Impacts of thermal hydrolysis
INTRODUCTIONThis chapter deals with the most significant impacts of thermal hydrolysis in more detail. That is to say, its influence on rheological properties of sludge, dewatering, production of recalcitrant compounds and concerns surrounding ammonia toxicity in digestion due to higher loading rates. Treatment of emerging contaminants is also referred to. The influence of thermal hydrolysis on biogas production is presented in Chapter 5, along with other benefits. This chapter also summarizes the various studies which have been conducted on understanding the influence of thermal hydrolysis on microbial communities and their evolvement during the digestion process.
INFLUENCE ON SLUDGE RHEOLOGYRheology change due to thermal hydrolysis is arguably the most important consequence of the technology on sludge treatment as it allows higher digester loading ratesdue to increased ease of downstream transportand aids in dewatering (Stickland, 2015). In the informative review by Eshtiaghi and coworkers (2013), sludge is described as a non-Newtonian shear thinning thixotropic fluid, which behaves as a thixotropic colloidal suspension at high shear rates but exhibits polymeric behavior at low shear. The flow behavior of waste-activated sludge has been successfully modelled using the