Technical and Commercial Considerations in the Removal of Priority Substances as specified within the EU Water Framework Directive from treated domestic sewage: Case study from a 16,000 PE non-rural WwTP
Nkrumah-Amoako, K., Khan, M., Parocki, D., Nabeerasool A.M.
Arvia Technology Ltd. , UK
(free)
Abstract:
Arvia Technology, a specialist water treatment company, has developed a unique approach for the treatment of hard to treat (recalcitrant) and toxic compounds. The treatment process is based on a proprietary graphite adsorbent Nyex™ which self regenerates in-situ without the use of chemicals.
Over a 12-month period ending March 2017, Arvia Technology in conjunction with Anglian Water have operated a pilot unit at a 16,000 PE WwTW to investigate the removal of a range of micropollutants including emerging contaminants (Priority Substances). The project was part of the EA sponsored Chemicals Investigation Programme (CIP2).
An extensive list of contaminants was selected for study, including metals, pharmaceutical and chemical residuals. Removal efficiencies of up to 99 % were routinely demonstrated at an operating cost of up to 0.15 kWhm-3. Results of the trial were used to cost up a range of full scale systems from 2,000 – 500,000 PE for companies such as Anglian Water and Thames Water.
Keywords
Electrochemical oxidation, Adsorption, Advanced Oxidation Process, Self-regenerating adsorbent, Nyex, Organic Destruction Cell
Introduction
Arvia Technology commissioned a 12-month Pilot demonstration of its Organic Destruction Cell technology at St. Ives Wastewater Treatment Works (WwTW) in Cambridgeshire for tertiary removal of a range of micropollutants from the effluent of the wastewater plant. This was part of a UK Water Industry Research’s (UKWIR’s) Chemicals Investigation Programme (CIP), a £35 million investigation into the source and removal of trace substances in the WwTWs’ effluents with the view to establish a basis of a national-scale assessment of the risks posed by chemicals in WwTW discharges (European Council Directive 2000/60/EC).
In preparation of the new Asset Management Period 6 (AMP6, 2015-2020) under the Water Framework Directive, this CIP was updated into a new £140 million CIP2 programme which focused on more site-specific issues and removal of priority substances, substances pending review to be classified as priority substances and other micropollutant compounds of specific concern (Bolong et al., 2009; Luo et al., 2014). Arvia’s ODC technology was selected as a tertiary treatment option for Phase C2b – “Pilot plants – Technologies not looked at in AMP5 CIP”.
The fates of a total of 55 determinands, listed below, were investigated over the course of the 12-month study:
- Metals: nickel, lead, copper, zinc, cadmium, mercury, iron, aluminium, chromium, both dissolved and total fraction;
- Priority substances: “penta” cogeners 28, 47, 99, 100, 153 and 154 (BDEs), di (2-ethylhexyl) phthalate (DEHP), nonylphenol, nonylphenol with 1, 2 and 3 ethoxylate units, tributyltin compunds (TBT), octylphenols (4-(1,1′,3,3′- tetramethylbutyl)-phenol), hexabromocyclododecane, benzo(a)pyrene;
- Special pollutants: Perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), fluoranthene, triclosan, cyphermetrin;
- Steroids: estrone (E1), 17α-estradiol (E2), 17β-ethinyl estradiol (EE2);
- Pharmaceuticals: diclofenac, ibuprofen, atorvastatin, para and ortho hydroxy atorvastatin, propranolol, atenolol, erythromycin, norerythromycin, azithromycin, clarithromycin, ciprofloxacin, metformin, ranitidine, carbamazepine, 10,11-epoxy carbamazepine, sertraline, norsetraline, fluoxetine, tamoxifen, trixylenyl phosphate, 1,2,3 benzotriazole (tautomers 1H and 2H), tolytriazole (4, 5 methyl benzotriazole).
Arvia’s ODC technology is primarily an organics treatment technology, and thus no treatment of the metals was anticipated. For the purpose of this work, a selected list of priority substances and pharmaceutical compounds are discussed.
