime stone drain (ALD) methods and was better compared to

. The beads were stable to physical and environmental

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97

C (as compared to 200

C), the removal

bent is stable and used for removing metals including gold from gold cyanide.

CO3

presence of suspended solids interfered with the operational efficiency.

at 3 over 12 bed volumes. At lower temperature of 100

the Biotrench method in terms of metal removal [224].

to a significant extent [222].

neutralization is done by Na<sup>2</sup>

obtain residue.

Such promising results encouraged field trials.

**Table 13.** Commercial biosorbents.

biosorption as a treatment have emerged. A few commercial biosorbents are available, as shown in **Table 13**. There is a dearth of field trials for a seemingly promising decade-old technology.

Volesky and Naja reported that the lack of commercialization was due to non-technical reasons—due to lack of partners. Computer models based on pilot tests can reduce the scope of field tests. Data and cases of application can attract investors, consultants, distributors, and clients [220].

The BV Biosorbex Inc. is a Canadian company, started by Professor Bohumil Volesky of McGill University, Montreal, Canada, involved in commercializing biosorption. Its services include the biosorption-based removal of heavy metals from industry waters using reactors carrying novel biosorbents as granules offered at the 1/10th the cost of ion exchange resins. The biosorbents may be made from industrial waste, algal biomass, and specialized biomass. The biosorbents are reported to function between pH 4–10 and 5–75°C with efficiencies of >99.9% at 10–50 ppb concentrations of heavy metal and organic matter (<5000 mg/L). The company can conduct labscale studies, consultancy, design process, and operate waste treatment plants. Pilot biosorption systems may involve column, fluidized bed, or mixed tank reactors. The company plans to capture 15% of market of ion exchange resin (http://www.bvsorbex.net/invest.htm).

AlgaSorb by Biorecovery Inc. has algal biomass immobilized in silica gel. In a pilot study two columns in series with different biosorbents of algae were used to remove mercury from groundwater. Algasorb 624 with high Hg retention but high leakage was used followed by AlgaSorb 620 having the opposite characteristics. Sodium thiosulphate (0.1 M) followed by deionized water (10 bed volumes) was used for regeneration. The study was successful for varying levels of mercury and in the presence of Ca, Mg, and organic matter [221]. Immobilization protects algae against decomposition by microbes. Also, a hard material suitable for packing into columns is obtained. A portable effluent treatment equipment has two columns operating in series or parallel at flow rates of 1 gallon/min and has 0.25ft<sup>3</sup> of AlgaSorb in each column. Equipment for operating at higher flow rates has been designed. Both metal cations and oxyanions can be bound while Ca, Mg, Na, and K ions do not interfere to a significant extent [222].

Bioclaim by Vistatech Partnership Pvt. Ltd. developed *B. subtilis* biomass obtained by treating with NaOH and immobilizing in binders like polyetheimine and glutaraldehyde. The biosorbent is stable and used for removing metals including gold from gold cyanide.

US Bureau of Mines devised bio-fix beads by immobilizing biomass in porous polysulfone beads. Immobilized *Sphagnum* biomass has 4-5-5.0 meq cations per gram capacity comparable to ion exchange resin, with an operational pH range of 3.0–8.0, and metal affinity in the order of Al > Cd > Cu > Zn > Fe > Mn > Ca > Mg. Majority of equilibrium sorption occurred in 20 min. Bio-fix was used for four onsite field trials. The regeneration by sulfuric acid and subsequent neutralization is done by Na<sup>2</sup> CO3 . The beads were stable to physical and environmental deterioration and displayed over 95% removal over 250 cycles of regeneration. The source of wastewater and the presence of organic matter below 50 mg/L did not inhibit metal removal. Such promising results encouraged field trials.

A three column-circuit (lead, scavenger and elution) was used to remove metals from wastewater from taconite operation. Several metals (Ni, Co, Cu, Zn) were removed (98%) with 20 min residence time and 40–50BV of solution at low temperatures of water (1–3°C) or air (<=0°C). The metals were precipitated by treating the elute with MgO and evaporating to obtain residue.

biosorption as a treatment have emerged. A few commercial biosorbents are available, as shown in **Table 13**. There is a dearth of field trials for a seemingly promising decade-old

Volesky and Naja reported that the lack of commercialization was due to non-technical reasons—due to lack of partners. Computer models based on pilot tests can reduce the scope of field tests. Data and cases of application can attract investors, consultants, distributors, and

The BV Biosorbex Inc. is a Canadian company, started by Professor Bohumil Volesky of McGill University, Montreal, Canada, involved in commercializing biosorption. Its services include the biosorption-based removal of heavy metals from industry waters using reactors carrying novel biosorbents as granules offered at the 1/10th the cost of ion exchange resins. The biosorbents may be made from industrial waste, algal biomass, and specialized biomass. The biosorbents are reported to function between pH 4–10 and 5–75°C with efficiencies of >99.9% at 10–50 ppb concentrations of heavy metal and organic matter (<5000 mg/L). The company can conduct labscale studies, consultancy, design process, and operate waste treatment plants. Pilot biosorption systems may involve column, fluidized bed, or mixed tank reactors. The company plans to

capture 15% of market of ion exchange resin (http://www.bvsorbex.net/invest.htm).

AlgaSorb by Biorecovery Inc. has algal biomass immobilized in silica gel. In a pilot study two columns in series with different biosorbents of algae were used to remove mercury from groundwater. Algasorb 624 with high Hg retention but high leakage was used followed by AlgaSorb 620 having the opposite characteristics. Sodium thiosulphate (0.1 M) followed by deionized water (10 bed volumes) was used for regeneration. The study was successful for varying levels of mercury and in the presence of Ca, Mg, and organic matter [221]. Immobilization protects algae against decomposition by microbes. Also, a hard material suitable for packing into columns is obtained. A portable effluent treatment equipment has two columns operating in series or parallel at flow rates of 1 gallon/min and has 0.25ft<sup>3</sup>

of

technology.

96 Biosorption

**Table 13.** Commercial biosorbents.

**Biosorbent Source** AlgaSORB *Algal biomass*

AMT-Bioclaim *Bacillus* sp. Bio-Fix Different biomass Rahco Different biomass MetaGeneR Different biomass AquaSorb Activated carbons P.O.L. Sorb Sphagnum Peat Moss MSR *Rhizopus arrhizus Azolla* Biofilter *Azolla filiculoides*

B.V.SORBEX Biomass from various sources

clients [220].

Employing a similar setup, 90–95% of removal was obtained for Zn, Fe, and Mn. However, the presence of suspended solids interfered with the operational efficiency.

In a low maintenance circuit, beads filled in bags made of Polymax B material were placed in troughs or in buckets in the flow of wastewater discharge. Over a 11-month period, Fe concentration of wastewater from an abandoned silver mine was reduced to below 1 ppm level from 20 to 60 ppm levels. This involved 2300 L of beads placed in troughs. Both bucket and trough circuits were used to treat discharge for abandoned mine containing Cd, Cu, Fe, Pb, and Zn. Drinking water standards were (85–89% removal) met with either system at flow rates of 0.3–0.5 L/min with weekly replacement of 50% of beads. Operating cost with bio-fix beads compared well with lime precipitation treatment for similar wastewaters [223].

BIOS process by the Noranda technology center utilized a bed of sawdust, algae and sphagnum moss near seepage. The metal-saturated biomass is later disposed of (as tailings or sent to smelter) or washed for recovery of metals. The bed contained bark (20 years old), wood pulp, and sawdust. Total void volume was 7 L. A Plexiglas reactor was used in 30 L capacity to treat acid mine drainage (AMD). Over a 7-day residence time at room temperature, pH was not effected but Cu (100%) and Zn (65%) were removed.Better metal removal (95–100% for Al, Cu, Zn, Fe) was achieved for a 14-day residence time. The pH did not increase and stabilized at 3 over 12 bed volumes. At lower temperature of 100 C (as compared to 200 C), the removal of metal (except for Cu) ions was reduced. The process compared well with lime organic mixture (LOM) and the anoxic lime stone drain (ALD) methods and was better compared to the Biotrench method in terms of metal removal [224].

Later, different combinations of treatments (LOM/BIOS/ALD, BIOS/ALD and LOM/ALD) were executed to treat AMD. The volume of the initial reactor was 30 L except in the case of LOM/ALD (20 L). The downstream reactors were of 4 L. With LOM/BIOS/ALD, As, Cd and Cu were removed beyond detection. Fe and Zn were also reduced by 93 and 50%, respectively. The pH was increased to 6.3. With the BIOS/ALD system, pH increased to 6.3 and As, Cd, and Cu were removed beyond detection. Metal Al was reduced to 0.7 ppm while Fe and Zn were removed at 99 and 38% efficiency. BOD and COD were negligible. There was no influence of low temperature. The LOM/ALD was referred as the best treatment, achieving the removal of all metals including Zn (99%) and Mn (68%), not attained with other combinations, along with negligible BOD and COD [225].

this regard, biosorption may be applied to wastes and effluents before it enters the sewage or

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However, with the aim of treating effluent/remediating water resources of all/most contaminants, it may be an advantage to have all pollutants (metal or contaminants) removed simultaneously using a non-specific/non-selective biosorbent and reducing the number of operations/steps. Multiple biosorbents of different specificities/selectivities can also be used. The strains or biomass used as the biosorbent should be of safe origin especially for water treated for human or animal consumption. Hence, pathogens and toxin-producing organisms need to be avoided. In this regard biomass from food-grade microorganisms like lactic acid

Regeneration and immobilization of biomass in order to reduce the cost of biomass involve the use of hazardous solvents which can lead to pollution. Hence, the use of harmless chemi-

The existing waste can be classified as solid (degradable and non-degradable) and liquid in nature. A lot of solid non-biodegradable wastes (plastic) can be recycled to form chemically and mechanically robust and inert matrices to hold the biosorbent. Degradable wastes or biomass (agricultural/domestic/industrial) can be employed as biosorbents. A compatible biosorbent-matrix combination can then be employed to treat liquid discharge/effluents. This can make the waste treatment economical and sustainable while addressing the problems of

Nature provides a diversity of biomass varying in binding specificity, efficiency, and ruggedness. This diversity can be tailored to site-specific waste treatment needs by applying the advanced techniques of recombinant DNA technology, synthetic biology and so on. Strains can be modified to express single/multiple metal-binding proteins on the cell surface. Chimeric proteins with multiple metal-binding domains having suitable binding and regeneration conditions can be engineered and expressed. Binding and regeneration conditions for the biosorbents can also be manipulated. Strains tolerant to harsh waste environments, and/or able to accumulate the toxic metals can be developed. However, laws regulating the dispersal or release/containment of genetically modified organisms will need to be considered. Techniques like genome shuffling are considered natural and can be employed for the modification of microorganisms. Confusion exists on the Crispr–Cas9 technology if it can be considered a genetic modification. Also, biosorption processes involving dead biomass may

Nanotechnology is a cutting-edge technology involving the development of novel materials through the manipulation at nanoscale. The use of biomass has been explored to produce nanometal particles of silver, Cu, gold and so on. This novel use of biosorption linking the wastewater treatment to synthesis/the recovery of metals/nanometals from wastewater makes

The development of novel efficient biosorbents (nanocellulose, nanocomposites like pectin/

nanocellulose) has also been obtained by varied treatments including solvents, heat, and so

/*Sphaerotilus natans*, ostrich bone waste-zero valent iron, polyaniline-modified

natural discharge streams like rivers, seas and so on.

cals may be explored.

solid and liquid effluents simultaneously.

be a convincing argument against such regulations.

economic sense for capital investment.

O4

TiO2

, nano Fe<sup>3</sup>

bacteria and (wine/beer yeast) and agro-waste is of significance.

AquaSorb is a granular, powdered, and extruded activated carbon used primarily for the treatment of water, waste liquid streams and the recovery and recirculation of process liquors. The source of carbon which is activated for water treatment is from coconut shell, coal, and wood raw material by chemical or steam activation. Specially designed AquaSorb for the use in liquid phase adsorption systems in the range of granular, ground, and extruded (pelletized) form can be supplied by Jacobi Carbons. It can be applied as home water filters for the dechlorination of water, in order to reduce chloramines and produce water with good taste, more pure and palatable than the normal municipal water (https://www.wateronline.com/ doc/aquasorb-activated-carbon-0001).

The highest grade of Sphagnum Peat Moss is used for the development of P.O.L. Sorb which acts as a superb adsorbent for solutions due to the inherent capillary action of the activated peat which provides powerful wicking action that encapsulates oils, solvents, heavy metals, pesticides, herbicides, and so on which are in contact. It is manufactured by The ARK Enterprises, Inc. The raw material of POL Sorb is leafy, stem free, and least an abundant part of the peat in its natural or partial biodegraded state (http://www.arkent.com/POL%20 Sorb%20Flyer.pdf).

MSR is a biosorbent produced by immobilizing the inactivated cells of *Rhizopus arrhizus* with the desirable particle size of 0.5–1.2 mm. The characteristic features of the biosorbent are that it is resistant to chemicals, compression and abrasion, high porosity, and is with good wetting ability. These proprietary immobilized particles (MSRs) were used for the recovery of uranium from lore leaching operations [226].
