Characteristics, Process Parameters, and Inner Components of Anaerobic Bioreactors

Abstract

The anaerobic bioreactor applies the principles of biotechnology and microbiology, and nowadays it has been used widely in the wastewater treatment plants due to their high efficiency, low energy use, and green energy generation. Advantages and disadvantages of anaerobic process were shown, and three main characteristics of anaerobic bioreactor (AB), namely, inhomogeneous system, time instability, and space instability were also discussed in this work. For high efficiency of wastewater treatment, the process parameters of anaerobic digestion, such as temperature, pH, Hydraulic retention time (HRT), Organic Loading Rate (OLR), and sludge retention time (SRT) were introduced to take into account the optimum conditions for living, growth, and multiplication of bacteria. The inner components, which can improve SRT, and even enhance mass transfer, were also explained and have been divided into transverse inner components, longitudinal inner components, and biofilm-packing material. At last, the newly developed special inner components were discussed and found more efficient and productive.

Helminth Egg Removal Capacity of UASB Reactors under Subtropical Conditions

“…Average ambient temperature varied from 21.4 to 28.5 °C. Although counterintuitive, the decreasing trend in helminth egg removal efficiency at an increasing sludge bed height in the studied lab-scale reactor might be explained by an increase in turbulence, created by the biogas production and formation of channels through the sludge bed [62,63] during all studied velocities. The possible saturation with helminth eggs during previous experiments could also have influenced the stability of the system with respect to helminth egg removal.…”

Review of Upflow Anaerobic Sludge Blanket Reactor Technology: Effect of Different Parameters and Developments for Domestic Wastewater Treatment

“…Organically bound nitrogen is transformed to ammonium and sulfate is reduced to hydrogen sulfide. Moreover, sludge generation is low and sludge produced is highly stable with good dewaterability characteristics [42]. Under aerobic conditions, there is a complete loss of biomass energy in low value heat during the oxidation of organic matter, whereas under anaerobic degradation process, the original energy of the biomass is not changed.…”

“…In case of sewage, the OLR usually is applied in the range of 1.0-2.0 KgCOD/m 3 ⋅day [42,101]. UASB reactor is preferred for its potential to treat wastewater having low content of suspended solids and gives higher methane yield [27].…”

“…When the solids removal efficiency in UASB is related to the OLR, it is important to differentiate between these parameters. It is therefore inferred that OLR is an insufficient design parameter to guarantee good performance of anaerobic reactors [42].…”

A Modified Bio-Ecological Process for Rural Wastewater Treatment

“…The increase of the HRT from 24 h to 72 h increased the COD removal efficiency from 60% to 72%, however, when HRT increased from 72 h to 96 h no significant changes in the COD removal efficiency occurred. Excessively long HRTs reduce the up-flow velocity in each reactor compartment and the nutrition distribution for microbes; therefore, no significant changes occurred in the COD removal rate [34]. Extending HRT increased the reactor volume and construction costs [35].…”