“…Smallscale treatment using minimal technology has been investigated but efficiency results were low and actual producer costs could not be calculated (Westerman and Arogo, 2005). Full-scale, multi-step processes that combine solids separation, denitrification, and phosphorus removal to produce discharge-quality effluent have been proposed for treating swine waste slurry (Martinez-Almela and Barrera, 2005;Vanotti et al, 2007), but surveys have shown that pork producers need a simple, low-tech, low cost, easy-to-operate system that creates more beneficial and easily utilized products from the waste if they are to invest in a treatment system (Cates et al, 2006;Walker, 2008).…”