Pumping-induced Well Hydraulics and Groundwater Budget in a Leaky Aquifer System with Vertical Heterogeneity in Aquitard Hydraulic Properties

In groundwater hydrology,aquitard heterogeneity is often less considered compared to aquifers,despite its significant impact on groundwater hydraulics and groundwater resources evaluation.A semi-analytical solution is derived for pumping-induced well hydraulics and groundwater budget with consideration of vertical heterogeneity in aquitard hydraulic conductivity(K)and specific storage(S_(s)).The proposed new solution is innovative in its partitioning of the aquitard into multiple homogeneous sub-layers to enable consideration of various forms of vertically heterogeneous K or S_(s).Two scenarios of analytical investigations are explored:one is the presence of aquitard interlayers with distinct K or S_(s) values,a common field-scale occurrence;another is an exponentially depth-decaying aquitard S_(s),a regional-scale phenomenon supported by statistical analysis.Analytical investigations reveal that a low-K interlayer can significantly increase aquifer drawdown and enhance aquifer/aquitard depletion;a high-S_(s) interlayer can noticeably reduce aquifer drawdown and increase aquitard depletion.Locations of low-K or high-S_(s) interlayers also significantly impact well hydraulics and groundwater budget.In the context of an exponentially depth-decaying aquitard S_(s),a larger decay exponent can enhance aquifer drawdown.When using current models with a vertically homogeneous aquitard,half the sum of the geometric and harmonic means of exponentially depth-decaying aquitard S_(s) should be used to calculate aquitard depletion and unconfined aquifer leakage.

Link Budget and Enhanced Communication Distance for Ambient Internet of Things

Backscatter communications will play an important role in connecting everything for beyond 5G(B5G)and 6G systems.One open challenge for backscatter communications is that the signals suffer a round-trip path loss so that the communication distance is short.In this paper,we first calculate the communication distance upper bounds for both uplink and downlink by measuring the tag sensitivity and reflection coefficient.It is found that the activation voltage of the envelope detection diode of the downlink tag is the main factor limiting the back-scatter communication distance.Based on this analysis,we then propose to implement a low-noise amplifier(LNA)module before the envelope detection at the tag to enhance the incident signal strength.Our experimental results on the hardware platform show that our method can increase the downlink communication range by nearly 20 m.

Discussion on Construction Project Cost Budget Settlement Review

Construction project cost control involves many complex contents,forming a large amount of data information.If the processing method is unreasonable,it will likely affect the cost control efficiency.Therefore,in the current construction project management,the review of project cost budget settlement is the focus to solve the cost management problems of construction projects and promote the development of the construction industry.This article mainly analyzes the influencing factors and current situation of construction project cost budget settlement review,and based on this,it explores the project cost budget settlement review strategy to promote the healthy development of construction project cost work.

Nutrient Budget and Soil Nutrient Status in Greenhouse System

This paper is based on nutrient budget and its effects on soil nutrient status in typical greenhouse system in China to provide a basis for raising the utilization rate of fertilizers and maintaining the sustainable development of agriculture in the greenhouse.By investigating the management of 18 representative greenhouses in Shouguang,Shandong Province,China,and analyzing both the greenhouse and open field soil samples,the soil nutrient budget and the trend of nutrient accumulation and translocation in soils were thus studied.The results under greenhouse system showed that the average annual inputs of N,P2O5 and K2O were 4 088,3 655 and 3 437 kg ha-1,respectively.The total inputs of N,P2O5 and K2O provided by chemical fertilizers which are the main source of soil nutrient were 63,61 and 66%,respectively.The utilization rates of N,P2O5 and K2O were only 24,8,46% and the input ratio among N,P2O5 and K2O （1：0.9：0.8） was quite different from the uptake ratio （1：0.3：1.4）.It had caused the excess of N,P2O5 and K2O in the soil,and the theoretical surpluses were 3 214,3 401 and 2 322 kg ha-1,respectively,for N,P2O5 and K2O.The level of the organic matter,total nitrogen,nitrate nitrogen,available phosphorus,and available potassium was increased substantially,and their maximum level was observed in the topsoil （0-20 cm） with an average value being 1.4,1.9,21.2,5.4,and 3.7 times higher than that of the open field soil,respectively.The greenhouse soils showed leaching of the nutrients,especially NO3- which would cause a potential risk to the quality of groundwater in the area.It is necessary to apply more organic manure and provide nutrients according to the crop requirements and soil fertility as it could not only produce high crop yield,but also be beneficial to balance the soil nutrient and improve the utilization rate of fertilizers.Further,there would be no significant surplus of nutrients which may leach out of soil to contaminate the environment.

A Study of Influencing Systems and Moisture Budget in a Heavy Rainfall in Low Latitude Plateau in China during Early Summer

Analysis of a heavy rainfall in a lower latitude plateau and characteristics of water vapor transportation have been conducted by using conventional data and denser surface data. The results show： （1） the heavy rainfall was caused by a series of mesoscale systems under favorable large-scale conditions when the warm moister air and cold air interacted with each other. At the same time, the coupling between the upper- and lower-level jets was revealed. It is also found that there exists some different characteristics among the main influencing systems of heavy rainfalls in Yunnan, such as the Indian-Myanmar trough and the path of the cold air, compared with those in East and South China. （2） The interaction between mesoscale convergence lines near the ground may be a possible triggering mechanism for the occurrence of mesoscale systems, and the dynamical and thermal dynamical structure of the mesoscale systems was very obvious. The convergence lines may relate closely to the terrain of Yunnan, China. （3） The computation of the water vapor budget reveals that the primary source of water vapor supply for heavy rainfall was in the Bay of Bengal. In this case, the water vapor could be transported into Yunnan even though the amount of water vapor was less than that in the lower troposphere in East and South China. In addition, the analysis for three-dimensional air parcel trajectories better revealed and described the source location and the transportation of water vapor to Yunnan.

Nitrogen Budget in Recirculating Aquaculture and Water Exchange Systems for Culturing Litopenaeus vannamei

In order to investigate the culture characteristics of two indoor intensive Litopenaeus vannamei farming modes, recirculating aquaculture system(RAS) and water exchange system(WES), this study was carried out to analyze the water quality and nitrogen budget including various forms of nitrogen, microorganism and chlorophyll-a. Nitrogen budget was calculated based on feed input, shrimp harvest, water quality and renewal rate, and collection of bottom mud. Input nitrogen retained in shrimp was 23.58% and 19.10% respectively for WES and RAS, and most of nitrogen waste retained in water and bottom mud. In addition, most of nitrogen in the water of WES was TAN(21.32%) and nitrite(15.30%), while in RAS was nitrate(25.97%), which means that more than 76% of ammonia and nitrite were removed. The effect of microalgae in RAS and WES was negligible. However, bacteria played a great role in the culture system considering the highest cultivable cultivable bacterial populations in RAS and WES were 1.03×10^(10) cfu mL^(-1) and 2.92×10~9 cfu mL^(-1), respectively. Meanwhile the proportion of bacteria in nitrogen budget was 29.61% and 24.61% in RAS and WES, respectively. RAS and WES could realize shrimp high stocking culture with water consuming rate of 1.25 m^3 per kg shrimp and 3.89 m^3 per kg shrimp, and power consuming rates of 3.60 kwh per kg shrimp and 2.51 kwh per kg shrimp, respectively. This study revealed the aquatic environment and nitrogen budget of intensive shrimp farming in detail, which provided the scientific basis for improving the industrial shrimp farming.

Dynamic phosphorus budget for lake-watershed ecosystems

Lake eutrophication caused by excess phosphorus （P） loading from point sources （PS） and nonpoint sources （NPS） is a persistent and serious ecological problem in China. A phosphorus budget, based on material flow analysis（MFA） and system dynamic （SD）, is proposed and applied for the agriculture-dominated Qionghai Lake watershed located in southwestern China. The MFA-SD approach will not only cover the transporting process of P in the lake-watershed ecosystems, but also can deal with the changes of P budget due to the dynamics of watershed. P inflows include the fertilizer for agricultural croplands, soil losses, domestic sewage discharges, and the atmospheric disposition such as precipitation and dust sinking. Outflows are consisted of hydrologic export, water resources development, fishery and aquatic plants harvesting. The internal P recycling processes are also considered in this paper. From 1988 to 2015, the total P inflows for Lake Qionghai are in a rapid increase from 35.65 to 78.73 t/a, which results in the rising of P concentration in the lake. Among the total P load 2015, agricultural loss and domestic sewage account for 70.60% and 17.27% respectively, directly related to the rapid social-economic development and the swift urbanization. Future management programs designed to reduce P inputs must be put into practices in the coming years to ensure the ecosystem health in the watershed.

Estimating the Budgets of Nutrients for Phytoplankton Bloom inthe Central Yellow Sea Using a Modified LowerTropic Ecosystem Model

A modified lower trophic ecosystem model （NEMURO） is coupled with a three-dimensional hydrodynamic model for anapplication in the central Yellow Sea. The model is used to simulate the horizontal distributions and annual cycles of chlorophyll-aand nutrients with results consistent with historical observations. Generally, during the winter background and spring bloom periods,the exchange with neighboring waters constitutes the primary sources of nutrients. Howerver, during the winter background period,the input of silicate from the layer deeper than 50 m is the most important source that contributes up to 60% to the total sources. Dur-ing the spring bloom period, the transport across the thermocline makes significant contribution to the input of phosphate and silicate.During the post spring bloom period, the relative contribution of relevant processes varies for different nutrients. For ammonium,atmospheric deposition, excretion of zooplankton and decomposition of particulate and dissolved nitrogen make similar contributionsFor phosphate and silicate, the dominant input is the transport across the thermocline, accounting for 62% and 68% of the totalsources, respectively. The N/P ratio averaged annually and over the whole southern Yellow Sea is up to 51.8, indicating the potentialof P limitation in this region. The important influence of large scale sea water circulation is revealed by both the estimated fluxes andthe corresponding N/P ratio of nutrients across a section linking the northeastern bank of the Changjiang River and Cheju Island.During the winter background period, the input of nitrate, ammonium, phosphate and silicate by the Yellow Sea Warm Current isestimated to be 4.6~ 101~, 2.3x 101~, 2.0x 109 and 1.2x 101~ mol, respectively.

Influence of stocking density on growth, body composition and energy budget of Atlantic salmon Salmo salar L. in recirculating aquaculture systems

大西洋大马哈鱼斑鳟属 salar 在四袜子 densitieshigh 密度 D 被饲养<候补选手class=“ a-plus-plus ”> 1 (最后的密度 39 kg/m <啜class=“ a-plus-plus ”> 3 ),媒介密度 D <候补选手class=“ a-plus-plus ”> 2 ( 29 kg/m <啜class=“ a-plus-plus ”> 3 )和 D <候补选手class=“ a-plus-plus ”> 3 ( 19 kg/m <啜class=“ a-plus-plus ”> 3 ),和低密度 D <候补选手class=“ a-plus-plus ”> 4 ( 12 kg/m <啜class=“ a-plus-plus > 3 )for 调查的 40 天他们的 growt 上的袜子密度的效果袜子密度显著地没以重量影响特定的生长率(SGR < 潜水艇 class= “ a-plus-plus ” > w ) 但是确实以精力影响了特定的生长率(SGR < 潜水艇 class= “ a-plus-plus ” > e ) 。袜子密度显著地影响了定量水平( RL <潜水艇class=“ a-plus-plus ”> w 和 RL <潜水艇class=“ a-plus-plus ”> e ),喂变换比率( FCR <潜水艇class=“ a-plus-plus ”> w 和 FCR <潜水艇class=“ a-plus-plus ”> e )并且明显消化的好坏率( ADR )。定量水平和 FCR < 潜水艇 class= “ a-plus-plus ” > w 趋于与增加增加密度。在最高的密度 D 的鱼 < 潜水艇 class= “ a-plus-plus ” > 1 和最低密度 D < 潜水艇 class= “ a-plus-plus ” > 4 显示出更低的 FCR < 潜水艇 class= “ a-plus-plus ” > e 和更高的 ADR 与比在中等密度。袜子密度显著地影响了身体的蛋白质和精力内容但是没影响它的潮湿，类脂化合物，或灰内容。为在低密度、高密度的组的新陈代谢的精力的开销在中等密度的组是比那低的。袜子密度从排汇物影响了精力利用，但是没在排泄率上有效果。到在高密度和低密度的生长的更大的精力分配可以被归因于减少的新陈代谢的率并且增加了明显的消化的好坏率。这些调查结果提供将在 Atlantic-salmon-farming 工业帮助合适的袜子密度的选择的信息。

Production of Pacific White Shrimp Polycultured with Swimming Crab at Different Densities, and Nutrient Budget in the Enclosure System

This study was to evaluate the effect of stocking densities on the nitrogen and phosphorus budgets for a polyculture of the crab Portunus trituberculatus and the Pacific white shrimp Litopenaeus vannamei.The shrimps(initial weight,0.012 g)were cultured at a density of 45 shrimp m^(-2),and juvenile crabs(initial weight,0.024 g)were cultured at five densities of 0,3,6,9,and 12 crabs m^(-2).The treatments were grouped as C0S45,C3S45,C6S45,C9S45,and C12S45,respectively.Water quality parameters,growth of shrimp and crabs,and nitrogen and phosphorus budget were measured.The results indicated that the shrimp performances in polyculture treatments C3S45 and C6S45 were superior to those in the crab-free treatment(C0S45).The crab in treatments C3S45 and C6S45 exhibited a significantly higher final mean weight and carapace width/length than those in treatments C9S45 and C12S45.The final size and survival of crabs had a negative correlation with the increasing crab stocking density.The contents of total phos-phorus and total nitrogen and the comprehensive contamination index values were higher in the C9S45 and C12S45 treatments than in the other treatments.The conversion ratios of nitrogen for crab and shrimp growth in treatment C3S45 were significantly higher than those in the crab-free treatment.These findings indicate that polyculturing shrimp with crabs at suitable densities can improve productivity,profitability,nutrient utilization,and the environmental quality.From the 60-day treatments,the optimal culture densi-ties were 3-6 crabs m^(-2) and 45 shrimps m^(-2).

Carbon and nitrogen budget in fish-polychaete integrated aquaculture system

Integrated multi-tropic aquaculture(IMTA)systems have been used in China for many years and have achieved significant economic,social,and ecological benefits.However,there is still a lack of benthic bioremediation species that can effectively utilize the aquaculture particulate organic waste in the system.Polychaete Perinereis aibuhitensis Grube is used as an environmental remediation species for large-scale aquaculture to reduce particulate organic waste,which is of great significance to environmental protection.To improve bio-elements utilization efficiency,P.aibuhitensis was applied for IMTA indoor fish(Hexagrammos otakii)farming.Results showed that in the system,production of 1 kg of the fish discharged 2141-2338 mg of carbon and 529-532 mg of nitrogen,while in the monoculture of the fish,the figures were 3033-3390 mg and 764-794 mg,or 24.84%-35.26%and 30.35%-33.32%less,respectively.This approach promoted IMTA technology that could utilize the particulate organic waste from intensive aquaculture and reduce the adverse environmental effects.

COMPARATIVE STUDIES ON NITROGEN BUDGETS OF CLOSED SHRIMP POLYCULTURE SYSTEMS

April to October, 1997 comparative studies on the nitrogen budgets of closed shrimp polyculture systems showed that, in all the studied polyculture systems, nitrogen from feeds and fertilizers were the main input items, which comprised 70.7%-83.9% of the total input nitrogen, 3.2%-7.4% of which was provided by nitrogen fixation. It was in monoculture enclosures (Y 4, Y 11 and Y 12) that the percentage reached the maximum value. The output nitrogen in harvested products comprised 10.8%-24.6% of total input nitrogen, and the highest percentage, 24.6%, was found in shrimp fish tagelus polyculture systems. In shrimp monoculture and shrimp fish polyculture systems, they were 19.1% and 21.9%, respectively. The nitrogen utilization efficiency was different and varied from 12.2% to 20.1%. The highest, 20.1%, was found in shrimp fish tagelus polyculture systems, and the average of 20.0% was found in shrimp tagelus polyculture systems. The lowest, 12.2%, was found in shrimp monoculture systems. All the nitrogen utilization efficiencies in shrimp fish systems or shrimp scallop systems seemed to be higher than that of the monoculture system, but they showed little statistical difference. The main outputs of nitrogen were found in sediment mud, and comprised 48.2%-60.8% of the total input, the lowest percentage was found in shrimp fish tagelus polyculture systems, and the highest percentage in shrimp scallop systems. During the experiment, nitrogen lost through denitrification and ammonia volatilization comprised 1.9%-6.2%, averaged 2.8%, of the total input, and the loss through seepage comprised 5.9%-8.9% of the total. The estimated nitrogen attached to the enclosure wall comprised 3.7%-13.3% of the total, and was highest in shrimp monoculture systems. Compared with the classic shrimp farming industry, the closed shrimp polyculture systems may improve the nitrogen utilization efficiency, and hence reduce the environmental impacts on coastal waters. The nitrogen discharging rates for all the studied polyculture systems ranged from 3.0% to 6.0% of total input nitrogen.

Incentive-compatible and budget balanced AGV mechanism for peer-to-peer energy trading in smart grids

Peer-to-peer(P2P)energy trading refers to a type of decentralized transaction,where the energy from distributed energy resources is directly traded between peers.A key challenge in peer-to-peer energy trading is designing a safe,efficient,and transparent trading model and operating mechanism.In this study,we consider a P2P trading environment based on blockchain technology,where prosumers can submit bids or offers without knowing the reports of others.We propose an Arrow-d’Aspremont-Gerard-Varet(AGV)-based mechanism to encourage prosumers to submit their real reserve price and determine the P2P transaction price.We demonstrate that the AGV mechanism can achieve Bayesian incentive compatibility and budget balance.Kernel density estimation(KDE)is used to derive the prior distribution from the historical bid/offer information of the agents.Case studies are carried out to analyze and evaluate the proposed mechanism.Simulation results verify the effectiveness of the proposed mechanism in guiding agents to report the true reserve price while maximizing social welfare.Moreover,we discuss the advantages of budget balance for decentralized trading by comparing the Vickrey-Clarke-Groves(VCG)and AGV mechanisms.

Organic carbon budget in shrimp polyculture enclosure ecosystems

The organic carbon budget in shrimp polyculture ecosystems was studied with five experimental enclosures. The results showed that: (l ) the total Organic carbon income of the ecosystems varied from 4 847. 46 to 6 154. 67 g, averaged (5 646. 94 t 551.09) g, the average ratio among its components, i. e., (phytoplankton production ): (periphyte production ): (feed casted) was 0. 73: 0. 11: 0. 16; (2) the total output of organic carbon varied from 3 310. 28 to 3 974. 79 g, averaged (3 644. 21 281. 44) g, the average ratio among its components, i. e., (plankton community respiration): (periphyton respiration): (benthic community): (culture animal production): (culture animal respiration) was 0. 53: 0. 19: 0. 15: 0. 04:0. 09; (3) the organic carbon accumulation varied from 1 383. 45 to 2 707. 31 g, averaged (2 002. 73 546. 76) g, which was 26% --44 % of the total organic carbon income; the sequence of organic carbon accumulation in the ecosystems of different polyculture types was Y5 (Penaeus chinensis -- Argopecten irradians) > Y7 (P. chinensis -- Taiwan red tilapia) > Y4 (P. chinensis ) > T5 (P. chinensis -- Taiwan red tilapia -- Sinonovacula constricta ) > Y6 (P. chinensis S. constricta ); (4) the average conversion rate of organic carbon income to P. chinensis was (l. 77 0. 62) % (Y6>T5 > Y4 >YS > Y7), and that to total culture animals was (2. 18 0. 79) % (T5 >Y6 > Y5 > Y4 > Y7).

Carbon Budget Dynamics over a Rain-Fed Maize Agricultural Ecosystem in Northeast China and Its Regulation

Based on the eddy-covariance observation data over rain-fed maize agricultural ecosystem during 2005-2011, the dynamics of net ecosystem CO2 exchange (NEE) and its control mechanism were analyzed in the present study. We found that the average carbon budget of non-growing season, growing season and annual were 153.16 - 202.03 g C/m2, &minus;689.36 - &minus;488.17 g C/m2, and &minus;316.96 - &minus;487.33 g C/m2, respectively. Maize carbon content of grain yield was &minus;226.6 - &minus;339.94 g C/m2, accounting for 55.4% of carbon budget in the growing season. From sowing to seven-leaf stage, the carbon budget of this ecosystem was characterized by carbon release, with the rate of 0.028 &plusmn;0.0056 mg CO2 m&minus;2&sdot;s&minus;1. From seven-leaf to mature stage, the carbon budget was characterized by carbon absorption, with the rate of &minus;0.256 &plusmn;0.0693 mg CO2 m&minus;2&sdot;s&minus;1. The key meteorological factors affecting annual carbon budget included daily average temperature (R = &minus;0.81, P = 0.03) and saturated vapor pressure deficit (R = &minus;0.64, P = 0.12). At the same photosynthetically active radiation (PAR) level, CO2 assimilation rate was linearly correlated with leaf area index (P 【0.05), and the slopes increased with PAR, indicating the increase in net ecosystem CO2 exchange in growing season was unlikely to be resulted from the extension of growing season. On the contrary, the carbon sink of rain-fed maize ecosystem in growing season might be decreased by extending the growing season ahead of the sowing date.

Link Budget and Networking Analysis of FuTURE 4G TDD Trial System

The FuTURE 4G Time Division Duplex (TDD) trial system uses 3.5 GHz carrier frequency and several crucial technologies including broadband Multiple Input Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM). These technologies challenge the link budget and networking analysis of the FuTURE 4G TDD trial network. This paper analyzes the practical 3.5 GHz propagation model and the link budget of Radio Frequency (RF) parameters of the trial system. Moreover,it introduces networking analysis and network planning of the trial system,which combines the field test results of the MIMO system. The FuTURE 4G TDD trial system and its trial network have been accomplished with successful checkup. The trial system fulfills all the requirements with two Access Points (AP) and three Mobile Terminals (MT),which supports multi-user,mobility,a high peak rate of 100 Mb/s,High-Definition TV (HDTV),high-speed data download,and Voice over IP (VoIP) services.

Effective Budgetary Control System:A Regression Model for Indian Listed Companies

Budgetary control system is a sin quo non for every business irrespective of whether it is small,medium or large.It is used for forecasting,fixing the responsibility of the departments,and the effective utilization of resources.It in turn leads to increase in the productivity,profitability and return on investment.Budgetary control system helps the senior managers to ensure that spending limits are adequate.Budgetary control system becomes one of the most vital and critical area of business management.Presently,much attention has been given to improving of budgetary control and planning and their interrelationship in developing countries including India.Two-way analysis is made in this paper:One is developing predictor model for an effective budgetary control system for listed companies in India and the other is the analysis on the quality reporting system for financial statements especially budgetary control system.The method of research is empirical which tests the feasibility of solution using empirical evidences based on the statistical applications.The result of the current study shows that effective budgetary control factors are prominent in determining the budgetary control system in Indian listed companies and have significant correlation between dependent and independent variables.The study suggested initiating steps for using budget as a tool for optimum use of available resources,for avoiding conflicts among departments while allocation of resources and for increasing the inspirational quality of the budget for budgetary control.

Construction of Enterprise Financial Management System Based on Comprehensive Budget Management

Economic development and social progress have put forward new requirements for the construction of corporate financial management system,and the role of comprehensive budget management has become more and more significant,which has been highly valued and paid attention within the enterprise.Based on comprehensive budget management,it can promote the smooth development of daily business activities of the enterprise,continuously improve the level of financial management,create favorable conditions for the construction of the financial management system of the enterprise,and promote the realization of the strategic goals of the enterprise.This paper mainly discusses the construction of enterprise financial management system based on comprehensive budget management,and focuses on some targeted improvement measures.

Effect of copper on the growth of shrimps Litopenaeus vannamei : water parameters and copper budget in a recirculating system

Shrimps( Litopenaeus vannamei) were intensively cultured in a recirculating aquaculture system for 98 days to investigate effects of 0.3 mg/L Cu on its performance, Cu budget, and Cu distribution. Shrimps in Cu-treated systems had greater mean final weight(11.10 vs 10.50 g), body length(107.23 vs 106.42 mm), survival rate(67.80% vs 66.40%), and yield(6.42 vs 5.99 kg/m 3), and lower feed conversion ratio(1.20 vs 1.29) than those in control systems but the differences were not significant. Vibrio numbers remained stable(10 4 –10 6 colony forming units/mL) in the rearing tanks of both control and treated systems. Total ammonium-N, nitrite-N, nitrate-N, pH, chemical oxygen demand, 5-day carbonaceous biochemical oxygen demand, and total suspended solids were similar in controls and treatments. Dissolved Cu concentration in the treated systems decreased from 0.284 to 0.089 mg/L while in the control systems it increased from 0.006 2 to 0.018 mg/L. The main sources of Cu in the treated systems were the artificially added component(75.7% of total input), shrimp feed(21.0%), water(2.06%), and shrimp biomass(1.22%). The major outputs of Cu occurred via the mechanical filter(41.7%), water renewal(15.6%), and draining of the sediment trap(15.1%). The foam fractionator removed only 0.69% of total Cu input. Harvested shrimp biomass accounted for 11.68% of Cu input. The Cu concentration of shrimps in the Cu-treated systems(30.70 mg/kg wet weight) was significantly higher than that in control systems(22.02 mg/kg). Both were below the maximum permissible concentration(50 mg/kg) for Cu in seafood for human consumption in China. Therefore, recirculating systems can be used for commercial on-growing of Litopenaeus vannamei without loss of shrimp quality, even in water polluted by 0.30 mg/L Cu. The mechanical filter is the main route for Cu removal.