Waste Water Management, System optimization and increasing capacity
Well the season is over and it appears to be a very bountiful year, with late season heat and with the rain holding off long enough to bring in the grapes. This article is for wineries utilizing ponding systems to meet the discharge requirements established by the Regional Water Quality Control Board. This is a growing concern as the RWQCB’s staff has increased dramatically within the last 2 years.
What this means to you is that those annual reports you have been submitting are now actually being reviewed. If you are not hitting the numbers you committed to, your facility may be in jeopardy. And as you know with most bureaucratic agencies there is an increased pressure to justify and fund their existence and this directly means fines. Initially it will begin with an onsite review and maybe a notice of violation, continued operation in this manner can quickly become costly. I was involved with a winery in the central valley who was threatened to have their use permit revoked, in effect moth balling a multi million dollar facility, all due to mishandling waste water. All of which indicates it is in your best interest to improve the manner in which the winery waste water is managed.
If the waste water ponds smell they are not working properly and this directly causes irregular BOD reduction. Also a smelly pond is a direct violation of your waste water discharge permit. The best part is that with proper pond management this scenario can be avoided.
As you all know my passion is optimizing waste water systems for wineries, typically I am promoting a new very compact waste water system known as Bio Reactors. These systems are much smaller in foot print than ponding systems, measured in feet versus acres. They are very effective placed in front of existing pond systems to reduce the BOD load quickly and efficiently, and allowing the pond to polish the effluent to meet the ever more stringent state discharge requirements. These systems can be configured to not only reduce BOD but also nitrates, another growing concern.
The type of aeration system utilized in Bio Reactors is a 100% more efficient means of transferring oxygen to the effluent per electric horse power compared to floating aerators. This is and will become a growing issue when the cost of electric power increases an anticipated this winter.
Dissolved Oxygen Control and Optimization of Ponds
A newer development I am working on is directly related to the upcoming increase in energy cost. As we all know PG&E and SCE are talking of raising the cost of electric power by 50% this winter to cover all of the money they lost this last summer with the petroleum price increase. And similar to taxes once the price goes up will it ever go down, not likely. In response to this I have developed a method of reducing, controlling and optimizing the amount of dissolved oxygen in the waste water ponds.
The dissolved oxygen level of a waste water pond should be a 2.0, any more is a waste of power and money and any less could lead to anaerobic digestion and the resulting odors. The control system I am promoting, designing and installing utilizes a dissolved oxygen meter and a variable frequency drive to automatically control the dissolved oxygen at the optimum level. The advantage of this system is that rather than turning off the floating aerators, they are turned down. This enables the same complete aeration coverage without having blind spots in the pond. The savings can be significant, and the BOD reduction maximized.
For every 20 hp floating aerator with the cost per kW of $.10 then the annual cost to run the aerator is $20,000 each.
Often a waste water pond is installed and operated at a large expense and this is increased with the daily cost of running floating aerators, yet the BOD reduction is irregular at best. The nose knows when the system is out of whack by the telltale sulfide odors, this is present during crush, bottling, and tank cleaning operations. All of these operations cause a shock load to the ponds with the larger than usual amount of BOD from the dissolved sugars in the effluent to the pond
A very basic piece of equipment may help resolve this problem and that is a proportional pH control system, cost $3500 installed. The bacteria that consume the BOD thrive at a pH of 6.8-7.2, and sure they can live outside this range but at a very reduced level. During Crush the effluent to the pond is often 4.5 and during tank cleaning the pH is over 10 due to the caustics used. During the time the ponds need to be reducing the most BOD the pH is severely hampering the effectiveness of the bacteria to consume the incoming BOD load. The result is odors and effluent that does not meet the state’s requirements.
During certain operations of the winery including Crushing, Racking, Bottling and tank and barrel cleaning the ponds receive significantly more of a BOD load than the other times of the year. This is known as shock loading, and the inability of the ponds to handle this type of loads is quickly indicative by again odors.
What is occurring is that the natural level of bacteria, Bio Mass, is unable to reduce the incoming load. The solution is known as Bio Augmentation, adding more Bio Mass. This is easily accomplished by adding freeze dried microbes to the ponds. These microbes are a select blend, particularly suited to degrade sugars. And although these microbes occur naturally they are only a subset of the microbes that exist in the pond. What you are doing is skewing the population in your favor, in essence turbo charging the population by adding only the microbes you need to quickly consume the dissolved sugars.
When, how often and how many pounds of bacteria are required to be added will vary with each facility, and throughout the year. There is a simple test to measure the bacteria population and this is known as an emhoff cone, although a graduated cylinder will also work. By grabbing a 1000 ml sample and letting it settle for 30 minutes (no more and no less) and recording the settled amount, one is able to determine the optimum Bio Mass required during all periods of a wineries operation. And again this will vary based upon the type of operation being performed, i.e. the level required during crush will vary versus that required during tank cleaning.
This information is not obvious and is unique, and as a result it is often beneficial to work with a waste water engineer or one versed in all aspects of waste water. This includes one versed in equipment including sources and supplies, testing, permitting, staff training, system oversight. As you probably already know, waste water management is becoming a very critical aspect of winery management, and soon will become a costly one if not handled correctly.
The article was developed by Glenn Wensloff, a waste water engineer, who heads Elutriate Systems. They are located at 1398 Deer Canyon Road, Arroyo Grande, CA 93420. They have a web site www.Elutriatesystems.com, where more articles about waste water are posted along with a list of services and products they provide. They provide an onsite review of your existing waste water system and very practical and low costs means of improving the systems performance. They also work with new and expanding wineries to meet the ever increasing effluent restrictions imposed by the RWQCB, city and county agencies. Elutriate Systems is offering a free booklet “An Operators Guide to Winery Waste Water Systems” please call for your copy.