Manure Management Lessons to be Learned

Peter Brown

It is now quite clear where the new reality for dairy farmers across America will lie. Following the initial settlement from the Cow Palace dairy case, where cow manure and specifically its sulfur content, was declared a toxic substance by the EPA. To the Lost Valley Farm situation, the word is that there is a new sheriff in town and he is cleaning up.

First, Cow Palace, in 2013 a CAFO in Sunnyside, Wa, with about 11,000 head of dairy cows, and three neighboring farms were advised that contamination from their manure spreading operations had gotten into the aquifers and local streams with high Nitrate levels. The importance of this case was that the suit was Federal addressing a situation that had up to then been handled at a State level. The plaintiffs were aided and abetted from a DC based groups, although the damage was real and the results positive. It was also the first time that manure had ever been declared a toxic waste.


Not only are the big guns on the field, they cover not just Washington and Oregon, but will reverberate all over the country.

Then in 2015 another case showed up, about 100 miles due south of the Cow Palace. The lost Valley Farm is a converted tree farm within view of the Columbia River. It was bought by Greg te Velde, a successful California dairy man who ran two dairies in Picton, Calif. and came from a long line of Dutch dairy people.   He had already started a dairy operation in Oregon, at the Three Mile Valley farm but bought the Lost Valley Farm and applied for and got permission to build a 30,000 cow operation on essentially a virgin tree farm.  Financing was applied for and granted by Rabobank out of San Francisco.

For reasons not quite clear, the whole project was put on afterburner. Even though the permits were in place, there was not enough time to design and install the complete system and shortcuts were taken. Lagoons to store the manure and waste water were dug and filled, but they were too small for the amounts being installed. But why worry? The age old systems of dairy farms through the centuries were that you used the manure to fertilize the fields and in an ageless tradition, this is what happened in Boardman.

There is a difference between a couple of hundred cows wandering aimlessly in unlimited pastureland, coming home to be milked and wandering off again, dropping off what all bovines drop off regularly and a concentration of 17,000 cows in a barn, with hard surface and center runnels, the difference is simply that the manure has to be handled in a way that is commensurate with its value. Each cow produces 20 tons of manure a year, 30,000 cows produce 600,000 tons of manure a year. That manure is handled for a large part by sluicing with water that must be, at the very least, grey water quality, that water takes the manure to the lagoons, and there it is supposed to evaporate.


That was then, and now the dairy is closed facing bankruptcy and unable to meet its obligations to their lenders, the Tillamook cheese factory, the city of Boardman, their 100 some employees and the Federal government. It’s not as if this was unexpected or unanticipated. The reason for te Velde’s  haste are his own, but out of concern for not just the Lost Valley Farm and its supporters, there is much that could have been done with a little more time and a better grasp of modern dairy technology.

Hans Camstra is a Dutch system engineer specializing in renewable energy, digesters and large recycling systems, He has the knowledge and connections to conceive and design money making alternatives for dairies facing  what will rapidly become the norm for American dairy operations. The technology is not new, but it will require serious infrastructure changes as well as basic rethinking of how we go forward with the large mega dairies coming on stream these days. As a matter of fact, the dairy neighboring te Velde’s operation runs 70,000 cows.

“The first thing I had to understand was the sheer enormity of operations with 30,000 cows.”said Camstra. “That is an enormous number of animals to handle in one space. But it’s all a matter of perspective. The simplest way for any engineer to work out the problems is to break them down into manageable units. In my case I think the dairy should be separated into distinct sections, each having the same basic facilities and serving a central processing plant.”

In Camstra’s mind, 10,000 cow units are more than feasible and can be handled in a single unit comprising a barn, milking operation and manure handling operations. The logic behind the modular approach is that each section can pick up the slack from a section that is down; they can trade efficiencies and maximize revenues depending on the market for what can be produced.

But also much bigger facilities are possible up to any scale, because of this modular set up based on a number of digesters combined together in one system. A modern digester is not the hole in the ground lined with plastic sheeting, open to the wind and rain that destroyed te Velde’s operation by dumping more water in a cold climate than the system could absorb. Once the water came over the sides, there was no keeping it from invading the aquifers, sloshing into the barns and creating an unhealthy quagmire. It was a chain reaction that could not be stopped because the backup systems were just as inefficiently designed and close to saturation. The bulk of the overload was water, the digestate in suspension never had a chance to settle and even if it had, there was no way to manage it.

Cow manure, when fresh is 78% water with the remnants whatever survives passing through four stomachs. There is a lot of grassy matter, and most of it will decompose in a  well designed digester. It is the design that is key to efficiency and for recuperating the gas, the settlement, the specific chemicals and the water.

“The farmer must remember that he can run his system as if there is no limit to the amount of energy he needs. For example, heating a 10,00 cow digester is not done in huge vats, you can run heating coils inside the unit, powered by either heat from the generators running on endless amounts of Biogas, you can radiate heat with the unlimited electricity or you can simply design the digester to hoard and retain all the heat that it can. Or you can do all three of course. The public utility will not send you a bill, in a well designed system you will be getting checks!” according to Camstra.” And prevent huge penalties for polluting the environment and water supply. We design, using existing components, for efficiency. Based on on the ground research and measurements of all the variables we can measure.”

So where does this energy come from? What form can it take? Is it marketable? How much is recycled? Will it pacify the EPA, the local community? Can cows still produce their annual 9,000 liters of milk a year?

The energy, which is captured, just like the milk, is in the form of methane gas. Paradoxically methane is defined as an odorless, colorless gas that is caused by the anaerobic decomposition of the liquids and solids in the manure, the digestate, which is 90% water. This water evaporates in the classical lagoon, leaving the smell behind. Hard at work, underwater and in an insanely toxic environment tiny bacteria have at it, and in the process release the methane into the cover over the digester. The bacteria are breaking down the complex chemical components into oxygen, hydrogen, sulfur and carbon. 1kg cow dung produces 250g of biogas (methane gas) over 24hrs.or  6,374 cubic feet of methane. (Biogas 23 m3/ton manure input. Methane about 13 m3 / ton manure input)

The newer digester operates in a completely anaerobic environment and is designed to allow the infusion of other elements to promote the creation of the gas. If you add glycerin or other organic materials, the process is accelerated and can take a lot less than the usual 21 days. And the biogas yield / methane yield increases substantially.  One can also run more manure through and maintain a more equitable distribution. What stays behind is water and lots of it. Passing that water through a purifier allows it to be recycled as gray water, suitable for barn maintenance, application on fields for irrigation and can be further purified, technically yes to drink, but is it feasible?  but at least as clean it can be drained safely into the river or … to actual drinking levels. This process takes care of one of the major issues in Boardman and Cow Palace, the pollution of aquifers due to the spreading of untreated manure on fields.

Make no mistake here, dairies consume enormous quantities of water, not just to keep the animals hydrated, but at every stage of the operation water is used in industrial quantities influenced by several factors, the cow herself uses between 12 and 17 gallons a day depending on temperature, sprinkler washing systems can use up to 40 gallons per cow, per day.  Clearly, water is a major resource needed for the health of the animals, how it is used is a major concern. Yet, many dairies do not have active measures to conserve or reuse existing water and it becomes a pass through commodity that ends up on fields. With the right equipment water can be made drinkable but what is more interesting is that manure contains 80% which means that for every cow producing 20 tons of manure it mostly produces water meaning small wonder that the neighbors become part of the growing list of people opposed to CAFOs.

It also means that anyone starting a serious manure management program has to create a schedule that will deliver the manure to the digester within 24 hours to ensure that all the moisture is added to system to enhance the process and to prevent unwanted odor. But just dumping a pile of manure in a swimming pool is not enough, the science of digesters has advanced so far that even in industrial sized operations with up to 10,000 cows, fine tuning the handling of the manure allows the farmer to actually run electrical power plants for profit, or sell bio-methane for even more income and high concentrated nutrients / fertilizer.

Many factors influence how much gas is produced, how much fertilizer is extracted, how clean the water is on the other end. For example, adding vegetable and crop waste to the digester can increase gas production up to four times, adding glycerin from a nearby biodiesel facility supercharges the yield.  More heat also adds to production, the usual twenty day cycle from entry to depletion can also be manipulated and in some specialized digesters depletion of gas production can actually take place after ten days, but it leaves a lot of undigested digestate so you have a problem to process this too active digestate. It must be composted and cleaned by bio filters or reverse osmosis systems.

The organic solids in manure, which provide most of the gas, represents a mere roughly between 5 and 8 % of the total mass and the equation on how to break it down is both complex and financially difficult. For example, from the top will your system provide electricity or gas? If you want electricity will it connect to the grid or only for the farm, these are serious consideration because they entail a host of subsequent decisions. If you opt for selling the gas you must keep a few new considerations in mind. Simple compressed natural gas can be cleaned up, impurities taken out and you end up with a CO2/methane mix that can be used in many applications from powering cars and trucks to heating. Or you can decide to go all the way, depending on the local market, and set up a system to inject your gas into the pipelines. This is the most lucrative option and requires the biggest investment. (Don’t forget the heat that’s left over, it’s energy too)

Whatever choice the dairy decides to make, be assured that his options are dwindling, the EPA, local ordinances, finances and other considerations will make the selection for you. That brings up the last question, how far do you want to go? My advice is simple, go as far as finances permit, even if you need to make deeper investments in equipment, because no matter where you are, there will always be a reason to take that added step. But rest assured, you will not regret doing it because you know that if you are not careful, the day will come when, just like Lost Valley Farm, you could face bankruptcy for not anticipating the extent of the changes.

So what are you looking at?

At the very least your covered lagoons are toast, they have become a convenient place to warehouse manure overflow in times of crisis like heavy rains, system breakdowns or temporary parking lots for too much manure. They can be incorporated in the overall plan, but should not be considered core part of the solution. You need one or another digester solution, a place that can be heated, hold 25 days of accumulated manure as it is processed, where you can add allow the bacteria to do their job on the digestate and extract all the methane it will take to break down the solids.

Then you need to decide what else you want to pull out of the manure, nutrients, fertilizer, compost, bedding, wood pellets, specific chemicals, smell, clean water, dry barns, sanitary floors and all the rest that can be discussed once you have completed an initial survey.

The last questions are the financials, how much will it cost and how do you finance the operation. If you have none of the equipment you should consider the whole new operation as a new business, a new way to generate income, profit and loss, return on investment that should be part of any well run dairy, but with a foreign twist to it. Those calculations are made by specific spreadsheets for each system and are part of most of our projects. The greatest store of experience, off the shelf equipment, tried and true solutions are in Europe in the triangle formed between the dairies of Switzerland, Germany and The Netherlands, and not surprisingly, those countries, having already saturated their markets, are now looking to new, untried markets and the West Coast looms large in their sights because it is still virgin sales territory. Germany alone has 1800 digesters, it is the law and it is supported by the whole industry,  the population and the courts. They have a lot less territory, their groundwater is much more vulnerable and they have learned that only an interlocking and comprehensive set of technologies, legislation and cooperation can make the system work. The idea is to overbuild to the most stringent requirements, the financial reason is solid, the more you must sell from your new business, the more money you will make and the less you will have to worry going forward. Monitoring will be done from the Netherlands to support local companies and the farmer to operate and maintain the installation and to improve performances.

In Europe, biofuels, photovoltaic, renewable energy and windmills work with the farmers, the legislation and society to protect the ecosystems. So they have some of the best technology AND financing in place to protect the industry. An American farmer looking for affordable systems can profit from a Norwegian EXIM bank loan guarantee for up to 85% of the project at 2.5% for 18 years, a guarantee that local banks seem to think is like manna from heaven and even better when the Dutch bank is located in San Francisco. They express surprise when told of the stories of utilities charging up to $500,000 to install suitable transformers in California, but they are not surprised when a large dairy has to shut down because they ran afoul of local legislation. They went through all that many years ago, and they lined up the support to allow income to flow in a measurable, sustainable and steady manner.  They also worked to put a series of measures together that would mitigate the damage, compensate the farmer and integrate their solutions with the comprehensive rules, laws and grants that constitute the backbone of the Paris Accords.

Their experience is at your disposal, but it is not a readymade, the equipment is off the shelf and prices can be quoted within a week for each section. What is less obvious is the amount of engineering work, from soil studies to local laws and requirements. This where a bi-continental team is essential, what works over there has to be adapted over here. The results have to be conveyed in a technical language that meets the new requirements and those requirements are in flux. At the outset, a very serious intake and sampling, analyzing has to be done and it all kicks off with clear starting points and commitment to make it work. The EPA is under fire and it may be severely restricted, but that is only temporary and any new facility housing more than 100 cows (I have heard) will certainly have to be upgraded later. Europe, for the most part has not gone into the giga-dairies that are sprouting up all over the US; what we do have is land.

The land masses devoted to dairies are for the most part the reason behind the pollution issue. If you have 7,000 acres, you tend to feel that what worked before will continue to work now and a simple lagoon and spread operation works, until it doesn’t. That is what happened at the Lost Valley Farm, too much stuff and not enough storage. Obviously a larger lagoon was not the solution, only treatment works and if you have to do it anyway, at least make it pay. Your neighbors will not only appreciate it, they will love you for it, and you will enjoy the financial benefits if doing the right thing.

EDITOR’S NOTE:  Peter Brown is an industry consultant based in San Jose, Calif.  He may be contacted at [email protected] or at 408.206.7035