Impact of fouling on the decline of aeration efficiency under different operational conditions at WRRFs

Oxygen transfer efficiency in an aerobic granular sludge reactor: Dynamics and influencing factors of alpha

“…The gas-liquid mass transfer coefficient k L a O 2 describes the transfer of oxygen from the gas phase to the liquid phase in process water. These k L a O 2 values were likely obtained under fouling conditions as the diffusers were about three years in operation since last cleaning [33].…”

“…Besides surfaceactive compounds, it is known that the alpha factor is affected by a wide range of other potential components and conditions in different ways and magnitudes [44]. These other components and conditions are part of the reactor design, such as diffuser type, distribution and tank depth [37] as well as related to operational aspects such as fouling [33], SRT [45], MLSS concentration and rheology [46], microbial activity [47] and soluble microbial metabolites. As these components are assumed to stay constant over a short term period, they were not taken into account as they will not likely influence the increase of alpha over the aeration phase of a specific cycle.…”

Effects of Environmental Conditions and Bed Configuration on Oxygen Transfer Efficiency in Aerated Constructed Wetlands

“…Since aerated wetland technology is now the spearhead of the wetlands treatment technology being established everywhere to treat different pollutants, further research dealing with diffuser fouling and oxygen transfer rates is relevant and necessary. This research will be important to determine accurate design parameters for the aeration systems in aerated constructed wetlands in the same way as is available for the design of aeration systems for the activated sludge process [31]. A better understanding of diffuser fouling phenomena will improve energy savings in aeration, because in different kinds of aerobic technologies, energy expenses represent between 25% and 60% of the operating costs [8,32].…”

Influence of diffuser design on selected operating variables for wastewater flotation systems: a review

“…Additionally, operating process variables play a role in the formation of biofilms on diffusers. This includes levels of dissolved oxygen, the concentration of ions in the wastewater to be treated as well as the soluble substrate availability, which collectively promote biofilm growth (Garrido-Baserba et al 2018). Consequently, sparger systems attributes can favour fouling which can be grouped into three categories which are biological, organic and inorganic fouling with biofouling or the development of biofilm on diffusers being of great concern (Meng et al 2009).…”