Recovery of nitrogen from swine manure containing high-ammonia using gas-permeable membrane technology andreduced chemicals.

摘要

We are presenting a new and effective way of recovering ammonia from liquid manures. The recovery of nutrients from wastes for re-use as concentrated plant fertilizers is a new paradigm in manure management. In the work presented in this paper a new process using gas-permeable membranes at low pressure was applied to raw swine manure containing high-ammonia (2,390 mg NH4+-N/L) to recover the nitrogen. The process was refined further. To increase the ammonium (NHs) recovery rate (that is normally carried out using an alkali), in this study we used low aeration and nitrification inhibition. The aeration reacted with the natural alkalinity, which released OH- and increased the manure pH above 8.5. This pH increase promoted gaseous NH3 release from themanure and rapid permeation through the submerged membrane with excellent (98%) recovery of the N. Ammonia emissions losses were less than 1.5%. The new approach substituted for large amounts of alkali chemical that were needed to obtain the same effectand reduced the operational costs of NHS recovery by 57%.