Proposal for a new internal processing approach for secondary product from car body surface treatment at the wastewater neutralization station of the automotive paint shop

Martin DROZD^a, Vratislav KAVALIER^b

^a Institute of Sustainable Regional and Local Development, Faculty of European Studies and Regional Development, Slovak University of Agriculture in Nitra, Trieda Andreja Hlinku 2, 949 76 Nitra, Slovakia, e-mail: xdrozdm@uniag.sk
^b Jaguar Land Rover Slovakia s.r.o., Horné lúky 4540/1, Nitra, Slovakia, e-mail: vkavalie@jaguarlandrover.com

The study focuses on evaluating a change in the management of secondary product generated in an automotive paint shop during the application of coatings on vehicle bodies, through its treatment in a newly designed technology integrated into the existing operation of the wastewater neutralization station (NS). The proposed technology allows for the separation of secondary product into filtrate (1,080 t·y⁻¹) and sludge (120 t·y⁻¹), enabling more efficient and environmentally responsible processing directly at the point of origin. Laboratory tests confirmed the effectiveness of FeCl₃ as a coagulant in the separation process, reducing the chemical oxygen demand (COD) concentration from 177,000 mg·L⁻¹ in the original secondary product to 92,360 mg·L⁻¹ in the filtrate and further to 616 mg·L⁻¹ in the treated wastewater. Compliance with key legislative COD and other pollutant limits was confirmed, as the plant´s outlet COD value (1,200 mg·L⁻¹) remained within the permitted range despite a 100% increase following the addition of filtrate. The implementation of internal waste treatment has eliminated dependence on external end-of-life facilities, resulting in annual cost savings of €227,943 and a reduction in carbon footprint by 26.6 t CO₂·y⁻¹, primarily due to decreased reliance on tank truck transport. The integrated technological process comprises pipeline transport, coagulation, neutralization, flocculation, and sludge dewatering. The estimated volume of filtrate, 5.4 m³·d⁻¹, is marginal in comparison to the plant’s average daily wastewater volume of 1,453 m³·d⁻¹. The findings confirm the technology’s environmental safety, operational viability, and support for sustainable automotive waste management.

Keywords: automotive paint shop, COD, secondary product, neutralization station, wastewater treatment

Effect of operating parameters on greenhouse gas production during wastewater treatment

Lenka SMETANOVÁ^a, Josef K. FUKSA^a, Martina PLECITÁ^a, Miroslav ČEŠPIVA^b, Petra ZABLOUDILOVÁ^b, Josef ZEMAN^b

^a TGM Water Research Institute, p.r.i.., Podbabská 2582/30, 160 00 Praha 6, e-mail: lenka.smetanova@vuv.cz
^b Czech Agrifood Research Center, p.r.i., Drnovská 507/73, 161 00 Praha 6

Wastewater treatment plants (WWTPs) are primarily designed and operated to achieve the highest possible effluent quality, contributing to the reduction of pollution in receiving waters; however, they are also sources of gaseous emissions into the atmosphere. Currently (also in connection with the new Urban Wastewater Treatment Directive), attention is shifting towards ensuring that WWTPs are sustainable in terms of other environmental impacts as well. One such aspect is the production of greenhouse gases. Emissions associated with wastewater treatment arise from the generation of electricity consumed during wastewater management and other energy sources (indirect emissions), as well as from the treatment processes themselves – both naturally occurring and intensified (direct emissions). In this paper, we examine the influence of operating parameters on direct emissions of carbon dioxide, nitrous oxide, and methane arising during municipal wastewater treatment, and we present the results of measurements of selected greenhouse gases above the water surface of an aeration tank in a small-scale (domestic) wastewater treatment plant.

Keywords: Wastewater treatment, Emissions, N₂O, Greenhouse gases, Organic load, Nitrogen load

Utilization of Waste Glass for Partial Replacement of Cement in Cementitious Composite According to ČSN EN 196-1

Aleš PALIČKA, Zdeněk PROŠEK
Czech Technical University in Prague, Faculty of Civil Engineering, Thákurova 7, 166 29 Prague 6, Czech Republic

This paper presents an experimental assessment of the potential use of finely ground waste glass as a secondary raw material for partial replacement of Portland cement in cement-based composites. The study aimed to evaluate the effect of different dosages of waste glass powder (WGP) on mechanical properties (compressive strength, flexural tensile strength, and dynamic modulus of elasticity) and selected microstructural characteristics. Standard cement paste mixtures were prepared in which cement was replaced by WGP at 10 – 50 wt. %, and the results were compared with a reference mixture without replacement. The tests showed a decrease in strengths and dynamic modulus of elasticity with increasing WGP content, with the most pronounced changes already observed at lower replacement levels. Microstructural analysis (SEM/EDS) confirmed good mechanical integration of glass particles within the cement matrix. The results provide experimental input for optimizing mixture design with WGP (e.g., by adjusting fineness or combining it with other reactive supplementary materials) and support the material valorization of waste glass within the framework of a circular economy in the construction sector.

Keywords: Waste Materials, Waste Glass, Recycling, Mechanical Properties, Cement