Practical Environmental Management Reduces Costs, Refines Quality

The results of an electroplating process are beneficial, but for the plating facility that must handle and dispose of effluents with high levels of total dissolved solids (TDS) and hazardous chemicals, this surface finishing method can be challenging. To uphold environmental sustainability while maintaining high production standards requires intentional strategies.

Established in 1975, Gator Systems is a 45,000-sq.-ft. manufacturer and surface treatment company located in Mumbai, Maharashtra, India. Over the last couple years, it has implemented methods for reducing TDS and recovering the expensive tin metal used for a customer’s automotive OEM project that requires plating nuts and bolts (fasteners) for motorcycle batteries. Its tin recycling method, as well as the meticulous treatment process it has developed for its plating effluents, reduces the environmental footprint and ultimately lowers operational costs, according to the company.

The electroplating plant within the business employs about 10 people who are involved in the plating operation alone. The plating process enhances the fasteners it manufactures with copper, zinc, lead, tin and nickel coatings while implementing quality and environmental safety standards.

This year marked a company milestone: it manufactured 300 million fasteners in one year.

Versatile equipment

Gator Systems operates two plating lines, one fully automated and one semi-automatic. The Growell & Weil system is equipped with automation features such as online monitoring, event alarms and data logging (supervisory control and data acquisition) systems, which according to Bhushan Shelat, director of marketing, enhance traceability, control and ease of maintenance.

This system, as well as the semi-automatic system from Progalvano, have been installed within the last five years. Each line is equipped with customized features that support a variety of substrates, plating finishes and coating thicknesses tailored to the needs of not only automotive, but also construction and industrial manufacturing industries that Gator services.

“Our automated systems streamline throughput and enhance quality control through integrated sensors and monitoring tools that maintain strict tolerances,” Shelat explains.

Regulatory comparison

When comparing regulatory requirements in the U.S. versus India, there are some similarities and differences, according to Shelat.

Similarities include the focus on controlling pollutants in electroplating processes, particularly heavy metals such as chromium, nickel, cadmium, and zinc. Regulations in both countries aim to limit air and water pollution by controlling emissions, managing hazardous waste and enforcing treatment of wastewater before discharge. The countries share the primary goal of reducing the release of toxic substances to protect the environment and human health.

The differences in regulations boil down to more stringent effluent guidelines for plating facilities in the U.S., which results in higher compliance rates here. 

“The U.S. regulatory framework often mandates more frequent monitoring, reporting and independent inspections,” Shelat explains.

Regarding technological requirements, in India, while regulations encourage the use of ETPs and recycling systems for wastewater, many smaller electroplating units struggle to implement advanced technologies because of financial and space constraints. Some units are shifting toward common treatment facilities to share costs. In the U.S., the EPA requires advanced technologies to be implemented.

Hazardous substances management is also different in each country. In India, there is a strong emphasis on managing hexavalent chromium, cyanide and other hazardous chemicals. “Regulations require treatment to convert hexavalent chromium to the less toxic trivalent state, with solid waste managed according to the Hazardous Wastes Rules,” Shelat explains. “However, the disposal options are often limited, leading to potential risks if not properly handled​.”

In the U.S., the EPA’s regulations for hazardous substances are stricter.

As for key process differences, Shelat sums it up:

• Wastewater treatment: The U.S. typically employs more advanced systems for removing contaminants from electroplating effluents, including activated carbon, ion exchange and membrane filtration systems. In India, treatment often involves traditional neutralization and precipitation, with varying levels of sophistication depending on the scale of the operation.
• Air quality controls: U.S. regulations often necessitate more comprehensive air quality controls for fumes generated during electroplating, while Indian regulations may not uniformly require such systems, especially for smaller operators. This can lead to differences in how airborne emissions are managed between the two countries.

Reducing effluent contamination

Although these reasons alone are good reasons to reduce effluent contamination, Gator Systems also understands that quality control is another incentive. Because the company has many automotive OEM customers, it must meet stringent auto industry standards while plating battery fasteners on its automated line, including the highest level of corrosion resistance that can withstand harsh climates and road conditions.

Shelat explains that processes to reduce effluent contamination contribute to more stable manufacturing processes that are cost effective and minimize defects. But these developments did not happen overnight. Gator’s engineers began with a couple pilots to ensure their ideas were feasible and that they could get the results they were hoping for.

“Once they were successful, we completely implemented this in our main production line, which runs 24/7,” Shelat says. “The pilot started in November of 2022. We did the pilots over six to eight months before having the confidence to implement it on the entire production line.” 

“Having less TDS in the effluent puts less burden on our ETP process,” Shelat says.

The new system helps the company focus on ensuring that the generated rinse effluent’s contamination is reduced as well as the plating and drag-out effluents and process effluents. It uses a carbon steel-based material to plate the battery bolts, then a copper undercoat, which is between 3 and 5 microns thick, followed by a tin coat that is 8 to 10 microns thick.

Rinse effluent treatment: Gator’s cascade rinse tanks, which remove excess carryover of chemicals from process tanks, are continuously overflown with fresh deionized water before being drained to the effluent treatment plant (ETP). These rinse tanks are discarded continuously with a particular flow rate to keep them fresh and within the alkaline/acidic ratio to near-neutral pH. The TDS and contamination of these tanks is relatively low.

“Having less TDS in the effluent puts less burden on our ETP process,” Shelat says.

Plating and drag-out treatment: Plating and drag-out effluents have the highest TDS and metal content. Proper treatment, however, reduces the TDS to manageable levels before discharge.

The company’s system isolates and neutralizes heavy metals and other contaminants from effluent streams using advanced ion-exchange columns, membrane filtration and oxidation processes. “This combination enables us to capture and treat plating effluents with high precision and minimal waste,” Shelat explains.

For drag-out effluents, optimized drag-out rinse methods significantly reduce chemical loss by controlling rinse stages and maintaining optimal chemical concentrations. This is followed by targeted treatments to recover residual plating chemicals.

Process effluent treatment: Process effluents created from pickling or degreasing processes are highly acidic or contain high alkaline and require treatment to neutralize contaminants before disposal. Here is how it works:

• Collection and neutralization: Effluents are collected and neutralized to a balanced pH using acids or bases.
• Coagulation and flocculation: Chemicals are added to clump contaminants together, making them easier to remove.
• Sedimentation and filtration: The larger particles settle, and the clarified liquid undergoes further filtration to remove remaining solids.

Process effluents created from pickling or degreasing processes are highly acidic or contain high alkaline and require treatment to neutralize contaminants before disposal.

• Heavy metal removal and reuse: Heavy metals are primarily removed through an electrolytic recovery system, enabling the reuse of metals and lowering the strain on RO filtration. Any remaining trace metals are filtered out with RO, ensuring clean discharge. Additionally, adopting a chrome-free process eliminates the environmental risks associated with traditional chrome usage.
• Sludge management: Sludge from the process is dewatered and handled as hazardous waste.

Tin recovery and reuse

Tin metal recovery and reuse are other avenues Gator Systems has taken to cost effectively protect the environment while reducing effluent contamination, raw material costs and treatment costs. This closed-loop recovery approach not only conserves valuable resources but also aligns with the company’s commitment to environmental responsibility and sustainability, Shelat says.

The company’s tin recovery process primarily targets metal separation directly from the drag-out rinse before it enters the main treatment system. First, the system isolates tin particles from the drag-out rinse using a combination of electrochemical deposition and ion exchange. This separation step captures tin at the source, minimizing contamination in the main effluent treatment line.

The reclaimed tin is then recycled back into the plating processes or refined further as a recyclable by-product.

Tin recovery not only lowers the TDS and hazardous sulfates in treated effluents, but the electrolytic recovery process ensures high purity tin, which is critical for consistent quality in plating applications. Also, with lower TDS levels, the load on the reverse osmosis system is reduced.

Data collection and analysis play a crucial role in optimizing the tin recovery process. Regular monitoring of tin and sulfuric acid concentrations in drag-out tanks enables timely interventions and adjustments.

Takeaways for U.S. platers

Gator System’s methods that emphasize precision plating, integrated inspection, optimized workflow and eco-friendly practices can teach U.S. plating facilities lessons in enhancing efficiency, quality and sustainability. 

Here are some takeaways: 

• Advanced automated coating systems ensure uniformity and corrosion resistance.
• Implementing optical inspection systems throughout the plating process enables early defect detection, reducing waste and ensuring quality.
• Streamlined, end-to-end plating minimizes manual intervention and bottlenecks, leading to faster turnaround times.
• An emphasis on sustainability, including waste reduction and efficient resource usage, showcases the importance of integrating eco-friendly measures to meet environmental standards.