2020 Vol. 10, No. 2

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2020 Vol.10, No.2
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2020, 10(2): .
Abstract(239) PDF(8478KB)(85)
Abstract:
The bottleneck and countermeasures in the pollution control of livestock and poultry breeding in China
LI Hongna, WU Huashan, GENG Bing, ZHU Changxiong
2020, 10(2): 167-172. doi: 10.12153/j.issn.1674-991X.20200003
Abstract(735) PDF(936KB)(442)
Abstract:
With the large-scale and rapid development of livestock and poultry breeding in China, significant achievements had been made in the utilization of fecal sewage resources, but 40 percent of fecal sewage had not been rationally and effectively utilized. The bottleneck problems causing the current situation mainly included: unreasonable distribution of breeding, mismatch of breeding scale, and great difficulty in the utilization of fecal sewage resources. In addition, there were few complete sets of effective technologies for the prevention and control of breeding sewage, especially those that were economically applicable, and many technologies were expensive or inefficient. Aiming at the key and difficult points for livestock and poultry breeding sewage control technology, the National Major Science and Technology Program for Water Pollution Control and Treatment (Major Water Program) had developed a batch of practical technologies. According to the characteristics of some regions, a set of management technologies for breeding pollution prevention and control was developed which, to some extent, could resolve the circulation issue from the source control to the resource utilization. More than 10 technical specifications (guidelines) were formulated and published, having provided a good support for livestock and poultry breeding pollution control in China. In view of the large scale base of livestock and poultry breeding in China, high proportion of scattered breeding, weak infrastructure and management mechanism, etc., some countermeasures and suggestions were put forward, including controlling the breeding pollution through legal system and classified measures, strengthening the establishment of high efficient collection, transformation and utilization technology system of livestock and poultry manure, promoting the study of standardized and normalized combination of planting and breeding technology mode, strengthening the cultivation of the third-party social service organizations, and enhancing policy support, etc.
Characteristics and source analysis of water-soluble inorganic ions in PM2.5 in Yanqing District, Beijing
ZHANG Juan, WANG Wei, ZHAO Ying
2020, 10(2): 173-182. doi: 10.12153/j.issn.1674-991X.20190085
Abstract(486) PDF(2315KB)(153)
Abstract:
The atmospheric PM2.5 samples were collected from June 2017 to May 2018 in Yanqing District, Beijing. The pollution characteristics of nine water-soluble inorganic ions in PM2.5 were analyzed, and the sources were analyzed by SPSS software. The results showed that the average concentration of total water-soluble inorganic ions in PM2.5 in Yanqing District was 28.0 μg∕m 3, of which S O 4 2 - , N O 3 - and N H 4 + were the main water-soluble inorganic ions, accounting for 82.1%. Influenced by weather, the concentration of N O 3 - and S O 4 2 - was high in autumn and low in winter, while the concentration of N H 4 + was high in autumn and low in summer. Influenced by meteorological conditions and construction activities in winter, the concentration of Ca 2+, Mg 2+, Na + was the highest in winter. According to the charge balance analysis, the anions and cations in PM2.5 basically reached equilibrium in spring, with weak acidity in summer and autumn, and weak alkalinity in winter. The mean values of SOR and NOR in PM2.5 were 0.53 and 0.27, respectively, and there were obvious secondary transformation processes in the atmosphere. The ratio of N O 3 - ∕S O 4 2 - was 1.66, which indicated that vehicle exhaust contributed a lot to water-soluble inorganic ions in PM2.5. According to the correlation analysis between N H 4 + and S O 4 2 - , N O 3 - , Cl —in PM2.5 in Yanqing District, N O 3 - and S O 4 2 - existed in the form of (NH4)2SO4, NH4HSO4, NH4NO3 and HNO3. Pearson correlation analysis using SPSS software showed that the correlations between any two of N O 3 - , S O 4 2 - , N H 4 + in PM2.5 in Yanqing District were strong, indicating that the secondary reaction was significant; the correlations between any two of Ca 2+, Mg 2+, Na + were strong, indicating that the sources of pollution may be the same; Cl - was strongly correlated with K +, and Cl -mainly existed in the form of KCl in the atmosphere. Using factor analysis module to analyze the main components, it was found that the main pollution sources in Yanqing District were biomass combustion, dust pollution and motor vehicle exhaust emissions.
Design of self-cleaning pipe segment for concentration measurement of cooking fume particulate matter and analysis of influencing factors
QIN Jinwei, ZHOU Wu, CAI Xiaoshu, WANG Wentao
2020, 10(2): 183-191. doi: 10.12153/j.issn.1674-991X.20190107
Abstract(417) PDF(3946KB)(116)
Abstract:
For the on-line concentration measurement of cooking fume particles with light scattering method, considering the vulnerability of oil fume pollution on the measurement system, a rectangular pipe with the across-section size of 450 mm×400 mm was taken as an example to design a self-cleaning cooking fume particulate matter concentration measurement section by ejecting clean air to protect the optical components with Venturi effect. By using computational fluid dynamics (CFD) method, the pressure distribution characteristics and throat negative pressure levels of four types of measuring sections including linear, VitoHinsch, bicubic and quintic curves were compared and analyzed. It was found that the pressure loss of the VitoHinsch section was the smallest, which was 41% and 35% lower than that of the linear and quintic curve under the same conditions. Experimental measurement system was constructed based on the VitoHinsch profile, and the experimental data of the throat pressure under different working conditions were used to verify the simulation model. The experimental and simulation data of the composition distribution in the pipe segment were compared. The results showed that the error between experiment data and simulation data of the pressure near the measuring element was within 20%. Under the lowest flow rate, the throat negative pressure met the requirements,and the best measurement position was the mainstream area 20 mm away from the wall.
Study on coking deactivation of SCR denitration catalyst in a coke-oven plant
HU Zhijian, AN Lu, LI Yongguang
2020, 10(2): 192-196. doi: 10.12153/j.issn.1674-991X.20190112
Abstract(555) PDF(1095KB)(124)
Abstract:
The plate type SCR catalyst which was deactivated in flue gas denitration before desulfurization in a coke-oven plant was studied. Specific surface and pore size distribution analyzer, elemental analyzer, TG-DSC analysis, and X-ray photoelectron spectroscopy (XPS) were used to characterize the deactivation catalyst, and the denitration activity test of the untreated catalyst with that of the calcined catalyst was compared. The results showed that compared with fresh catalyst, the specific surface area and pore volume of deactivation catalyst were greatly reduced. The surface of catalyst was seriously polluted, and a large amount of ammonium bisulfate∕ammonium sulfate and coke deposit was adsorbed on the surface of catalyst. The coke deposit existed as element carbon with the content of 0.87%. The calcination temperature of 350 ℃ could remove the ammonium bisulfate on the surface of the deactivated catalyst, resulting in the recovery of a small part of the catalyst activity; however, after the treatment of 400-500 ℃, the appearance and activity of the catalyst were greatly restored. This was because the deposited coke was oxidized to carbon dioxide at 400-500 ℃ and was separated from the catalyst surface, resulting in the recovery of catalytic activity. The results of denitration activity test further proved that the coke deposition was the main cause of catalyst deactivation. A bag filter could be set before denitration to catch the tar, coke and other harmful substances in the flue gas, so as to effectively reduce the harmful effect of coke deposition on the SCR denitration catalyst.
Bioavailability of organic phosphorus in Lake Chaohu sediments
LU Yanmin, ZHANG Jingtian, ZHANG Xinbo, XIAO Zhe, XU Xiaoling, HUO Shouliang
2020, 10(2): 197-204. doi: 10.12153/j.issn.1674-991X.20190125
Abstract(531) PDF(3644KB)(155)
Abstract:
Organic phosphorus in sediments can be converted into inorganic phosphorus, which may accelerate lake eutrophication process. Sectional sediment samples were collected in Lake Chaohu, organic phosphorus in sediments were extracted by Ivanoff method, and alkaline phosphatase activity in sediments were determined. The hydrolysis effects of alkaline phosphatase on NaHCO3 extracted Po (NaHCO3-Po), HCl extracted Po (HCl-Po) and NaOH extracted Po (NaOH-Po) in sediments were studied. The results indicated that Po content at C14 sampling station in the eastern half of the lake was higher than that at C4 sampling station in the western half of the lake. The proportion of NaOH-Po, HCl-Po, NaHCO3-Po and Residual-Po in total organic phosphorus was 41.70%, 12.82%, 11.05% and 2.22%, respectively at C4 sampling station, 43.75%, 19.00%, 6.12% and 4.22%, respectively at C4 sampling station, and the concentrations of different forms of organic phosphorus were in the order of NaOH-Po>HCl-Po>NaHCO3-Po>Residual-Po. The alkaline phosphatase activity at C4 sampling station was higher than that at C14 sampling station due to high eutrophication level in the western half of Lake Chaohu. NaHCO3-Po, HCl-Po and NaOH-Po could be hydrolyzed by alkaline phosphatase, and the hydrolysis contents of various organic phosphorus in surface layers at C4 and C14 stations were significantly higher than those in deep layers, indicating that the bioavailability of organic phosphorus produced by human activities were higher. Indeed, the hydrolysis ratio of NaHCO3-Po was highest with 65.78%-69.47% averaged values due to its simple and small molecular compounds.
Pollution characteristics and ecological risk assessment of heavy metals in the sediment of Hengshui Lake
LIU Li, ZHANG Jiawen, CHEN Fenfei, SHENG Sheng, TIAN Ziqiang, WANG Jian
2020, 10(2): 205-211. doi: 10.12153/j.issn.1674-991X.20190126
Abstract(739) PDF(777KB)(186)
Abstract:
Eleven sampling points were set in Hengshui Lake to analyze the concentration distribution of heavy metals including Cr, Ni, Cu, Zn, As, Cd, Pb, Mn, Co, Sb and Tl in sediment. The degree of heavy metal pollution was evaluated by the method of geo-accumulation index and potential ecological risk assessment index. Pearson correlation analysis was conducted by SPSS. The results showed that the average concentrations of other heavy metals in the sediment of Hengshui Lake were lower than the background value of Layer A soil in Hebei Province except for Cd and Co. The concentrations of Cr, Ni, Cu, Zn, As and Pb at each sampling point were lower than the soil risk screening values of agricultural land in Soil Environmental Quality, Agricultural Land Risk Control Standards for Soil Contamination (Trial) (GB 15618-2018). Sb and Co were lower than the soil risk control values of construction land in Soil Environmental Quality, Construction Land Risk Control Standards for Soil Contamination (Trial) (GB 36600-2018). There were 8 sampling points of Cd whose concentration exceeded the agricultural land risk screening value of GB 15618-2018, and 1 point was higher than the construction land risk control value of GB 36600-2018. The evaluation results of the geo-accumulation index method showed that Cd was generally moderately polluted, Co was generally mildly polluted, and the nine heavy metals of Cr, Ni, Cu, Zn, As, Pb, Mn, Sb and Tl could be regarded as non-polluted. The results of potential ecological risk index evaluation indicated that the impact degree of each pollutant on the ecological risk of Hengshui Lake was Cd>>Co>As>Sb≈Pb>Cu>Ni>Cr>Mn≈Zn. The RI average value was 270.79, which was a medium ecological hazard. However, the contribution rate of Cd to RI was as high as 91%, which was the main pollution factor. Cd pollution was possibly caused by Yellow River water diversion into the lake and other human activities.
Fluxes and influencing factors of phosphorus release in sediments in northern lacustrine areas of Jiaxing City
MA Yingqun, CHI Minghui, WEN Quan, CAO Wei, QIN Yanwen, LIU Zhichao, YANG Chenchen
2020, 10(2): 212-219. doi: 10.12153/j.issn.1674-991X.20190090
Abstract(542) PDF(1781KB)(156)
Abstract:
In order to understand the effect of phosphorus release from sediment on water pollution, the diffusive gradients in thin-films technique (DGT) was introduced to clarify phosphorus fluxes and its influencing factors in sediments in Fen Lake, Liansidang Lake and Beiguandang Lake in northern lacustrine areas of Jiaxing City. The effect of phosphorus release from sediment on overlying water was evaluated. The results showed that concentrations of soluble available phosphorus (DGT-P)in sediment water interface (SWI) displayed various trend at three sampling sites and generally showed the following decreasing order: Liansidang Lake (0.735 mg∕L) > Beiguandang Lake (0.154 mg∕L) > Fen Lake (0.077 mg∕L). In terms of vertical distribution, the concentrations of DGT-P in the surface sediments of the three lakes were higher than that of overlying water. But the situation was different within the range of ±10 mm at the SWI; there was no obvious concentration gradient of DGT-P at the SWI of Fen Lake, indicating that the phosphorus release capacity of sediments to overlying water was weak, while that of Liansidang Lake presented an obvious concentration gradient and had a strong phosphorus release capacity, and that of Beiguandang Lake was between the two. From the perspective of the phosphorus release fluxes at the SWI, the phosphorus release flux of each lake sediment had a limited effect on the overlying water. Among them, the phosphorus release flux at the Liansidang Lake SWI was the highest (0.490 mg∕(m 2·d)), and its contribution to overlying water was also the highest (1.93%), which showed the source of phosphorus. The second was Beiguandang Lake, whose phosphorus release flux was 0.047 mg∕(m 2·d), and its contribution to overlying water was 0.24%. The phosphorus release flux at the SWI of Fen Lake was close to 0 and showed a phosphorus sink. Correlation analysis showed that the migration and transformation of phosphorus was significantly affected by the reduction and dissolution of iron oxides in SWI, meanwhile attention should also be paid to the influence of organic matter mineralization on phosphorus release in sediment.
Simulation study on decomposition and release of nutrients from aquatic macrophyte communities in confluence area between lake and river
CHEN Hongsen, YE Chun, LI Chunhua, CAI Xuyi, WEI Weiwei
2020, 10(2): 220-228. doi: 10.12153/j.issn.1674-991X.20190108
Abstract(602) PDF(2650KB)(147)
Abstract:
Decomposition of aquatic macrophyte in winter and spring is one of the important factors affecting the water quality. In order to study the suitable biomass of the declining aquatic macrophyte community in confluence area between lake and river, the decomposition experiments of the biomass of stems and leaves of remaining 0%, 20%, 40%, 60%, 80% and 100% aquatic plants after harvesting were conducted in laboratory from December 25, 2018 to April 25, 2019 in near-natural conditions. The results showed that in the decomposition process of aquatic macrophyte, the biomass of stems and leaves was the key factor affecting the nutrient concentration in water, mainly showing that the larger the biomass, the worse the physical and chemical indicators of DO, Eh and pH, and the higher the nutrient concentrations of TN and TP. The correlation analysis showed that the biomass of stems and leaves of aquatic macrophyte was significantly positive correlated with the content of total nitrogen and total phosphorus in water (P<0.01), and the correlation coefficient (R) was 0.88 and 0.83, respectively. Under near-natural conditions, aquatic macrophyte decomposed for 4 months, and the changes of nutrient content were still not stable. The remaining 20% of the biomass of stems and leaves of aquatic macrophyte after harvesting was conducive to maintaining better water quality in confluence area between lake and river.
Effect of aluminum sludge biological packing on nitrogen and phosphorus removal from black and odorous water
ZHANG Ruibin, WANG Leyang, PAN Zhuoxi, ZHOU Nai, ZU Baiyu, XI Daoguo
2020, 10(2): 229-234. doi: 10.12153/j.issn.1674-991X.20190101
Abstract(472) PDF(1783KB)(191)
Abstract:
The treatment effect of combination of aluminum sludge, polypropylene fiber biological packing and foxtail algae in black and odorous water was simulated. The results showed that the aluminum sludge biological packing could regulate the pH of the water system, and the foxtail algae could improve the dissolved oxygen content, so as to create the micro-environment beneficial to the microorganisms. The effluent quality of aluminum sludge biological packing was better than that of polypropylene fiber biological packing, basically reaching Class Ⅴ standard of Environmental Quality Standards for Surface Water(GB 3838-2002). Especially, the combination of aluminum sludge biological packing and foxtail algae had the best overall removal effect on water pollutants, and the effluent quality was better than that of GB 3838-2002 Class Ⅳ standard. The removal rates of CODCr, TP, TN and NH3-N were 74.62%, 93.59%, 93.19% and 96.46%, respectively.
Discussion on the construction of environmental emergency interception dam with constructed wetlands for cross-border rivers
GAO Shengwang, LI Meng, HAO Aimin, ZHU Jianchao, LIU Xiaoyu, XIA Xunfeng, LUO Xinping
2020, 10(2): 235-241. doi: 10.12153/j.issn.1674-991X.20190040
Abstract(482) PDF(1392KB)(117)
Abstract:
There are many cross-border rivers in China. In order to ensure the water quality of cross-border sections to meet the standards, it is necessary to strengthen the prevention of water environmental pollution risk of cross-border rivers. The solutions to the construction of the environmental emergency interception facilities for the cross-border rivers were put forward, and the design ideas and principles discussed. It was proposed that the environmental emergency sewage interception facilities should include emergency interception dams and supporting sewage receiving wetlands, and the requirements for the design of the facilities were elaborated from the aspects of dam design, wetland design, emergency measures design, minimal environmental impact and operating conditions. Taking a cross-border river in the northwest of China as an example, the case design of environmental emergency sewage interception facilities was carried out. Based on the analysis of the characteristics of the river and the risk sources of the water environment, the design was carried out from the aspects of project location comparison, the selection of the dam type, the dam height and the main design parameters of the constructed wetland, and the treatment efficiency of the environmental emergency sewage interception facility was simulated. The results showed that the construction of environmental emergency sewage interception facilities would greatly improve the environmental risk prevention ability of the river, and the facilities could play the role of drainage and restoration of other wetlands along the coast when no water pollution accident occurred.
Research progress in isotope methods for tracing contaminants in water environment
MA Wenjuan, LIU Danni, YANG Fang, WANG Heli, WANG Xihuan, LI Chongwei, LIAO Haiqing
2020, 10(2): 242-250. doi: 10.12153/j.issn.1674-991X.20190081
Abstract(1965) PDF(1202KB)(590)
Abstract:
The sources identification and pollution process control of contaminants in aquatic environment is still a challenge in watershed pollution management. Isotope technology for tracing pollutants sources and the pollution processes is one of the effective methods to solve this problem. The application situations of isotope technology in water pollution sources research at home and abroad in recent years were summarized. The basic principles and characteristics of isotope technology were introduced briefly. The research progresses in stable isotope technology for tracing different pollutants, as well as the corresponding migration and transformation processes in water environment were summarized. Compared with the traditional methods, e.g. hydrochemistry, it was proposed that isotope technology had its unique advantages, while limitations still existed. Combined with the traditional hydrochemistry and fluorescence spectroscopy, the efficiency and environmental friendliness of isotope technology could be greatly improved. The prospects for the application of isotope tracing technology in aquatic environment were carefully addressed.
Study on permeable reactive barrier technology for the remediation of polluted groundwater
WANG Hongquan
2020, 10(2): 251-259. doi: 10.12153/j.issn.1674-991X.20190129
Abstract(1172) PDF(1469KB)(246)
Abstract:
With the increasingly serious environmental problem of groundwater pollution in China, the remediation of polluted groundwater is extremely urgent. Permeable reactive barrier(PRB)is a new technology for groundwater remediation of contaminated sites, which can effectively remove organic chlorides, heavy metals and inorganic ions with the advantages of good treatment effect, low cost and little impact on ecology and environment. PRB technology has been widely used in the engineering field and commercialized in the United States, which is currently used in the laboratory research and field-pilot demonstration in China. The contaminants-removing principles, structure types, active packing materials, reactive mechanism and engineering application of PRB system were summarized, and the technical issues of long-term effective performance of PRB system, as well as the application prospects and key research directions of PRB technology were pointed out, so as to provide references for the R&D and application of PRB technology and the remediation of polluted groundwater in China.
Alkaline detoxification pretreatment of acetaldehyde wastewater under the condition of long reaction time
WANG Hong, ZHANG Meng, ZHU Zemin, SONG Yudong, LI Jie, XIAO Juqiang, ZHOU Yuexi
2020, 10(2): 260-266. doi: 10.12153/j.issn.1674-991X.20190130
Abstract(446) PDF(2750KB)(106)
Abstract:
Acetaldehyde wastewater contains high concentration of toxic organic compounds, including aldehydes and organochlorines. It has strong inhibition on the microorganisms in wastewater biological treatment system, and it is difficult to treat directly by biological treatment, so detoxification pretreatment is needed. The effects of prolonging reaction time and raising reaction temperature on the dosage of alkali required for alkaline detoxification of acetaldehyde wastewater were investigated. The results indicated that alkaline pretreatment could effectively remove aldehydes and organochlorine toxic organic compounds from wastewater, and significantly reduce the anaerobic biological toxicity and aerobic biological toxicity of wastewater. The anaerobic biological toxicity was more reasonable for the evaluation of detoxification efficiency than the concentration of toxic substances. Prolonging reaction time and raising reaction temperature were beneficial to reducing the alkali dosage required for sufficient detoxification of acetaldehyde wastewater. When the reaction time was prolonged from 3 h to 10 h, the reaction temperature was raised from 60 ℃ to 70 ℃, the alkali dosage required for the sufficient detoxification was reduced by 50%, and the cost of regents saved by about 3.7 yuan per ton of wastewater.
Parameter determination and engineering application of water reuse technology in hospital domestic sewage treatment
DONG Xinyang, LIU Wei
2020, 10(2): 267-272. doi: 10.12153/j.issn.1674-991X.20190028
Abstract(590) PDF(1203KB)(139)
Abstract:
In order to meet the requirements for water reuse after treatment of domestic sewage from the hospitals, the process of “pretreatment+bio-contact oxidation+high efficiency precipitation+filtration disinfection” was proposed according to the characteristics of domestic sewage from hospitals, and the optimal process conditions determined by a small trial test. The process was applied in the upgrading and transformation project of domestic sewage in a specialized hospital in Tianjin. The optimal process conditions were determined by the small trial test, i.e. volumetric load of 0.50 kg∕(m 3·d), pH of 7.5-8.0, gas-water ratio of 15, the joint dosing of poly aluminum chloride and polyacrylamide (15.0,1.0 mg∕L respectively) and ClO2 dosing of 12 mg∕L. The engineering application results showed that the process was in good condition and the water quality of effluent reached the reuse water quality requirements for toilet flushing of Standard for Municipal Sewage Reuse, Municipal Mixed Water Quality (GB∕T 18920-2002).
Study on the effect of chemical conditioning method on the dewatering effect of biochemical sludge
SHI Wanli, ZHANG Dapeng, ZHAO Zehua, ZHANG Cheng, GENG Xinxiang, MA Wenying
2020, 10(2): 273-279. doi: 10.12153/j.issn.1674-991X.20190114
Abstract(657) PDF(903KB)(135)
Abstract:
In view of the high water content of biochemical sludge in urban sewage treatment plants, which was not conducive to the following treatment, the sodium hypochlorite oxidation method, Fenton oxidation method and Fenton + calcium oxide combined method were used to dewater the sludge, respectively, combined with single factor analysis to optimize external conditions. The experimental results showed under the optimized conditions, the sludge moisture content could be reduced from 89.90% to 78.44%, and the filtrate quality was about 50% of the initial sludge quality, when sodium hypochlorite was selected as the oxidant. The moisture content of sludge could be reduced to 65.32%, and the filtrate quality increased to 60% in Fenton oxidation system. After combined with calcium oxide, the moisture content of sludge could be further reduced to 51.06%, and the filtrate quality was about 56% of the initial sludge quality. The addition of calcium oxide promoted the hydrolysis of iron ions, and iron hydroxide-calcium sulfate and excess calcium sulfate crystallized. The rigid skeleton constructed could form a large number of water-permeable channels in the sludge, and thus improve the dewatering performance of biochemical sewage. Considering the sludge dewatering effect and chemical cost, Fenton + calcium oxide combined method was found to be the best conditioning method.
Pollution characteristics and health risk assessment of heavy metals in farmland soil downstream of a copper mine slag dumps
CHENG Rui
2020, 10(2): 280-287. doi: 10.12153/j.issn.1674-991X.20190095
Abstract(510) PDF(4330KB)(149)
Abstract:
In order to explore the pollution status and evaluate the pollution risk of heavy metals (Cu, Pb, Cd, As and Sb) influenced by copper deposits, the concentration of heavy metals of three farmland soil plots (block 1 #,2 # and 3 #) downstream of a copper mineslag dump in Jiangxi Province were analyzed. The results showed that the average contents of the five heavy metals in the three plots were higher than the background values in Jiangxi Province (normal soil), and the average contents of Cu, Cd in block 1 # and Cu, Sb, As in block 3 # exceeded the paddy field standard limit (with pH<6.5) of Soil Environmental Quality-Risk Control Standards for Soil Contamination of Agricultural Land (Trial) (GB 15618-2018). The analysis of Nemero Composite Index showed that the P of blocks 1 #, 2 # and 3 # was 11.30, 1.25 and 2.95 respectively, which were at the level of heavy, light and medium pollution, respectively. The Muller's Accumulated Index analysis showed that block 1 # and 3 # were differently polluted by Cu, Cd, Sb, Pb, As, and block 2 # was polluted by Cu, Pb, Sb, As at different levels. The health risk analysis showed that there was no non-carcinogenic risk for adults and children in the three farmlands, and the carcinogenic risk (CR) for children exceeded the maximum acceptable limit (1.0×10 -4) stipulated by US EPA. The CR of blocks 1 # and 3 # for adults also exceeded the maximum acceptable limit, with unacceptable carcinogenic risk. The CR of the three carcinogenic heavy metals was in the order of As>Cd>Pb, and the contribution of three exposure routes to carcinogenic risk was oral>skin>breathing.
Condition optimization of pesticide contaminated soils remediation by modified Fenton reagent
YAN Xianghua, LIU Xinghai, WANG Xingrun, ZHAO Caiyun, TONG Xuejiao
2020, 10(2): 288-292. doi: 10.12153/j.issn.1674-991X.20190094
Abstract(491) PDF(1533KB)(157)
Abstract:
Fenton reagent modified by EDTA-2Na was applied to study the chemical oxidation remediation of chlorinated organics and BTEX in pesticide contaminated soils. The effects of EDTA-2Na, H2O2, FeSO4 dosage and H2O2 dosing times on pollutants degradation rate were studied. The results showed that the degradation rate of benzene was increased by 29.6 percentage points and that of 1,2-dichlorobenzene by 26.4 percentage points when EDTA-2Na was added in the ratio of 1∶1 to Fe 2+. Under the same experimental conditions, the degradation rates of benzene, 1, 2-dichlorobenzene increased with the addition of EDTA-2Na, H2O2, FeSO4, H2O2 concentrations, as well as with H2O2 dosing times, and then gradually stabilized. The suitable process parameters were identified as follows: H2O2 dosage 3.0 mmol∕g, n(H2O2)∶n(FeSO4)∶n(EDTA-2Na)=10∶1∶1, and reaction time 2 hours, and H2O2 added within 4 times. Under these conditions, the degradation rate of benzene was high up to 86.0%, and that of 1,2-dichlorobenzene was up to 83.6%.
Spatiotemporal variation characteristics and driving forces of natural resources utilization in Jiangsu Province
WU Xinyi, ZHANG Yan
2020, 10(2): 293-302. doi: 10.12153/j.issn.1674-991X.20190080
Abstract(515) PDF(2790KB)(148)
Abstract:
Abstract Based on the revised three-dimensional model of ecological footprint, the per capita ecological footprint, footprint depth and footprint size of Jiangsu Province from 2009 to 2016 were measured, and the spatiotemporal variation characteristics of natural resources utilization in the province were quantitatively analyzed. Then, the driving factors of per capita three-dimensional ecological footprint were discussed by using the revised T-form correlation analysis. Additionally, the grey model GM(1,1) was established to predict the evolution trend of ecological footprint and ecological carrying capacity of Jiangsu from 2019 to 2022. The results showed that: (1) From 2009 to 2016, the per capita ecological footprint, per capita ecological deficit, footprint depth and footprint size were all increasing while the per capita ecological carrying capacity slightly decreased. Cultivated land, woodland, grassland, water area and fossil energy land were all in the state of ecological deficit, except for construction land. The ecological footprint of fossil fuel land occupied a dominant position of the whole province; the footprint depths of grassland and water area were much higher, so the overdraft of resource stocks was very serious. The footprint size of cultivated land accounted for the main part of that of whole area, but it declined slightly during the research period. There were great differences in footprint depth and footprint size among 13 cities in Jiangsu Province, with the footprint depth in the order of southern region＞ central region＞ northern region, and the footprint size in the order of northern region＞ central region＞ southern region.(2)Inducting the development of tertiary industry, improving energy efficiency and regional trade exchanges could alleviate the expanding trend of per capita ecological footprint in Jiangsu Province, while the growth of per capita GDP, urbanization level and the increasing of population scale could promote the growth of ecological footprint.(3)The results of grey prediction showed that the per capita ecological footprint would continue to grow from 2019 to 2022, while the per capita ecological carrying capacity would decline slightly. Therefore, the phenomenon of ecological deficit would continue to exist and become more serious, and the pressure on the ecological environment would further intensify.
Research on pyrolysis kinetics and products analysis of waste circuit boards
XIE Yibiao
2020, 10(2): 303-309. doi: 10.12153/j.issn.1674-991X.20190099
Abstract(563) PDF(1318KB)(120)
Abstract:
Under nitrogen condition, thermo gravimetric analysis(TGA) was used to test the pyrolysis characteristics and reaction kinetics of waste printed circuit boards (WPCB) powder. Py-GC∕MS and TG∕MS were used to analyze and discuss the pyrolysis products of WPCB. The results showed that the pyrolysis process of WPCB powder was divided into three stages, including evaporation of water, decomposition of organic matter and stabilization. The decomposition stage included volatilization and decomposition of organic matter and decomposition of residue, whose apparent activation energy was 250.74 and 23.58 kJ∕mol, respectively, and the pre-exponential factors were 1.35×10 31 and 3 428.92 min -1, respectively. The main products of the pyrolysis of the WPCB powder included aromatic compounds which mainly substituted by benzene ring-substituted aromatic compounds and bromine-containing compounds, and a small amount of low molecular weight hydrocarbons, benzofurans, etc. The benzene ring-substituted aromatic compounds mainly included benzene, toluene, ethylbenzene, xylene, phenol, isopropyl phenol, while the bromine-containing compounds mainly included methyl bromide, ethyl bromide, bromophenol, dibromophenol and hydrogen bromide.
MFCA-based cost optimization analysis for typical secondary zinc production process
ZHANG Jinyu, RUAN Jiuli, LIU Caitian, WANG Yibo, XIA Xinyue, GUO Yuwen
2020, 10(2): 310-315. doi: 10.12153/j.issn.1674-991X.20190109
Abstract(537) PDF(2578KB)(102)
Abstract:
Conventional cost accounting approaches cannot well reflect the loss cost of production processes, especially waste treatment costs. Using the material flow cost accounting (MFCA) which was based on the material metabolism balance, and on the basis of determining the system boundary of the production processes at the enterprise level, the flow and distribution of material cost, energy cost and waste disposal cost among all processes were calculated. By applying MFCA to the typical secondary zinc production process, the calculation indicated that material cost had the largest proportion in the total input cost, accounting for 76.16%. And waste management cost and energy cost accounted for 12.50% and 11.19% of the total cost, respectively. Controlling the zinc material losses of rotary kiln was the key factor to reduce production costs and improve economic efficiency, and the resource and energy saving and waste reducing were also beneficial to decreasing cost losses.
Benefit accounting analysis of sponge transformation in building and communities: taking Rose Community in Guyuan City as an example
FAN Chao, SUN Xueliang
2020, 10(2): 316-322. doi: 10.12153/j.issn.1674-991X.20190019
Abstract(573) PDF(3337KB)(112)
Abstract:
Taking Rose Community in Guyuan City as an example, the ideas and project contents of the sponge transformation were put forward according to the community characteristics such as large green space area and less difficulty in the renovation of broken rain-falling pipes, and the economic and ecological benefits after the sponge transformation were calculated. The results showed that, by means of the sponge transformation, which was to reconstruct the drainage system and construct the sinking green land, grass ditch, rainwater garden, rainwater tank, reservoir and permeable pavement, etc., the comprehensive rainfall runoff coefficient could be reduced by 0.21 and the runoff reduced by 5 137.85 m 3∕a in the residential area, thus resulting in good effect of rainwater regulation and storage. The sponge transformation had certain economic benefits, which could save the urban drainage facilities cost of 411.03 yuan∕a, the tap water cost of 4 159.20 yuan∕a, and the water-saving benefit of 28 155.42 yuan∕a. After the sponge transformation, it could absorb 8.18 t∕a of carbon, release 6.31 t∕a of oxygen and absorb 50.73 kg∕a of sulfur dioxide, resulting in significant ecological and environmental benefits.

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