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Micropollutant Concerns

Water Cycle & Ozone Treatment Solutions.


The term micropollutant comprises synthetic substances that originate from anthropogenic activities and appear in small concentrations below several micrograms per liter in natural waters (e.g. industrial chemicals, pesticides, pharmaceuticals, hormones).

Emerging contaminants or CECs

Emerging contaminants or Contaminants of emerging concern (CECs) refers to any chemical discovered in water or in the environment that had not previously been detected, or were only present at insignificant levels. CECs can range from pharmaceuticals and personal care products to persistent organic pollutants used in many industrial processes.​

CECs is the general term covering a wide class of different types of chemical compounds, including:​

Disinfection by-products, Endocrine Disruptors, Industrial Chemicals, Natural Toxin Analysis, Persistent Organic Pollutants (POPs), Pesticide Analysis, Pharmaceuticals and Personal Care Products (PPCP)​.

These chemicals make it into lakes and rivers and have a detrimental effect on fish and other aquatic species. That have also been shown to bioaccumulate up the food web – putting even non-aquatic species at risk when they eat contaminated fish.

Micropollutants & CEC in the water cycle​ – A matter of positioning​

micropollutants & CEC in the water cycle diagram
  • Micropollutants are detected in the environment at trace concentrations ranging from ng/L  to μg/L​

  • Emerging Contaminants from more common ng/L – dilution effect usually occurs when they are discharged into the receiving environment


Context​ – Since 20 years

  • Pristine WW Sipibel (hospital WW),​

  • Micropolis-Procédés (2012-2016)  =>  Design / Sizing / Industrialisation​

  • Regard – Bordeaux Métropole (sources characterization)​

  • From which families of compounds?​​

  • >110 000 registered substances in Europe…​

Micropollutants are detected in the environment diagram
product types
measurement and development diagram

Why micropollutants?​

Emergence and democratization of new laboratory measurement techniques.​

  • Organic or mineral substances​

  • Proven negative effects for environment and human health

  • > 200 to 1000 new every year​

  • Contamination sources​ – Mostly from human activity…

  • > 90% of the European households and industries are connected to a WWTP

Emergence and democratization of new laboratory measurement techniques diagram

Examples of micropollutants​ – Huge family of organic compounds

Examples of micropollutants diagram

WWTP Toxicity? Treated water from secondary clarifier

Treated water from secondary clarifier diagram

Which Toxicity?

  • Bioaccumulation​

  • Biomagnification​

  • Endocrine disruptors​

  • Antibiotic resistance​

  • Cocktail effect

types of toxicity diagram

Micropollutant treatment in Switzerland – well engaged

Concept 2006 – Sensitive waterbodies​

Responsibility with respect to surrounding countries ​


Regulation:  ​

Entry into force of the law since 01/01/2016 (only country)​ treatment in WWTP before discharge​ removal of 80% of a list of 12 indicators​


Main technologies selected:​

  • Ozone​

  • Activated carbon (AC)​

  • Combination of both ozone & AC​



  • 10 plants with treatment in operation ozone 50% (3 plants with Ozonia generators)​

  • 20 plants in planning​



120 to 130 WWTPs equipped by 2040 (approx. 50% of WW)​​


K figures:​

  • Ozone dosage 0,3 to 0,6 g O3/ g DOC​ (< 10 mg/l)​

  • Hydraulic Retention time (HRT) 15 to 20 min​

  • Transfer efficiency > 95%​

  • Usual Generator size Ozonia M ​1 to 20 kg O3/h​

Quaternary treatment (Ozone followed by biofilter)​:

  • Ozone + sand filter​

  • Ozone + GAC

Micropollutant treatment in Switzerland map
substance and description chart
raw water to treated water diagram

Micropollutants treatment by ozone

Micropollutants treatment by ozone diagram

Ozonia Scope

Ozonia Scope diagram

FOCUS on Delta UV – Differentiating ozone dosage control

FOCUS on Delta UV – Differentiating ozone dosage control diagram

ARA Neugut – Case study​

ARA Neugut – Case study​
removal rates from 2016 to 2018 chart

At glance:​

  • 150 000 PE​

  • 15 000 to 55 000 m3 / d​

  • Treatment of micropollutants ​- Implemented 2014

  • 2 x Ozonia CFV05 (11 kg O3/h)​

  • Max. Ozone dose = 7 g/m3​

  • Design dose: 0,7 g O3 / g DOC


Key considerations for implementation​​:

  • Assess bromate risk (Bromide > 100 microg / l) – presence of industrial WW​

  • Ozone followed by a biofiltration step (Ozone + BAC)​

  • Split the dose – global optimization and bromate mitigation​

  • Ensure micropollutant removal rate & dose optimization by on-line delta UV control​

Ozone solution:​

  • Proven solution​

  • Robust, reliable & easy to operate​

  • Wide removal spectrum & Cost effective​​



Brave thinking.

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