The influence of nitrified supernate’s recycle ratio on the removal of coking wastewater

The influence of the recycle ratio on the removal of coking wastewater has been researched using the anaerobicanoxic-aerobic （A/A/O） biofilm process. The research indicates that the concentrations of chemical oxygen demand （COD） and NO3 -N in the water are the lowest when the recycle ratio is 3：1 ,but the removal efficiency of total cyanide （TCN） is the highest when the recycle ratio is 1： 1. The removal efficiency of NH4^＋ -N is more than 99% at all three different recycle ratios. Compared with Grade A of the National Discharge Standard （GB 8978--1996）, the effluent NH4 -N is standard,but COD and TCN can not meet the requirements and further treatment processes are needed.

Quantitative estimation of social stock for metals Al and Cu in China

Social stock for metal determines secondary or recoverable resources to a certain extent.Top-down analysis method for the studying of metal in social stock was given.Influences of metal consumption under three circumstances,that is keeping constant,varying in a linear trend and in an exponential trend,on one kind of metal’s social stock,recyclable ratio and average age were analyzed.Al-contents and Cu-contents in social stock for China during the period 2006-2009 were calculated.The results reveal that Al-contents and Cu-contents in social stock kept increasing and reached 88.9 million tons and 51.4 millions tons in 2009,respectively,their average recyclable ratios are 1.45% and 0.30%,and the average ages are 4.65 years and 6.89 years,respectively.The recyclable ratios and average ages of Al-contents and Cu-contents in social stock will rise in future along with the decline of the increasing rate of aluminum consumption and copper consumption.

Quantifying the Spatial Characteristics of the Moisture Transport Affecting Precipitation Seasonality and Recycling Variability in Central Asia

Moisture contribution and transport pathways for Central Asia(CA)are quantitatively examined using the Lagrangian water cycle model based on reanalysis and observational data to explain the precipitation seasonality and the moisture transport variation during 1979-2015.Westerly-related(northwesterly and westerly)transport explains 42%of CA precipitation and dominates in southwest CA,where precipitation is greatest in the cold season.Southeast CA,including part of Northwest China,experiences its maximum precipitation in the warm season and is solely dominated by southerly transport,which explains about 48%of CA precipitation.The remaining 10%of CA precipitation is explained by northerly transport,which steadily impacts north CA and causes a maximum in precipitation in the warm season.Most CA areas are exposed to seasonally varying moisture transport,except for southeast and north CA,which are impacted by southerly and northerly transport year-round.In general,the midlatitude westerlies-driven transport and the Indian monsoon-driven southerly-related transport explain most of the spatial differences in precipitation seasonality over CA.Moreover,the contribution ratio of local evaporation in CA to precipitation exhibits significant interdecadal variability and a meridionally oriented tripole of moisture transport anomalies.Since the early 2000s,CA has experienced a decade of anomalously low local moisture contribution,which seems jointly determined by the weakened moisture contribution from midlatitudes(the Atlantic,Europe,and CA itself)and the enhanced contribution from high latitudes(West Siberia and the Arctic)and tropical areas(South Asia and the Indian Ocean).

A research of material input and environmental impact for Chinese economy:1990-2005

The process of economic activities is on the basis of tremendous material inputs.China has been discharging an enormous amount of waste,giving rise to a wide range of environmental impacts.The method of economy-wide material flow analysis(EW-MFA)is one of the effective tools to examine the flow of materials entering physical economies,and recognize early environmental problems.Relevant researches are still at the early stage in China and most focus on material throughput but are rarely concerned about the utilization of recycling resource and environmental impact.Based on more than 3,000 items of data related,materials entering Chinese economy are classified into three types,and then the characteristics of material input and environmental impact are presented for the years 1990-2005 by using the indicators derived from EW-MFA.The Ratio of Recycled Material(RRM) is added as the new indicator in order to be in accordance with the need of circular economy being promoted in China.Results show that the great changes in the structure of material input cause the continuous increase of industrial solid waste emissions and the bogging down of material productivity.The RRM reveals that the utilization of recycling resources remains at a fairly low level in China.Finally,some weakness of EW-MFA is discussed according to the calculated results.

Stress-strain relationship of recycled self-compacting concrete filled steel tubular column subjected to eccentric compression

As a typical compression member,the concrete-filled steel tube has been widely used in civil engineering structures.However,little research on recycled self-compacting concrete flled circular steel tubular(RSCCFCST)columns subjected to eccentric load was reported.In this study,21 specimens were designed and experimental studies on the stress-strain relationship of were carried out to study the mechanical behaviors.Recycled coarse aggregate replacement ratio,concrete strength grade,length to diameter ratio and eccentric distance of specimens were considered as the main experimental parameters to carry out eccentric compression tests.The corresponding stress-strain relationship curves were used to analyze the influence of concerned parameters on ecentric load-bearing capacity of RSCCFCST columns.The experimental results show that the strain of the eccentric compression stress-strain curves increase with the increase of recycled coarse aggregate replacement ratio and concrete strength grade.With increase of eccentric distance,the ductility of specimens increases while the bearing capacity decreases.Moreover,a phenomenological model of RSCCFCST columns is proposed,which exhibits versatile ability to capture the process during loading.The present study is expected to further understanding the behaviors and to provide guidance of RSCCFCST columns in design and engineering applications.

Combined effects of volume ratio and nitrate recycling ratio on nutrient removal,sludge characteristic and microbial evolution for DPR optimization

The optimization of volume ratio(V_(An)/V_(A)/V_(0))and nitrate recycling ratio(R)in a two-sludge denitrifying phosphorus removal(DPR)process of Anaerobic Anoxic Oxic-Moving Bed Biofilm Reactor(A^(2)/O-MBBR)was investigated.The results showed that prolonged anaerobic retention time(HRT An:1.25→3.75 hr)exerted favorable effect on chemical oxygen demand(COD)removal(57.26%→73.54%),poly-β-hydroxyalkanoates(PHA)synthesis(105.70→138.12 mg COD/L)and PO_(4)^(3-)release(22.3→38.9 mg/L).However,anoxic retention time(HRT A)and R exhibited positive correlation with PHA utilization(43.87%-81.34%)and denitrifying phosphorus removal(DPR)potential(NO_(3)-/PO^(3-)_(4):0.57-1.34 mg/mg),leading to dramatical TN removal variations from 68.86%to 81.28%.Under the V An/V A/V O ratio of 2:6:0,sludge loss deteriorated nutrient removals but the sludge bioactivity quickly recovered when the oxic zone was recovered.The sludge characteristic and microstructure gradually transformed under the dissolved oxygen(DO)control(1.0-1.5→1.5-2.0 mg/L),in terms of sludge volume index(SVI:194→57 m L/g VSS),median-particle-size(D 50:99.6→300.5μm),extracellular polymeric substances(EPS)(105.62→226.18 mg/g VSS)and proteins/polysaccharides(PN/PS)ratio(1.52→3.46).Fluorescence in situ hybridization(FISH)results showed that phosphorus accumulation organisms(PAOs)(mainly Cluster I of Accumulibacter,contribution ratio:91.79%-94.10%)dominated the superior DPR performance,while glycogen accumulating organisms(GAOs)(mainly Competibacter,contribution ratio:82.61%-86.89%)was responsible for deteriorative TN and PO_(4)^(3-)removals.The optimal HRT A and R assembled around 5-6.5 hr and 300%-400%based on the PHA utilization and DRP performance,and the oxic zones also contributed to PO_(4)^(3-)removal although it showed low dependence on DO concentration and oxic retention time(HRT_(0)).

Contributions of Local and Remote Atmospheric Moisture Fluxes to East China Precipitation Estimated from CRA-40 Reanalysis

China Meteorological Administration(CMA) recently released its 40-yr(1979–2018) global Chinese reanalysis(CRA-40) dataset. To assess performance of the CRA-40 data in quantifying the regional water cycle, contributions of local and remote atmospheric moisture fluxes to precipitation in East China derived from CRA-40 are compared with those derived from the ECMWF reanalysis version 5(ERA-5). Observed precipitation and evaporation data are also used for validation. As for mean precipitation, CRA-40 matches the observation better in winter and spring than in summer, with a larger wet bias(1.41 mm day^(-1)) in summer than that in ERA-5(0.97 mm day^(-1)), particularly over South China. The conservation of atmospheric water vapor over East China measured by CRA-40 is comparable to that of ERA-5. Both reanalyses show a dominant role of the remote moisture transport in the East China precipitation.In comparison, the annual precipitation induced by the moisture influx from the west of the study domain in CRA-40 is 80 mm less than that in ERA-5. The recycling ratio of annual mean precipitation in CRA-40 is approximately21.1%, slightly larger than that in ERA-5(20.1%). The maximum difference of each hydrological component between the two datasets appears in the summer horizontal moisture influx(3.57 ×10^(7) kg s^(-1);ERA-5 is larger) and winter runoff(1.84 ×10^(7) kg s^(-1);CRA-40 is larger). CRA-40 shows better performance than ERA-5 in capturing the interannual variability of precipitation over East China, as evinced by a higher correlation coefficient with the observation(0.77 versus 0.33). The trend of summer precipitation since 2011 is better reproduced in CRA-40. Both reanalyses show prominent contribution of the southern moisture influx to the interannual variation of precipitation. This study demonstrates the reliability of CRA-40 in representing the hydrological cycle over East China and provides a useful reference for future application of CRA-40 in water cycle studies.

NUMERICAL SIMULATIONS OF EFFECTS OF LAND SURFACE PROCESSES ON CLIMATE——IMPLEMENTING OF SSiB IN IAP/LASG AGCM AND ITS PERFORMANCE

This is an investigation of exchanges of energy and water between the atmosphere and the vegetated continents,and the impact of and mechanisms for land surface-atmosphere interactions on hydrological cycle and general circulation by implementing the Simplified Simple Biosphere (SSiB)model in a modified version of IAP/LASG global spectral general model(L9R15 AGCM). This study reveals that the SSiB model produces a better partitioning of the land surface heat and moisture fluxes and its diurnal variations,and also gives the transport of energy and water among atmosphere,vegetation and soil explicitly and realistically.Thus the coupled SSiB-AGCM runs lead to the more conspicuous improvement in the simulated circulation,precipitation,mean water vapor content and its transport.particularly in the Asian monsoon region in the real world than CTL-AGCM runs.It is also pointed out that both the implementation of land surface parameterizations and the variations in land surface into the GOALS model have greatly improved hydrological balance over continents and have a significant impact on the simulated climate. particularly over the massive continents. Improved precipitation recycling model was employed to verify the mechanisms for land surface hydrology parameterizations on hydrological cycle and precipitation climatology in AGCM. It can be argued that the recycling precipitation rate is significantly reduced,particularly in the arid and semi-arid region of the boreal summer hemisphere,coincident with remarkable reduction in evapotranspiration over the continental area.Therefore the coupled SSiB-AGCM runs reduce the bias of too much precipitation over land surface in most AGCMs,thereby bringing the simulated precipitation closer to observations in many continental regions of the world than CTL-AGCM runs.