摘要 : Capturing organics from wastewater is recognized as the initial step towards carbon valorization, since the direct valorization of organics in domestic wastewater is limited by the low concentration. An innovative method was proposed in our former research, which utilizes captured organics from wastewater as raw material for producing a coarse flocculant, thereafter, using the coarse flocculant to capture organics from wastewater in a cyclical manner. Hydrothermal processing (HTP) and chemical modification are jointly applied to coarse flocculant production . Besides, the hydrothermal liquid fraction of concentrated organic matter was indicated as the potential effective precursor. However, the role of hydrothermal liquid fraction as precursor for coarse flocculant and the regulatory mechanism remain unclear. Therefore, this study aims to evaluate the characteristics of the hydrothermal liquid fraction under different alkaline addition, temperature and time from the perspective of coarse flocculant preparation. The results demonstrated that the dissolved polymeric substances extracting through HTP and acid precipitation process exhibit a high molecular weight (reaching up to 9929 Da) and abundant functional groups (including C O, C N, OH, C O C, etc.). Furthermore, the addition of NaOH, along with relatively moderate temperature and time were recommended for producing the flocculant precursor. Specifically, this study suggests a temperature of 140 °C and a duration of 30 min for the flocculant precursor producing.

摘要 : Two biofilm sequencing batch reactors (BSBRs) were conducted under alternating aerobic/anaerobic (Ae/An) sequence and alternating anaerobic/aerobic (An/Ae) sequence to investigate the effects of operation sequences on phosphorus removal and recovery performance. The Ae/An BSBR had advantages in phosphate enrichment, phosphorus concentration of enrichment solution can reach 99.08 mg/L. While An/Ae BSBR exhibited a higher kinetic rate for phosphate uptake and release up to 0.48 mmol/gVSS. In An/Ae BSBR, the remarkable increase of phosphate concentration in aerobic stage put a great strain on the phosphate uptake of biofilms that led to an increase of phosphorus accumulation in the biofilm (P biofilm ). However, the poly-P proportion in TP biofilm decreased which triggered the metabolisim of polyphosphate accumulating organisms (PAOs) shifting from polyphosphate accumulating metabolism (PAM) to glycogen accumulating metabolism (GAM) and suppressed the phosphorus enrichment performance of the An/Ae BSBR. The phosphate uptake rate (PUR) of biofilms was in alignment with the bulk phosphate concentration. PAOs were dominated by Rhodoplanes and Saprospiraceae in the Ae/An BSBR, whereas Thiothrix was predominant in the An/Ae BSBR. Notably, the Candidatus Competibacter, considered as a denitrifying glycogen accumulating organisms (DGAOs), showed a dominant proportion in the microbial community of both BSBRs. The higher expression of actP in the An/Ae system indicated a greater capacity for the uptake of acetate, while the Ae/An system was is more adept for degrading acetate represented by the higher relative abundance of ackA, pta and acsA genes The high phosphorus loading in the An/Ae system suppressed the ppk expression but enhanced the ppx expression.

摘要 : The pilot-scale simultaneous denitrification and methanation (SDM)-partial nitrification (PN)-anaerobic ammonia oxidation (Anammox) system was designed to treat anaerobic digestion effluent of kitchen waste (ADE-KW). The SDM-PN was first started to avoid the inhibition of high-concentration pollutants. Subsequently, Anammox was coupled to realize autotrophic nitrogen removal. Shortcut nitrification–denitrification achieved by the SDM-PN. The NO 2 – -N accumulation (92 %) and NH 4 + -N conversion (60 %) were achieved by PN, and the removal of TN and COD from the SDM-PN was 70 % and 73 %, respectively. After coupling Anammox, the TN (95 %) was removed with a TN removal rate of 0.51 kg·m −3 ·d -1 . Microbiological analyses showed a shift from dominance by Methanothermobacter to co-dominance by Methanothermobacter, Thermomonas, and Flavobacterium in SDM during the SDM-PN. While after coupling Anammox, Candidatus kuenenia was enriched in the Anammox zone, the SDM zone shifted back to being dominated by Methanothermobacter . Overall, this study provides new ideas for the treatment of ADE-KW.

摘要 : Exploring the effects of different S/N ratios on the simultaneous accumulation of S 0 and NO 2 − -N in the autotrophic denitrification process is of great significance for the enhanced Anammox denitrification and S 0 resource recovery. The results showed that the low S/N ratio avoided the S 2− accumulated toxicity, and the reactor could be quickly started within 9 days. When S/N ratio was 1, the highest S 0 accumulation efficiency (S 0 AE) and NO 2 − -N accumulation efficiency (NiAE) could be obtained synchronously, which were 77.41 % and 87.83 %, respectively. The production of S 0 and NO 2 − -N was up to 0.57 kg/(m 3 ·d) and 0.18 kg/(m 3 ·d), respectively. Too high or low S/N ratio would affect the S 0 AE and NiAE, respectively. With the increasing S/N ratio, sqr and narG genes expressions were enhanced and soxB and nirK genes expressions were weakened. Thiobacillus, Azoarcus and Pseudaminobacter were the dominant genera performing denitrification and desulphurization in double short-cut sulfur autotrophic denitrification.

摘要 : The effects of Fe(III) concentration on nitrogen removal efficiency in Anammox sludge were studied in short-term and long-term. The proper amount of Fe(III) could enhance the nitrogen removal efficiency of Anammox bacteria, 0.09mol/L was the most suitable concentration, the nitrogen removal rate was 0.238kg/(L·d), compared with the control group increased by 14.2%. The nitrogen removal rate was decreased gradually with the influent Fe(III) concentration increased constantly. When the Fe(III) concentration increased to 0.18mol/L, the nitrogen removal rate dropped to 0.215kg/(L·d)decreased by 10.75% compare with 0.09mol/L. The half-saturation constant (KFe) was 0.012mol/L, the inhibiting kinetic constant (KI) was 0.449mol/L obtained by Haldane inhibition kinetic model fitting. The long-term experiment results showed that at 0.09mol/L Fe(III) concentration, the nitrogen removal rate of Anammox increased the fastest, and gradually decreased with the increase of Fe(III) concentration. the conversion ratio of NO2--N and NH4+-N was significantly lower than the theoretical value of 1.32, fluctuate between 1.108 and 1.227, and decreased with the increase of concentration of Fe(III), presumably due to the addition of Fe(III) instead of NO2--N as electron acceptor. Scanning electron microscope results showed that the addition of Fe(III) could make the Anammox bacteria cell structure more stable.

摘要 : Implementing appropriate measures to recycle and convert the organic matter in sewage into valuable products can effectively contribute to resource recovery. The macromolecular products derived from the hydrothermal liquid phase of sewage sludge (HL-MMP) were utilized as raw materials for preparing coarse organic flocculant (Co-flocculant), which can be re-used to enhance organic matter removal from sewage via flocculent settling. Two distinct chemical modification methods, namely etherification and grafting copolymerization, were compared and analyzed in terms of their suitability for the preparation. Through coagulation experiments, it was found that the Co-flocculant obtained from both methods yield satisfactory turbidity and COD removal. However, to achieve a higher turbidity and COD removal, the required dosage of the Co-flocculant (M-GTA) obtained by etherification is significantly larger than that of the Co-flocculant (M-DMC) obtained by graft copolymerization. Meanwhile the HL-MMP and Co-flocculant were characterized using FTIR, XPS, SEM and Charge Density, Intrinsic Viscosity of the latter were measured. The results of FT-IR and XPS showed that HL-MMP possesses numerous functional groups, which can serve as active sites for both modifying reactions. The charge density of the Co-flocculant obtained through the two methods is similar, however, the intrinsic viscosity of M-GTA is lower than that of M-DMC, indicating that the graft copolymerization seems to form products with larger molecular weight . Additionally, the analysis of the reaction mechanism revealed that the HL-MMP exhibits self-polymerization and bound monomer, DMC, facilitates polymerization in the graft copolymerization. Conversely, in the etherification, polymerization mainly depend on the addition of etherized monomer, GTA. The difference of reaction mechanisms can explain the relative quantitative requirements of modifying monomers and different preparation conditions. Therefore, graft copolymerization is deemed more suitable for modifying HL-MMP to synthetic Co-flocculant and deserves further comprehensive and detailed investigation.

摘要 : Recovering phosphorus from wastewater is an effective way to alleviate the crisis of phosphate resources. At present, the common phosphorus recovery process in wastewater treatment plants is mainly the sidestream process to recover phosphorus from excess sludge, which has a shortage of complicated processes and low recovery efficiency. The mainstream phosphorus recovery process with biofilm can realize simultaneous removal and enrichment of phosphorus. The process is simple and efficient, thus has more development prospects. Due to the significant differences in operating principle and mode, the regulation measures for the two processes are not the same. In this paper, the A2O process and biofilm sequencing batch reactor process were taken as the representative and the similarities and differences in the operating principles and modes of the sidestream and mainstream phosphorus recovery processes were compared, also, the influences of regulatory factors such as temperature, pH, hydraulic residence time, dissolved oxygen, carbon source and phosphorus storage capacity on the two processes were summarized based on the metabolic mechanism of phosphorus accumulating bacteria. The differential mechanism was expounded to provide a reference for the further development of the phosphorus recovery process of biofilm.

摘要 : In order to investigate effects of operation mode on the phosphorus removal and recovery performance of PAOs-biofilm, the continuous operating PAOs-biofilm reactor was carried out to recovery phosphorus from synthetic sewage wastewater with different operation modes. It showed that the operating modes resulted in significant differences of the environment for phosphorus uptake and release (phosphorus concentration in water). Under the "anaerobic-aerobic alternating" mode, the high phosphorus loading in aerobic phase strengthened the phosphorus uptake ability of the PAOs-biofilm, and the phosphorus recovery performance depended on the limitation of phosphorus uptake. In contrast, under the "aerobic-anaerobic alternating" mode, the high concentration of phosphorus in anaerobic phase depressed the phosphorus release ability of the PAOs-biofilm, which could be the main reason for the limited phosphorus recovery performance. Such differences in environment resulted from the operation modes led to different aerobic phosphorus uptake, anaerobic phosphorus release and carbon source utilization rate of biofilm. The average Prel/Cupt under "anaerobic-aerobic alternating mode" was 0.213 mmol P /mmol C, which was much higher than that of 0.046 mmol P/mmol C under "aerobic-anaerobic alternating" mode. In summary, the PAOs-biofilm showed higher efficiency in phosphorus removal under "anaerobic-aerobic alternating" mode, while it exhibited a more superior performance in phosphorus recovery under "aerobic-anaerobic alternating" mode, with phosphorus recovery liquid of 99.90 mg/L.

摘要 : Humic acid (HA) is a typical refractory organic matter, so it is of great significance to investigate its effect on the performance of Anammox granular sludge. When the dosage of HA ≤ 50 mg/L, HA promotes the total nitrogen removal rate (NRR) to 1.45 kg/(m3·day). When HA was between 50 and 100 mg/L, the NRR of Anammox was stable. At this time, the adsorption of HA causes the sludge to gradually turn from red to brown, but the activities of heme and enzymes showed that its capacity was not affected. When HA levels reached 250 mg/L, the NRR dropped to 0.11 kg/(m3·day). Moderate HA levels promoted the release of extracellular polymeric substance (EPS), but excessive HA levels lead to a decrease in EPS concentrations. HA inhibited Anammox activity, which indirectly hindered the transmission of substrate and accumulated substrate toxicity. Although HA promoted the increase of heterotrophic microbial abundance in Anammox system, the microbial diversity decreased gradually. With the increase of HA concentration, the abundance of Candidatus_Brocadia, the main functional microorganism of Anammox system, decreased gradually, while the abundance of Candidatus_Kuenenia increased gradually. © 2023

摘要 : CPS60@SA/La composites were developed through sodium alginate coating and lanthanum ion crosslinking using nano-calcium peroxide-loaded sepiolite as the basic skeleton. Then, their phosphorus removal performance and mechanisms in eutrophic water bodies were investigated through batch adsorption experiments and characterization analyses. The results showed that as-prepared composites had good oxygen release and phosphorus removal ability, and nano-calcium peroxide and lanthanum sites were recognized as the main active components. With the increase in the CPS60@SA/La hydrogel dosage, the phosphorus removal efficiencies increased accordingly. The removal process of CPS60@SA/La for high-concentration phosphorus followed the description of the pseudo-second-order kinetic model and Langmuir isotherm model, with a maximum adsorption capacity of 198.25 mg·g-1 (20°C). The as-prepared CPS60@SA/La exhibited good phosphate removal performance in the pH range of 3-9, and the coexistence of F-, HCO3-, CO32-, and HA had a slight inhibition effect on the phosphorus removal by CPS60@SA/La. In the actual river water, CPS60@SA/La composites could slowly release oxygen and maintain the concentration of dissolved oxygen of approximately 8.51 mg·L-1, which could provide good conditions for the aerobic microorganisms at the sediment-water interface, with good removal and inactivation ability for phosphate in both overlying and pore water, and their removal performance was stable. Thus, its use is expected to enhance the self-purification ability of surface water bodies.