Le Halberg (groundpilot57)

With the increase of curing time or dosage, the residual state of each heavy metal increased by 7%-86%. The results showed that the slag-based modifying agent could effectively solidify heavy metals in sludge and reused solid wastes such as sludge.Cold acclimation is an effective approach for improving the nitrogen removal performance and operational stability of partial nitritation/ANAMMOX (PN/A) combined processes at low temperatures. To explore the specific effects of cold acclimation on the characteristics of sludge, differentiations in temperature sensitivity, granular morphology, composition of extracellular polymer substance (EPS), and bacterial community structure between PN/A granular sludges cultivated at medium-high temperature (30℃) and acclimated to low temperature (15℃) were investigated in this study. The results of reaction thermodynamics showed that the nitrogen removal performance of the granules acclimated to low temperature (GL) was significantly higher than that of those cultivated at medium-high temperature (GH) under the low temperature (10-20℃), and the apparent activation energy (Ea) of total inorganic nitrogen removal for the former was decreased by 28.4%. Compared with GH, GL had a smaller average particle size of 25.8% and higher EPS contents of 16.6%, resulting in a significant lower settling property. Based on the high-throughput sequencing results, GL exhibited a higher diversity of bacterial community, and a lower relative abundance ratio (0.04) of aerobic ammonium-oxidizing bacteria (Nitrosomonas) and anaerobic ammonium-oxidizing bacteria (Candidatus_Kuenenia) than 0.34 for GH. It indicated that the PN/A granules held a strong ability to retain slow-growing autotrophic bacteria in the system, even under low temperatures. These findings could provide meaningful references for analyzing the self-adaption mechanisms of PN/A sludge to low temperature conditions and promote the industrial application of combined processes.In this study, three sequence batch reactors were selected to evaluate the effects of salt-tolerant activated sludge acclimation. The effect of salinity increase rate on pollutant removal, physicochemical characteristics of activated sludge, and microbial community were investigated. The results showed that a rapid salinity increase to 30‰ (within 30 d) reduced removal efficiencies of COD and NH4+-N from 85.5% and 98.5% (18 d) to 72.2% and 81.7% (51 d), respectively. In comparison, a slower salinity increases to 30‰ (within 90 d) had a minor effect on COD and NH4+-N removal. During the rapid salinity increase, a stable shortcut nitrification occurred under 20‰ salinity, in which the effluent NO2--N reached 11.13 mg·L-1 and NO3--N decreased to 0.56 mg·L-1. When salinity increased to 30‰, the nitrite accumulation rate was about 90%, and the removal efficiency of total nitrogen increased to approximately 75%. The contents of polysaccharide and protein in extracellular polymer substances increased as salinity increased, and the polysaccharide content increased significantly when the salinity was higher than 15‰. High-throughput sequencing results illustrated that microbial diversity reduced as salinity increased, following the Shannon index decrease from 8.06 (0‰ salinity) to 4.34 (rapid salinity increase) and 6.17 (slower salinity increase). As salinity increased, Micropruina, Denitromonas, TM7a, and Marinicella exhibited good salt tolerance. The relative abundance of Denitratisoma, Defluviimonas, Arenimonas, and Denitromonas decreased more significantly following the rapid salinity increase compared with that after the slower salinity increase.In this study, a SBR reactor was selected to explore the effect of nitrogen and phosphorus removal by aerobic granular sludge under different initial anaerobic time using intermittent gradient aeration (decreasing dissolved oxygen concentration in each aeration section) and actual domestic wastewater with low C/N ratio as the influent matrix.