Historical Data On The Success Of Turned Windrow Composting

Thursday, August 30th, 2018

There isn’t a universal definition of composting. Most define the word as a biological decomposition and stabilization of organic substrates under conditions that allow this state as a direct result of produced heat. All can agree that the final product should be stable and free of pathogens. For those who produce compost, keeping it free of pathogens and properly aerated is vital to the success of business and operations.

What is a pathogen?

A pathogen is a microorganism that is commonly found in sewage, waste, or runoff water on farms and in other areas. Most pathogens are parasites that live off the host and the diseases they cause come from indirect contact. These microorganisms need some form of shelter to survive, and compost can provide the perfect environment. This is why turning compost the right way is so important.

How to make good compost

Good compost needs a proper balance of materials that should contain large amounts of carbon. Obtaining the right mix will require experimentation and patience. Grinding, chipping, or shedding the material will increase the surface area, so that good microorganisms can feed and break down the biosolids. This approach should produce a better compost mixture that improves the pile’s insulation and maintains the best temperatures.

The microorganisms that live inside compost need moisture to survive. Water is the key element that helps transport microorganisms within the mix. Also, water helps with making the nutrients more accessible to the other microbes.

Historical research data on turned windrow composting

Most of the research data available on windrow composting methods provides an outline on how to use biosolids effectively. One report released in 1982 by by M.D Iacoboni, J.R. Livingston, and T.J. LeBrun focused on creating compost inside an aerated windrow that stood between 4-5 feet high and 14 feet wide. The report, titled Windrow and Static Pile Composting of Municipal Sewage Sludges, showed that the moisture content needs to be at least 50 percent. This makes odor emissions increase temperature, a process that is needed to kill pathogens. Too often, this equation wasn’t consistently met in the area of study, Los Angeles County.

The researchers were able to confirm that no oxygen formed in the windrow after the turning process. They came to the conclusion that the temperature of the natural convection, or chimney effect, inside the windrow can only be achieved if windrows aren’t covered. The researchers observed a rapid decline with the temperature until a cover was removed.

The final data

The final data report found that turning windrows at least three times-per-week will optimize the mix and increase porosity in the windrow. This will help to maintain an aerobic condition, which should help to promote sludge drying. Exposing the windrow to air and sun promotes dryness inside the windrow. The process used in the study ensured that the biosolids were consistently subjected to the required temperature to kill pathogens.

It was confirmed through their observations that turning the ingredients creates better aeration. By not aerating compost, you would need to kill pathogenic microbes often or risk the potential of pathogen regrowth occurring more often. Odor emission was reduced significantly with a larger aerated windrow during the study. But, the area also had some form of odor that could be omitted with the help of an aeration blower.

The researchers concluded that forced aeration composting of biosolids was not as effective as turning compost windrows. Each method was measured by pathogen reduction and total biosolids reduction.

How the study affects windrow size

Larger windrows can provide more natural ventilation than smaller piles, but they need lower moisture content to maintain the right porosity levels. You can expect the same odor emissions during the turning process, but you might get a higher rate of anaerobic pockets in the center of the larger windrow. Turning windrows will help to aerate the compost and help the decomposition process to move faster.

How to turn windrows effectively

One of the best methods for turning windrows, especially larger piles, is by using a compost turner. These machines are designed to move composting materials around for optimum aeration. Whether you are a municipality, composting on a dairy farm, or need to make your own product for a winery, finding the right machine is vital.

There are many options available on the market today, but it is best to find compost turners that fit your unique needs. You can find models with drums or paddles, and many can be self-propelled or used with a tractor. These machines come in a variety of sizes and can be custom-made to fit your operational specifications.

Windrow composting with SCARAB compost turners

If you would like to learn more about compost turners and effective windrow composting, the experts at SCARAB International can help. Our Machines can be used for small, medium or large composting projects. We have New, Used, and Refurbished compost turners, as well as Leasing Options. Call us today at (806) 883-7621 or Contact Us by email for more information about our Products.