WASTE MANAGEMENT
PIH-105
pork industry handbook
COOPERATIVE EXTENSION SERVICE • PURDUE UNIVERSITY • WEST LAFAYETTE, INDIANA
Scraper Systems for Removing Manure From Swine Facilities
Authors:
Dale Vanderholm, University of Nebraska
Stewart Melvin, Iowa State University
Reviewers:
Lynn Cole, Mt. Blanchard, Ohio
Mike Kula, Gettysburg, South Dakota
Arthur W. Selders, West Virginia University
Larry Stewart, University of Maryland
Scraper systems are a means of removing manure and other wastes from swine buildings for storage or treatment outside the building. Like other methods that allow for frequent waste removal, they reduce odor and gas production within the building from stored wastes and improve the environment. Scraper systems are adaptable to gestation, farrowing, nursery and finishing buildings and may be used either under slats or in open gutters. They can be installed in new buildings or incorporated into existing buildings. The wastes can be transported to the storage or treatment area by pumps, other mechanical means, or gravity, and full automation can usually be achieved.

Although scrapers can handle solid or semisolid wastes, the high moisture content of swine manure, along with the additional moisture from waterers, washing operations, and other sources, usually dictates that scraped swine waste from buildings be handled as a liquid. The liquid is normally stored in outdoor earthen storages or in aboveground or underground tanks. To minimize storage and transport requirements, additional dilution water is usually not added to the scraped wastes.

Scraper systems adapt well to frequent and regular loading of anaerobic digesters for biogas production because of a minimal amount of dilution water and because they are operated regularly. Frequent collection of the manure minimizes the loss of readily digestible organic materials necessary for efficient biogas production, although recent studies of scraper systems have indicated high nitrogen losses through ammonia volatilization.

Frequent collection of wastes by scrapers conserves nitrogen because it brings the wastes quickly to storage, where relatively little nitrogen is lost.
Scrapers, particularly chain link type, have been suc-
cessfully used for scraping swine wastes where chopped bedding such as straw, corn cobs, peanut hulls, or similar material is used on solid floor areas and is allowed to work its way through slats or to open scrapers.

Scraper Configuration (see Fig. 1)
One drive unit can drive from 1 to 6 scrapers, depending upon the building layout and the manufacturer’s recommendations. Single scrapers are commonly used in modified open-front buildings with partially slotted floors, while multiple units are commonly used for farrowing and nursery areas, as well as in totally slotted finishing buildings. The manufacturer usually specifies the number of gutters that can be served by one drive unit, the maximum length of chain and/or cable, and the maximum area to be scraped. The configurations in Figure 1 are for illustrative purposes only. Check with your individual supplier regarding the manufacturer’s recommendations for your situation.

Scraper Characteristics and Operation
Commercial scrapers generally range from 2 to 12 ft. wide. When scraping under slats, the required vertical clearance between the gutter floor and the underside of the slats ranges from 7 to 18 in., depending upon the scraper type. Unless access for maintenance is required or additional depth for emergency storage is desired, additional clearance offers little advantage and adds to the construction cost. However, additional clearance, such as may occur in remodeled facilities, is not harmful. Gutters designed for scraper use are not intended for long-term manure storage. Using them for this purpose may overload the drive unit or break the cables or chains.
Cooperative Extension work in Agriculture and Home Economics, state of Indiana, Purdue University, and U. S. Department of Agriculture cooperating. H. A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the acts of May 8 and June 30, 1914. The Cooperating Extension Service of Purdue University is an affirmative action/equal opportunity institution.