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Recently, water contamination caused by the misuse of antibiotics has become a growing concern. In this study, an economical chitin/calcite composite (CCA) was extracted from crab shell waste, and the effects and mechanisms of its removal of ciprofloxacin (CIP) and tetracycline (TC) from aqueous solution were investigated. The functional groups of chitin and the metal phase of calcite gave CCA the ability to remove antibiotics. Experiments on kinetics, isothermal adsorption, thermodynamics, co-removal, and reusability were conducted to systematically explore the adsorption performances of CCA toward antibiotics. The pseudo-second-order (FSO) and Langmuir models suited the data obtained from experiments best and displayed a good fit for the chemisorption and a certain homogeneity of adsorption sites. At 25 °C, the maximum adsorption capacities (Qmax) toward CIP and TC were 228.86 and 150.76 mg g-1, respectively. The adsorption mechanisms of CCA with TC and CIP are pH dependent since pH can affect the surface charge of CCA and the form in which CIP and TC are existing. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) demonstrated that the keto-O and carboxyl groups of CIP and the carbonyl, hydroxyl, and amido groups of TC could be responsible for the binding with the calcite and the functional groups of chitin through surface complexation, cation bridge and hydrogen bonding.

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High levels of phosphorus released into the environment can cause eutrophication issues in wastewater, therefore discharge concentrations of such element are regulated in many countries. This study addresses the pressing need for effective phosphorus removal methods by developing a novel La2(CO3)3 and MnFe2O4 loaded biochar composite (LMB). A remarkable adsorption capacity towards the three forms of phosphorus from wastewater, including phosphate, phosphite, and etidronic acid monohydrate (as a representative of organic phosphorus), was exhibited by LMB (88.20, 16.35, and 15.95 mg g-1, respectively). The high saturation magnetization value (50.17 emu g-1) highlighted the easy separability and recyclability of the adsorbent. The adsorption process was well described by the Langmuir isotherm model and the pseudo-second-order kinetic model, which mainly involved chemisorption. Characterization results confirm the effective loading of La2(CO3)3 with ligand exchange and electrostatic attraction identified as the primary mechanisms. Importantly, the LMB demonstrated exceptional selectivity for phosphorus in wastewater samples containing various substances, exhibiting minimal interference from competing ions (Cl-, NO3-, SO42-, and CO32-). These findings enhance the understanding of LMB's application in efficient wastewater phosphorus removal. Holding significant promise in wastewater remediation, the LMB acts as an effective adsorbent, contributing substantially to the prevention and control of various types of phosphorus pollutants, thereby mitigating wastewater eutrophication.

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To treat gibberellin (GA) wastewater, a full-scale, multi-stage combined contact process was developed. This whole process employs three anaerobic reactors followed by micro-aerobic, anoxic/aeration and biological oxidation treatment. Pollutant removal results showed that the combined process could remove more than 98% of the chemical oxygen demand (COD), NH3N, and SO42- pollutants because of the different microbial communities in each reactor. 16S rRNA gene sequencing was used to examine the microbial communities in the internal circulation (IC) and in the two up flow anaerobic sludge blanket (UASB) reactors, as well as to investigate the effect of sampling elevation on the microbial community. The results showed that Firmicutes and Euryarchaeota were the most dominant phyla at the bacterial and archaeal levels, respectively. High levels of Synergistaceae_uncultured were detected in IC and UASB1. Chloroflexi_uncultured was the dominant genus of bacterial communities within UASB2, and Methanosaeta was the dominant genus of archaeal communities. Principal coordinates analysis (PCoA) revealed variations among the microbial communities in 9 samples, and Venn analysis showed different operational taxonomic units (OTUs) among samples collected at various elevations within the three anaerobic reactors. However, partial Mantel tests indicated no significant correlation between the microbial community structure and elevation in the three anaerobic reactors.

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Pharmaceutical wastewater is a typical type of wastewater with high concentrations of organic pollutants, but research on this subject is limited. The aeration tanks of three different pharmaceutical wastewater treatment systems were seeded with the same inocula and stably operated for 40 days. Then, aerobic sludge samples from the three aeration tanks were collected to provide insight into the bacterial community composition of the activated sludges. Additionally, we investigated the effects of wastewater characteristics and the type and operation of the technological system on the microbial communities. High-throughput sequencing analysis demonstrated that the communities enriched in the three reactors had differing. The dominant phyla detected were Proteobacteria, Chloroflexi, Bacteroidetes and candidate division TM7, while the dominant clones were uncultured Candidatus Saccharibacteria bacterium, uncultured Saprospiraceae bacterium, PHOS-HE51(AF314433.1), uncultured Anaerolineaceae bacterium and Blastocatella, suggesting their importance in pharmaceutical wastewater treatment plants. According to the wastewater parameters and canonical correspondence analyses, we can conclude that uncultured Candidatus Saccharibacteria bacterium, uncultured Anaerolineaceae bacterium and Blastocatella contribute to ammonium nitrogen ( ) removal; uncultured Saprospiraceae bacterium plays an important role in treating nitrogen; and chemical oxygen demand and PHOS-HE51 contribute to total phosphorus removal.

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Gibberellin wastewater cannot be directly discharged without treatment due to its high concentrations of sulfate and organic compounds and strong acidity. Therefore, multi-stage anaerobic bioreactor + micro-aerobic+ anoxic/aeration (A/O) + biological contact oxidation combined processes are used to treat gibberellin wastewater. However, knowledge of the treatment effects of the A/O process and bacterial community structure in the aeration tank reactors of such systems is sparse. Therefore, this study was conducted to investigate the treatment effects and operation of the A/O process on gibberellin wastewater, as well as changes in the bacterial community structure of activated sludge in the aeration tank during treatment. Moreover, removal was examined based on evaluation of effluent after A/O treatment. Although influent chemical oxygen demand (COD), NH3-N and total phosphorus (TP) fluctuated, effluent COD, NH3-N and TP remained stable. Moreover, average COD, NH3-N and TP removal efficiency were 68.41%, 93.67% and 45.82%, respectively, during the A/O process. At the phylum level, Proteobacteria was the dominant phylum in all samples, followed by Chloroflexi, Bacteroidetes and Actinobacteria. Proteobacteria played an important role in the removal of organic matter. Chloroflexi was found to be responsible for the degradation of carbohydrates and Bacteroidetes also had been found to be responsible for the degradation of complex organic matters. Actinobacteria are able to degrade a variety of environmental chemicals. Additionally, Anaerolineaceae_uncultured was the major genus in samples collected on May 25, 2015, while Novosphingobium and Nitrospira were dominant in most samples. Nitrosomonas are regarded as the dominant ammonia-oxidizing bacteria, while Nitrospira are the main nitrite-oxidizing bacteria. Bacterial community structure varied considerably with time, and a partial Mantel test showed a highly significant positive correlation between bacterial community structure and DO. The bacterial community structure was also positively correlated with temperature and SO42-.

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The characteristics of thermophilic anaerobic sequencing batch reactor (ASBR) treating thermal-hydrolyzed sewage sludge were investigated. The results showed that increasing the OLR (COD) of the thermophilic ASBR treating thermal-hydrolyzed sewage sludge from 7.762 kg/(m3 x d) to 13.106 kg/(m3 x d) lead to the "acidification" of the reactor with the accumulation of the volatile fatty acid (VFA) and the drop of the pH and gas production. This acidification is recoverability. The OLR(COD) of the thermophilic ASBR treating thermal-hydrolyzed sewage sludge can reach to 10 kg/(m3 x d) after the system was recovered. Under the OLR(COD) of 2.523, 4.196, 7.762 and 10.091 kg/(m3 x d), the methane yield (CH4/COD(input)) of thermophilic ASBR were 250, 247, 219 and 187 mL respectively. There are significant linear relationship among OLR and MPR, the methane yield. With the increase of the OLR, the methane production rate increased while the methane yield reduced.

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Three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM)was applied to characterize the loosely bound extracellular polymeric substances (LB-EPS) and tightly bound extracellular polymeric substances (TB-EPS) extracted from aerobic sludge in wastewater treatment. The results showed that three fluorescence peaks were identified in threedimensional excitation emission matrix fluorescence spectra of the LB-REPS and TB-EPS: peak B (lamda ex/ lamda em = 270-280 nm/345-360 nm), peak C (lamda ex/ lamda em = 330-340 nm/410-430 nm)and peak D (lamda ex/ lamda em = 390 nm/450-470 nm). The peak B was attributed to the protein-like fluorophores, peak C to the visible fulvic-like fluorophore and peak D to the humic-like fluorophore. Results of the peak intensity showed that the major component of the LB-EPS and TB-EPS is protein-like organic matter, then followed by (from high to low): fulvic-like organic matter and humic-like organic matter. The effects of both pH and concentration were significant to the 3DEEMs of LB-EPS and TB-EPS, but the degree is not the same. LB-EPS has the particular chemical structures which are different from the TB-EPS.

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Startup experiment was conducted for thermophilic anaerobic sequencing batch reactor (ASBR) treating thermal-hydrolyzed sewage sludge using the strategy of the step-wise temperature increment: 35 degrees C-->40 degrees C-->47 degrees C-->53 degrees C. The results showed that the first step-increase (from 35 degrees C to 40 degrees C) and final step-increase (from 47 degrees C to 53 degrees C) had only a slight effect on the digestion process. The second step-increase (from 40 degrees C to 47 degrees C) resulted in a severe disturbance: the biogas production, methane content, CODeffluent and microorganism all have strong disturbance. At the steady stage of thermophilic ASBR treating thermal-hydrolyzed sewage sludge, the average daily gas production, methane content, specific methane production (CH4/CODinfluent), TCOD removal rate and SCOD removal rate were 2.038 L/d, 72.0%, 188.8 mL/g, 63.8%, 83.3% respectively. The results of SEM and DGGE indicated that the dominant species are obviously different at early stage and steady stage.

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Fluorescence spectroscopy is widely used to elucidate the origin and structure of organic matters in water substance. Due to its high sensitivity, good selectivity and nondestructive nature, fluorescence technique is suitable to the study of chemical and physical properties of organic matters. Three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) was applied to analyze the effects of organic removal by traditional purification process. The results show that 3DEEM is able to disclosure the changes of organic matters in the treatment processes effectively. Traditional purification process can remove some fulvic-like organic matter, but cannot remove it completely. Coagulant sedimentation basically does not have an effect of fulvic-like organic matter removal. The removal proportion of fulvic-like organic matter through filtration is 5%-15%.