Bioaugmentation of overloaded anaerobic digesters restores function and archaeal community

Effects of organic loading rate on reactor performance and archaeal community structure in mesophilic anaerobic digesters treating municipal sewage sludge.

In this study, the organic loading rate (OLR) of a high-solids anaerobic digestion (HSAD) system was increased from 3.4 to 5.0 gVS L(-1) day(-1) and reactor stability, performance and microbial community structure were determined. Laboratory simulations (3.5 L) of the full-scale process (500 dry ton year(-1)) were conducted using continuously stirred-tank mesophilic reactors. OLRs of 3.4 gVS L(...

Dairy Manure Anaerobic Digesters

Study of Struvite Precipitation in Anaerobic Digesters

-In this paper struvite formation and crystal forms in anaerobic digesters under differing feed types and support media have been studied. Struvite appears when the medium contains magnesium, ammonium and phosphate ions. NH + can be supplied from protein degradation, phosphate from bacterial exudation and Mg 2+ by the supports. The precipitation of struvite has also been checked with real feedi...

Hydrodynamics Study of Sludge in Anaerobic Digesters

Inadequate design and improper mixing operation in anaerobic digesters often lead to poor mixing and digester failures due to the presence of dead zones formed in the digester. More research is required to understand the mixing phenomena in anaerobic digesters and thus improve their efficiency. This paper investigates the efficiency of mixing of digester sludge in a mechanically agitated vessel...

Modeling of ammonia speciation in anaerobic digesters.

Anaerobic digestion of high-nitrogen wastes such as animal manure can be inhibited by high concentrations of un-ionized ammonia, NH(3) (aq). Understanding the toxicity of NH(3) (aq) to anaerobic digestion requires a method for determining its concentration. Previous work on ammonia toxicity in anaerobic digesters has utilized a simple equilibrium calculation for estimating NH(3) (aq) concentrat...