Evaluation of three manure pit additives in commercial scale manure channels and simulated outdoor lagoons

Abstract

The objective of this thesis was to evaluate the effectiveness of three manure pit additives in commercial scale manure channels and simulated outdoor storage. The additives were American BioCatalysts (ABC), Pit Boss (PB) and Westbridge (WB). Results from two sets of indoor trials were combined to provide eight replicates of each additive. The protocol consisted of manure accumulation, pretreatment and treatment. Air and slurry samples were taken on Days 28 and 35 of the treatment phase. The outdoor phase that followed determined if residual effects resulting from indoor treatment existed. Manure was transferred from the manure channels to outdoor storage lagoons where it was stored in simulated lagoons. Samples were taken on Days 49 and 63. In terms of odour threshold reduction, the additives' effectiveness varied from producing no reduction to reductions of 66%. The 66% reduction produced by PB in the outdoor trial was the only significant odour threshold reduction in the experiment. During indoor storage, the additives produced minor odour threshold reductions. The additives were able to promote H2S reductions of 14 to 76% and consistent yet minor NH3 reductions in the indoor trials. None of the additives produced practical reductions in Total Solids or solubilization that could have improved manure-handling ease. Perhaps the strongest attribute of all of the additives was the ability to maintain elevated nutrients and micronutrient levels. Higher levels of TKN were maintained by all of the additives and the ability of the additives to maintain nitrogen in the available form, especially on Day 35 representing a potential of 9 to 25% more available nitrogen during field application. Likewise, the additives resulted in 4 to 23% more P while promoting elevated ortho-phosphate levels during the indoor trial. Improvements in nutrient value were also observed in potassium, copper and zinc results. Only with respect to waste strength reduction was the effectiveness of the additives relatively poor. In order to make more progress in the field of manure pit treatment, research must be directed towards understanding the modes of action of manure pit additives. With this information, optimization of their performance would lead to better results. Note:Page 81 is missing.