When the Rain Comes

When the Rain Comes: How North Coast Harvest Activities Impact Wastewater Treatment

For North Coast wineries, late summer and early fall are a flurry of activity. The air is filled with the sweet scent of fermenting grapes, and the energy is palpable as crews work around the clock to bring in the harvest. It’s a critical time for winemaking, but it also marks a significant period for a winery’s environmental operations, particularly its wastewater treatment system.

At Epsilon Water LLC/Epsilon Consulting, we’ve seen firsthand how the volume and composition of process wastewater change dramatically during this period. Understanding these changes is crucial for a smooth and compliant harvest, especially as we head into the wet season.

The Harvest Wastewater Challenge

Grape harvest activities generate a high volume of process wastewater from a variety of sources:

• Crush Pad Operations: Washing and cleaning equipment, bins, and floors.
• Pressing and Fermentation: Spills, tank cleaning, and sanitizing.
• Barrel and Tank Maintenance: The heavy use of water for flushing and preparing vessels for new juice.

This wastewater isn’t just a high-volume flow; it’s also high strength. It’s loaded with solids, sugars, and organic matter (measured by biochemical oxygen demand, or BOD). This puts an immense strain on a wastewater treatment system, which is designed to handle a consistent load. During harvest, the system has to work overtime to keep up with the fluctuating and often extreme surges.

The Upcoming Rainy Season

The challenge doesn’t end when the last grape is picked. The transition from harvest to the rainy season adds another layer of complexity. For many wineries that rely on land application for wastewater disposal, the start of the rains can shut down their irrigation fields. Once the soils are saturated, no more treated effluent can be applied, forcing the winery to rely solely on its storage capacity.

If the wastewater system has not been operating at peak efficiency during harvest, or if it was simply overwhelmed by the high-strength flows, the stored effluent may not be fully treated. This can lead to a few critical issues:

• Storage Pond Capacity: If the treatment system can’t process the harvest wastewater quickly enough, storage ponds may fill up before the rainy season begins, creating a risk of spills or unpermitted discharges.
• Compliance Risks: Unpermitted discharges to nearby creeks or streams can lead to significant fines and regulatory action from agencies like the Regional Water Quality Control Board.
• Odor Issues: High concentrations of untreated organic matter in a full pond can create foul odors, which is a nuisance to neighboring properties and a compliance issue.

Our Recommendations for a Proactive Approach

To prepare for this double-whammy of harvest intensity and winter rains, we encourage North Coast wineries to be proactive.

1. Optimize Your System Now: During harvest, monitor your wastewater system daily. Adjust aeration, nutrient levels, and flow to ensure your treatment process is as efficient as possible.
2. Monitor Your Storage: Keep a close eye on your storage pond levels. If you see them rising faster than anticipated, it’s a red flag that your treatment system isn’t keeping pace.
3. Prepare for a Controlled Shutdown: As the first significant rains are forecast, make a plan to shut down your irrigation fields. This helps protect the soil structure and ensures you are in compliance.
4. Have a Spill Plan Ready: Ensure your Spill Prevention and Emergency Response Plan (PW-SPERP) is up to date and that all staff are trained in it. This plan is your roadmap for handling any unexpected discharge events.

A successful harvest isn’t just about the quality of the wine; it’s about the health of your entire operation, from the vineyard to the wastewater system. By managing your treatment process effectively during this critical time, you can ensure a smooth transition into the winter and protect both your business and the environment.

Contact Epsilon Consulting today to discuss how we can help develop or enhance your winery’s wet weather preparedness.

Michael Long, Manager Epsilon Water LLC- Epsilon Consulting

• Phone: 707-333-9167
• Email: michael@epsilonwater.com
• Website: epsilonwater.com

by Michael Long