The composting method must fit the individual farm operation. Highly sophisticated and expensive composting operations are not likely to be a viable option for small farming operations. Some factors to consider when selecting the particular method of composting include:
(i) Operator management capability—The management capability of the operator is an important consideration when selecting the right composting method. Even simple composting methods require that the operator spend additional time in monitoring and material handling. The operator should fully understand the level of management that is required. The windrow method generally is the simplest method to manage, but requires additional labor for periodically turning the compost mix. The static pile is generally next in complexity because of having to maintain blowers and work around perforated pipe. In-vessel composting can be the simplest or the most difficult to manage, depending on the sophistication of the system.
(ii) Equipment and labor availability—Consider what equipment is available for loading, unloading, turning, mixing, and hauling. The windrow method requires extra equipment and labor to periodically turn the rows. All methods require some type of loading and unloading equipment.
(iii) Site features—If a limited amount of space is available, then the static pile or in-vessel method may be the only viable composting alternatives. Proximity to neighbors and the appearance of the compost operation may make the windrow and static pile methods unattractive alternatives. If the only composting site has limited accessibility, then the static pile or in-vessel method should be considered because of less mixing requirements. Siting considerations are discussed more fully in the Siting and area considerations section that follows.
(iv) Compost utilization—If the compost is to be marketed commercially, then a composting method that produces a predictable, uniform product should be considered. Because of varying climatic conditions, the windrow method may not produce a predictable end product. Sophisticated in-vessel methods provide the most process control; therefore, they produce the most uniform and predictable product.
(v) Climate—In extremely wet climates the static pile and aerated composting methods may become too wet to compost properly unless measures are taken to protect the compost from the weather. In very cold climates, the composting process may slow in the winter. Sheltering the compost pile from the wind helps to prevent a slowdown in the composting process. The windrow and static pile methods are the most vulnerable to freezing temperatures because they are exposed to the elements. All methods may perform unsatisfactorily if the organic waste and amendments are initially mixed in a frozen state.
(vi) Cost—Composting capital and operating costs vary considerably depending on the degree of sophistication. The windrow method generally has the least capital cost, but also has the most operational costs. The in-vessel method usually has the highest initial capital cost, but the lowest operational cost.
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