Microplastic abundance, characteristics and removal in large-scale multi-stage constructed wetlands for effluent polishing in northern China

2021 ◽  
pp. 132752
Author(s):  
Xu Zhou ◽  
Yingxin Zhao ◽  
Guowei Pang ◽  
Xulong Jia ◽  
Yanxing Song ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Large Scale ◽  
Northern China ◽  
Multi Stage

scholarly journals Large-scale multi-stage constructed wetlands for secondary effluents treatment in northern China: Carbon dynamics

2018 ◽  
Vol 233 ◽  
pp. 933-942 ◽  
Author(s):  
Haiming Wu ◽  
Jinlin Fan ◽  
Jian Zhang ◽  
Huu Hao Ngo ◽  
Wenshan Guo
Keyword(s):  
Constructed Wetlands ◽  
Large Scale ◽  
Northern China ◽  
Carbon Dynamics ◽  
Multi Stage ◽  
Secondary Effluents

scholarly journals Farm Size, Risk Aversion and Overuse of Fertilizer: The Heterogeneity of Large-Scale and Small-Scale Wheat Farmers in Northern China

Land ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 111
Author(s):  
Haixia Wu ◽  
Hantao Hao ◽  
Hongzhen Lei ◽  
Yan Ge ◽  
Hengtong Shi ◽  
...  
Keyword(s):  
Risk Aversion ◽  
Large Scale ◽  
Northern China ◽  
Fertilizer Application ◽  
Chemical Fertilizer ◽  
Farm Size ◽  
Small Scale ◽  
Fertilizer Use ◽  
Deviation Degree ◽  
Small Scale Farmers

The excessive use of fertilizer has resulted in serious environmental degradation and a high health cost in China. Understanding the reasons for the overuse of fertilizer is critical to the sustainable development of Chinese agriculture, and large-scale operation is considered as one of the measures to deal with the excessive fertilizer use. Under the premise of fully considering the resource endowment and heterogeneity of large-scale farmers and small-scale farmers in production and management, different production decision-making frameworks were constructed. Based on the 300 large-scale farmers and 480 small-scale farmers in eight provinces of northern China wheat region, we analyzed the optimal fertilizer use amount and its deviation as well as the influencing factors of small-scale and large-scale farmers, then further clarified whether the development of scale management could solve the problem of excessive fertilizer use. The empirical results show that: (1) both small-scale farmers and large-scale farmers deviated from the optimal fertilizer application amount, where the deviation degree of optimal fertilizer application of small-scale farmers is significantly higher than that of large-scale farmers, with a deviation degree of 35.43% and 23.69% for small and large scale farmers, respectively; (2) not all wheat growers in North China had the problem of excessive use of chemical fertilizer, as the optimal level of chemical fertilizer application in Heilongjiang and Inner Mongolia are 346.5 kgha−1 and 335.25 kgha−1, while the actual fertilizer use amount was 337.2 kgha−1 and 324.6 kgha−1, respectively; and (3) the higher the risk aversion level, farmers tended to apply more fertilizer to ensure grain output. Therefore, increasing farm size should be integrated into actions such as improving technological innovation and providing better information transfer to achieve the goal of zero-increase in Chinese fertilizer use.

Large-scale hybrid accidental urban wetland for polluted river purification in northern China: Evidence and implications for urban river management

2021 ◽  
Vol 22 ◽  
pp. 101542 ◽  
Author(s):  
Mathieu Nsenga Kumwimba ◽  
Xinzhu Li ◽  
Wei wang ◽  
L.H.D.K.U. De Silva ◽  
Linlin Bao ◽  
...  
Keyword(s):  
Large Scale ◽  
Northern China ◽  
River Management ◽  
Urban River ◽  
Polluted River ◽  
Urban Wetland

Carbon Footprint Assessment of a Large-Scale Pig Production System in Northern China: A Case Study

2018 ◽  
Vol 61 (3) ◽  
pp. 1121-1131 ◽  
Author(s):  
Yuanqing Zhou ◽  
Hongmin Dong ◽  
Hongwei Xin ◽  
Zhiping Zhu ◽  
Wenqiang Huang ◽  
...  
Keyword(s):  
Large Scale ◽  
Ghg Emissions ◽  
Northern China ◽  
Manure Management ◽  
Traditional Practice ◽  
Enteric Fermentation ◽  
Pig Production ◽  
Transport Distance ◽  
Feed Production ◽  
Crop Planting

Abstract. China raises 50% of global live pigs. However, few studies on the carbon footprint (CF) of large-scale pig production based on China’s actual production conditions have been carried out. In this study, life cycle assessment (LCA) and actual production data of a typical large-scale pig farm in northern China were used to assess the greenhouse gas (GHG) emissions or CF associated with the whole process of pig production, including feed production (crop planting, feed processing, and transportation), enteric fermentation, manure management, and energy consumption. The results showed a CF of 3.39 kg CO2-eq per kg of live market pig and relative contributions of 55%, 28%, 13%, and 4% to the total CF by feed production, manure management, farm energy consumption, and enteric fermentation, respectively. Crop planting accounted for 66% of the feed production CF, while feed processing and transportation accounted for the remaining 34%. Long-distance transport of semi-raw feed materials caused by planting-feeding separation and over-fertilization in feed crop planting were two main reasons for the largest contribution of GHG emissions from feed production to the total CF. The CF from nitrogen fertilizer application accounted for 33% to 44% of crop planting and contributed to 16% of the total CF. The CF from the transport of feed ingredients accounted for 17% of the total CF. If the amount of nitrogen fertilizer used for producing the main feed ingredients is reduced from 209 kg hm-2 (for corn) and 216 kg hm-2 (for wheat) to 140 kg hm-2 (corn) and 180 kg hm-2 (wheat), the total CF would be reduced by 7%. If the transport distance for feed materials decreased from 325 to 493 km to 30 km, along with reducing the number of empty vehicles for transport, the total CF would be reduced by 18%. The combined CF mitigation potential for over-fertilization and transport distance is 26%. In addition, the use of pit storage, anaerobic digestion, and lagoon for manure management can reduce GHG emissions from manure management by 76% as compared to the traditional practice of pit storage and lagoon. This case study reveals the impact of planting-feeding separation and over-fertilization on the CF of the pig supply chain in China. The manure management practice of pit storage, anaerobic digestion, and lagoon is much more conductive to reducing the CF as compared to the traditional practice of pit storage and lagoon. Keywords: Greenhouse gas, Life cycle assessment, Mitigation, Pig.

Two key switches in regional stress field during multi-stage deformation in the Carboniferous−Triassic southernmost Altaids (Beishan, NW China): Response to orocline-related roll-back processes

2021 ◽  
Author(s):  
Zhonghua Tian ◽  
Wenjiao Xiao ◽  
Brian F. Windley ◽  
Peng Huang ◽  
Ji’en Zhang ◽  
...  
Keyword(s):  
Stress Field ◽  
Large Scale ◽  
Electron Backscatter Diffraction ◽  
Volcanic Rocks ◽  
Structural Deformation ◽  
Regional Stress ◽  
Regional Stress Field ◽  
Multi Stage ◽  
Beishan Orogenic Collage ◽  
Roll Back

The orogenic architecture of the Altaids of Central Asia was created by multiple large-scale slab roll-back and oroclinal bending. However, no regional structural deformation related to roll-back processes has been described. In this paper, we report a structural study of the Beishan orogenic collage in the southernmost Altaids, which is located in the southern wing of the Tuva-Mongol Orocline. Our new field mapping and structural analysis integrated with an electron backscatter diffraction study, paleontology, U-Pb dating, 39Ar-40Ar dating, together with published isotopic ages enables us to construct a detailed deformation-time sequence: During D1 times many thrusts were propagated northwards. In D2 there was ductile sinistral shearing at 336−326 Ma. In D3 times there was top-to-W/WNW ductile thrusting at 303−289 Ma. Two phases of folding were defined as D4 and D5. Three stages of extensional events (E1−E3) separately occurred during D1−D5. Two switches of the regional stress field were identified in the Carboniferous to Early Permian (D1-E1-D2-D3-E2) and Late Permian to Early Triassic (D4-E3-D5). These two switches in the stress field were associated with formation of bimodal volcanic rocks, and an extensional interarc basin with deposition of Permian-Triassic sediments, which can be related to two stages of roll-back of the subduction zone on the Paleo-Asian oceanic margin. We demonstrate for the first time that two key stress field switches were responses to the formation of the Tuva-Mongol Orocline.

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