Advanced Oxidation Processes (AOP) refers to a set of chemical treatment procedures enhanced by Ultra sound and UV activation, designed to remove organic and inorganic materials in waste water.


Contaminants are oxidized by four different reagents: ozone, hydrogen peroxide, oxygen, and air, in precise, pre-programmed dosages, sequences, and combinations. These procedures may also be combined with Ultra Sound reactors, UV irradiation and specific catalysts. This results in the development of hydroxyl radicals.

The AOP procedure is particularly useful for cleaning biologically toxic or non-degradable materials such as aromatics, pesticides, petroleum constituents, and volatile organic compounds in waste water.

The contaminant materials are converted to a large extent into stable inorganic compounds such as water, carbon dioxide and salts, i.e. they undergo mineralization.

A goal of the waste water purification by means of AOP procedures is the reduction of the chemical contaminants and the toxicity to such an extent that the cleaned waste water may be recycled or, at least, dumped into a conventional sewage treatment.


AOP Purposes


The AOP (Advanced Oxidation Processes) is usually used for removing contaminants from waste water coming out of several types of heavy industries like:

  • Petrochemical & Plastic Industry
  • Chemical Industry.
  • Food Processing Industry.
  • Pharmaceutical Industry.
  • Metal and Metal Plating Industry.
  • Textile and Dying Industry
  • RO & NF brine streams  

Conventional AOP Methods

Advanced chemical oxidation processes make use of (chemical) oxidants to reduce COD/BOD levels, and to remove both organic and oxidisable inorganic components. The processes can completely oxidize organic materials to carbon dioxide and water. AST is using a wide variety of advanced oxidation processes.

Chemical oxidation processes using hydrogen peroxide, ozone, combined ozone & peroxide CLO2  Ultra Sound & Ultra-violet enhanced oxidation such as US/UV/ozone, US/UV/hydrogen peroxide, US/UV/air and catalytic reagent. Advanced Oxidation Processes are particularly appropriate for effluents containing refractory, toxic or non-biodegradable materials.

The processes offer several advantages over biological or physical processes, including:

  • Process operability(No biological process)
  • Unattended operation with very small foot print.
  • The absence of secondary wastes (sludge).
  • The ability to handle fluctuating flow rates and compositions.

Conventional oxidation processes are very often high capital and operating costs and not effective in reducing the COD contamination from the waste water.

Conventional oxidation processes such as biological treatment, demands long operating cycle (up to 48 hours) and very big footprint.  


AST AOP Improved Technology

AST has developed the improved AOP technology that supports the standards of the environmental preservation authorities require low COD levels.

The COD level output after conventional waste water treatment of is usually not low enough, and further steps are necessary to enforce the process in order to reduce the excess of COD contamination.

Conventional oxidation processes reduces COD level by aerobic and anaerobic biological digestion. Some of the compounds that create COD in the waste water are not responding to the biological treatment as a result of their chemical nature, some of them are toxic to the digesting micro-organisms, and others need more effective oxidation process in order to be removed from the wastewater.

Chemicals like aromatic rings, phenols, chlorinated carbohydrates, lipids and certain proteins are usually not affected by the biological process.

AST improved the process in the following matter:

  • Operating coasts has been reduced dramatically
  • One operating cycle takes only 30-60 minutes
  • Waste water can be recycled for industry re-use 

All AOP outputs are environmental friendly


We on AST improved the oxidation process by adding the help of free radicals (OH0 + OH-). By adding to the reaction solution, energy sources like: ultrasound cavitations, UV light radiation or catlization by metal ions; free radicals are created and enhance the oxidation process so it produces an overhaul and more intense oxidation process of all COD components.


We developed at AST a method and a computerized software to determine and calculate an effective AOP for a specific chemical based on COD compounds level. 

AOP Applications


We on AST succeeded to fit the improved integrated AOP systems for the following applications:

  • Petro chemical Effluents treatment (COD, turbidity, electricity conductivity, TSS).
  • Polymers and resins factories effluents recovery.
  • Pharmaceutical factories effluent treatment (high load of salinity and COD effluents).
  • Dairy production effluents treatment - (high load of BOD, COD and fat removal).
  • Food processing effluent treatment and recycling.
  • Heavy metal effluents recovery.
  • High capacity cooling tower water recycling.
  • High way service stations effluents treatment.
  • NF & RO brine streams treatment

 Typical AOP System Components

AST AOP systems consist of the following components:

  • Equalization Buffer Tank / Treated Water Buffer Tank - Accumulates the treated water.
  • PLC with HMI (Programmable Logic Controller) - Controls the system and the AOP Process.
  • UV/US Reactors - Enforces creation of free radicals.
  • UV/US Reactors Controller - Controls the UV/US reactors operation.
  • Flow Control Valves and Flow Meters – Controls the flow.
  • Automatic Selector Valves - Controls the flow.
  • Dosing Pumps - Enforces waste water / treated water to flow within the system under pressure.

AOP System –
Typical Continuance Flow - Principle of Operation

The following drawing describes a typical AST AOP system principle of operation: Waste water or any other contaminated water flows into a collection tank where they accumulated and ready for AOP. The contaminated water is pumped from the lower section of the collection tank into the US reactors inlet where free radicals, created by the ultra-sound energy are added to the water to highly enhance the oxidation process. Dosing pumps add pre-calculated doses of (chemical) oxidants to the water coming out of the US reactors to complete the oxidation process. The water flows back into the upper section of the collection tank and from there into the treated water buffer tank through another series of dosing pumps. The treated water accumulated within the buffer tank is now ready for re-use or for any other re-cycling process.


The PLC controls all the AOP process through all stages include the US reactor operation, analyzers to measure pH, ORP and Electricity Conductivity.


AOP System – Typical Batch Flow - Principle of Operation


Waste water or any other contaminated water flows into one of the conditioning tanks where they accumulated and treated chemically ready for AOP. The contaminated water is pumped from the lower section of the conditioning tank into the US reactors inlet where free radicals, created by the ultra-sound energy are added to the water to highly enhance the oxidation process.

Dosing pumps add pre-calculated and controlled doses of (chemical) oxidants to the water coming out of the US reactors to complete the oxidation process. The water flows back into the upper section of the conditioning tank and recycled until the oxidation process is end and the COD is destructed.

During this process the second tank was already fill-up and the waste water were treated, ready to start the Advanced Oxidation Process.

At the stage that the process is accomplished in the first conditioning tank, the PLC controller changing the valves start the AOP recycling in the second tank, while the treated water from the first tank are being pumped into the treated water buffer tank.

At this stage the water, free from COD, can be treated either for further advanced treatment like membranes and be recycled as high quality water back to the factory process, or can be dumped into the municipal sewage system or river.


The PLC controls all the AOP process through all stages include the US reactor operation, analyzers to measure pH, ORP and Electricity Conductivity. 

High load contaminated (COD) effluents

 In some industries such as the Pharmaceutical and Chemical industries or Glucose & Proteins industries, the manufacturing process produces toxic and non degradable effluents.

 AST clean water technologies developed a process that can treat these effluents with a fast and cost effective aggressive Advanced Oxidation Process [AOP].

The patented process to calculate the required oxidation agents and free radical combined with inline Ultrasound reactor.

The free radicals (OH0 + OH-) are achieved by adding to the reaction the energy, by the form of ultrasound cavitations catlyzation by metal ion free radicals are created and enhanced   the oxidation process which result in complete oxidation of all the COD components.




Vibrating Flat Sheet Membrane (VSEP) Ultra-RO Filtration Membrane

The VSEP technology has developed as an alternative method for producing intense shear waves on the face of a membrane. The technique is called Vibratory Shear Enhanced Processing (VSEP). In a VSEP System, the feed slurry remains nearly stationary, moving in a leisurely, meandering flow between parallel membrane leaf elements. Shear cleaning action is created by vigorously vibrating the leaf elements in a direction tangent to the faces of the membranes.

The shear waves produced by the membrane's vibration cause solids and foulants to be lifted off the membrane surface and remixed with the bulk material flowing through the membrane stack. This high shear processing exposes the membrane pores for maximum throughput that is typically between 3 and 10 times the throughput of conventional cross-flow systems.

The VSEP membrane filter pack consists of leaf elements arrayed as parallel discs and separated by gaskets. The disc stack resembles records on a record changer with membrane on each side. The disc stack resembles records on a record changer with membrane on each side.  





AST - mobile containerized ‘plug & play’, portable water systems mobile water purification units supply fresh drinking water from any water source, anywhere.

Mobile units can produce drinking water from almost any source including seawater, 
surface water, and brackish water. Produced water meets World Health organization (WHO) drinking water quality guidelines.

AST water mobile purification units have maintained potable water supply following natural disasters and humanitarian crises. Emergency drinking water was provided to international relief organizations in the wake of the Indian Ocean tsunami, after flooding in Bangladesh and for refugees in Kosovo, Albania, and Sudan.

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The Solution

The basic concept of the ROTEC system is smart "flow reversal". To avoid scaling, the system alternates the desalination process direction flow (switching of the entrance and exit of the feed stream) before reaching the critical point in which scaling forms. Flow reversal at the induction time halts the crystallization of minerals, lowers salinity levels in feed water and "cleans" membranes and pipes. While simple in concept, this operation is complex to implement and requires a gradual and precise process that can be hazardous to the desalination plant equipment if not properly performed.

Implementing the ROTEC system results in many benefits for the desalination plant: Enhanced performance - Higher recovery rates and lower waste brine volume in any RO plant; Easy installation – existing desalination plants can install the ROTEC system with only a brief down-time period; Fallback - ROTEC's system is installed in a non-disruptive manner in existing plants or configured as a feature in new plants, allowing for easy fallback; Lower maintenance costs – Desalination plants implementing the ROTEC system can expect longer periods between regular maintenance work on critical elements such as the membrane and connected valves. This will directly translate into lower maintenance costs and fewer down-time periods; Suitable for new and existing plants;

ROTEC will sell "Customized Service & Equipment Packages" to enable application, adaptation or incorporation of Flow Reversal technology in existing and/or new BWRO desalination plants. This package includes all relevant equipment, engineering services and other supporting services that are required to apply the Flow Reversal technology.

The Market

The ROTEC system is best suited for brackish water RO and industrial use desalination plants. In the past 45 years, the desalination industry has grown from virtually zero, to over 60[1] billion m3 of treated water annually. While it is unclear exactly how many commercial desalination plants exist worldwide, there is information about over 16,000 desalination facilities that have been built for commercial and municipal use. Current addressable market size is $7.1 Billion. It is estimated that by retaining an annual growth rate of 9% this market will reach $9 Billion by 2017.

The Competition

ROTEC's competition is from existing and developing anti-scalant technologies, mainly chemical compounds that are added to the feed water at various stages and inhibit scale formation, new membrane materials having the potential to increase recovery rates and increase their resistance to scale deposition and companies offering technological solutions for raising recovery rates in new and existing desalination plants.

ROTEC's main competitive advantage stems from the system's ability to perform as an add-on to existing plants and alongside other high recovery solutions.  Thus, a desalination plant utilizing anti-scalant chemicals to achieve higher recovery rates may add ROTEC's system to further increase its recovery rate and lower waste brine ratio. In this case 1+1 > 2.

ROTEC is an easily installed, non-expensive eco-friendly solution that allows easy fallback.




Low conductivity RO product for juice production factory

The RO system in the juice factory is working on filtered lake water .

It has been running for 3 years @ recovery of 75%.

AST retrofitted the system with ROTEC flow reversal technology to increase recovery to 91%, maintaining high product quality and lowering CIP demand (was  1/month, currently unknown frequency)

The water quality is constantly monitored. Also the operation parameters are weekly analyzed.

Local team operates the system with remote and local AST support when needed.

AST performed the system retrofit in less than 1 week of system downtime, and the startup sequence has been rapid to quickly return to production. The upgrade operates in coordination with the main system PLC which did not require any change.

After the retrofit the system is producing ~64% less brine.


ROTEC's catalogue

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Shanghai province, China


Produce RO product at <20µS maintaining a high recovery.

Process Capacity:

~48m³/h @ 89-91% recovery rate on RO with ROTEC technology retrofitted system




WellToDo developed a unique process to convert various common water contaminants into nonpolluting compounds. The process utilizes a novel catalyst developed by WellToDo that enables a chemical reaction used to remove the contaminants. The main benefit of this method is that it removes water contaminants without generating any brine or byproducts.


Available contaminants removal methods rely on moving the contaminants from the main water stream and concentrating them into a concentrate stream. This concentrate stream requires further treatment and adds costs and complexity.  The WellToDo process is applicable for a wide range of contaminants and in the case of nitrate, it is the only physical chemical removal process that does not generate any concentrate or byproducts.

The WellToDo innovation is twofold.  In the world of water treatment, catalysis is a big innovation as these kind of processes are quite rare.  In the world of catalysis, a significant shown by WellToDo is the catalyst support used.  Catalysts are metal particles supported on some form of high surface area substrate. Activated carbon is a very common form of catalyst support and is widely used.  Activated Carbon comes in two main forms:

  • Powdered activated carbon and
  • Granular activated carbon.

Powdered activated carbon allows for high surface area but, when used as a catalyst support in packed beds, creates a very high pressure drop through the bed, thereby increasing operational costs.  Granular activated carbon offers a low pressure drop but it's low surface area increases the required reactor volume and system foot print thereby increasing capital costs.

The WellToDo innovative catalyst uses Activated Carbon Cloth (ACC) as the catalyst support.  This cloth is woven from micron size fibers of 100% Activated Carbon.  The fiber size with its porus surface and the fact that these fibers are woven into a fabric structure, offers exceptionally high surface area combined with low pressure drop.  The benefits gained are:

  • small reactor volumes
  • small system foot print and
  • low pumping costs due to the low pressure drop of the catalyst

This technology is encapsulated in the Catalytic Module – the WellToDo CORE product.  This catalytic module is a standard water treatment element ready to be used with off the shelf components to assemble an entire water treatment system.

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The WellToDo 8" Catalytic Module.