The Effective Treatment of Contaminated Water

The Investigation Of An Advanced Oxidation Process (AOP) In Wastewater Treatment

Treating contaminated water successfully is vital to providing a sustainable means of water consumption and usage. It's well known that industrial processes, power generation and offshore exploration processes cause significant pollution and degradation to rivers, groundwater, lakes and marine waters. Successful treatment of contaminated water is vital to sustainable water consumption and usage. Semiconductor photocatalysis advanced water treatment is a clean and actively researched technology.  This research looks at a low cost, simple  and sustainable water treatment using semiconductor as a catalyst.

Power Plant ImageIt has been suggested that by 2025, approximately 5.5 billions of the global population will suffer severe fresh water stress. The UK Environment Agency also estimated that 300,000 hectares of land and groundwater in the United Kingdom may be affected to some extent by industrial or natural contamination. All of these facts demonstrate the importance of effective treatment of contaminated water to provide a sustainable means of water consumption and usage.

In our field pilot study, an advanced oxidation process (AOP) was investigated as a potential wastewater treatment method. We tested the efficiency of an industrial scale twin tank (Tank A and Tank B) photocatalytic reactor with methylene blue (MB), toluene and contaminated groundwater (collected as part of a groundwater monitoring exercise samples from ex-gas works).

The photocatalytic reactor was designed for the remediation of industrial effluent, oil and gas wastewater and other waste streams such as contaminated groundwater. MB was chosen as it is widely considered as an indicator for photocatalytic degradation. Toluene, also known as methyl-benzene, was chosen as a hydrocarbon analogue because of its presence in industrial solvents and crude oil.

Clean Water ImageThe reactor was designed to use pellets which were directly submerged in the effluent. Treatment of MB using Tank A of the photocatalytic reactor showed 97.89 % removal efficiency and total organic carbon (TOC) reduction of 84.40 % after 150 minutes. Treatment in continuous mode was more effective than single tank batch mode; approximately 95.88 % removal of MB was demonstrated in continuous mode.  FT-IR analysis suggested that 91.41 % of total petroleum hydrocarbon (TPH) removal was achieved after the treatment of contaminated groundwater using the photocatalytic reactor. These promising results demonstrate a desirable prospect for environmental application and show that the reactor could remove up to 97.89 % of MB by treatment with the reactor for 150 minutes. In the efficiency test, for toluene contaminated effluent, the reactor achieved 92.58 % and 92.64 % of toluene and TOC removal efficiency respectively.   Treatment of the contaminated groundwater collected from an ex-gas work site showed that the reactor was capable of removing more than 90 % of total hydrocarbon.

Semiconductor photocatalysis advanced water treatment is a clean technology which has been actively researched. The industrial-scale semiconductor photocatalytic reactor discussed here employs a low cost, simple mechanism for water treatment using pelletised catalyst in the effluent. The catalyst in pellet form (granular) was unmodified and directly submerged in the effluent, which maximised the surface area for exposure to  dissolved oxygen and the pollutants. The reactor can be operated at low cost and no filtration is required after treatment. Moreover, the reactor was designed to be mobile and modular to support treatment on-site as well as off-site as well as in very remote areas. These results show a promising prospect for use of the reactor in environmental remediation. It is intended that information obtained in this work will contribute to further optimisation of the reactor. 

And lastly...... this study was made possible by: