Municipal Waste Contamination
Domestically produced wastewater discharged to sewage treatment works includes contaminants such as soaps, cleaning fluids, pharmaceuticals, medical drugs and personal care products.
Active Pharmaceutical Ingredients (APIs), in particular, are considered difficult to remove from wastewater as older or less sophisticated treatment systems are far less effective at removing them. These cover a whole range of pharmaceutical and veterinary medicinal products which have become contaminants of emerging concern.
Such products include antibiotics, antidepressants, anticonvulsants, antimicrobials, antihistamines, anticonvulsants, anti-inflammatory’s, heart medicines, lipid regulators and diabetes treatments.
Pharmaceutical compounds may be released to the natural environment after a person has taken the medicine and it has passed through them, improper disposal of unused medicines or from use in animals. Following a flush down into the sewer, these compounds are then being released into rivers through the standard wastewater treatment process or out of a combined sewer overflow (CSO). These overflow systems are of particular concern as untreated sewage is a likely significant source of these compounds.
Many of these pharmaceuticals or medicinal residues discharged into urban wastewater, can therefore potentially adversely affect the ecological state of our rivers and streams. Concentrations have been found at what are being considered of ecotoxicological concern for aquatic life. This is also an issue for human health as this pharmaceutical pollution can travel downstream to become the influent source for our drinking water treatment works. They can then have hazardous effects on human and aquatic life because of possible bioaccumulation in the food chain.
Some of these pollutants may include what are classed as persistent, bio accumulative and toxic substances (PBTs) which are compounds that have high resistance to degradation.
In addition, although the wastewater may be treated to some extent in the sewage treatment works, the leftover solid product is known as ‘sludge’. This sludge is rich in nutrients and in some regions, this is spread onto land by farmers to act as a fertilizer and benefit the soil.
However, there is increasing concern that this sewage sludge also still contains a cocktail of contaminants including pharmaceuticals and PFAS chemicals which can then more easily make their way into the river systems.
Urban Wastewater Regulations
Water and wastewater treatment regulations in Europe have undergone significant changes in recent years to include substances found in urban and domestic wastewater discharges.
The Urban Wastewater Treatment Directive – 91/271/EEC, was first adopted in 1991, related to the treatment and discharge of urban wastewater and certain industrial sectors.
This Directive has now been updated to address new sources of urban pollution and new pollutants that have emerged, such as pharmaceutical and cosmetic micropollutants.
The updated Directive applies to a broader of areas and new standards will be applied to micropollutants, including systematic monitoring of PFAS now being required. The new law is aimed at ensuring that the costs of any advanced treatment will mostly be covered by the responsible industry, rather than by water tariffs or the public purse.
Whereas the original Water Framework Directive (WFD) 2000/60/EC established EU water policy, the Groundwater Directive (GWD) 2006/118/EC provided a framework for the protection of groundwater against pollution. The Directive 2008/105/EC then established the environmental water quality standards. These were all amended in 2022 to set new standards for a series of chemical substances of concern to address chemical pollution in water. The annexes to this proposal in particular, set out more detail on the specific substances of concern.
One method used to determine the allowable threshold for these products is the predicted no-effect concentration (PNEC). PNEC is the concentration of the chemical which marks the limit at which below no adverse effects to its exposure in an ecosystem are measured.
PNEC values are used as targeted treatment objective or an environmental assessment tool. PNEC is used extensively in Europe by the European Chemicals Agency, the Registration, Evaluation, Authorisation and Restriction of Chemicals program (REACH) and other toxicology agencies to assess environmental risk.
Wastewater Treatment with Activated Carbon
Activated carbon has an extremely porous structure with a huge surface area that enables it to adsorb a wide range of pollutants before their potential release into the environment. Activated carbon therefore is considered a very effective way of removing trace substances such as pharmaceuticals and medicinal drugs from wastewater.
Activated carbon is typically used in the fourth treatment step in the sewage treatment works with an increasing use of granular activated carbon for this application. Granular activated carbon is typically installed in filter beds or vessels, sometimes on sand or gravel media, where the water to be treated typically passes downflow through it. Once granular carbon has become saturated with the adsorbed organics and/or is so less effective in operation, it can be recycled by thermal reactivation for reuse which reduces the CO2 footprint of the purification treatment.
Historically, powdered activated carbon (PAC) which are very small particles of activated carbon – typically between 1 and 100 μm in diameter, have been used for this application. The PAC would be added to the wastewater directly, agitated, left in contact with the solution for a period time, and subsequently separated by filtration.
PAC has the advantages that they can be easily used for short periods, ie when peak problems exist and then stopped when such treatment is no longer needed. However, PAC cannot be reused and is disposed of through the biological sludge gasification or incineration. Therefore, PAC has a more important CO2 footprint as compared to the use of reusable granular activated carbon.
Chemviron’s range of virgin, reactivated and renewable grades of carbons are designed to be highly efficient for trace contaminant removal. We will be pleased to advise on the most appropriate carbon for your specific needs.
What Pharmaceutical and Medicinal Pollutants Can Be Removed Using Activated Carbon?
Activated carbon, in granular or powder form, is highly effective for the removal of a wide range of organic and hydrocarbon pollutants, non-biodegradable compounds and micropollutants from wastewater.
Some of the Active Pharmaceutical Ingredients, medicinal and medical care products that have been found in waste waters and can be removed with activated carbon technology are noted in the table below:
| Acetaminophen | Diclofenac | Ketoprofen |
| Amisulprid | Erythromycin | Metformin |
| Atenolol | Estrone | Methyl benzotriazole |
| Azithromycin | Ethinylestradiol | Metoprolol |
| Benzotriazole | Fexofenadine | Naproxen |
| Benzoylecgonine | Fluoxetine | Norfluoxetine |
| Beta estradiol | Furosemide | Orlistat |
| Caffeine | Gabapentin | Paracetamol |
| Candesartan | Hydrochlorothiazide | Primidone |
| Carbamazepine | Hydroquinone | Propranolol |
| Carbamazepine epoxide | Irbesartan | Simvastatin |
| Cetirizine | Ibuprofen | Sotalol |
| Citalopram | Iohexol | Sulfamethoxazole |
| Clarithromycin | Iomeprol | Sulfanilamide |
| Cocaine | Iopamidol | Trimethoprim |
| Cyclophosphamide | Iopromide | Venlafaxine |
| Diatrizoate |
As many API substances can be quite difficult to remove from wastewater, Chemviron is able to provide technical advice and support on the likely effectiveness of activated carbon as an appropriate solution.
How Can Chemviron Help You?
The selection of the most appropriate activated carbon may depend on several factors. This includes the types and range of compounds or contaminants that need removal, their concentrations, the treatment scheme involved, and also the pH of the waste stream involved.
As a manufacturer of coal, coconut and wood activated carbons in both granular and powder forms, Chemviron is able to produce and select the most appropriate product for the treatment solution required.
Performance Evaluation to Ensure the Most Effective Solution is Selected
Since each water source may contain different combinations of pollutants, it may be appropriate to carry out a laboratory test on a representative water sample. Such tests can assess the likely effectiveness of activated carbon to meet the required treatment requirements and enable us to propose the most appropriate technical solution.
Isotherm testing is a quick laboratory method to evaluate the removal of organics from water. Pilot testing is much more effective at indicating likely carbon usage but can be time consuming. Chemviron can however, provide support and advice using our pilot units, which include our range of smaller mobile carbon filters.
Alternatively, there is the Accelerated Column Test (ACT), which was developed by our own team of scientists & engineers. This is an improved bench-scale procedure that combines the speed of an isotherm test, with the accuracy of a pilot column. The ACT simulates a full-scale treatment system to provide breakthrough test data for the removal of the defined organic impurities, but in a much shorter time.
The ACT can be applied to all types of water and as Chemviron have been running these tests for well over forty years, we have an extensive reference library. With this extensive technical experience, Chemviron can work with you to advise and recommend the optimum performing product for your specific application.
Spent Carbon Recycling and Mobile Carbon Filters for Sustainability and Cost Savings
When granular activated carbon is being used, once the installed carbon in the filter has become less effective in operation, it can be recycled by thermal reactivation for reuse. Reactivation involves treating the spent carbon in a high-temperature furnace where the undesirable organics on the carbon are thermally destroyed. Recycling activated carbon by thermal reactivation is a sustainable and environmentally friendly technology that meets all our objectives to minimise waste and reduce CO2 emissions.
If this is a new or localised treatment application, why not consider using our mobile carbon filters that are available for rental? These can be used on site as a treatment vessel and then to transport carbon to and from the site, without the need for any on-site carbon exchange. Chemviron has a range of these mobile carbon filters of different sizes and capabilities including those for use in low pH environments.
If you need technical support to evaluate your likely treatment options, help with the choice of activated carbon, the use of our reactivation service, the help of our mobile carbon filter service or just some further advice, please contact us – contact our technical team.