A dry powder inhaler having a housing, at least one single dose storage chamber able to contain a single unit dose, a discharge path adjacent the storage chamber, and a flexible and bendable seal plate closing the discharge path. At least one of the first and second end plates comprises multiple layers of material joined together, such that a non-uniform internal structure is formed. The annular secondary seal may be primarily elastomeric and a passage for permitting the flow of fluid may further permit the flow of fluid from the borehole to the annular space. By withdrawing solids, containing lignins remaining from hydrolysis of biomass, from the vessel, and filtering the solids, to result in a filtrate for recycle to the vessel and provide filtered solids for subsequent processing. Finally, in certain embodiments, the separated concentrate portion may be de-watered to a remaining composition of matter comprising iron in greater proportion than in the iron ore tailings byproduct.