Waste water ponds – how wineries deal with waste water – Brief Article
(This is an ongoing series of wastewater articles for wineries. Previous articles and projects are posted at elutriatesystems.com for review.)
The recent energy crisis has increased our awareness of both energy use and costs. While home power rates have increased, the cost of power for industrial users has increased even more. Comparing last year’s power cost with this year’s monthly billing will quickly show how much of an increase your winery has experienced. If the amount is significant and you would like to reduce this trend then this article is one aspect of reducing operating costs.
As the winery industry is softening following the dot-coin die off, reducing operating costs is increasingly important. A savings in operating costs is magnified in the market place, and a reduction in operating costs is on the same par as increasing case production. It is continually amazing when a successful cost reduction is incorporated, as thoughts of this should have been done sooner are typical.
Typically, wineries have wastewater ponds where the effluent is collected; smaller wineries sometimes use septic systems. The purpose of these ponds is to reduce the ROD (biological oxygen demand) and adjust the pH. The BOD discharge levels for wineries can approach 5,000 to 20,OOOppm for spills, pure wine or juice. The high levels of ROD are directly attributed to the dissolved sugars.
The Regional Water Quality Control Board sets the limits and conditions of discharge. Usually they require a pH of 5 to 9, and a BOD level currently approaching levels below 200ppm and sometimes as low as 30ppm. Most wineries have state discharge permits, which are renewed every 5 to 7 years; upon renewal it is often for lower levels of BOD and TSS (total suspended solids).
The method commonly used to reduce the BOD levels in the ponds’ effluent is to utilize floating aerators. Floating aerators satisfy the biological oxygen demand by mixing oxygen from the air into pond water. And while this is a known method of aeration, it is not very efficient. The amount of oxygen transferred to the water is roughly 3%.
Another method of aeration–fine bubble diffusers–is five times more efficient. This method utilizes a rotary blower designed to deliver high volumes of air at low pressures. Remember that only 20% of air is actually oxygen. The air is delivered to fine bubble diffusers that produce very small bubbles. The smaller the bubble, the greater oxygen transfer. This directly means that if a winery is using (5) 10 hp floating aerators then the same aeration is provided by (1) 10 hp blower. In effect, the cost of the electric horsepower to operate the ponds has just decreased by 80%.
As wineries expand production, loading to the ponds also increases. The amount of ROD to the ponds increases, and the amount of aeration required increases proportionally. There are several means to increase pond reduction efficiency; making the ponds larger should not be the first option considered. This is in regards to considering the cost of the acreage taken up by the ponding system and the low level of efficiency resulting from aerating a large body of water.
There are four direct means of increasing the performance of the wastewater ponds:
(1) Proper pH control. During crush, the dissolved sugars reduce the effluent to 4.0 pH. By adjusting the pH to 7.0, the bio mass, the organism that actually reduces the ROD, will survive, flourish and consume.
(2) Rio Augmentation is adding the optimum bio mass that is designed to consume sugars. A product that the author uses extensively, B560, is made by Bio Systems (phone (800) 2322 847). By adding the freeze-dried bio bugs to your existing wastewater system during heavy loading periods, crush, racking and bottling, the bio mass is skewed and increased to optimize the bacteria that do the actual ROD digestion.
(3) Proper aeration. Maintaining a dissolved oxygen (DO) level of 2.0ppm, no more, no less, is necessary for optimum ROD reduction. A dissolved oxygen level below 2.0ppm results in smelly anaerobic conditions and BOD reduction is poor. Maintaining a DO above 2.0ppm wastes electricity. Another program promoted by the author utilizes dissolved oxygen meters and variable frequency drives on the existing floating aerators to optimize the DO levels. The DO levels may change continually during the day as the loading rate varies.
(4) Bio Reactors. Rather than increasing the existing ponding system, by adding a Rio Reactor upstream of the pond, the load to the pond is significantly reduced. A Bio Reactor is the most efficient means known to reduce wastewater. This same process is utilized by most sewer companies already and is tried and true. A Rio Reactor is a series of tanks, or a vault, where the effluent is highly aerated and pH adjusted. The effluent then flows to a clarifier where the bacteria settle. The settled bacteria are returned to the incoming high BOD stream. This influx of hungry bacteria results in rapid BOD reduction. The reduced BOD wastewater can then flow to an irrigation pond for land application or can be sent to an aesthetically pleasing pond that is an asset to the winery, surrounded by lawns, trees and picnic benches.
Another Wastewater Solution
Elutriate Systems has developed a unique means of using existing fire retention ponds or tanks as a means of also reducing winery wastewater effluent. In essence, the retention required by the fire department can be winery effluent versus well water; a potential fire can be put out by either.
The possibility of getting dual usage out of a required fire retention system by also using it as a Bio Reactor is exciting. This will give both large and small wineries the ability to utilize and incorporate this technology at a significantly reduced cost. Often the cost of retaining the effluent in tanks or ponds is half the system cost.
By converting the fire retention system to a Bio Reactor, reduced BOD loads can be sent to the existing wastewater system. This would reduce and eliminate the telltale mall odors that effect ponds during crush, racking and bottling. The operating cost of the wastewater systems will be reduced as some of the inefficient floating aerators can now be turned off. The reduced BOD effluent can then be used for irrigation or land application. These systems can be easily expanded with future growth or decreased allowable discharge levels.
Byron Vineyard & Winery
Byron Winery started its new wine cellars with a septic system for its wastewater solution. It promptly failed due to the heavy BOD loads during crush. The odors of the failed system would back up into the winery jeopardizing the barrel storage and detracting from the beautiful, new facility. The short-term solution was to have a septic truck pump out the sump and haul the winery waste offsite for disposal. This solution lost its appeal $19,000 later.
After consulting with Elutriate Systems about the optimum way to handle the winery wastewater, a simple solution was developed. The effluent is now pumped to an irrigation pond, where it is screened before entering the pond. The pond is aerated with a very efficient three lobe rotary blower and fine bubble diffusers system. The system is performing as anticipated–during crush the pond did not smell, and water clarity also indicated the success of the design.
(Glenn Wensloff heads up the firm Elutriate Systems, a company specializing in designing, installing, permitting, starting and operating wastewater systems for wineries.
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