The North Carolina legislature is near final approval of its annual farm bill, which includes a new method to permit operations at hog farms so they can convert liquid waste into consumer natural gas. The House voted on Thursday for the measure, which makes changes in more than a dozen categories related to agriculture. A similar version passed the Senate last month and could soon be on Gov. Roy Cooper's desk. Interest is growing in biogas because of the potential revenue source. Some Democrats complained the permit process would be too swift and could omit concerns over air quality.