Electrochemical Solutions for Environmental Remediation

ELECTROCHEMICAL (e-T) TREATMENT OF WATER AND AQUEOUS WASTE

Electrochemical technology relies on the use of electrons for the on-site generation of coagulants or oxidants, using compact and modular equipment that can be set up in reduced spaces and easily extended, if necessary.

Overview of the technology and its capacities

Electrochemical technology relies on the use of the electron for the on-site generation of coagulants or oxidants.

Electrocoagulation (e-ECT)

The technique works by means of an electric field in the space between the cathode and anode (sacrificial anode, which generates the ferric or aluminium hydroxides/coagulants). Although the process is similar to the physical-chemical treatment, it offers highly superior performance both in terms of the efficiency of the electro-reduction – oxidation – chemical absorption processes and in terms of a substantial reduction in sludge generation (between 30% and 75% less). The process has been successfully used on solids / colloids / heavy metals / hydrocarbon water, oily water, emulsions, or COD / TOC / easily coagulable total nitrogen.

Electrochemical technology reproduces the traditional physical-chemical treatment except that it generates the necessary coagulants on-site without the need to add new salts like aluminium polychloride, ferric chloride, etc.

In addition to acting as a physical-chemical treatment, the electro-chemical reaction results in:

  • Molecular breakdown reactions (improvement of biodegradation).
  • Oxidation-reduction reactions.
  • Chemical and electro-chemical absorption.
  • Separation and breaking of emulsions / oils in the process.
  • High efficiency in the removal / elimination of heavy metals.
  • Higher suspended solids removal rate with high colloid removal efficiency.
  • Lower volumes of sludge compared to the physical-chemical process.

Reactors with an automated self-cleaning system

Proprietary technology (reactors) under patent.

Electro-oxidation (e-EOT/e-EOTph/e-EDT)

This process acts through an electric field in the space between anodes and cathodes (long-lasting / non-sacrificial), which are made of catalytic noble metals that produce direct anodic oxidation, or indirect oxidation by forming oxidants in the reaction media. This process works far better than high intensity biological treatments (MBR/SBR/UASB), chemical oxidative treatments (using pressure/high temperature oxidation) and/or mixed treatments. The only difference with high intensity biological treatment is that the EO technique can act on both biodegradable and non-biodegradable molecules.

The electro-oxidation/electrodisinfection technique is also used for the production of disinfectants to treat, sanitise and disinfect wastewater. The best known technique is the on-site generation of chlorine using sea water or a sodium chloride solution. Ref: e-EOT

The electro-oxidation/electrodisinfection technique is also used for the production of disinfectants to treat, sanitise and disinfect wastewater. The best known technique is the on-site generation of chlorine using sea water or a sodium chloride solution. Ref: e-EDT

e-Watts has developed a new highly efficient treatment for the oxidation of high organic loads (COD’s between 5000mg/L and 50.000mg/L) either toxic or non-biodegradable (API’s, emerging pollutants, etc.) for the Chemical-Pharmaceutical and Petrochemical industry that results in an equal or better performance than BDD electrodes but is 10 times cheaper.Ref: e-EOTph

Reactors with an automated self-cleaning system.

Proprietary technology (reactors) under patent.

Electro-Fenton (EF) with peroxi-coagulation (PC)

This technique works in the same way as electrocoagulation but adds hydrogen peroxide to generate most of free radicals that guarantee maximum oxidising power. Applicable in wastewater with a high organic or refractory load.

The electrochemical technique of Electro-Fenton (EF) with peroxi-coagulation (PC) consists of applying an electric field between an iron anode (sacrificial) and a cathode; the water to be treated is passed between this space and generates Fe2+ to act with the hydrogen peroxide, inserted or produced cathodically, causing the Fenton reaction. This process generates a large number of free radicals that act by strongly oxidising any pollutants present in the effluent. Once all the hydrogen peroxide has been absorbed, the residual iron present is removed from the solution, increasing pH levels and separated through physical techniques of decantation, flotation or cross-flow ultrafiltration.

This technique is usually applied to highly refractory, toxic or complex waste, where other techniques have failed to bring about the desired results (COD, high organic loads or waste difficult to biodegrade or oxidise by chemical or biological techniques).

Reactors with an automated self-cleaning system.

Proprietary technology (reactors) under patent.

Capacities. (e-ECT / e-EOT/ e-EDT/ e-EOTph / e-EPT)

Técnica / ReactorRef: e-ECTRef: e-EO / e-EDT / e-EOTphRef: e-EPT
m3 / h / reactor
Model I
Model II

0,5 – 20
5 – 80

0,5-50/0,5-500/0,5-50
1-150/1-1.500/1-150

0,5 – 20
5 – 80
m3/h/reactor10 – 1.50010-3.500/100-100.000/10-3.50010 – 1.500

NOTE: The treatment capacity depends on the pollutant load to be removed per m3 and the final electrical load applied. Ah/m3.

Solutions and applications

High non-biodegradable and / or toxic organic loads: (e-EOTph)

Applied directly or before applying biological treatment.

Improvement of effluent biodegradability: (e-EOTph / e-EOT)

Applied directly or before applying biological treatment of effluent.

Removal of biologically persistent pollutants: (e-EOTph)

Applied directly in water before discharge to remove biorefractory compounds.

Lack of space and extension of biological treatment: (e-ECT / e-EOTph)

Applied before biological treatment to reduce load and residence time.

Too many soluble salts in the final effluent: (e-ECT / e-ERT)

Substitutes chemical treatments for electrochemical systems + reverse osmosis (RO), or applied before discharge.

Presence of metals and low emission limits: (e-ECT)

Highly effective on any type of heavy metal.

External management of excessive aqueous waste: (e-EOTph)

Liquid waste is treated prior to on-site general treatment.

External management of excessive sludge: (e-ECT / e-EOTph)

Substitutes physical-chemical treatment for EC and / or biological treatment for EOTph.

Water recovery: (e-ECT)

Substitutes physical-chemical treatment for e-ECT.

Decontamination of contaminated groundwater: (e-FRR)

Applied directly on groundwater. Short duration on-site treatment.

Regeneration of scrubbing water: (e-SCR)

Applied to regenerate the scrubbing solution in-situ.

Expensive and hazardous disinfectants: (e-DSR)

On-site generation of disinfectant.

Recovery of valuable metals: (e-EDT)

Valuable metals are recovered from the effluent by electrodeposition.

Improved performance in biodigesters / deammonification: (e-NHR)

Ammonium is constantly removed from the interior of the digester without reducing the digestible organic matter, cogenerating hydrogen and increasing methane production by 30%-50%.

Hydrogen production and/or cogeneration: (e-HHT)

A special EOT/ERT reactor is used for the production of pure hydrogen or in certain wastewater/liquid waste treatments co-generating hydrogen at the same time.

Benefits

Benefits of the technology (R = Reduction / Recovery)

  • No sludge produced (e-EOT) / 0% or much less (e-ECT) / <30%-75% than other technologies. (R)
  • Possible effluent recovery. (R)
  • The sludge produced (e-ECT) is inert and easily dewatered.
  • Multiple treatment of pollutants.
  • Treatment of non-biodegradable, refractory or toxic water.
  • Treatment of water with high salinity, organic and nitrogenous load.
  • The process itself allows purification and disinfection.
  • Eliminates colour and odour.
  • Eliminates heavy metals.

Benefits of the process (S = Sustainable)

  • Low operating costs and proportional to the load.
  • No reagents required. (S).
  • Produces the least CO2 (S).
  • Fast (instantaneous or max. 1h), optional online treatment.
  • Automated and remote controlled.
  • Low maintenance. Self-cleaning reactors.

Structural benefits

  • No civil works required.
  • Minimal footprint.
  • Optional modules and easy expansion.
  • Optional transfer of the treatment system. · Mobile and compact plants.
  • Optional on-site treatment.

Other technologies and treatments

Membrane treatments: (w-MET)

Microfiltration, Ultrafiltration, Reverse Osmosis, EDR.

Biological Treatments: (w-BIT)

SBR, MBR, Anaerobic digesters. UASB.

UV radiation treatments: (w-UVT)

Low and medium pressure.

Evaporation Crystallization Treatments: (w-EVT)

1 to 4 effects. low temperature / vacuum evaporators.

Sludge Dewatering Treatments: (w-DET)

Filter presses. centrifuges. thermal drying.

Incineration / Calcination Treatments: (w-ICT)

Incinerators / Calcinators for non-toxic waste.

Business cases

Chemical Industry

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Pharmaceutical Industry

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Automotive Industry

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