Project Overview

Problems to be solved

Since first European directive in 1975, much progress has been made in tackling point source contamination of Europe ‘s waters. But sever pressures remain regarding Priority Hazardous Substances, PHS [DECISION No 2455/2001/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 20 November 2001 establishing the list of priority substances in the field of water policy and amending Directive 2000/60/EC]. Human health is threatened by high concentrations of pesticides, heavy metals, hydrocarbons, chlorinated hydrocarbons, etc. dissolved in water which source is usually industrial wastewaters containing PHS at low-medium concentration (<500 mg/L). In this context, the IPPC Directive (96/61/EC) has requested the development of technologies and management practices for specific industrial sectors (see Annex I of the Directive) for the minimisation of pollution and for the development of water recycling. Due to the lack of available on-site treatment technologies, a large quantity of the industrial activities included in Annex I of IPPC Directive are not treating these wastewaters appropriately. As consequence, simple, low cost and at hand technologies are strongly necessary. CADOX is addressed to develop a suitable technology that could fulfil this gap. CADOX technology will focus on non-biodegradable chlorinated solvents (NBCS), biocides and plant protection products, considered as PHS and which producers are included as objective of the IPPC Directive implementation.


Scientific and technical approach

Although everybody recognizes the strong potential of Advanced Oxidation Processes (AOPs) for PHS-containing wastewater treatment, it is also well known that operational costs of these AOPs for the total oxidation of hazardous organic compound remains relatively high compared to those of a biological treatment. However, their use as a pre-treatment step for the enhancement of the biodegradability of wastewater containing recalcitrant compounds can be justified if microorganisms in a biological treatment readily degrade the intermediates resulting from the reaction. Therefore, the coupling of AOPs and biodegradation has a great advantage over either treatment alone in the remediation of organic contaminants. This Project will create and demonstrate a new technology that could reduce substantially the treatment costs of wastewaters containing PHS. Thus, the problem-solving approach of the project tends to determinate the best conditions to combine TiO2/Photo-Fenton photocatalysis (driven by Solar Energy), Ozone and Biodegradation to the treatment of wastewaters originated in industries and containing highly toxic compounds considered as PHS.


Expected impacts

Due to the lack of available on-site treatment technologies, a large quantity of the industrial activities included in Annex I of IPPC Directive are not treating their wastewaters appropriately. Besides, under the requirements of the Water Framework Directive, emissions of PHSs would need to be reduced to zero. CADOX technology favours the application of safe, cost effective, modern and efficient technologies for reducing the necessities of banning substances very important for the economic growth. Consequently, the implementation of the CADOX will help to safeguard the future of most industries and to prove their environmental competitiveness. The main deliverable for exploitation will be the CADOX Technology Handbook. This handbook is expected to help the marketing of the technology and to be like a matrix indicating the adequate combinations for the most effective treatment. As result it is expected that all participants will increase their competitiveness and consolidate their current position. From the technological point of view, the development of a new hybrid Solar-AOP/Biotreatment process with strong market possibilities is considered the most important contribution of the project. The development of Solar Energy Technologies is an important topic for the EU, which in general lacks conventional non-renewable sources of energy. CADOX proposal is considered of significant importance because the research developed in the field of AOPs during the last years has led to a reasonable knowledge of the processes, but practical and economical systems are not yet available.