Related theme: Future-proof Site (Re)Development & Transformation
Period: 2014 - underway
Client: Philips, USA
TAUW contact:
Ralf Engelhardt
In 2024, TAUW was honoured to win in the category ‘Best Oversees Project’ at the prestigious Brownfield Awards. This wonderful recognition by Environment Analyst highlights a project that we are very proud of.
A large former industrial site in the São Paulo Metropolitan area required remediation, but presented a unique boundary condition. After industrial activities had ceased, the site was transformed into a university area with several educational buildings. The environmental impacts caused by the industrial activities had not been assessed before the conversion, and the site formerly owned and operated by Philips Brasil, was contaminated mainly by Chlorinated Volatile Organic Compound (CVOC) due to different industrial processes. TAUW Germany and local Grupo EPA Brazil formed a cross-continental, multinational and diverse team (TAUW-EPA) in collaboration with Philips’s US division to remediate the site’s contamination.
We faced a challenge due to the presence of the educational centre, as a significant portion of contamination plumes in the soil and groundwater were located below and between the large university buildings, with limited access for remediation activities and with the university activities ongoing. This being a sensitive issue, various stakeholders had to be involved in the environmental processes and remediation activities from the beginning. Additionally, the ongoing remediation works are subject to strict procedures by the São Paulo state environmental authority because the site is located in a designated “Critical Area” where the deep aquifer used for drinking water production is affected.
Figure 1: Site of interest (left) and delineated source zones with contamination source and main contaminants of concern (right)
The contaminated areas of concern are widely spread over the university area and a step-by step remediation approach was chosen by Philips/ TAUW-EPA to tackle the different areas according to previously agreed priorities. The step-by-step remediation was implemented and operational in 2019 and is still underway.
As the overall manager, TAUW is responsible for investigation design, remediation planning and supervision as well as for the financial management. The ongoing and completed remediation activities include removal via excavation and large-hole boring, pollutant degradation via in-situ chemical oxidation and the securing of groundwater at the site boundary through a hydraulic barrier. We prioritize innovative approaches when possible by assessing them through a social, economic and environmental lens.
By committing to sustainable remediation solutions, we reduced the impact on the environment and were more cost-effective, as well. Using the principles of a circular economy, we focused on sustainable solutions such as implementing renewable energy sources at the site by using a solar thermal system for the activation of oxidant solution required in the remediation process. Additionally, water treated in the on-site water treatment plant is being re-used in the remediation process and excavated soil could be repurposed following solid waste processing. In another part of the site, a bespoke automized oxidant solution prep and dosing system was designed and implemented to save time and costs.
Figure 2: Solar thermal panels installed on a building roof (left) and design for chemical protection roof equipped with a photovoltaic system (right)
Figure 3: Persulfate is delivered in big bags and lifted by a crane to be poured into a storage tank. From there, persulfate powder is added to the mixing tank as required to prepare oxidant solution of the desired dosage. Level sensors automatically indicate when new oxidant solution needs to be prepared.
By implementing green, sustainable remediation practices, we were able to provide not only more sustainable and cost-effective solutions, but successful ones. We achieved a 98% and 90% reduction in two CVOC compounds – 1,1,1-TCA and TCE respectively, following remediation via two in-situ chemical oxidation cycles in the inner courtyard of an academic building on campus. Our commitment to both an effective remediation, in addition to finding creative and innovative solutions benefits the people, planet and prosperity.
Figure 4: Average 1,1,1-TCA and TCE concentrations at Area 1 over the course of the ISCO treatment
The success of the project is due to the partnership of the innovative TAUW team with Grupo EPA, which is being managed by the TAUW representative office in São Paulo in close coordination with the customer Philips.
"Throughout the project, our international team commits to maximizing sustainability across the entire project lifecycle, by screening every option on the full sustainability spectrum — social, environmental and economic —this guidance encouraged the team to explore exciting, new ideas." — Ralf Engelhardt
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