Hahn's Estate Winery, New wastewater system
The best in the state and here is why...
By Elutriate Systems (805) 474-9390
Hahn's Estate has had tremendous growth in the past several years. As part of the states wastewater requirements they designed a ponding system with Cannon and Associates from San Luis Obispo, with the traditional plastic lined pond and floating aerators. But when Hahn's Estate decided to install the pond they realized that they had outgrown the design size by twice. The area that was designated for the wastewater ponds issue further compounded the issue in that pond expansion would not fit in the narrow canyon.
So Hahn's Estate Winery turned to Elutriate Systems of Arroyo Grande who specializes in very efficient and rapid BOD (biological oxygen demand) digestion wastewater systems. The thought is that if we canít make them bigger lets make them the most efficient possible, and this is exactly what was done
BOD occurs from winery wastewater and is composed of dissolved sugars during crush, with wineries having BOD levels of over 10,000 ppm; pure wine has a BOD level of over 140,000 ppm. Barrel washing, tank rinsing, bottling and raking all contribute to high levels of BOD, with carbohydrates and alcohols throughout the year but not to the level caused during crush. BOD is a measurement of how much oxygen is required to break the carbohydrate chain down to more stable by products like carbon dioxide.
Elutriate Systems converted the facultative ponding system into a Bio Reactor. The floating aerators concept was scrapped in favor of a much more efficient fine bubble diffuser system. In a facultative ponding system the pond has three different layers based upon the aeration provided by the floating aerators. The top layer has a high level of dissolved oxygen and this is where most of the BOD digestion occurs, the middle zone of the pond has some dissolved oxygen and transitions to the bottom of the pond, which is devoid of oxygen. So as one gets lower in the pond less and less BOD digestion occurs.
The bottom of the pond is anaerobic, devoid of oxygen. This is where the bacteria, which actually consume the BOD is digested. The facultative pond process is a carryover of the sewer industry, and when fecal waste is involved this works well as digesting this bacteria in this manner is beneficial. But with winery wastewater this is a poor design although very traditional and entrenched in the wine industry.
In the wine industry it is much more astute to view the bacteria from the wastewater as Compost Tea. This is a beneficial non-fecal bacteria that is good for the soil, and eliminates the need for both fertilizers and pesticides. The reader is encouraged to do a web search on compost tea to verify for themselves the power of this wonder brew.
The ponds are now aerobic digesters with the aeration occurring on the bottom of the pond, the whole pond volume rapidly digests the BOD. The bacteria, which traditionally dropped from suspension, elutriated, is now kept in intimate contact with the high BOD influent. The efficiency of the system utilizing the existing footprint has just increased tremendously and it keeps getting better. Between the two ponds we installed a series of clarifiers, which allow the bacteria to fall from suspension and this concentrated bacteria is pumped back to the incoming high BOD influent. The more critters eating at the food basket the faster the food is digested. The thicker the bacterial soup the faster the BOD is digested, the smaller the system has to be, the less volume of water needs to be aerated, the savings quickly compound.
The effluent flows from the clarifier into the second pond, which is also aerated with fine bubble diffusers. From the last pond the effluent flows to an irrigation pond where it is distributed and applied to the vines through the drip irrigation system.
Dissolved oxygen sensors control the blowers and variable frequency drives. As the BOD is digested the blowers slow down automatically. The first pond is also where the pH is adjusted to 6.8-7.2 to make the environment more compatible for the bacteria to thrive. The bacteria blend used is B560 and is obtained from Bio Systems (800) 232-2847.
As Hahnís Estate continues to expand their winery production and market presence the next wastewater system expansion will involve placing a large tank before the ponds and converting this into a Bio Reactor. With a tank it is easy to get a height of 20í, it is hard to make a pond 20í deep. The increased depth allows for better oxygen transfer to the water, which directly results in higher levels of dissolved oxygen while minimizing electrical energy.