Membrane-based technologies for post-treatment of anaerobic effluents

Abstract

Anaerobic digestion-based processes for converting wastewater into clean water and energy are attracting ever-growing industrial interest. However, apart from the microbial digestion step, current technologies require further progress from an integrated process point of view, including post-treatment steps. Anaerobic effluents normally undergo extensive post-treatment steps to meet stringent discharge standards, while valuable nutrients are rarely recovered. Additionally, a significant portion of the produced methane remains inevitably dissolved in the effluent, which is eventually released into the environment, causing economic loss and global warming concerns. To address these issues, several membrane-based technologies show significant promise. Here, we review current progress in membrane-based recovery of dissolved methane and nutrients, highlighting opportunities where membrane-based technologies can improve the post-treatment of anaerobic effluents. Lastly, we also share our perspectives for promising research directions and how to secure the competitiveness of membrane-based technologies for anaerobic wastewater treatment processes, focusing on current challenges for membrane development, biofouling mitigation strategies, and small-scale to large-scale implementation.

Removal of total phosphorus, ammonia nitrogen and organic carbon from non-sterile municipal wastewater with Trametes versicolor and Aspergillus luchuensis

“…According to the literature (Hansen et al, 2007;Pelendridou et al, 2014;Rongwong et al, 2018;Yoo, 2018), the cost of typical treatment technologies such as a coagulation-flocculation process for wastewater treatment, is in the range from 0.35-8.5 EUR/m 3 ; for membrane-based technologies -from 2 EUR/m 3 ; for conventional biological treatmentfrom 0.035 to 1 EUR/m 3 while the fungal treatment growth and operation costs may vary from 200 to 2000 EUR/m 3 . The fungal treatment costs highly depend on fungal growth requirements (temperature, incubation time, electricity of shaking, composition of media).…”

Membrane Contactors for Maximizing Biomethane Recovery in Anaerobic Wastewater Treatments: Recent Efforts and Future Prospect

“…However, in D-CH 4 recovery, the residual pollutants such as suspended solids and organics in the feed solution should also be considered together during the selection of the flow configuration. For example, Cookney et al, Henares et al, and Rongwong et al supplied the liquid to the shell side for the high organic content anaerobic effluents such as UASB and vice versa for low organic-containing effluents such as AnMBR [13,[37][38][39]. Even though the lumen side operational mode offers the better CH 4 recovery efficiency, a higher risk of membrane clogging limits such operation mode.…”

“…More importantly, although membrane wetting and fouling seem to be two separate issues that can be possibly dealt with one by one, those two are mostly related to each other. For example, highly hydrophobic membranes that are capable of preventing pore wetting are generally vulnerable to membrane fouling [13]. Thus, many researchers have studied to mitigate or eliminate such problems to increase the overall productivity in MCs for the biomethane recovery.…”

“…For instance, Crone et al demonstrated the potential feasibility of self-sustaining anaerobic processes based on the recovery of the produced CH 4 from both the headspace (gas phase) of the reactor and the D-CH 4 in effluents [8]. Previously, we also proposed a conceptual system of energy self-sufficient anaerobic wastewater process enabled by employing a membrane contactor (MC), as shown in Figure 1 [13]. The rationale behind Figure 1 is to maximize the recovery of produced CH 4 in the gaseous form at the head space as well as dissolved form in the liquid effluent (i.e., recovery of D-CH 4 using an MC) followed by the conversion of CH 4 to electricity using a micro turbine.…”

“…The techno-economic feasibility of MC for CH4 recovery from an liquid effluents is yet to be finely investigated, since to date, no sufficient studi been conducted at an industrial scale. [13].…”