Free ammonia pre-treatment of secondary sludge significantly increases anaerobic methane production

A novel free ammonia based pretreatment technology to enhance anaerobic methane production from primary sludge

“…Our previous study demonstrated that FA pretreatment technology was also able to enhance anaerobic methane production from secondary sludge (Wei et al, ). This indicated that the FA pretreatment technology could be implemented on the mixture of primary sludge and secondary sludge to maximize methane production from the waste stream of the WWTPs.…”

“…The effect of FA pretreatment on methane production from primary sludge is also different from that from secondary sludge. For instance, FA pretreatment on secondary sludge improved both B 0 and k with the highest improvement being approximately 22% and 140% in comparison to the secondary sludge without pretreatment, achieved at FA concentrations of 420–680 mg NH 3 ‐N/L (Wei et al, ). The reasons behind that still require further study.…”

“…Our recent study showed that free ammonia (FA) as a novel pretreatment technology, could increase anaerobic methane production of secondary sludge (Wei et al, ). Anaerobic digestion tests demonstrated that the highest improvement in biochemical methane potential (B 0 ) and hydrolysis rate (k) was achieved at FA concentrations of 420–680 mg NH 3 ‐N/L, and was determined as approximately 22% and 140% in comparison to the secondary sludge without pretreatment (Wei et al, ). Importantly, FA is a renewable chemical that can be attainted on site directly from the waste stream (i.e., anaerobic digestion liquor) of the WWTPs.…”

“…The anaerobic digestion liquor generally has an FA concentration of 30–560 mg NH 3 ‐N/L (i.e., ammonium concentration of 1.0–2.0 g NH 4 + ‐N/L at a pH 7.5 ∼ 8.6 and temperature 33°C) (Cervantes, ; Fux et al, ). The technology was further clarified to be economically favorable in terms of enhancing methane production of secondary sludge (Wei et al, ). However, the effect of FA pretreatment on methane production from primary sludge has not been reported.…”

Chlorate and Other Oxychlorine Contaminants Within the Dairy Supply Chain

“…A methane-based MBfR has also been shown to be applicable in perchlorate reduction and could be advantageous as methane is inexpensive, and in wastewater treatment it can provide a solution for energy recovery as methane is respired by anaerobic digestion of bio-solids (Liu, Zhang, & Ni, 2015;Sun et al, 2017;Wei, Zhou, Wang, Sun, & Wang, 2017). This approach also has the potential to reduce greenhouse gas emissions that are produced during wastewater treatment (Silva-Teira, Sánchez, Buntner, Rodríguez-Hernández, & Garrido, 2017;Sun, Pikaar, Sharma, Keller, & Yuan, 2015).…”