Dry reusing and wet reclaiming of used sodium silicate sand

Based on the characteristics of used sodium silicate sand and the different use requirements for recycled sand, "dry reusing and wet reclaiming of used sodium silicate sand" is considered as the most suitable technique for the used sand. When the recycled sand is used as support sand, the used sand is only reused by dry process including breaking, screening, dust-removal, etc., and it is not necessary that the used sand is reclaimed with strongly rubbing and scraping method, but when the recycled sand is used as facing sand (or single sand), the used sand must be reclaimed by wet method for higher removal rate of the residual binders. The characteristics and the properties of the dry reused sand are compared with the wet reclaimed sand after combining the different use requirements of support sand and facing sand (or single sand), and above the most adaptive scheme has also been validated.

Reclaiming the Future

Built on land taken from the Atlantic Ocean,Nigeria’s ambitious new ultramodern megacity could set the tone for the country to regain its African economic powerhouse status

Amine reclaiming technologies in post-combustion carbon dioxide capture

Amine scrubbing is the most developed technology for carbon dioxide（CO2） capture.Degradation of amine solvents due to the presence of high levels of oxygen and other impurities in flue gas causes increasing costs and deterioration in long term performance,and therefore purification of the solvents is needed to overcome these problems. This review presents the reclaiming of amine solvents used for post combustion CO2capture（PCC）. Thermal reclaiming, ion exchange, and electrodialysis, although principally developed for sour gas sweetening, have also been tested for CO2 capture from flue gas.The three technologies all have their strengths and weaknesses, and further development is needed to reduce energy usage and costs. An expected future trend for amine reclamation is to focus on process integration of the current reclaiming technologies into the PCC process in order to drive down costs.

How do inundation provoke the release of phosphorus in soil-originated sediment due to nitrogen reduction after reclaiming lake from polder

Different N and P fractions inmicrocosm incubation experiment was measured using highresolution in-situ Peeper and DGT techniques combining with sequential extraction procedure.The results showed the synchronous desorption and release of PO_(4)^(3-),S^(2-)and Fe^(2+)from the solid soil-originated sediment.This trend indicated that the significant reduction of Fe-P and SO_(4)^(2-) occurred in the pore water during the inundation.The concentrations of PO_(4)^(3-) in the overlying water and pore water increased to more than 0.1 and 0.2 mg/L at the beginning of the incubation experiment.Decreased NO_(3)^(-) concentrations from more than 1.5 mg/L to less than 0.5 mg/L combining with increasing NH^(4+) concentrations from less than 1mg/L tomore than 5 mg/L suggested the remarkable NO_(3)-reduction via dissimilatory nitrate reduction to ammonia(DNRA)pathway over time.High NH^(4+) concentrations in the pore water aggravated the release of Fe^(2+) through reduction of Fe(Ⅲ)-P as electric acceptors under anaerobic conditions.This process further stimulated the remarkable releasing of labile PO_(4)^(3-) from the solid phase to the solution and potential diffusion into overlying water.Additionally,high S^(2-) concentration at deeper layer indicated the reduction and releasing of S^(2-)from oxidation states,which can stimulated the NO_(3)^(-)reduction and the accumulation of NH^(4+)in the pore water.This process can also provoke the reduction of Fe-P as electric acceptors following the release of labile PO_(4)^(3-)into pore water.Generally,inundation potentially facilitate the desorption of labile P and attention should be paid during the reclaiming lake from polder.

Reclaiming the Roads

I live in an apartment block at a busy intersecting crossroads of Chegongzhuang Road, west Beijing, and recently have noted my

Selective adsorption of tetracycline by β-CD-immobilized sodium alginate aerogel coupled with ultrafiltration for reclaimed water

In this work,a novel composite material based on β-cyclodextrin-immobilized sodium alginate aerogel(β-CD/NaAlg) was developed utilizing cross-linker of epichlorohydrin and applied as an adsorbent to remove tetracycline antibiotics from reclaimed wastewater.A series of characterizations were utilized to confirm the successful synthesis of the adsorbent and this β-CD/NaAlg presented a three-dimensional network at the nanoscale or microscale.Under optimal conditions(pH=4,t=8 h,β-CD:NaAlg=9,adsorbent dosage = 1.5 g·L-1),the maximum removal rate of β-CD/NaAlg to tetracycline was 70%.The adsorption behavior of tetracycline on β-CD/NaAlg conformed to the Freundlich isotherm model(R2=0.9977) and the pseudo-second-order kinetic model(R^(2)=0.9993).Moreover,the adsorbent still removed 55.3% of tetracycline after five cycles.Specially,the adsorbent was integrated with ultrafiltration to adsorb tetracycline antibiotics from simulated reclaimed wastewater,and the removal rate of tetracycline reached 78.9% within 2 h.The existence of Cr(Ⅵ) had a negligible impact on tetracycline removal,while the presence of humic acid exhibited a promoting effect.The possible adsorption mechanisms were also elucidated through X-ray photoelectron spectroscopy and density functional theory analysis.In summary,β-CD/NaAlg represents an environmentally friendly,efficient,and sustainable adsorbent for removing tetracycline antibiotics from reclaimed water.

Performance evaluation and chemical property analysis of RWMA binders with 100% artificial reclaimed asphalt

The performance evaluation and chemical property analysis of the recycled warm mix asphalt （RWMA） binders containing 100% artificial reclaimed asphalt （ RA） are presented, and the combined effects of different percentages of the rejuvenator and warm mix additive （WMA） additives on RWMA binders are analyzed through laboratory tests. Three types of WMA additives ad one commercial rejuvenator named GST were selected to restore the artificial RA. The laboratory performace tests including the penetration test, softening test ad rotary, viscosity （RV） test were carried out. In addition, the Fourier transform infrared spectroscopy （FTIR） test was performed to explore the chemical property of RWMA binders. The results of the performance tests indicate that the rejuvenator GST has the ability to restore the artificial RA; choosing the optimum content of WMA additives and rejuvenator is the key to restoring 100% artificial RA, since the combined effects of them play an important role in determining the basic laboratory performance of RWMA binders. The FTIR tests show that the process of recycling mainly adjusts the chemical component of aged asphalt and no remarkable change is observed in the FTI1R spectra of RWMA binders in terms of chemical functional groups with the introduction of WMA additives.

Influence of Reclamation Works on the Marine Environment in a Semi-Enclosed Bay

The flow and seawater exchange rates have been predicted using a two-dimensional numerical model and a Lagrangian method for a semi-enclosed shallow bay where reclaiming and dredging works are scheduled. The wind effect on the flow and material transport has been emphasized, and a thirty-year mean value of wind has been considered in the numerical simulation. As a whole, even after the reclaiming and dredging are conducted, the flow pattern looks similar to the original state. However, velocity variations up to 20% to 100% appear in the vicinity of the construction area. In the case of summcr wind forcing, the seawater exchange rate increases from 71.6% to 82.9% after the reclaiming and dredging, as indicated by a particle-tracking method. On the contrary, in the case of winter wind forcing, thc seawater cxchange rate appears to be 97.2% under natural conditions but decrcases slightly to 93.2% aftcr the rcclaiming and dredging. Thus, the wind forcing plays an important role in controlling the seawater exchangc rates. The seawater cxchange rate is further improved by 15% if the dredging is simultaneously carried out with the reclaiming. This suggests that the dredging can be an effective means to mitigate the variation of flow.

An investigation of oxygen pressure acid leaching of Gacun complex Cu-Pb bulk concentrate

The treatment of the Gacun complex Cu-Pb bulk concentrate with high Zn,Ag,etc.,by oxygen pressure acid leaching was studied.The pri-mary copper and leadminerals in the concentrate are tetrahedrite and galena.The treatment of tetrahedrite was rarely studied,and most of silver occurred in themineral too.The optimum operating parameters of oxygen pressure acid leaching were established by conditional tests.Under these parameters,the result of pilot scale test showed that the leaching percentages of copper and zinc were separately as high as 98.9 wt.% and 94.9 wt.%,while lead and silver were transformed into sulfate and sulfide precipitations,respectively.The copper and zinc in lixivium were reclaimed by extraction-electrowinning and purification-electrowinning,respectively,and the lead and silver in the residue were reclaimed separately by carbonate transformation-silicofluoric acid leaching and thiourea leaching.

美国区域排污权交易市场“RECLAIM计划”的经验及启示

美国是最早实践排污权交易政策的国家,在南加州地区实施的区域排污权交易市场"RECLAIM计划",通过激励固定源NO_x和SO_x持续减排,最终实现空气质量改善,形成了完善的交易机制和政策体系。RECLAIM计划在政策目标设定、管理对象纳入标准、削减目标制定、初始配额分配、交易市场运行机制、监测数据核查以及排污许可证制度保障等方面进行详细规定和论证,对我国排污权交易市场的优化具有重要借鉴意义。基于此,提出建立区域排污权交易市场、制定科学的排污权交易政策内容、颁发区域固定源排污许可证等对策建议。

Impacts of Irrigation with Reclaimed Water on Endophytic Bacteria in Chinese Cabbage in Urumqi City

[Objective] This study aimed to investigate the feasibility of agricultural irri- gation with reclaimed water in Urumqi City. [Method] Chinese cabbages were used as experimental materials and irrigated with control water, 50% reclaimed water and 100% reclaimed water, and then the number of endophytic bacteria in Chinese cab- bages was measured. [Result] Using 50% reclaimed water, the fresh weight of Chi- nese cabbage was improved by 68.94%; however, with the deepening internalization of exogenous microorganism internalization, the total number of endophytic bacteria and coliform flock in Chinese cabbages treated with 50% reclaimed water was sig- nificantly higher than the other two treatment groups （P〈0.05）. [Conclusion] Re- claimed water enhances both the weight of Chinese cabbage and the number of endophytic bacteria, which is unsuitable for irrigation of edible crops such as Chi- nese cabbage. Strengthening disinfection during the process of sewerage treatment could solve this problem.

Oxygen pressure acid leaching of Gacun complex Cu concentrates

The treatment of the Gacun complex Cu concentrate with high contents of Pb,Zn,Ag,etc by oxygen pressure acid leaching was studied.It is unusual that tetrahedrite,whose treatment was rarely studied,is the primary copper mineral of the concentrates.Most of silver also occurs in the mineral.The optimum operating parameters of oxygen pressure acid leaching were established by conditional tests.Pilot scale test was carried out under the parameters,and the leaching rates of copper and zinc are as high as 97.10% and 89.83% while lead and silver are transformed into sulfate and sulfide respectively and stay in leaching residue.The copper and zinc in lixivium were reclaimed by extraction-electrowinning and purification-electrowinning,respectively,and the lead and silver in the residue were reclaimed separately by chloride leaching and thiourea leaching.The extraction rate of copper achieves 96%,and the leaching rates of lead and silver reach 90% and 95%,respectively.

Dynamic Analysis and Dimensional Synthesis of Easy-to-Protect Large-Load Robot for Extracting Fermented Grains

To improve the operation situation of difficulty and low efficiency in the extraction of fermented grains(FG),a high-load and large-workspace reclaiming robot for ceramic cylinder fermentation is designed,and a reclaiming effector is designed according to the operating characteristics.Firstly,the kinematics and singularity of the mechanism are analyzed.A multi-domain polar coordinate search method is proposed to obtain the workspace and the volume of the mechanism.Secondly,the dynamic modeling is completed and the example simulation is carried out.Thirdly,the motion-force transmission index of the mechanism is established.And based on the global transmissibility and the good-transmission workspace,the dimensional synthesis of the driving mechanism is completed by using the performance atlas-based method.Finally,aiming at the regular workspace size,stiffness and loading capacity,the Pareto optimal solution set of the executive mechanism dimension is obtained by using the multi-objective particle swarm optimization(MOPSO)algorithm.This paper can provide a theoretical basis for the optimal design and control of FG reclaiming robot.

Ecological Technologies of Applying Plants on Glass Curtain Walls

Integrated landscaping technology of reclaiming condensed water from the thermal channel of double-pane glass curtain wall and applying the reclaimed water in micro irrigation of natural plants was explored.Selection of plant species for the internal space of glass curtain wall and vertical greening outside was studied to meet the ecological technological requirements of glass curtain wall.Progressive experiment of new technology and simulated calculation of indexes were applied to obtain solar radiation consumption,meet the ecological characters of plants in glass curtain walls,and finally improve indoor and outdoor thermal environment.The results showed that new ecological technologies of applying plants on glass curtain walls help realize ecological utilization of glass curtain walls,further reduce energy consumption of buildings,achieve and even surpass the standards of national 3-star green buildings.

一种排污权初始分配结构设计框架

作为一种新型环境政策,排污权交易在美国已经成功地演进为总量控制型排污权交易,这被认为是最接近市场经济的环境管理手段。在国内,排污权交易也日益受到政府的重视。自1988年以来,中国的许多地方都先后试点了排污权交易,但多停留在补偿政策,很少有关于总量控制型排污权交易的尝试。在政策设计的技术层面,造成这种状况的一个主要原因是缺乏有效的排污权初始分配结构设计框架。为此,在区域清洁激励市场计划排污权初始分配结构的基础上,针对渐进式减排战略指导下的总量控制型排污权交易计划,分纵向结构设计和横向结构设计两部分,提出了一种具有通用性的排污权初始分配结构设计框架。这有助于合理进行排污权初始分配。

Effect of heavy metals on soil microbial activity and diversity in a reclaimed mining wasteland of red soil area

The microbial biomass, basal respiration and substrate utilization pattern in copper mining wasteland of red soil area, southern China, were investigated. The results indicated that soil microflora were obviously different compared with that of the non-mine soil. Microbial biomass and basal respiration were negatively affected by the elevated heavy metal levels. Two important microbial ecophysiological parameters, namely, the ratio of microbial biomass C（ Cmic ）/organic C（ Corg ） and metabolic quotient（qCO2 ） were closely correlated to heavy metal stress. There was a significant decrease in the Cmic/Corg ratio and an increase in the metabolic quotient with increasing metal concentration. Multivariate analysis of Biolog data for sole carbon source utilization pattern demonstrated that heavy metal pollution had a significant impact on microbial community structure and functional diversity. All the results showed that soil microbiological parameters had great potential to become the early sensitive, effective and liable indicators of the stresses or perturbations in soils of mining ecosystems.

Plant Diversity Performance After Natural Restoration in Reclaimed Deyeuxia angustifolia Wetland

Deyeuxia angustifolia wetlands were widely distributed in the Sanjiang Plain in Northeast China. Due to strong demand for food production, large-area wetlands were reclaimed to farmlands, which threatened regional ecological security greatly. Since the 21 th century, returning farmlands to wetlands was widely adopted for natural restoration in the Sangjiang Plain. As the first reflection of wetland restoration, vegetation succession of restored D. angustifolia wetlands should be fully assessed. In this study, vegetation investigation was carried out in three restored D. angustifolia wetlands with 5, 8 and 12 yr restoration, respectively. Meanwhile, a natural D. angustifolia wetland was selected as reference wetland. Results showed that community composition changed greatly and there was visible community succession. Community dominant species changed from composite to gramineae as restoration time increasing.At first, weeds community appeared in the restored wetlands, especially the xerophytes developed to the pioneer species rapidly. And then, mesophytes and wetland species became the dominant species in the restored wetlands. Finally, wetland species, especially D. angustifolia, occupied the dominant position of restored community. Shannon-wiener index(H) and Simpson index(D) both decreased to close to natural D. angustifolia wetlands. Compared with natural D. angustifolia wetland, species composition and diversity in restored wetlands were more complex and higher. As restoration time increasing, there were not significant differences between community characteristics of restored wetlands and natural wetland. All these suggested that vegetation in reclaimed D. angustifolia wetland could be restored naturally, but its restored period is 10 yr at least. From another angle, it is important to protect current natural wetlands.

水泥稳定全深式沥青路面回收料配合比试验研究

在沥青路面病害详细调查的基础上,确定沥青路面再生的施工方式。将水泥稳定全深式沥青路面回收料用于道路基层配合比,并设计水泥稳定再生混合料基层;通过调节水泥掺配剂量和回收沥青路面材料掺配比例,进行配合比设计试验。对试验结果进行统计分析,最终确定适宜于道路基层的最优配合比为:回收料掺配比例50%,水泥剂量2%。

Effects of reclaimed water irrigation and nitrogen fertilization on the chemical properties and microbial community of soil

The ecological effect of reclaimed water irrigation and fertilizer application on the soil environment is receiving more attention.Soil microbial activity and nitrogen（N）levels are important indicators of the effect of reclaimed water irrigation on environment.This study evaluated soil physicochemical properties and microbial community structure in soils irrigated with reclaimed water and receiving varied amounts of N fertilizer.The results indicated that the reclaimed water irrigation increased soil electrical conductivity（EC）and soil water content（SWC）.The N treatment has highly significant effect on the ACE,Chao,Shannon（H）and Coverage indices.Based on a 16S ribosomal RNA（16S rRNA）sequence analysis,the Proteobacteria,Gemmatimonadetes and Bacteroidetes were more abundant in soil irrigated with reclaimed water than in soil irrigated with clean water.Stronger clustering of microbial communities using either clean or reclaimed water for irrigation indicated that the type of irrigation water may have a greater influence on the structure of soil microbial community than N fertilizer treatment.Based on a canonical correspondence analysis（CCA）between the species of soil microbes and the chemical properties of the soil,which indicated that nitrate N（NO3-–-N）and total phosphorus（TP）had significant impact on abundance of Verrucomicrobia and Gemmatimonadetes,meanwhile the p H and organic matter（OM）had impact on abundance of Firmicutes and Actinobacteria significantly.It was beneficial to the improvement of soil bacterial activity and fertility under 120 mg kg^-1 N with reclaimed water irrigation.