Recover waste thinner in collision repair operations

Submitted through the COP31 Sustainable Transformation Awards · SKD Türkiye (WBCSD Global Network Partner)

The company operates authorised vehicle sales and after-sales services in the retail automotive sector and employs more than 1,000 people.

Collision repair operations require painting processes, and painting operations rely heavily on solvents. Thinner is routinely used to clean spray guns, brushes and other equipment after each painting operation. During use, it becomes contaminated with paint residues and, due to its volatile organic compound (VOC) content, is managed as hazardous waste. VOCs are organic compounds that readily evaporate into the air and are commonly found in solvents such as paint thinners.

Traditionally, the process follows a linear model: purchase thinner, use it once, dispose of it as hazardous waste, and purchase new thinner. This approach creates multiple impacts simultaneously, including the consumption of virgin solvent, hazardous waste management costs, and VOC emissions associated with solvent use and disposal.

The initiative challenges this linear approach by treating contaminated thinner as a recoverable resource rather than a waste stream. Through solvent recovery, thinner is regenerated and returned to the process for reuse. This shifts the focus from merely complying with waste management requirements to preventing hazardous waste generation at its source.

The project was developed in line with the automotive group's sustainability strategy, which is built on three pillars: Climate, People and Innovation, and supports its broader circular economy objectives. The initiative was first implemented at the Avcılar facility in İstanbul in 2025.

Location of the initiative: Avcılar, İstanbul, Türkiye

Used thinner is separated from paint residues by on-site distillation and returned to the cleaning cycle. This allows the same solvent to be recovered and reused repeatedly instead of being replaced after a single use.

The recovery unit is located directly within the Collision repair workshop. As a result, contaminated thinner is recovered at the point of generation, avoiding the need to transport it off site for waste treatment or recovery.

The initiative represents a change in the operating model, not simply the introduction of new equipment. Under the conventional linear approach, contaminated thinner is treated as waste after use. In the new model, the solvent is recovered and returned to the process, transforming a waste stream into a reusable resource and moving the workshop from a linear to a circular operating model.

The initiative has moved beyond the pilot stage. The recovery unit was purchased and put into active operation at the Avcılar site, with operational responsibility assigned to the paint shop team within the collision repair workshop. The practice is therefore embedded in routine workshop operations rather than being limited to a temporary trial.

Continuity is built into the operating routine. Occupational health and safety checks are conducted quarterly, while maintenance responsibilities are assigned to designated staff. The recovery process is therefore managed under the same operational controls as other workshop activities.

Performance is monitored by comparing thinner consumption and disposal before and after implementation. The assessment uses thinner consumption records, purchasing data, recovered volumes, reductions in hazardous waste and the estimated impact on VOC emissions.

Figure 1: The thinner recovery loop: cleaning, contamination, on-site distillation, recovery and reuse

Figure 2: On-site solvent recovery and the environmental results of the first five months of operation

Figure 3: Recovery unit installed in the collision repair workshop

Sustainability impact

Climate

The climate impact of the initiative comes from two main sources: the reduced amount of hazardous waste requiring treatment and disposal, and the reduced need to purchase new thinner. Under the GHG Protocol Scope 3 framework, these impacts are primarily associated with Category 5: Waste Generated in Operations, through avoided hazardous waste treatment and disposal, and Category 1: Purchased Goods and Services, through avoided purchases of new thinner.

Since November 2025, the initiative has avoided the consumption of 890 litres of new thinner at the site. The project has also prevented an estimated 516 kg of volatile solvent from being released to the atmosphere and avoided approximately 1,245 kg CO2e of greenhouse gas emissions during the first five months of operation.

Based on the same consumption model, the five-year projection for the site indicates the potential to avoid 9,026 litres of new thinner consumption. This would correspond to preventing approximately 5,235 kg of volatile solvent from being released to the atmosphere and avoiding approximately 12,728 kg CO2e of greenhouse gas emissions over five years. These figures are projections rather than achieved results and are reported accordingly.

Nature

The primary environmental benefit of the initiative is the prevention of hazardous waste at source. By separating paint residues from used thinner through distillation and returning the recovered solvent to the cleaning cycle, contaminated thinner is recovered and reused rather than being sent for treatment and disposal as hazardous waste. This shifts the approach from managing waste after it is generated to preventing waste generation at source.

The initiative also reduces the potential release of solvent into the environment by keeping the recovered thinner within a controlled reuse cycle. Resource efficiency is improved by keeping the same material in use for longer and reducing the need for new thinner. This creates a more circular use of resources within collision repair operations, replacing the conventional use-and-dispose model with a recovery-and-reuse approach.

Social

The initiative contributes to a safer working environment by reducing the amount of contaminated thinner that needs to be stored and managed as hazardous waste within collision repair operations. This can reduce employees' potential exposure to volatile organic compounds (VOCs) associated with the handling and storage of waste thinner.

Occupational health and safety requirements were assessed before the recovery unit was installed, and safety checks are scheduled on a quarterly basis. This helps integrate the recovery process into the workshop’s regular occupational health and safety practices and ensures that the process is operated under appropriate safety controls.

The initiative also provides workshop teams with a practical example of circular economy in their daily operations. By recovering and returning a material previously treated as waste to the production process, the initiative helps demonstrate how resource recovery can be integrated into an existing operational process.

Business impact

Benefits

The initiative demonstrates that circular economy solutions can deliver environmental and business value at the same time. At the Avcılar site, initial results showed a 75 per cent reduction in thinner consumption and a 60 per cent reduction in thinner-related costs, so lower resource consumption translated directly into measurable operating cost savings.

By recovering and reusing thinner within collision repair workshops, the project reduces the need to purchase new thinner while also decreasing the volume of hazardous waste requiring treatment and disposal. This makes resource efficiency an integral part of the business case rather than an environmental benefit delivered at additional operating cost.

The recovery unit has been integrated into daily operations at Avcılar, with operational responsibility assigned to the workshop team and maintenance responsibilities formally established. This supports the continuity of both the environmental and financial benefits beyond the initial implementation phase.

The model also has significant potential for replication. The scalability of the model creates an opportunity to extend the same resource-efficiency approach across a broader operational network.

Costs

The main upfront cost of the initiative is the investment in the thinner recovery unit. Before the purchase decision, the solution was evaluated through a supplier demonstration, site assessment and testing process, including technical suitability and occupational health and safety requirements. This assessment helped confirm that the equipment was appropriate for the operational conditions of the collision repair workshop before the investment was made.

The solution also requires ongoing operational resources, primarily for regular maintenance of the recovery unit. Maintenance responsibilities have been assigned to the relevant workshop staff and incorporated into the operating model to support safe and continuous operation. Quarterly occupational health and safety checks are also conducted as part of the established control process.

For wider deployment, investment feasibility depends on the operating conditions of each site. Thinner consumption and vehicle throughput are considered alongside technical suitability and occupational health and safety requirements when assessing whether the solution is appropriate for additional locations. Key considerations for scaling include sufficient thinner consumption to support the investment, safe operation of the equipment, regular maintenance and the long-term adoption of the new process by workshop teams.

The demonstration and testing approach provides a practical model for future deployment. Technical and financial suitability can be assessed at site level before an equipment investment is made, enabling more informed investment and scaling decisions across the network.

Impact beyond sustainability and business

Co-benefits

The recovery model has potential applications beyond automotive collision repair. Similar operations that use solvents for cleaning after painting processes may be able to apply the same principle of recovering and reusing solvents instead of following a single-use and disposal model. This creates an opportunity to transfer the operational learning gained from the initiative to other solvent-intensive processes.

The initiative also demonstrates that sustainability improvements can be achieved through changes to existing operational processes, without requiring a fundamental redesign of the wider operation. The experience gained through supplier testing, site assessment, implementation and day-to-day operation creates practical knowledge that can support the evaluation and deployment of similar resource-efficiency solutions.

A further co-benefit is increased employee engagement with circular economy principles. By seeing a material previously treated as waste recovered and returned to use within their own workplace, workshop teams gain a tangible understanding of how circularity can be integrated into everyday operations. This practical experience can help strengthen awareness of resource efficiency and encourage the identification of further improvement opportunities.

Potential side-effects

The distillation unit requires electricity during operation, representing an additional energy input to the process. However, this should be considered alongside the broader benefits of the initiative, including reduced virgin thinner consumption, hazardous waste generation and associated emissions.

Distillation separates reusable thinner from paint residues rather than eliminating the residues entirely. The remaining residue therefore still requires appropriate management following the recovery process.

As solvent distillation involves flammable materials, occupational health and safety assessment is an important part of implementation. Safety approval was obtained before installation, and quarterly occupational health and safety checks form part of the ongoing control process.

Typical business profile

The model is particularly relevant for operations that use solvents to clean equipment after painting processes, including vehicle collision repair workshops and after-sales service operations, as well as manufacturing or maintenance facilities with similar painting activities.

The approach is most relevant for sites that generate a consistent volume of contaminated solvent, as higher solvent consumption increases the potential for solvent recovery, reuse and avoided hazardous waste generation.

Implementation requires coordination across operational and support functions, including operations, purchasing, finance, occupational health and safety, and sustainability. Following installation, day-to-day responsibility for the recovery process can be integrated into the relevant workshop team.

Approach

1. Quantify the solvent flow before changing anything: Record thinner purchases, consumption over a defined period and the volume sent for hazardous waste treatment and disposal. This establishes the baseline, disposal costs and potential recovery volume before any equipment is considered.

2. Research the recovery options: Identify and assess available solvent recovery and distillation equipment based on technical suitability, capacity and cost. The equipment should be sized according to the site's actual solvent flow rather than the largest available capacity.

3. Run a demonstration using the workshop's own material: Arrange a supplier demonstration with the technically and commercially suitable unit, using contaminated thinner generated at the site. In this case, the demonstration was carried out in June 2025, allowing the recovery yield and technical suitability to be assessed using real operating conditions.

4. Complete the site survey and safety assessment: Conduct a site survey and obtain the required occupational health and safety approvals for operating solvent distillation equipment in the workshop. Complete the testing and assessment phase before committing to the investment. In this case, the assessment was completed in September 2025.

5. Make the investment decision and start recovery: Purchase the unit once the test results and site assessment confirm its suitability, and begin the recovery process. Start measuring recovered volumes from the beginning of operation to enable comparison with the baseline. In this case, the investment decision was taken in November 2025.

6. Transfer responsibility to the workshop team: Assign day-to-day operational responsibility to the paint team within the collision repair workshop and assign maintenance responsibilities to designated staff.

7. Establish routine safety and maintenance controls: Schedule occupational health and safety checks on a quarterly basis and incorporate equipment maintenance into the workshop's routine control system. This helps embed the recovery process into normal operations beyond the initial implementation phase.

8. Track performance and prepare for replication: Monitor avoided new thinner consumption, hazardous waste reduction, avoided volatile solvent release, estimated avoided CO2e emissions and the percentage reduction in thinner consumption. For potential new sites, assess thinner consumption, vehicle throughput, technical suitability and occupational health and safety requirements before planning investment and deployment. Continue monitoring sustainability indicators centrally after implementation.

Stakeholders involved

• Project leads: The initiative was developed with senior management sponsorship and cross-functional ownership, helping integrate the project into both operational and sustainability priorities.

• Company functions: Operations, purchasing, finance, sustainability and occupational health and safety functions contributed at different stages of the initiative. Operations provided the existing thinner-use requirements, site conditions and feasibility needs; purchasing and finance supported the technical and commercial assessment; sustainability established the environmental impact indicators; and occupational health and safety supported the safety assessment and ongoing quarterly checks. Following installation, day-to-day operation of the recovery unit was transferred to the relevant workshop team, together with maintenance responsibility.

• Main providers: The equipment supplier supported the demonstration and testing phase, allowing the recovery solution to be assessed using contaminated thinner generated at the site before implementation.

• Other: Operational feedback from workshop users, together with occupational health and safety assessments and maintenance requirements identified during implementation, informed the integration of the recovery process into day-to-day operations.

Key parameters to consider

Reported results should clearly distinguish between actual operating results and longer-term projections. Projections based on current consumption patterns depend on operating conditions and paint activity remaining broadly comparable over time.

Site-level thinner consumption is a key consideration when assessing the suitability of the recovery system, as the potential for recovery and cost savings depends on the volume of thinner that would otherwise be purchased and subsequently managed as hazardous waste.

Occupational health and safety assessment is an essential part of implementation. Solvent distillation needs to be assessed against site-specific safety requirements before installation, with appropriate safety checks incorporated into routine operations. At this implementation, occupational health and safety checks are conducted quarterly.

Clear operational ownership and planned maintenance are also important for continuity. At the Avcılar site, responsibility for operating and maintaining the recovery system has been integrated into the routine responsibilities of the workshop team.

Implementation and operations tips

Measure both solvent consumption and waste management: Establish the baseline using thinner purchasing and consumption data together with the volume and cost of hazardous waste treatment and disposal. This provides a more complete basis for assessing both the operational and financial impact of the recovery system.

Test the solution using the site’s own contaminated thinner: Use actual waste solvent from the operation during the demonstration and testing phase. This allows the technical suitability and recovery performance of the proposed solution to be assessed under the site’s real operating conditions before the investment decision.

Complete the safety assessment before investment: Assess site-specific occupational health and safety requirements before installing solvent distillation equipment. This helps identify any necessary safety measures or site requirements before committing to the investment.

Build operational ownership from the start: Involve the workshop team in the testing and implementation process and clearly assign responsibility for day-to-day operation and maintenance once the system is installed. This helps integrate recovery into routine workshop operations.

Assess site conditions before scaling: Before replicating the solution at another location, evaluate thinner consumption, operational conditions, technical suitability and occupational health and safety requirements. These factors help determine whether the recovery system is appropriate for each site.