Effect of effluent recycling and shock loading on the biodegradation of complex phenolic mixture in hybrid UASB reactors

Process bioengineering applied to BTEX degradation in microaerobic treatment systems

“…The use of effluent recirculation can aid in the distribution of the liquid at the inlet of the treatment system, reducing the concentration gradient and toxicity of the substrate along the bioreactor and providing a more efficient mass transfer between substrate and microbiota, which, consequently, could influence positively the conversion of substrate into biogas (Mohan et al, 2007;Zuo et al, 2014). However, depending on the composition of the wastewater, the configuration of the treatment system and the recirculated flow rate, the results may be quite different (Díez-Montero et al, 2016;Giustinianovich et al, 2015;Ramakrishnan and Gupta, 2008).…”

Anaerobic treatment of fresh leachate from a municipal solid waste incinerator by upflow blanket filter reactor

“…In fact, the concentrations , HCO 3 -/CO 3 2-, and NH 4 + /NH 3 were the main contributors for the buffering capacity of the anaerobic bioreactor. Hence, effluent recycling does not reduce the alkalinity required for neutralization of carbonic acid, but it does dilute the incoming COD, thus reducing the damage caused by unionized VFA and supplying inherent alkalinity [7,10]. Thus, due to the enhanced buffering capacity of the UBF reactor by effluent recycling, a smaller fluctuation of biogas production was obtained under each increasing OLR.…”

“…Under the condition of unstable operation, intermediates such as VFAs and alcohols accumulate in varying degrees. The most common causes of instability are related not only to hydraulic or organic overloading, but also to the presence of toxins and changes in the substrate [7].…”

Anaerobic Processes

“…The anaerobic degradation of polycyclic aromatic compounds, phenanthrene, and pyrene, was investigated using mangrove sediment from Taiwan Four identical 13.5-L bench-scale hybrid UASB reactors were used in the treatment of synthetic coal wastewater to determine the effects of effluent recycling and shock loads on biodegradation (Ramakrishnan and Gupta, 2008). Four different effluent recirculation ratios (R/F) were employed (0.5, 1.0, 1.5, and 2.0).…”