by Tom Rehberger, PhD., Rob Bailey, Larry Hawkins

One issue that has gained increasing notice in dairy circles is the subject of manure and waste management. Many factors have caused this concern. First of all, the increasing size of dairy units adds several factors, including having enough acres available to properly handle the waste. Encroaching suburbia around many midwestern and eastern farmsteads require proactive good neighbor policies in the area of odor control. Proper nutrient management also can add welcome assets (nitrogen) to the farm profit equation. Expense and time to properly and efficiently agitate and pump the waste materials is yet another issue to be dealt with.

ANC’s contribution to these concerns is in the development of balanced rations that are more efficient and designed to better utilize necessary nutrients which, in turn, help reduce the amount of animal waste. This has also helped to limit the amount of excess N, P, and K that appear in the manure storage. Now, in addition to this, ANC is working with research scientists that have been developing ways in which we can offer production agriculture cost-effective answers to waste management problems. In looking at the problems of animal waste and ways to solve them, we saw that the next step to reducing the problem was to increase the value of the animal waste itself, thus the development of ANC's DWT (Dairy Waste Treatment) product.

DWT has been developed to address many of the day-to-day problems involved with manure management. A product needs to positively effect the decomposition of animal waste in a safe, cost efficient manner. Through the use of new technologies such as DNA fingerprinting for microbials, we have been able to show how and why such a product works. Many of the difficulties dairymen face with stored waste is due to a slow down in microbial decomposition. Let us look at the specifics and ways to speed this up.

The Problem of Crust Build-Up
The accumulation of crust due to the use of various bedding materials and the undigested portion of feed-stuffs can be a real challenge to dairy producers. Producers dealing with this challenge have utilized mechanical means to try and solve the problem. Mechanical solutions are usually reactive rather than proactive, and reactive solutions really do not address the source of the problem. DWT, with its combination of powerful lignin degraders and facultative (aerobic and anaerobic) bacteria, work to synergistically breakdown crust and solid buildup.

A research study on a Wisconsin dairy farm demonstrated a 62.5% reduction in viscosity. Viscosity is a measure of the flow characteristics of a liquid. For example, the viscosity of water at room temperature is 1 centipoise (cps), while typical liquid dairy manure with bedding has a viscosity of 2500-3000 cps. In this trial, the viscosity of the dairy manure was 2684 cps before treatment and was reduced to 1005 cps after treatment. The benefit of this reduced viscosity is easier agitation and pumping (less resistance to flow). This will result in more complete emptying of the storage facility and prevent the accumulation of excessive solids and surface crust.

Solids Accumulation
The problem of bottom solids (sludge) buildup is caused by inefficient microbial decomposition. The facultative anaerobes in DWT go to work on the solids where they are accumulating. DWT organisms can grow in both aerobic (oxygen) and anaerobic (no oxygen) environments to work on the liquification of the solids.

The combination of lignin degraders that work on surface crust and the facultative organisms working on the rest of the contents effectively reduce the solids and viscosity, making the waste much easier to handle.

What Happens to My Fertilizer Value?
Based on the Livestock Waste Facilities Handbook (MPS) calculations, anywhere from 15% to 75% of the nitrogen from dairy waste can be lost due to volatilization. This loss is due to microbial decomposition of the undigested proteins in the manure. As the proteins decompose into ammonia, amines, and other nitrogen compounds, nitrogen is lost as gases into the atmosphere. DWT changes the decomposition process and retains nutrients that would normally be lost. The Wisconsin research study demonstrated this retention of nutrients that normally would be lost during storage.

What About Dollars and Sense?
In the Wisconsin trial, the DWT made good economic sense in a number of areas. The reduced agitation time saves on both man-hours and tractor and equipment hours. The change in decomposition in the stored waste will allow more of the nutrients to be saved, and will also increase uniformity of field application.

What About Odor?
Offensive odors are primarily being caused by improper decomposition of waste. DWT and its proactive mode of action changes the decomposition process of stored waste, reducing the formation of offensive odors. The Wisconsin study showed a 68% reduction in volatile fatty acids (VFA's). Certain VFA's are the source of strong odors normally associated with manure. The reduction of these organic acids is in direct correlation to a reduction in odor.

Ease of Use
DWT is easy to use and apply. Dairymen initially apply 500 grams of DWT for every 100,000 gallons of stored waste. Then, once a month, they add 250 grams of DWT per 100 head of cows. It is mixed with water and allowed to sit for ten minutes before pouring into gutters or drop sites leading to manure storage. The small amount of wash water with soaps and chemicals that may get added do not affect the product, and if anything, make the additon of DWT even more important.

Summary
ANC, in cooperation with research scientists, have done the necessary ground work to identify problem areas and address challenges. Using the latest analytical equipment, such as DNA fingerprinting organisms, microbial populations can be traced to show cause and effect relationships in storage systems. DWT is a proactive, cost effective management tool that helps solve the waste management problems that producers face on a day-to-day basis. Ask your ANC consultant to further explain how DWT can help you control and direct the decomposition of dairy waste, drastically reduce problem odors, and save valuable nutrients!

HENSEN BROTHERS See Big Difference Using DWT
Hensen Brothers, a 230 cow dairy located one mile from Middleton, a Madison, Wisconsin suburb, saw a noticeable improvement using DWT on their two cement manure pits. The pits are emptied by pumping, with the solids removed with a front-end loader. Treatment was started in July of 1999. The two pits provided different challenges as one had sand and the other had sawdust and corn stalk bedding. The sand pit started foaming on Saturday and solids started rising to the top, the first treatment having been incorporated on the Thursday before.

The pit with the organic bedding didn't have as many visible differences until agitation began, probably due to more of a crust. It was obvious in both pits that something was definitely going on. The pits were emptied after only two monthly treatments with DWT. Jeff Monson, the herdsman, said, "The day we agitated and emptied the pits, the wind was blowing directly toward the house. However there was very little odor. Neighbors even commented favorably about the lack of odor. Agitation time was decreased from about 12 hours to 3 hours on each pit."