TOP® - Wet Oxidation

Thanks to the interdisciplinary skill of its personnel, 3V Group developed the TOP® - Wet Oxidation for Wastewater technology, a cutting-edge wet oxidation process used for the treatment of:

The technology is referred as TOP® because it works on the basis of Temperature, Oxygen and Pressure.

TOP® - Wet Oxidation technologies has the following main features:
  • Allows dissolved compounds to burn in water (flameless). Under dry conditions, such compounds would oxidize at much higher temperature and pressure;
  • Allows total chemical compounds destruction (99.9%)
  • Reduces COD content by 70% and makes the remaining 30% highly biodegradable, by demolishing complex molecules into simple molecules and therefore transforming 100% non-biodegradable waste into highly biodegradable waste

TOP® technology can be implemented on industrial scale, with the following main features

1. Continuous operation

Operations are performed on a continuous 24 hours cycle. There are no. 2 scheduled stops per year (usually one in summer and one in winter)
  • Scheduled management of maintenance. Critical process steps are redundant
  • Possibility of installing multiple modular "parallel" systems, to ensure operations also during any intervention of longer duration

2. Highly automated

  • Single Operator in Control Room
  • Automation based on DCS technology

3. Low utilities consumption

Electric Power:
  • Electrical consumption is mainly related to electrical pumps for oxygen injection and liquid waste pumping into through the process
Thermal Power:
  • Provided by the combustion process, depending on COD of the incoming stream
  • Process Heat is recovered to dry the inorganic fraction

4. Modularity

The architecture of the process allows for easy expandability of the plant capacity through installation of new Process modules that provide:
  1. increasing plant capacity without interrupting the treatment activity
  2. the optimal management of spare parts
  3. keeping a compact layout that minimizes the cost of revamping

5. Flexibility

Treatment of almost unlimited quantity of different streams.

TOP® - Wet Oxidation for Wastewater has a high performance long track record on a wide variety of waste streams:

Wastewater Active Principle (or critical state) Active Principle Reduction
Colours APHA Colour > 99,9%
Detergents MBAS-TAS > 99,9%
Pharmaceutical (antibiotics: Tetracycline) BOD/COD = 0,02 BOD/COD = 0,69
Fine Organics (Waters from nitration) NITRO-CRESOL 98,4%
Fine Organics (phenolic resins) APHA Colous-phenols 96,5% - 99,9%
Fine Organics (maleic dioxide) COD 67%
Pharmaceutical Cianydes > 99,9%
Reclamantion (draining off water from piezometers) Chlorinates > 87,5%

Residual COD - Organo-chlorinated reduction is also significant:

Test Before Wet Oxidation After Wet Oxidation
Dichloro methane pH in pH out Dichloro methane Dichloro methane Chlorides Chlorinated destruction
mg/l mg/l mg in the vent gas mg/l %
837 70 11,6 9,8 0,8 0,12 60 98,4
838 92 11,6 10,1 1 0,18 72 98,4
828 3500 12,6 10,0 29 5 98,8
830 3500 12,6 6,8 42 7 98,2
1,2 dichloro ethane pH in pH out 1,2 dichloro ethane 1,2 dichloro ethane Chlorides
833 89 11,4 8,4 1 0,12 70 98,5
834 94 11,4 10,2 1 0,12 70 98,6
822 3500 12,7 5,7 13 2 99,5
821 3500 12,7 5,5 11 1,5 99,6

Micro-Pollutants Reduction:
From 415 to 84 nanogram/kg. Equivalent toxicity reduction by 80%.

Campione in Campione out Abbattimenti
pH 7,0
Densita kg/L 1,20
Cloruri mg/L 27.000
COD mg/L 25.200 6.850 73%
Indrocarburi mg/kg 543 110 80%
IPA mg/kg < 0,1
PCB mg/kg < 0,1
Diossine nanog/kg
84 80%
Residuo a 105 °C % 28,3 27,7
Residuo a 555 °C % 24,3 24,8

TOP® is environmentally sustainable

1. Extremely low exhaust emissions (CO2)

The Wet Oxidation process produces low temperature (40-60 °C) gaseous emission (about 10-12% by mass with respect to an incinerator). Reaction gases are cooled and washed, the incondensable gases are burned in a heater. Gas emission from TOP plant are very low, since the gases discharged are substantially carbon dioxide produced during the reaction and oxygen fed in excess with respect to the COD converted.

2. No harmful emissions

The gases discharged by the plant are only carbon dioxide produced during the reaction and oxygen fed in excess with respect to COD converted. The reaction gases are cooled and washed before leaving the oxidation plant. Reaction conditions (temperature, pH, etc..) do not allow the formation of any hazardous substances (eg. Dioxins).

3. No fly ashes

Unlike incineration, Wet Oxidation process operates at much lower temperatures and in aqueous medium; the inorganic residue leaves the plant suspended in the liquid effluent and it is recovered by conventional decantation and filtration
W.O. does not require any treatments of gas emissions
W.O. does not generate any hazardous solid "gas suspended" to be disposed of through special landfills (fly ash).

4. High degradation of organic substances

High degradation of organic substances either dissolved or suspended. Liquid effluent totally biodegradable.

Bidegradability of residual COD: Example of wastewater coming from nitration of aromatic compounds. COD reduction graph

5. Oxidation and stabilization of heavy metals

The metals contained in the feeding (no other metals are added such as catalysers for example), at the operating conditions of the process, precipitate as oxides, so the content of such metals in the liquid effluent is drastically reduced.

6. Inorganic residue (TOP Filler) reuse for industrial and civil construction applications

Inorganic residue of Wet Oxidation treatment becomes TOP Filler, raw material that can be used to build roads.
Additional processing can lead to SpheraPor & MicroPor
Spherapor is a Lightening Structuring material; it is characterized by an open porosity almost nothing as the surface of the sphere shows vitrified. This feature prevents water absorption, whatever the application in which Spherapor is used, thus ensuring the high lightness of the final product. Mechanical strength up to 5 times higher than that of the reference products on the market it is combined with the low specific gravity; lightness and mechanical strenght, as well as a very high chemical inertness, make Spherapor a highly innovative solution for Lightweight Concrete, or Glue, markets particularly for the building field.

In 2013 such solid residue obtained the CE mark to be used as filler for bituminous materials and similar.

Comparison between TOP® - Wet Oxidation and other technologies for sludge treatment

Recovery Sustainability Environmental impact Compliance with best practices
Wet Oxidation 100 percent100% recovery 100 percent0% to landfill 100 percentzero discharge 75 percentinorganic fraction reuse
Dehydration + Landfill Disposal 25 percent25% recovery 25 percent75% to landfill 25 percentlarge footprint and leachate production 25 percent
Drying + Incineration 50 percent73% recovery 50 percent3% to landfill 25 percentpotential gaseous emissions and ashes to landfill 75 percentenergy recovery
Anaerobic Digestion 50 percent75% recovery 50 percent25% to landfill 75 percentpossible odor issues 75 percentbiogas production
Advantages Environmental acceptance
Wet Oxidation
  • Complete reduction of organic content
  • Zero discharge process, absence of hazardous gaseous compounds
  • Recovery of inorganic fraction for reuse
  • Small plant's surface area, no odors
100 percent
Dehydration + Landfill Disposal
  • Low public acceptance
  • Large surface areas permanently occupied
  • Leachate production
25 percent
Drying + Incineration
  • Low public acceptance
  • Potential gaseous emission to atmosphere
  • Ashes disposal to landfill
25 percent
Anaerobic Digestion
  • Potential patogens bacteria still present
  • Residual odors
75 percent
TOP® - Wet oxidation technology allows total chemical compounds destruction.
  • Chemical-Physical water treatment usually transfers contaminants from wastewater to wastewater sludge
  • Biological process is not adequately effective on high C.O.D. waters, and does not allow destruction of complex chemical, toxic or recalcitrant compounds (biologic reactors, anaerobic digestors)
  • Besides solvent-rich streams, Incineration is not cost effective on liquid waste with moderate to high water content. In addition to air emission and fly ash, incineration can also produce additional contaminants (dioxins and other micro-pollutants)
  • Sludge disposal to Landfill or Agriculture does not provide a sustainable long-term solution.

TOP® - Wet Oxidation technology industrial development

The first industrial plant - "the Multipurpose TOP®", launched in 1984 at the 3V Chemical Plant in Mozzo (BG). Italy, and has the capacity to treat 5 m3/h of mixed industrial wastewater with an organic load of 50.000 mg/l of C.O.D., achieving a reduction of around 80%.

A second mixed industrial plant - another "Multipurpose TOP®" started running in 1990 within the Grassobbio treatment center in Bergamo Italy and was initially designed to treat up to 12 m3/h, then was upgraded to treat 15 m3/h and now again is under expansion to provide a total treatment capacity of 18 m3/h. This plant treats waste with an organic load of up to 60.000 mg/l of C.O.D, achieving reductions that range (depending on the fed type of waste) from 75% to 85%. More info about our Treatment Center

A third plant, launched in January 1995, is a "Class B Dedicated TOP®" in Porto Marghera (VE). Italy, treating wastewater generated by the nitration of toluene. The plant treats up to 2 m3/h of liquid with a C.O.D. load of around 20.000 mg/l, achieving a reduction of more than 80%.

TOP® technology has already received international awards

  • 1990 Best Reparative Technology award from ENEA (the EU delegate for Italy)
  • 2006 BAT (Best Available Techniques) award from the EU-IPPC for O.F.C.s (Organic Fine Chemicals).