Investigates of substrate mingling ratio and organic loading rate of KOH pretreated corn stover and pig manure in batch and semi-continuous system:Anaerobic digestion performance and microbial characteristics

The effects of substrate mingling ratio(SMR)(1:1,1:2,1:3,3:1,and 2:1)and organic loading rate(OLR)(50-90 g total solids per liter per day)on anaerobic co-digestion performance and microbial characteristics were investigated for pig manure(PM)and pretreated/untreated corn stover in batch and semicontinuous anaerobic digestion(AD)system.The results showed that SMR and pretreatment affected co-digestion performance.The maximum cumulative methane yield of 428.5 ml·g^(-1)(based on volatile solids(VS))was obtained for PCP13,which was 35.7%and 40.0%higher than that of CSU and PM.In the first 5 days,the maximum methane yield improvement rate was 378.1%for PCP13.The daily methane yield per gram VS of PCP13 was 11.4%-18.5%higher than that of PC_(U)13.Clostridium_sensu_stricto_1,DMER64,and Bacteroides and Methanosaeta,Methanobacterium,and Methanospirillum had higher relative abundance at the genus level.Therefore,SMR and OLR are important factor affecting the AD process,and OLR can affect methane production through volatile fatty acids.

Transformation and performance of granular sequence batch reactor under conventional organic loading rate condition

Laboratory experiments were conducted to investigate the transformation and performance of a granular sequence batch reactor(SBR) under the conventional organic loading rate(OLR) condition.Aerobic granules were successfully cultivated in a SBR by means of alternative feeding load combined with reducing settling time after 60 d operational period.Subsequently,the black fungal granules were presented in reactor because of the filamentous overgrowth on the surface of aerobic granules.A small amount of fungal granules had no effect on the performance of granular SBR.Aerobic granules completely vanished and fungal granules eventually became the dominant species in subsequent 90 d operation after granulation.The three-dimensional excitation emission matrix(EEM) spectra result shows that the extracellular polymeric substances(EPS) component in both granules has no much difference,whereas the content of EPS in fungal granules is higher than that in bacterial granules.Due to their low bioactivity,the chemical oxidation demand(COD) and NH4-N removal efficiencies gradually decrease from 90.4%–96.5% and 99.5% to 71.8% and 32.9% respectively while the fungal granules become dominant in the SBR.

Spatiotemporal variations in the organic carbon accumulation rate in mangrove sediments from the Yingluo Bay,China,since 1900

Mangroves can not only provide multiple ecosystem service functions,but are also efficient carbon producers,capturers,and sinks.The estimation of the organic carbon accumulation rate(OCAR)in mangrove sediments is fundamental for elucidating the role of mangroves in the global carbon budget.In particular,understanding the past changes in the OCAR in mangrove sediments is vital for predicting the future role of mangroves in the rapidly changing environment.In this study,three dated sediment cores from interior and fringe of mangroves in the Yingluo Bay,China,were used to reconstruct the spatiotemporal variations of the calculated OCAR since 1900 in this area.The increasing OCAR in the mangrove interior was attributed to mangrove flourishment induced by climate change characterized by the rising temperature.However,in the mangrove fringe,the strengthening hydrodynamic conditions under the sea level rise were responsible for the decreasing OCAR,particularly after the1940 s.Furthermore,the duration of inundation by seawater was the primary factors controlling the spatial variability of the OCAR from the mangrove fringe to interior,while the strengthened hydrodynamic conditions after the 1940 s broke this original pattern.

Selective Area Growth and Characterization of GaN Nanorods Fabricated by Adjusting the Hydrogen Flow Rate and Growth Temperature with Metal Organic Chemical Vapor Deposition

CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposition （MOCVD）. The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2：N2 ratio is 1：1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature.

An in-situ biochar-enhanced anaerobic membrane bioreactor for swine wastewater treatment under various organic loading rates

A biochar-assisted anaerobic membrane bioreactor(BC-AnMBR)was conducted to evaluate the performance in treating swine wastewater with different organic loading rates(OLR)ranging from 0.38 to 1.13 kg-COD/(m3.d).Results indicated that adding spent coffee grounds biochar(SCG-BC)improved the organic removal efficiency compared to the conventional AnMBR,with an overall COD removal rate of>95.01%.Meanwhile,methane production of up to 0.22 LCH4/gCOD with an improvement of 45.45%was achieved under a high OLR of 1.13 kg-COD/(m3.d).Furthermore,the transmembrane pressure(TMP)in the BC-AnMBR system was stable at 4.5 kPa,and no irreversible membrane fouling occurred within 125 days.Microbial community analysis revealed that the addition of SCG-BC increased the relative abundance of autotrophic methanogenic archaea,particularly Methanosarcina(from 0.11%to 11.16%)and Methanothrix(from 16.34%to 24.05%).More importantly,Desulfobacterota and Firmicutes phylum with direct interspecific electron transfer(DIET)capabilities were also enriched with autotrophic methanogens.Analysis of the electron transfer pathway showed that the concentration of c-type cytochromes increased by 38.60%in the presence of SCGBC,and thus facilitated the establishment of DIET and maintained high activity of the elec-tron transfer system even at high OLR.In short,the BC-AnMBR system performs well under various OLR conditions and is stable in the recovery energy system for swine wastewater.

Assessment on Redox Conditions and Organic Burial of Siliciferous Sediments at the Latest Permian Dalong Formation in Shangsi,Sichuan,South China

The redox sensitive elements, molybdenum （Mo） and uranium （U）, in marine sediments from the latest Permian Dalong （大隆） Formation at the Shangsi （上寺） Section, Northeast Sichnan （四川）, South China, were analyzed by inductively coupled plasma mass spectrometry （ICP-MS） to determine their response to a range of redox conditions, and to estimate the organic carbon burial rate. On the basis of the correlation between anthigenic Mo abundance and organic carbon content in modern oceans, the organic carbon burial rates were calculated for the rocks at Dalong Formation, ranging from 0.48-125.83 mmol/（m^2.d）, which shows a larger range than the mineralization rate of organic carbon at the continental margins （1.6-4.23 mmol/（m^2-d））. The Zr-normalized Mo and U abundances show large fluctuations in the entire section. The maxima of Zr-normalized Mo abundance and thus the maxima of the organic carbon burial rates were observed at the interval between the 155th and 156th beds （404-407 m above the base of Middle Permian）. A decrease （the minimum） in U/Mo ratios is present in this interval. It is speculated that the oxygen-limited conditions and ultimately anoxia or euxinia may develop within this depth interval. In contrast, an enhanced enrichment of Zr-normalized U abundance is found, in association with less enrichment in Zr-normalized Mo abundance in the interval from the 151st to 154th beds （395-404 m above the base of Middle Permian）, inferring the dominance of a suboxic/anoxic depositional condition （denitrifying condition）, or without free H2S. The presence of small quantities of dissolved oxygen may have caused the solubilization and loss of Mo from sediments. It is proposed that the multiple cycles of abrupt oxidation and reduction due to the upwelling at this interval lead to the enhanced accumulation of authigenic U, but less enrichment of Mo. A decrease in the contents of U, Mo, and TOC is found above the 157th bed （407 m above the base of Middle Permian）, in association with the enhanced U/Mo ratio, suggesting the overall oxic conditions at the end of the Dalong Formation.

Experimental and modeling study of kinetics for methane hydrate formation in a crude oil-in-water emulsion

A low-viscosity emulsion of crude oil in water can be believed to be the bulk of a flow regime in a pipeline.To differentiate which crude oil would and which would not counter the blockage of flow due to gas hydrate formation in flow channels,varying amount of crude oil in water emulsion without any other extraneous additives has undergone methane gas hydrate formation in an autoclave cell.Crude oil was able to thermodynamically inhibit the gas hydrate formation as observed from its hydrate stability zone.The normalized rate of hydrate formation in the emulsion has been calculated from an illustrative chemical affinity model,which showed a decrease in the methane consumption（decreased normalized rate constant） with an increase in the oil content in the emulsion.Fourier transform infrared spectroscopy（FTIR） of the emulsion and characteristic properties of the crude oil have been used to find the chemical component that could be pivotal in selfinhibitory characteristic of the crude oil collected from Ankleshwar,India,against a situation of clogged flow due to formation of gas hydrate and establish flow assurance.

Effects of Caragana microphylla plantations on organic carbon sequestration in total and labile soil organic carbon fractions in the Horqin Sandy Land, northern China

Afforestation is conducive to soil carbon（C） sequestration in semi-arid regions. However, little is known about the effects of afforestation on sequestrations of total and labile soil organic carbon（SOC） fractions in semi-arid sandy lands. In the present study, we examined the effects of Caragana microphylla Lam. plantations with different ages（12-and 25-year-old） on sequestrations of total SOC as well as labile SOC fractions such as light fraction organic carbon（LFOC） and microbial biomass carbon（MBC）. The analyzed samples were taken from soil depths of 0–5 and 5–15 cm under two shrub-related scenarios： under shrubs and between shrubs with moving sand dunes as control sites in the Horqin Sandy Land of northern China. The results showed that the concentrations and storages of total SOC at soil depths of 0–5 and 5–15 cm were higher in 12-and 25-year-old C. microphylla plantations than in moving sand dunes（i.e., control sites）, with the highest value observed under shrubs in 25-year-old C. microphylla plantations. Furthermore, the concentrations and storages of LFOC and MBC showed similar patterns with those of total SOC at the same soil depth. The 12-year-old C. microphylla plantations had higher percentages of LFOC concentration to SOC concentration and MBC concentration to SOC concentration than the 25-year-old C. microphylla plantations and moving sand dunes at both soil depths. A significant positive correlation existed among SOC, LFOC, and MBC, implying that restoring the total and labile SOC fractions is possible by afforestation with C. microphylla shrubs in the Horqin Sandy Land. At soil depth of 0–15 cm, the accumulation rate of total SOC under shrubs was higher in young C. microphylla plantations（18.53 g C/（m^2·a）; 0–12 years） than in old C. microphylla plantations（16.24 g C/（m^2·a）; 12–25 years）, and the accumulation rates of LFOC and MBC under shrubs and between shrubs were also higher in young C. microphylla plantations than in old C. microphylla plantations. It can be concluded that the establishment of C. microphylla in the Horqin Sandy Land may be a good mitigation strategy for SOC sequestration in the surface soils.

The efficiency of long-term straw return to sequester organic carbon in Northeast China＇s cropland

Black soil is one of the most precious soil resources on earth because it has abundant carbon stocks and a relatively high production capacity. However, decreasing organic matter after land reclamation, and the effects of long-term inputs of organic carbon have made it less fertile black soil in Northeast China. Straw return could be an effective method for improving soil organic carbon（SOC） sequestration in black soils. The objective of this study was to evaluate whether straw return effectively increases SOC sequestration. Long-term field experiments were conducted at three sites in Northeast China with varying latitudes and SOC densities. Study plots were subjected to three treatments： no fertilization（CK）; inorganic fertilization（NPK）; and NPK plus straw return（NPKS）. The results showed that the SOC stocks resulting from NPKS treatment were 4.0 and 5.7% higher than those from NPK treatment at two sites, but straw return did not significantly affect the SOC stocks at the third site. Furthermore, at higher SOC densities, the NPKS treatment resulted in significantly higher soil carbon sequestration rates（CSR） than the NPK treatment. The equilibrium value of the CSR for the NPKS treatment equated to cultivation times of 17, 11, and 8 years at the different sites. Straw return did not significantly increase the SOC stocks in regions with low SOC densities, but did enhance the C pool in regions with high SOC densities. These results show that there is strong regional variation in the effects of straw return on the SOC stocks in black soil in Northeast China. Additional cultivations and fertilization practices should be used when straw return is considered as an approach for the long-term improvement of the soil organic carbon pool.

Performance evaluation of up-flow anaerobic sludge blanket(UASB) reactor for treatment of paper mill wastewater

The present study deals with the performance evaluation of the UASB reactor under varied organic loading rate(OLR) for the treatment of paper mill wastewater. The sludge granulation process started after 120 days from the start-up period. Sludge granules size was found to be 0 8 mm at OLR of 1 72 kgCOD/(m 3·d), which reached maximum size of about 1 0 to 1 2 mm at OLR of 2 1 kgCOD/(m 3·d). At the end of initial OLR of 1 0 kgCOD/(m 3·d) the VSS concentration was 12 86 gVSS/L, which got increased to 38 05 gVSS/L at the end of an OLR 2 1 kgCOD/(m 3·d). Most of the times VFA recorded were well within the limit of VFA reported in anaerobic fermentation process. Many times the pH observed was between 6 5 and 7 8, which is more favorable for any anaerobic process. It is also found that pH within the reactor increases along with the height of reactor. The total maximum biogas production was found to be 0 40 L/gCOD removals at OLR of 2 1 kgCOD/(m 3·d) and the maximum BOD removal at this stage was observed to be 90%.

Anaerobic tapered fluidized bed reactor for starch wastewater treatment and modeling using multilayer perceptron neural network

treatability of synthetic sago wastewater was investigated in a laboratory anaerobic tapered fluidized bed reactor （ATFBR） with a mesoporous granular activated carbon （GAC） as a support material. The experimental protocol was defined to examine the effect of the maximum organic loading rate （OLR）, hydraulic retention time （HRT）, the efficiency of the reactor and to report on its steady- state performance. The reactor was subjected to a steady-state operation over a range of OLR up to 85.44 kg COD/（m^3·d）. The COD removal efficiency was found to be 92% in the reactor while the biogas produced in the digester reached 25.38 m^3/（m^3·d） of the reactor. With the increase of OLR from 83.7 kg COD/（m^3·d）, the COD removal efficiency decreased. Also an artificial neural network （ANN） model using multilayer perceptron （MLP） has been developed for a system of two input variable and five output dependent variables. For the training of the input-output data, the experimental values obtained have been used. The output parameters predicted have been found to be much closer to the corresponding experimental ones and the model was validated for 30% of the untrained data. The mean square error （MSE） was found to be only 0.0146.

Microbial community dynamics at high organic loading rates revealed by pyrosequencing during sugar refinery wastewater treatment in a UASB reactor

The performance and rnicrobial community structure in an upflow anaerobic sludge blanket reactor （UASB） treating sugar refinery wastewater were investigated. The chemical oxygen demand （COD） removal reached above 92.0% at organic loading rates （OLRs） of 12.0-54.0 kgCOD/（m^3· d）. The volatile lhtty acids （VFAs） in effluent were increased to 451.1 mg/L from 147.9 mg/L and the specific methane production rate improved by 1.2 2.2-1bid as the OLR increased. The evolution of microbial comnmnities in anaerobic sludge at three different OLRs was investigated using pyrosequencing. Operational taxonomic units （OTUs） at a 3% distance were 353,337 and 233 for OLRI2, OLR36 and OLR54, respectively. When the OLR was increased to 54.0 kgCOD/（m^3· d） from 12.0 kgCOD/ （m^3· d） by stepwise, the microbial community structure were changed significantly. Five genera （Bacteroides, Trichococcus, Cho,seobacterium, Longilinea and Aerococcus） were the dominant fermentative bacteria at the OLR 12-0 kgCOD/（m^3· d）. However, the sample of OLR36 was dominated by Lacmcoccus, Trichococcus, Anaer-arcus and Veillonella. At the last stage （OLR = 54.0 kgCOD/ （m^3· d）, the diversity and percentage of femlentative bacteria were markedly increased. Apart from fermentative bacteria, an obvious shift was observed in hydrogen-producing acetogens and non- acetotrophic methanogens as OLR increased. Svntrophohacter, Geobacter and Methanomethylovor- ans were the dominant hydrogen-producing acetogens and methylotrophic methanogens in the samples of OLRI2 and OLR36. When the OLR was increased to 54.0 kgCOD/（m^3· d）, the mare hydrogen-producing acetogens and hydrogenotrophic methanogens were substituted with Destd/bvi- brio and Methanospillum. However, the composition of acetotrophic methanogens （Methanosaeta） was relatively stable during the whole operation period of the UASB reactor.

Three controllable factors of steady operation of EGSB reactor

The bench-scale EGSB (expanded granular sludge bed) reactor was operated to study the effect of sludge loading rate, pH value and nutrient element on the operation of the EGSB reactor and the control rule of these factors. Continuous flow was used to treat synthetic wastewater containing dextrose and beer, and the temperature of reactor was controlled at mesophiles temperature (33 ℃). The experimental results demonstrated that the proper sludge loading rate was 0.9-1.42 kg COD/(kg VSS·d); the pH value in the reactor was controlled by adding sodium bicarbonate, the proper additive quantity was 1000-1200 mg/L; the additive quantity of nutrient element was as follows: 41.3 mg/(SS·d) of FeCl2·4H2O, 4.3 mg/(SS·d) of CoCl2·6H2O, 8.2 mg/(SS·d) of NiCl2·6H2O, 7.5-13 mg/(SS·d) of CaCO3,and 56.7-22.7 mg/(SS·d) of 7Na2S·9H2O, respectively. When these parameters were properly determined, the EGSB reactor could treat wastewater with 400-5000 mg/L COD concentration. The COD removal efficiency was over 85%. The operation of the EGSB reactor was steady and the EGSB reactor had strong anti-shock load ability.

Rgwo performances of submerged membrane bioreactor treating brewery wastewater: A laboratory study

Performances of submerged membrane bioreactor （SMBR） treating brewery wastewater were investigated in this study. With little variation of COD：TN：TP ratio （100：5：1） in influent, SMBR showed high removal efficiency （ 〉 90% ） for both COD and NH4^＋ - N, and it also showed a strong resistive ability for shock organics loading rate, evidenced by no obvious fluctuation for COD in the effluent when the organics loading rate suddenly increased from 0. 27 g/（ gMLSS · d） to 0. 54 g/（ gMLSS · d）. Comparatively different with the COD removal, TN and TP removal showed a strong correlation with the growth stage of the sludge in SMBR. When the sludge was in the multiplication stage, about 45% of TN was removed and an average removal efficiency of 30% for TP was also observed. However, when the activated sludge was in the steady stage, the removal efficiency for TN decreased to about 30% , whereas, the removal efficiency for TP was very low, and sometimes even below zero. The results of GC/MS indicated that the residual organic matters in the effluent were mainly alkyl hydrocarbon with high molecular weight, and coupling with the results of electroseopic scanning, it is speculated that biomass formed at external and internal membrane fibers played an important role for the removal of small organics.

Treatment of Chinese traditional medicine wastewater in a submerged membrane bioreactor

A pilot scale test was conducted in a submerged membrane bioreactor SMBR with capacity of 10. 0 m^3/d for 120 days to treat high-strength Chinese traditional medicine wastewater. Performance of the SMBR was investigated with a sludge retention time （ TSR ） of 50 days, a hydraulic retention time （ THR ） of 8.0 h, membrane flux of 8. 0 IV（ m^2 · h） and dissolved oxygen （DO） concentration of 2. 0 - 3. 0 mg/L, respectively. It was observed that the SMBR had high capacity of COD and suspended solid （SS） removal. The influent COD concentration was fluctuated between I 000 and 5 000 mg/L, while the averaged effluent COl） concentration was only 44. 6 mg/L. The influent SS concentration was fluctuated between 1 000 and 1 600 mg/L, while little effluent SS was detected. It was found that the COD remove rate increased with mixed liquor suspended solids （MLSS） and organic loading rate （ROL）. In order to obtain good-quality effluent, the operational conditions of the SMBR were suggested as follows： the temperature was controlled above 10 ℃, MLSS about 7000 mg/L, R,L under 24. 76 kg/（ m^3 · d）, low vacuum value and constant water flux.

Organic matter and pH affect the analysis efficiency of (31)P-NMR

Solution ^（31）P nuclear magnetic resonance spectroscopy（ ^（31）P-NMR） is a useful method to analyze organic phosphorus（Po）, but a general procedure for the analysis method is lacking.The authors used solution ^（31）P-NMR, which was found to be an effective method for analysis of Po in Haihe River sediment, to analyze the Po in the surface sediment in Eastern China at the regional scale, and found that the Na OH-ethylenediaminetetraacetic acid（EDTA）extraction rate was affected by environmental factors. At the regional scale, the extraction rate showed a positive relationship with loss on ignition, when the extraction rate was lower than 60%. The extraction rate had no relationship with the loss on ignition when the extraction rate was higher than 60%. The extraction rate showed a negative relationship with p H, which means that the extraction rate was higher in acidic sediment and lower in alkaline sediment. The ratio of TC/TN（the ratio of total carbon to total nitrogen） was considered to represent the origin of organic matter in the sediment. The extraction rate was high when the TC/TN ratio was lower than 20, meanwhile the extraction rate decreased as the TC/TN ratio increased. The results show that the origin of organic matter in sediment significantly affects the Na OH-EDTA extraction rate. This study will give theoretical support for building an effective and general solution ^（31）P-NMR analysis method.

Pre-treatment of mscanthus sinensis with Bacta-sile to aid anaerobic digestion

The investigation of the biodegradability and methane potential of bacterial pre-treated miscanthus sinensis has been carried out.One percent solution of Bacta-sile:A silage promoter was used to pre-treat miscanthus sinensis at 25℃.The anaerobic digestion experiments were carried out at 25℃ and 35℃ in batch experiments.The organic loading rates(OLR)varied between 1.25 g and 7 g in different batch reactors.The results showed that the highest methane concentration was 57% from digester 1 while the lowest methane produced was 38% from digester 3.The low methane production from digester 3 was attributed to temperature changes and poor organic loading rate.Bacterial pretreatment aided biodegradation of miscanthus at 25℃.Operating temperature of 25℃ had a great effect on digestion experiments resulting to longer required Hydraulic Retention Time(HRT).

Larger floods reduce soil CO_(2)efflux during the post-flooding phase in seasonally flooded forests of Western Amazonia

Seasonally flooded várzea forests of Western Amazonia are one of the most productive and biodiverse wetland forests in the world.However,data on their soil CO_(2)emissions,soil organic matter decomposition rates,and soil C stocks are scarce.This is a concern because hydrological changes are predicted to lead to increases in the height,extent,and duration of seasonal floods,which are likely to have a significant effect on soil C stocks and fluxes.However,with no empirical data,the impact of altered flood regimes on várzea soil C cycles remains uncertain.This study quantified the effects of maximum annual flood height and soil moisture on soil CO_(2)efflux rate(R_(s))and soil organic matter decomposition rate(k)in the várzea forests of Pacaya Samiria National Reserve,Peru.The study was conducted between May and August 2017.The results showed that R_(s)(10.6–182.7 mg C m^(-2)h^(-1))and k(0.016–0.078)varied between and within sites,and were considerably lower than the values reported for other tropical forests.In addition,R_(s)was negatively affected by flood height(P<0.01)and soil moisture(P<0.001),and it decreased with decreasing river levels post flooding(P<0.001).In contrast,k was not affected by any of the above-mentioned factors.Soil moisture was the dominant factor influencing R_(s),and it was significantly affected by maximum flood height,even after the floods had subsided(P<0.001).Consequently,we concluded that larger floods will likely lead to reduced R_(s),whilst k could remain unchanged but with decomposition processes becoming more anaerobic.

Catalytic removal of phenol from gas streams by perovskite-type catalysts

Three perovskite-type catalysts prepared by citric acid method are applied to remove phenol from gas streams with the total flow rate of 300 mL/min, corresponding to a GHSV of 10,000/hr. LaMnO3 catalyst is first prepared and further partially substituted with Sr and Cu to prepare Lao.sSro.2MnO3 and Lao.sSro.2Mno.sCuo.203, and catalytic activities and fundamen- tal characteristics of these three catalysts are compared. The results show that phenol removal efficiency achieved with Lao.sSro.2Mno.sCuo.203 reaches 100% with the operating temperature of 200℃ and the rate of mineralization at 300℃ is up to 100%, while the phenol removal efficiencies achieved with Lao.sSro.2MnO3 and LaMnO3 are up to 100% with the operating temperature of 300℃ and 400℃, respectively. X-ray photoelectron spectroscopy （XPS） analysis shows that the addition of Sr and Cu increases the lattice oxygen of Lao.sSro.2Mno.sCuo.203, and further increases mobility or availability of lattice oxygen. The results indicate that Lao.sSro.2Mno.sCuo.203 has the best activity for phenol removal among three catalysts prepared and the catalytic activity of phenol oxidation is enhanced by the introduction of Sr and Cu into LaMnO3. Apparent activation energy of 48 kJ/mol is calculated by Mars-Van Krevelen Model for phenol oxidation with Lao.sSro.2Mno.sCuo.203 as catalyst.

Application of high OLR-fed aerobic granules for the treatment of low-strength wastewater: Performance, granule morphology and microbial community

Aerobic granules, pre-cultivated at the organic loading rate （OLR） of 3.0 kg COD/（m3 ·day）, were used to treat low-strength wastewater in two sequencing batch reactors at low OLRs of 1.2 and 0.6 kg COD/（m3 ·day）, respectively. Reactor performance, evolution of granule morphology, structure and microbial community at low OLRs under long-term operation （130 days） were investigated. Results showed that low OLRs did not cause significant damage to granule structure as a dominant granule morphology with size over 540 μm was maintained throughout the operation. Aerobic granules at sizes of about 750 μm were finally obtained at the low OLRs. The granule reactors operated at low OLRs demonstrated effective COD and ammonia removals （above 90%）, smaller granule sizes and less biomass. The contents of extracellular polymeric substances in the granules were decreased while the ratios of exopolysaccharide/exoprotein were increased （above 1.0）. The granules cultivated at the low OLRs showed a smoother surface and more compact structure than the seeded granules. A significant shift in microbial community was observed but the microbial diversity remained relatively stable. Confocal Laser Scanning Microscopy observation showed that the live cells were spread throughout the whole granule, while the dead cells were mainly concentrated in the outer layer of the granule, and the proteins, polysaccharides and lipids were mainly located in the central regime of the granule. In conclusion, granules cultivated at high OLRs show potential for treating low-strength organic wastewater steadily under long-term operation.