To meet the growing interest in the development of innovative biological nutrient removal (BNR) alternatives for energy neutrality, resource recovery, and decarbonization, the adsorption/bio-oxidation (A/B) process has been widely studied for carbon capture and shortcut nitrogen (N) removal, while limited research has focused on incorporating enhanced biological phosphorus (P) removal (EBPR), mainly due to the differential carbon usage characteristics of functionally relevant microorganisms. Here, a full-scale pilot testing with an integrated system combining A-stage high-rate activated sludge (HRAS) with B-stage partial (de)nitrification/anammox and side-stream EBPR (HRAS-P(D)N/A-S2EBPR) was conducted treating real municipal wastewater. The results demonstrated that, despite the low influent carbon load, the B-stage P(D)N-S2EBPR system achieved effective and stable P removal performance, especially when the volatile fatty acid (VFA) load from A-stage was elevated. Sludge fermentation in both A-stage and B-stage promoted carbon redistribution and likely provided more competitive advantages for ammonium-oxidizing bacteria and polyphosphate accumulating organisms, leading to carbon-efficient shortcut N removal mainly through partial nitrification pathway and influent carbon-independent EBPR simultaneously. Exposure to high VFA levels was considered a potential selection factor for the suppression of nitrite-oxidizing bacteria in the system. The involvement of internal carbon-accumulating organisms would potentially play an important role in endogenous denitrification. This study provided new insights into the effects of incorporating side-stream EBPR into the A/B process on microbial ecology, metabolic activities, and system performance.

Constructed rapid infiltration system (CRI) is a new type of sewage biofilm treatment technology, but due to its anaerobic zone lacks of the carbon sources and the condition for nitrate retention, its nitrogen removal perfomance is very poor; However, shortcut nitrification-denitrification process presents distinctive advantages, as it saves oxygen, requires less organic matter and needs less time for denitrification compared to conventional nitrogen removal method. Thus, if the shortcut nitrification-denitrification process could be applied to CRI system properly, the simpler, more economic and efficient nitrogen removal method will be obtained. But, as its reaction process shows that the first and the most important step of achieving shortcut nitrification-denitrification is to achieve shortcut nitrification. Thus, in this study, we explored the feasibility to achieve shortcut nitrification, which produces nitrite as the dominant nitrogen species in effluent, by addition of potassium chlorate (KClO₃) to the influent. In an experimental CRI model system, the effects on nitrogen removal, nitrate inhibition and nitrite accumulation were studied, and the advantages of achieving shortcut nitrification-denitrification were also analysed. The results showed that shortcut nitrification was successfully achieved and maintained in a CRI system by adding 5 mM KClO₃ to the influent at a constant pH of 8.4. Under these conditions nitrite accumulation rate was increased, while a lower concentration of 3 mM KClO₃ had no obvious effect. The addition of 5 mM KClO₃ in influent presumably allowed sufficient activity of ammonia-oxidizing bacteria (AOB) but inhibited nitrite-oxidizing bacteria (NOB) strongly enough to result in a maximum nitrite accumulation rate of up to over 80%. As a result, nitrite became the dominant nitrogen product in the effluent. Moreover, if the shortcut denitrification will be achieved in the subsequent research, it could save 60.27 mg carbon source (CH₃OH) consumption when treatment of per liter sewage in CRI system compared with full denitrification process.

Our understanding of pull-apart basins and their fault systems has been enhanced by analog experiments and simulations. However, there has been no opportunity to compare the faults that constitute pull-apart basins with surface ruptures during earthquakes. In this study, we investigated the effects of a 2018 earthquake (Mw 7.5) on a pull-apart basin in the Palu-Koro fault system, Sulawesi Island, Indonesia, using geomorphic observations in digital elevation models, optical correlation with pre- and post-earthquake satellite images. A comparison of active fault traces determined by geomorphology with the locations of surface ruptures from the 2018 earthquake shows that some of the boundary faults of the basin are inactive and that active faulting has shifted to basin-shortcut faults and relay ramps. We also report evidence of lateral spreading, in which alluvial fan materials moved around the end of the alluvial fan. These phenomena may provide insights for anticipating the location of future surface ruptures in pull-apart basins.