Role of polyferric sulfate and ferric chloride on anaerobic fermentation of sludge from novel two-stage process for resource recovery.

Polyferric sulfate (PFS) and ferric chloride (FC) were compared for their efficiencies in capturing organic carbon and phosphorus, and their effects on the anaerobic fermentation process of sludge from a pilot-scale two-stage reactor were studied. Both PFS and FC promoted organic carbon and phosphorus capture. Further study revealed that PFS-based sludge with a dosage of 18 mg Fe/Lsewage showed a better volatile fatty acids (VFAs) production performance (202.97 ± 2.38 mg chemical oxygen demand (COD)/g volatile solids (VS)) than that of FC-based sludge (169.25 ± 1.56 mg COD/g VS). Besides, the high dosage of PFS effectively promoted the activities of the α-glucosidase and proteases. The dissimilatory iron reduction process enhanced sludge flocs disintegration and the conversion of carbohydrates and proteins to VFAs. Non-hydroxyapatite phosphorus predominated in the total phosphorus of all samples. This study contributes to developing strategies for optimizing iron-based sludge management and high-value product recovery.

Larger hydroxyapatite aggregation from Ca2+ adhesion in ANAMMOX granular sludge caused by high dissolved oxygen.

Anaerobic ammonia oxidation (ANAMMOX), a sustainable biological process, is promising to remove NH4+-N from municipal sewage. In this study, results showed that the anammox granular sludge morphology changes with the alternation of dissolved oxygen (DO), mainly attributing to the adhesion of calcium ions (Ca2+) to the surface of sludge particles. Diverse characterization methods revealed that gray adhesions in the form of hydroxyapatite covered the original holes on the anammox granular sludge surface, including scanning Electron Microscopy (SEM), digital camera images, Energy Dispersive Spectrometer (EDS), and X-ray diffraction (XRD). Ex-situ degradation of NH4+-N and NO2--N yielded diverse outcomes. The protein to polysaccharide ratio (PN/PS) in the total extracellular polymeric substances (EPS) across 4 size groups demonstrated a decrease under O2 exposure. Microbial community analysis indicated norank_f_A4b and Nitrolancea being the most abundant genus under O2 exposure at day 1 and day 100, respectively. These findings offer an effective strategy to prevent size-larger granular sludge from deteriorating through changing DO and Ca2+ in municipal wastewater in ANAMMOX.

Role of polyurethane-modified layered double hydroxides on SCFAs extraction from waste activated sludge fermentation liquid for elevating denitrification: Kinetics and mechanism.

Extraction of short-chain fatty acids (SCFAs) from fermentation liquid of waste activated sludge (WAS) is the key bottleneck hindering its application as electron donor in denitrification. This study explores the feasibility of polyether-type polyurethane (PU)-modified layered double hydroxides (LDHs, prepared using eggshell waste as calcium source) in SCFAs adsorbing from WAS fermentation liquid (SFL). The adsorption parameters were first optimized by adsorption tests using artificial fermentation liquid (AFL). Then, adsorption kinetics, thermodynamic and isotherms were explored to further understand the adsorption mechanism. It revealed that SCFAs absorption by PU-LDHs from SFL was an endothermic and spontaneous process with positive enthalphy (ΔH◦) values and negative Gibbs free energy (ΔG◦) values. In addition, the maximum adsorption capacity of 208.0 mg SCFAs/g PU-LDHs was obtained from the Langmuir isotherm. Noting that both soluble carbohydrates and soluble proteins were simultaneously extracted, with efficiencies of 30.9%, 6.2%, respectively, compared with 62.9% SCFAs. The reuse tests confirmed that the prepared PU-LDHs can be used at least three times with high adsorptive capacity. With PU-LDHs-loaded SFL as external carbon source in the biodenitrification process, a denitrification rate of 0.014 mg NO3--N/mg mixed liquid suspended solids (MLSS)·d was recorded. This study provided a sound basis for the preparation of cost-effective biodenitrification carbon source from SFL by a novel adsorbent.

[Stability of the anterior teeth and hard tissue of skeletal class III malocclusion after orthodontic surgery: systematic review].

OBJECTIVE: This study aims to analyze the long-term stability of the anterior teeth and hard tissue of skeletal class III malocclusion after a three-year orthodontic surgery by systematic review. METHODS: All studies about skeletal class III malocclusion with orthodontic-surgery were searched by computer-based retrieval and manual retrieval; the deadline is December 2013. The literature, filtered according to the inclusion criteria and exclusion criteria, was performed with quality. assessment. The same indicators of the anterior location and hard tissue stability were combined and evaluated with metaanalysis and descriptive analysis by Rev Man5.2. RESULTS: Four before-and-after comparison study articles with 180 cases were included. The grades of the four literature evaluation were A. The meta-analysis results showed that comparing the three-year post-orthodontic-surgery and post-orthodontic-surgery, the total weighted mean difference (WMD) of Ul-SN was 4.29 (P<0.05); the WMD of Ll-MP, OB, OJ, SNA, SNB, ANB, and MP-SN were -1.58, 0, -0.41, -0.58, 0.25, -0.70, and 0.39, respectively (P>0.05). The measurement methods of A and B point position were different, hence the qualitative description were as follows: point A remained at a relatively stable position, and point B had some replacement compared with post-operative (P<0.05). CONCLUSION: To the skeletal class III malocclusion after three-year orthodontic-surgery, the position of the lower anterior teeth could be kept stable, as well as the overbite and the overjet of the anterior teeth; only the upper inci- sor has a lip-inclined relapse. The maxillary could also be kept stable, and the mandibular had a little relapse.