BIOmec: Re-qualification of washing waters for the automotive industry - The STEM Discovery Campaign BlogThe STEM Discovery Campaign Blog

DATE OF IMPLEMENTATION

Start date: 20/01/2021
End date: 27/04/2021

TEACHER INVOLVED

Honorata Pereira

ABSTRACT

The mechanics industries generate a contaminated effluent from the washing waters of parts of the automobile sector, which can cause damage to the environment when disposed of inappropriately. In fact, wastewater must be treated in order to acquire a physical-chemical profile established by environmental agencies that provide for standards and conditions for the discharge of liquid effluents generated by polluting sources. The great concern regarding these effluents contaminated with heavy metal ions and oils comes from the fact that they represent a danger to living beings. The Oliveira do Hospital region has several Mechanical Industries, as well as several companies in the field of mtal mechanics, which generate effluents contaminated with heavy metal ions and oils, from the washing water of automotive parts and from electroplating treatment and consequently, suffers from the environmental degradation generated by this sector.

The present work evaluates the potential for heavy metal ion contamination of water from washing parts in mechanic industries. Thus, in a first phase, we assess the impact of the spillage of this type of effluent on aquatic ecosystems. In the second phase, ways of removing oils from these waters are analyzed, using waste, such as “roof-mate”, eggshell, banana peel and paper, used as absorbents. In the third phase, filters with activated carbon, banana peel and eggshell were prepared to assess the potential for removal of the Cr^{6 +}and Ni^{2 +}cations.

Finally, a model was built with the most appropriate absorbents and filters to requalify the waters of the mechanical industries.

The results show that these waters have a large amount of oils and heavy metal ions, such as Ni^{2 +}and Cr^{6 +.}These waters, when released as effluent, interfere with aquatic ecosystems, causing the death of species less resistant to pollution.

Banana peel and coffee are good absorbers of the oil present in these waters. On the other hand, according to the experimental results, the banana peel is a good adsorbent of Ni^{2 +}and Cr^{6 +}ions.

LEARNIG SCENARIO LINK:https://drive.google.com/file/d/1MSzEcMgVl7nOsqN2qjJ5i2cgzlzzP1Tr/view?usp=sharing

Padlet: https://padlet.com/honorata_pereira/xk20rw7ah5um9iqy

THE IMPLEMENTATION CONTEXT

The Biomec project was developed in the 3rd year class, of the professional course of Industrial Maintenance Technician – Automobile Mechatronics. The 16 students in the class, aged between 16 and 18 years, were involved.
The learning scenario was developed by me, Honorata Pereira, in coordination with the Clube de Ciência Viva da Eptoliva. In this way, it was possible to involve other subjects, such as: Biology, IT, Arts, Maths, Citizenship and Development and Integration Area, as well as the community, namely the students’ families, the local mechanics industries and the company “Residence Metal Solucion and Lighting “, which provided the material for the model.

THE PROJECT ORGANIZATION

The project was divided into six parts:

Adaptation to climate change;
Waste and effluents from the mechanical industry;
What can we do to recover effluents;
Treatment of results;
Construction of a model for the recovery of effluents from the mechanics industry;
Presentation of results and dissemination.

In phase 1 of the project, in the integration area class, students watched a video on climate change and the circular economy, available at: https://www.youtube.com/watch?v=Lc4-2cVKxp0&ab_channel=COTEC).

Then they presented the video’s conclusions on jamboard: https://jamboard.google.com/d/1CHjLh7yHl81yPnIObDyeiJZf8ZnS_bx814KWG5sfN6o/edit?usp=sharing.

In the second phase of the project, students discussed, in the citizenship and development class, the residues and effluents from the mechanics industry, which they encountered when they carried out their training in the context of work and put their reflections on the jamboard https://jamboard.google.com/d/1CHjLh7yHl81yPnIObDyeiJZf8ZnS_bx814KWG5sfN6o/edit?usp=sharing. Subsequently the students visited the mechanics industry, where they carried out their training in the context of work. In each of the industries they collected the effluents.

In phase three, in the chemistry class, the students started by identifying what kind of substances they can find in the effluent. Thus, the teacher distributes the following documents to students:
PASQUALINI, A., 2004. Case study applied to electroplating. Master’s Dissertation, UFSC.
OSHA, 2004. “Health and safety topics: toxic metals”. US Department of Labor, Safety and Occupational Health (OSHA) [accessed 3 July 2006] http://www.osha.gov/SLTC/metalsheavy/index.html
EPA, 2008. Petroleum oils. Available at https://www.epa.gov/emergency-response/petroleum-oils
Which have been analyzed in chemistry, biology and physics classes, to devise experimental procedures to remove oils and ions from heavy metals.

In chemistry classes, solutions module, the techniques for separating mixtures, decanting and filtration were addressed and the experimental procedure for removing oils was prepared.
In the “Oxidation-Reduction Reactions” module, electroplating processes were covered: chrome plating, nickel plating and zinc plating, the main anti-corrosion processes used in car parts.

In physics classes, in the “Light and Light Sources” module, the interaction of radiation with matter was discussed and the spectrophotometric analysis of heavy metal ions, namely Ni^{2 +} and Cr^{6 +}and an experimental procedure was prepared to evaluate these ions.

In the biology class in the module “A Biosphere-Diversity and Organization” the impact of these effluents on ecosystems was discussed and an experimental procedure was prepared to assess the impact of the effluent on aquatic systems.

In phase four, in the mathematics class, the results were treated and graphs were created using Google Sheets.
In phase five, in the art class, a model was built to recover and reuse in the washing, the effluent waters from the mechanical industries.
In phase six, in the ICT class, students are preparing a video of the project using Powtoon and a student has already prepared a presentation using Google Slides.

LEARNING OUTCOMES

After this work, the students concluded that:

Regarding the impact of washing water in the workshops of aquatic ecosystems, it was found that at low concentrations no significant differences noted in both water cress as in the mosquito fish. However, for higher concentrations it was found that the fish either died or started to become more apathetic and with limited movements, during the 5 days of observation. In the case of the highest concentration the fish died. As for the watercress, the leaves started to turn yellow, having lost leaves in the case of the highest concentration.
Regarding the most effective absorbent, it is concluded that the absorbents that the banana peel and coffee are good oil absorbers, since the collected water did not exhibit a measurable amount of oil, Annex II, and in addition, that amount of water was higher. The roof-mate was the least efficient absorber because the volume of water collected was higher and had a greater amount of oil.
Regarding the filters, it was found that both activated carbon and banana peel adsorb the Cr6 + ion, however the banana peel filter is more effective because the final concentration in the sample has decreased by 70%. In the case of banana peel, the addition of carbonate did not have a positive effect, since the amount of chromium ion in the sample collected is higher than that of the filter with banana peel. However, the addition of calcium carbonate increased the efficiency of the activated carbon filter, which indicates that an increase in the pH of the medium favors the adsorption of the chromium ion by the activated carbon, with the same type of behavior being observed. for nickel ion, in which, in this case, the banana peel filter was also more efficient, given that the final concentration of nickel present decreased by about 67% in relation to the initial sample.

TEACHING OUTCOMES

As a teacher guiding the project, I feel very proud of the work developed by my students. On the other hand, this project made it possible to involve other disciplines, the community and the families of the students involved.
Regarding the project, I consider that there is a high concentration of polluting cargo, oils and heavy metal ions in these waters, which, when discarded without previous treatment, can have a significant impact on the environment, with the need for programs that intensify the discussion in the business environment on the use of effluent treatment and waste management technologies, in order to improve the performance of production processes and the preservation of the environment. There are alternative technologies available on the market that contribute significantly to the industrial sector, inserting it in the proposals to minimize waste, sustainability and socio-environmental responsibility, which can provide financial, environmental and social returns.

https://drive.google.com/file/d/1CstNRMCxOS3zgUSKOyUHG_0k451QrqOZ/view?usp=sharing