Ferric and sulfate coupled ammonium oxidation enhanced nitrogen removal in two-stage partial nitrification - Anammox/denitrification process for food waste liquid digestate treatment.

Liquid digestate of food waste is an ammonium-, ferric- and sulfate-laden leachate produced during digestate dewatering, where the carbon source is insufficient for nitrogen removal. A two-stage partial nitrification-anammox/denitrification process was established for nitrogen removal of liquid digestate without pre-treatment (>300 d), through which nitrogen (95 %), biodegradable organics (100 %), sulfate (78 %) and iron (100 %) were efficiently removed. Additional ammonium conversion (20 %N) might be coupled with ferric and sulfate reduction, while produced nitrite could be further converted to di-nitrogen gas through anammox (75 %) and denitrification (25 %). Notably, since increasingly contribution of hydroxylamine producing nitrous oxide, and up-regulated expression of electron transfer and cytochrome c protein, the enhanced ammonium oxidation was probably conducted through extracellular polymeric substances-mediated electron transfer between sulfate/ferric-reducers and aerobic ammonium oxidizers. Thus, the established partial nitrification-anammox/denitrification process might be a cost-efficient nitrogen removal technology for liquid digestate, benefitting to domestic waste recycling and carbon neutralization.

Internal limiting membrane peeling combined with mouse nerve growth factor injection for idiopathic macular hole.

BACKGROUND: The study was intended to confirm whether Pars Plana Vitrectomy (PPV) with Internal Limiting Membrane (ILM) peeling and intravitreal injection mouse Nerve Growth Factor(mNGF) was effective for the treatment of Idiopathic Macular Hole(IMH) by Optical Coherence Tomography Angiography(OCTA) and microperimetry. METHODS: A retrospective study was performed in adults' patients. A total of 44 eyes (March 2021-October 2021) with IMH who received surgical treatment in the Affiliated Eye Hospital of Nanchang University in Nanchang City, Jiangxi Province were selected. The subjects were treated using PPV combined with ILM peeling and intravitreal mNGF (combined group) or PPV combined with ILM peeling (placebo group). The Best Corrected Visual Acuity (BCVA), Optical Coherence Tomography Angiography (OCTA) and MP-3 microperimetry were carried out and observed at baseline, 1 week(1W), 1,3 and 6 months (1 M,3 M,6 M) postoperatively. RESULTS: The minimum diameter of MH were (568.650 ± 215.862)µm and (533.348 ± 228.836)µm in the Placebo and Combine group pre-operative. During the observation, the macular hole closure rate in the placebo group and combined group were 90% and 95.8% respectively and the difference was not statistically significant(p = 0.583). Compared to pre-surgery, the perimeter and circularity of Foveal Avascular Zone (FAZ) in the placebo group decreased at 1,3,6 M (p = 0.001, < 0.001, < 0.001) and 1W,1,6 M (p = 0.045,0.010, < 0.001) post-surgery respectively. And the perimeter and circularity of FAZ showed significant reduction in the combined group at 1,3,6 M (p = 0.005,0.004, < 0.001) and at each follow-up time point (all values of p < 0.001). The vascular density of SCP increased at 1W(p = 0.031) and 6 M(p = 0.007), the perfusion density of SCP was significantly improved at each follow-up time point (p = 0.028, 0.011, 0.046, 0.004) in the combined group. The BCVA in the combined group was more obvious than that in the placebo group at 1 M, 3 M and 6 M after operation (t1 = 2.248, p1 = 0.030; t3 = 3.546, p3 = 0.001; t6 = 3.054, p6 = 0.004). The changes of BCVA in the combined group was more conspicuous than that in the placebo group at each follow-up time point, and the difference was statistically significant (t1 = 2.206,p1 = 0.033;t2 = 2.54,p2 = 0.015;t3 = 3.546,p3 = 0.001;t6 = 3.124,p6 = 0.003).At 1 M, 3 M and 6 M, the MRS of 2° and 4° in the combined group was better than that in the placebo group(t = -2.429,-2.650,-3.510,-2.134,-2.820,-3.099 p = 0.020,0.011,0.001,0.039,0.007,0.004). During various time points, the MRS of 12°in the combined group was better than that in the placebo group, the difference was statistically significant (t = -3.151, -3.912, -4.521, -4.948, p1 = 0.003, < 0.001, < 0.001 < 0.001). The integrity of External Limiting Membrane (ELM) in combination group was better than that in placebo group at 6 M postoperative(p = 0.022) and that of Ellipsoid Zone(EZ) was preferable in the combined group at 3 M and 6 M after surgery(p = 0.012,0.004). Correlation analysis showed that the integrity of EZ was correlated with 12°MRS at 1 M, 3 M and 6 M after surgery(r = -0.318, -0.343,-0.322;p = 0.023,0.033, < 0.001). There was no correlation between postoperative ELM integrity and postoperative BCVA and 12°MRS(p > 0.05). CONCLUSIONS: Our results manifested that PPV combined with ILM peeling and intravitreal injection mNGF might be more effective for initial IMH. This method increased the blood flow, MRS and promoted the recovery of ELM and EZ in the macular and might improve the visual function of patients postoperatively.

Desulfurization of hydrophilic and hydrophobic volatile reduced sulfur with elemental sulfur production in denitrifying bioscrubber.

Volatile reduced sulfur compounds were odor and irritating toxic gas, which were commonly produced during waste and wastewater treatment. The autotrophic sulfide denitrifiers converted sulfide as alternative electron acceptor to reduce nitrate, which achieved simultaneous denitrification and sulfur oxidation. In this study, to investigate the effect of sulfur compounds solubility, S/N and oxygen on sulfur and nitrogen removal, a bioscrubber was studied for treatment of hydrophilic H2S and hydrophobic CS2. Both H2S and CS2 could be efficiently removed (99%), with the highest sulfide loading of 46.9 gS/m3·d. The elemental sulfur production was strongly correlated to S/N ratio (r = 0.969, p = 0.03), the highest elemental sulfur production efficiency achieved 92.0% under S/N ratio of 2.0 for treatment of H2S. Thiobacillus sp. bacteria was the pre-dominated sulfide-dependent denitrifiers (78.2%) before exposing to oxygen, while abundance of Cryseobacterium and unclassified Xanthomonadaceae aerobic sulfide oxidizer dramatically increased up to 40% and 7.3% after aeration. Remarkably increasing production of extracellular polymeric substance (197%) was observed after treatment of CS2, which might promote the hydrolysis of CS2 and stabilization of elemental sulfur. This study demonstrated the possibility to apply sulfide-dependent denitrification process for treatment of both hydrophilic and hydrophobic volatile reduced sulfur waste gas with elemental sulfur recovery.