Three-ways changed in headspace air on anaerobic fermentation.

Different headspace condition has a great influence on fermentation process. In this study, whey protein was used as substrate, and the headspace air was changed in three different ways (H mixed N, H mixed CO, N with different sparging rates) to explore the effects of these three methods on products. The result showed that H mixed with CO is more conducive to acid production.

Optimization of Polyaluminum Chloride-Chitosan Flocculant for Treating Pig Biogas Slurry Using the Box⁻Behnken Response Surface Method.

Flocculation can remove large amounts of nitrogen and phosphorus from wastewater, and the resulting nitrogen- and phosphorus-rich floc can be used to produce organic fertilizer. For biogas slurries containing high levels of nitrogen and phosphorus, ordinary flocculants can no longer meet the flocculation requirements. In this study, to fully utilize the advantages of the two flocculants and achieve efficient removal rates of nitrogen and phosphorus from a biogas slurry, chitosan (CTS) and polyaluminum chloride (PAC) were used as a composite flocculation agent to flocculate pig biogas slurries.