There are numerous solutions for a pig farm to control odor. Many of these solutions are low-cost and some can even produce profit! The below solutions, methods and machines for odor control are only a few of those we found on the internet

http://www.ozoneapplications.com - Ozone Solutions: A remarkable solution to odor problems using ozone to neutralize odors.
Odor Control for Livestock Systems (PDF)
Department of Animal Science, Iowa State University
http://www.scienceagogo.com - Low-cost, Low-tech odor solution for pig farms... Today, using EERC expertise in odor control technology, the area around the operation is nearly odor free.
http://www.epa.gov - Controlled anaerobic digestion with biogas recovery is one method to stabilize manure, reduce odor, and produce an energy resource that offers a return on investment.
http://www.thepigsite.com - Numerous articles about pig farm odors and control
http://nationalhogfarmer.com - 10 steps to managing odor.
http://www.bio-cascade.com - Clean Air and Water Systems
http://www.alken-murray.com - A case study of Clear-Flo 7000 used on a brand-new Oklahoma pig farm in 1993, with application illustrations and photos. Even with the ventilators closed, the only odor evident was straw and animal feed.
http://www.safetysorbzeolita.com - Safetysorb™ Zeolite can be used for the odor control of manure and urea from... pig farms...
http://www.bbe.umn.edu - ...several technologies can significantly reduce odor emissions from manure storage.
http://www.ces.purdue.edu - Methods and Practices to Reduce Odor
http://rcmdigesters.com - A Low-Cost Digester to Control Odors
http://www.ars.usda.gov - Welcome to SOMMRU, the Swine Odor and Manure Management Research Unit
http://www.eurekalert.org - A new tool to help minimize odor problems
http://www.solarwindsys.com - A real time treatment and purification of organics waste
http://ajrccm.atsjournals.org - Positive Human Health Effects of Dust Suppression with Canola Oil in Swine Barns
http://www.canada.com/vancouversun - "A green gift from pigs" Take liquid hog manure and turn it into solid organic fertilizer -- a relatively simple process -- and you eliminate the most harmful greenhouse gas it would otherwise produce.
http://www.truehealth.org - [excreta] ...can be turned into a huge environmental and economic benefit and profit centre by extracting the methane from the wastes with bio-digesters...