2018 Vol. 8, No. 3

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2018, 8(3): .
Abstract:
Analysis and comparison of PAHs, PFASs and OCPs sources in lake sediments by receptor model
HE Zhuoshi, LI Chaocan, ZHANG Jingtian, MA Chunzi, ZHANG Hanxiao, XU Qiujing, ZHANG Xinbo, HUO Shouliang
2018, 8(3): 231-240. doi: 10.3969/j.issn.1674-991X.2018.03.031
Abstract:
Receptor models were typically used in air pollution studies and few publications are available for receptor models that consider the details of parameters and procedures in evaluating the trace organic pollutants in sediments. PMF, Unmix and PCA-MLR are three receptor modes which have been widely used in source apportionment analysis in air pollution study. The sediment samples were collected from seven lakes in Jiangsu and Anhui provinces. Three models were applied to analyze the source apportionment of different semi volatile organic pollutants, polycyclic aromatic hydrocarbons (PAHs), perfluoroalkyl substances (PFASs) and organochlorine pesticides (OCPs). The aims of this study were to explore the applications of the three receptor models in the sediment pollution, based on a comparison of their modeling results. The three models exhibit consistent results, and the simulated values and measured values fit well, indicating that these models are well applied in the source apportionment of sediment pollutants. The results show that PAHs in the sediment in the study area are mainly from three sources, including vehicle exhaust, coal combustion and kerosene combustion. There are three main sources of PFASs in the sediment, including fluoropolymer processing aid, fluororesin coating and metal plating, textile treatments, precious metals and coatings industry, and food paper packing. The source of OCPs is mainly pesticide residues, including DDTs, hexachlorocyclohexane(BHC), and some endrin aldehyde, chlordane and sulfudan. Among the three receptor models, PMF can give corresponding weight to the data based on the uncertainty of the input data, Unmix has advantage of selecting indicators associated to specific sources into the model, while PCA-MLR can quantify the results of cluster analysis. Using multiple models to analyze the source apportionment of sediment pollutant can make the models complementary and the results more accurate, avoiding the limitation of a single model.
Distribution characteristics of organic matter, nitrogen and phosphorus in sediments of Xiao River
LI Renfei, TAN Wenbing, GAO Rutai, HUANG Caihong, ZHANG Hui, LI Dan, HE Xiaosong, XI Beidou
2018, 8(3): 241-247. doi: 10.3969/j.issn.1674-991X.2018.03.032
Abstract:
Given the scarcity of fresh water resources in Haihe Basin, an increasing amount of wastewater has been used for irrigation in the area, posing a major threat to the environmental health. The contents and distribution of organic matter (OM), nitrogen and phosphorus in different forms in the sediments of the Xiao River, a typical sewage river, were analyzed, and the release mechanism of pollutants from the sediments and their impacts on the local environment were investigated. The results show that the release mechanism of total nitrogen (TN) in the sediments is similar to that of the OM, the distributions of OM and TN in the sediments have no relations to the content of OM and TN in the river water. This may be due to the fact that the OM and TN of sediments in different river section are governed by different factors; in the river section without sediments dredging, OM and TN are mainly caused by the diffusion and release of deep sediments to surface sediments, and in the river section with sediment dredging, the contents of OM and TN are associated with the water project condition, microbial activities and other factors. The total phosphorus (TP) in the sediments has no relation to the TP in water, primarily due to the fact that the Ca-P and Fe/Al-P can be combined to form a kind of insoluble phosphate. The TP in the sediments has no relation to TN and OM, as the phosphate adsorption of sediments is significantly related to the contents of Ca 2+, Al 3+, and Fe 2+(or Fe 3+) in the water.
Evaluation of eutrophication of water body in Huailai section of Yongding River
ZHAO Jianguo, LI Hongbo, LIU Cunqi, LI Xiaoyu, CHEN Xinyong, YAN Donghua, LUO Ning
2018, 8(3): 248-256. doi: 10.3969/j.issn.1674-991X.2018.03.033
Abstract:
In order to understand the pollution characteristics of the Huailai section of the Yongding River, which is the key water pollution prevention and control area of the Haihe river system, the water quality monitoring was performed for a period of 1 years from November 2016 to October 2017. Six sampling points with 6 monitoring indicators were selected to expound the temporal and spatial variation characteristics of nitrogen and phosphorus in the river. The N/P ratio and the universal index formula using logarithmic power function were used to analyze the temporal and spatial variations of nutrient structure of nitrogen and phosphorus in water, assess the degree of eutrophication, and analyze the eutrophication risk. The results show that the water pollution in the Huailai section of the Yongding River is comparatively serious. TN is 13.25 times over the Class Ⅲ concentration limit of the surface water environment function area. The ON and N O 3 - -N are the main forms of TN. The mean value of TP is 0.64 mg/L, and each index has the characteristics of agricultural non-point source pollution. The temporal and spatial distribution of nitrogen and phosphorus in the water body is obvious. On the time scale, the concentration of nitrogen and phosphorus in the water body shows seasonal variation, and on the spatial scale, the distribution of nitrogen and phosphorus in the water body is similar. The average N/P ratio of the river section is 32.78, and the phytoplankton is overall in the state of phosphorus limitation. During the average water period, phosphorus is the limiting nutrient element, and the N/P ratio in the dry and flood periods is suitable for the growth and reproduction of algae. The temporal and spatial variation of water body in the Huailai section of the Yongding River is mostly in the ‘eutrophication’ stage. The maximum EI value is 228.11 in dry season and the lowest is 213.06 in flood season, while that in average water period is 218.30. The fluvial process of the river section is good, and the flow pattern is continuous. The flow velocity of the main stream is 0.43~1.45 m/s, which is much larger than that for the algal bloom. Therefore, the risk of cyanobacteria blooms in the main stream is low.
Effects of Margarya melanioides bioturbation on sediment of Ottelia acuminate constructed wetlands
YE Bibi, LI Guohong, JIN Ming, CHU Zhaosheng
2018, 8(3): 257-263. doi: 10.3969/j.issn.1674-991X.2018.03.034
Abstract:
The effect of Margarya melanioides (M. melanioides) bioturbation on the physical and chemical properties, nutrient content and microbes of the sediment of Ottelia acuminate constructed wetland was investigated through the simulation device of constructed wetland with two kinds of hydraulic retention time (HRT, 7 and 42 d). The results showed that M. melanioides bioturbation on the sediment was strengthen in the depth of 0-3 cm. M. melanioides significantly reduced the pH of the sediment in the depth 0-3 cm under both HRT 7 d and HRT 42 d situation, while increasing the oxidation-reduction potential (ORP) in the depth 0-7 cm significantly. Under HRT 7 d, the content of organic matter in the depth of 0-1 cm of sediment with M. melanioides-added group was significantly lower than that in the control group, which was 8.7% lower. Under HRT 7 d and HRT 42 d, the TN and TP content of the test group sediment in the depth 0-1 cm were both significantly lower than the control group, where TN decreased by 11.0%, 3.9%, TP decreased by 5.8%, 3.2%, respectively. The amount of bacteria of the test group under HRT of 7 d and 42 d was increased by 32 times and 5 times respectively compared with the control group, while the amount of actinomycetes was increased by 7 times and 1 times, respectively. The addition of M. melanioides to the Ottelia acuminate constructed wetland might change the pH and ORP in the surface of sediment, improve the quantity of microorganisms, and play a positive role in the degradation of nutrients in surface sediment. In addition, increased HRT is beneficial to increase the redox conditions of the Ottelia acuminate constructed wetland and decrease the TP content in the sediment.
Experimental study on refractory organic matter and nitrogen removal in landfill leachate
ZHAO Chen, XI Beidou, MA Tao, ZHANG Lieyu, HUANG Liangliang
2018, 8(3): 264-273. doi: 10.3969/j.issn.1674-991X.2018.03.035
Abstract:
Through the up-flow anaerobic sludge bed(UASB)simulation system, the effects of different environmental factors on the refractory organics and nitrogen synchronization removal in landfill leachate were studied. Then the removal efficiency of organic compounds and nitrogen in leachate was analyzed by using the humus in the UASB simulation system. Results show that under the pH of 7.9 to 8.4, ORP of -200 mV to -100 mV and -300 mV to -200 mV, the COD removal rate was 92.05% and 95.08%, and total nitrogen removal rate was 62.03% and 66.73%, respectively. The three-dimensional fluorescence spectrum analysis showed that humus in the leachate class material showed a trend of decrease, indicating that the denitrification bacteria may use the refractory organic matter in garbage leachate for the denitrification. The optimum ORP range was -300 mV to -100 mV for COD and total nitrogen removal, which realized the simultaneous removal of organic matter and nitrogen in landfill leachate.
Nitrification performance for secondary effluent from MWTP using bio-zeolite constructed wetland
HU Jiejun, DONG Jing, SHEN Zhiqiang, ZHOU Yuexi, CHEN Xuemin, FU Xiaoyong
2018, 8(3): 274-281. doi: 10.3969/j.issn.1674-991X.2018.03.036
Abstract:
The bio-zeolite constructed wetland (CW) pilot plant receiving a real secondary effluent of the municipal wastewater treatment plant(WWTP) was set up. The performance of bio-zeolite CW enhancing the nitrification of the WWTP secondary effluent and the effect of temperature on nitrification rate were explored during 273 days. The results indicated that the N H 4 + from secondary effluent was removed rapidly and effectively. Average removal rate of N H 4 + was 90.5% and the concentration of N H 4 + in the effluent was lower than 0.5 mg/L in the normal operation phase. After a short recovery period of 12 days, the average removal rate of N H 4 + was higher than 70%. The average removal rate of N H 4 + still remained at a relative high level as 67.6% in the low temperature stage (below 13 ℃). The temperature had signi?cant impact on the nitrification, and the average nitrification rate increased from 28% to 62% as the water temperature rose slowly from below 15 ℃ to above 25 ℃ in bio-zeolite CW. No obvious accumulation of nitrite nitrogen was found in the effluent of bio-zeolite CW except the low temperature stage, and the average concentration of nitrite nitrogen in the effluent was 0.16 mg/L. N H 4 + was mainly nitrified by microorganisms and transformed into nitrate.
Present situation and prospect of used lubricating oil recycling technology and management in China
LIANG Yangyang, LI Jinhui, DONG Qingyin, WANG Zhishi
2018, 8(3): 282-289. doi: 10.3969/j.issn.1674-991X.2018.03.037
Abstract(1403) PDF(860KB)(1063)
Abstract:
The recycling of used lubricating oil can not only reduce the pollution of the environment but also help to ease the shortage of the petroleum resources. The used lubricating oil management policy and the current situation of recycling technology were analysis. The process of used lubricating oil reclamation, reprocessing and refining were summarized, and the typical technologies such as precipitation, distillation, solvent refining and hydrofining, etc. introduced. The current applications of the technologies in treatment and recycling enterprises were surveyed, according to the intermediate links and refining process. China has established a relatively complete management system and related standards and regulations for used lubricating oil, but there are still some problems such as inadequate supervision of nonindustrial source lubricants, and some standards and regulations having been established for a long time. The survey shows that the enterprises using atmospheric and vacuum distillation (rectification) in intermediate links account for 47% in China, and more enterprises have applied more advanced molecular distillation and thin film evaporation technologies. For the refining stage, the enterprises using solvent extraction have the greatest proportion(26%). The hydrofining technology is more advanced, but the equipment investment is relatively high, and few enterprises use this technology.
Effects of drilling and thermal desorption process on the change of mineral oil compositions in oil-based mud
HE Min, ZHANG Silan, ZHANG Chun, WANG Dan
2018, 8(3): 290-296. doi: 10.3969/j.issn.1674-991X.2018.03.038
Abstract:
The compositions of three kinds of mineral oil which were from oil-based mud, oil-based cuttings and recycled mineral oil were studied by GC-MS, and the distribution characteristics of 16 PAHs with controlled priority listed by the US EPA were systematically analyzed. Based on the compositions and distribution characteristics of the organics in the mineral oil, the influences of the drilling and thermal desorption process on the change of mineral oil compositions were explored. The results show that there exist great differences of compositions among three kinds of mineral oil, among which the drilling process exerts significant influence on the mineral oil compositions of the oil-based mud. After drilling, the compositions of aromatics increase from 6 types to 16 types, with the relative content of aromatics increasing by 10%. The chlorinated hydrocarbon species and their relative content also increase obviously. The relative content of halogenated hydrocarbons in the mineral oil further increases after the thermal desorption process. The three kinds mineral oil are mainly with low-ring PAHs, and after the drilling and thermal desorption process, the PAHs in the mineral oil have the trend of changing from low ring to middle or high ring. Finally, by using the recovered mineral oil as the base oil, the experimental oil-based mud was evaluated, and it shows good performance as the recovered mineral oil can satisfy the requirement for composing the oil-based mud.
Analysis of hazardous characteristics of strontium salt residue in the production of strontium carbonate
WANG Xiyin, YANG Yanmei, YANG Yufei, YANG Jinzhong, HUANG Qifei
2018, 8(3): 297-301. doi: 10.3969/j.issn.1674-991X.2018.03.039
Abstract:
The strontium salt slag produced from the strontium carbonate production process in one strontium carbonate enterprise in different years was acquired. The contents and leaching concentrations of heavy metals and the amount of H2S after reacting with the acid in strontium slag were analyzed, and the risk characteristic of the strontium slag researched. The results showed that the Sr content of strontium slag was the highest, with the maximum value of 175 000 mg/kg and the average of 112 000 mg/kg. The maximum and average contents of Ba were 6 020 and 3 420 mg/kg, respectively. The contents of other heavy metals such as As, Cr, Cu, Ni, Pb, Be and Cd were below 100 mg/kg. The Sr concentration in strontium slag was the highest with the maximum and the average values of 360 and 180 mg/L, respectively. The leaching concentrations of Ba, Pb and As were all lower. The average concentration of H2S of strontium slag in acid reaction was 0.23 mg/kg and the maximum value was 0.45 mg/kg. The leaching of heavy metals in strontium slag and the concentration of H2S in acid reaction decreased with the increase of storage time.
Carbon emissions peak prediction in Gansu Province based on system dynamics
KONG Youhua, WANG Li, GUO Zhiling, JIANG Yunchao, WANG Bo
2018, 8(3): 309-318. doi: 10.3969/j.issn.1674-991X.2018.03.041
Abstract:
The carbon emissions peak was projected for Gansu Province which is mainly characterized by high energy-consuming industries and fragile ecology. Based on the analysis of the current situation, the carbon emissions in Gansu are divided into seven sectors, i.e. electricity, heat production and supply industry, ferrous metal smelting and rolling processing industry, petroleum processing, coking and nuclear fuel processing industry, non-ferrous metal smelting and rolling processing industry, non-metallic mineral products industry, chemical raw materials and chemical products manufacturing and transportation industry. The sub-sectors with largest carbon emission was chosen for each key energy-consuming sector, including electricity, heat industry, iron and steel industry, oil processing industry, aluminum and magnesium industry, cement industry, ammonia industry, and transportation industry. Then, the system dynamics models of sub-sector carbon emissions were established through Vensim PLE software, and eight different scenarios were set using scenario analysis method, being respectively fast-slow scheme, middle-slow scheme, slow scheme, fast-middle scheme, middle scheme, slow-middle scheme, fast scheme, middle-fast scheme, to forecast the carbon emissions peak in Gansu Province. The results show that the peak of carbon emission is 209-429 million tons, it will appear in 2028-2045. In consideration of the peak value, peak occurrence time and current development situation, middle scheme is the optimal way for achieving carbon emissions peak. According to the forecast results, it was proposed that Gansu Province should increase the industrial structure adjustment, energy structure optimization and production technology improvement.
Analysis and optimization strategies of air environmental protection industry chains
WU Na, FU Zeqiang, WANG Yanhua, WU Jia
2018, 8(3): 319-325. doi: 10.3969/j.issn.1674-991X.2018.03.042
Abstract:
Under the background of the urgent demand of air pollution control and national promotion of environmental protection industry development, and based on the definition of the concept and implications about air environmental protection industry, the characteristics and development status of different links in the upstream, downstream and mid-stream industry chains were analyzed from the aspects of leading function, product type and market situation. The upstream is the supply chain, mainly providing the downstream with raw materials, spare parts, technology and product development, etc. The mid-stream is the production chain which is responsible for equipment production concerning dust removal, desulfurization, denitration, VOCs treatment, etc. The downstream is the service chain, including air environmental technology services, environmental consulting services, air pollution facilities operation, air environment trade and financial services. On the basis of analyzing industry chain structure and development problems from links in industry chain, some suggestions to optimize the industrial chain were put forward, such as strengthening technological innovation, enhancing the comprehensive service ability of the air environment service industry, and perfecting related policies and legal system, etc.
Influence of performance and installation of ammonia spray branch pipes on uniformity distribution of NOx at the exit
XIAO Yujun, ZOU Yihui, ZHOU Xuebin, LI Caiting, ZHANG Wei, JIANG Sennian, LI Yang
2018, 8(3): 326-332. doi: 10.3969/j.issn.1674-991X.2018.03.043
Abstract:
Aiming at the different performances of SCR system owing to different structures of the flue and the ammonia-injection grid under the requirements of ultra clean emissions, the performances of typical SCR devices were analysed and optimized by testing and adjustment. The influence of branch pipe installation on the uniformity distribution of NOx at the exit was contrastively analysed, and the performances of ammonia spray branch pipes studied by the numerical simulation. The results showed that the relative standard deviations (RSDs) of inlet flue gas velocity distribution of the A, B sides of Test Device 1 were 12.4% and 14.4%, respectively. However, the performance and installation of the ammonia spray branch pipes before optimization could not realize in the NOx uniformity distribution in the depth direction of the exit cross section. After optimization, the partition control in the horizontal and vertical direction of the ammonia-injection grid system resulted in the uniform mixing of ammonia-nitrogen in Test Device 1, with the RSD of its outlet speed of 6.9%. In Test Device 2, the RSDs of the inlet flue gas velocity distribution and the outlet velocity distribution of the ammonia spray branch pipes were 27.8% and 23.7%, respectively. But, the RSD of NOx on the exit cross section was 16.3%, as a result of correct installation of ammonia spray branch pipes.
Research status and prospect of fluorinated wastewater and sludge utilization in photovoltaic industry
WANG Junjie, ZHAO Jiaojiao, MENG Xuchao, HUA Jing, JIAO Shaojun, ZHENG Yang
2018, 8(3): 333-342. doi: 10.3969/j.issn.1674-991X.2018.03.044
Abstract(1684) PDF(828KB)(574)
Abstract:
The photovoltaic industry in China is large, the treatment of fluorine-containing wastewater will generate a lot of by-products, fluorine-containing sludge, of which calcium fluoride accounts for more than 40%. It is noted that fluorine-containing sludge can replace natural fluorite ore after purification, and this will bring high market value. Accordingto the analysis of physical and chemical properties, fluoride-containing sludge not only has corrosive, toxic and other hazardous characteristics, but also has the difficulty of disposal and low utilization. Therefore, it was proposed to optimize washing pickling method by wastewater reuse and purification, so as to achieve the wastewater treatment and reduce the high cost of hydrofluoric acid inputs, while enriching F - and utilizing the newly generated Cl - containing wastewater and F - containing wastewater. By controlling the dosage of HCl, pH, reaction time, temperature and stirring rate, and comprehensively considering the operability and economic benefits of industrial production, the purity of calcium fluoride sludge can reach more than 90%.
Characteristics of sludge generation and discharge from photovoltaic cell industry in Jiangsu Province
GU Jinyi, ZHANG Jun, WANG Junjie, ZHAO Zehua, WANG Yuting, YE Fei, ZHANG Houhu, JIAO Shaojun
2018, 8(3): 343-348. doi: 10.3969/j.issn.1674-991X.2018.03.045
Abstract:
The rapid development of photovoltaic cell industry in Jiangsu Province has brought about environmental pollution problems, especially sludge and other solid waste pollution. Currently, there lack management standards and technical policies for the sludge hazardous waste treatment and identification in the industry, and relevant research is relatively scarce. Based on an overall investigation, five representative companies were chosen for study in photovoltaic cell industry in Jiangsu Province. The product types and the technological processes were investigated, and the product yields, sewage sludge generation, and fluoride content and heavy metal extraction content of mud with fluorine, etc. calculated. Taking one company for instance, the quantitative calculation was performed for each production link of fluoride generation. It turned out that the sludge discharge coefficient of photovoltaic cell companies was at 1.2-6.4 tons/MW, and the fluoride discharge coefficient was at 1.28-2.05 mg/MW. The output of sludge not only related to sewage load, but also related to the source, treatment technologies of sewage and sludge water content. The fluoride generation coefficient of typical companies was 2.859 tons/MW. The heavy metal extraction content of sludge was low.