Comparative research on phosphorus removal by pilot-scale vertical flow constructed wetlands using steel slag and modified steel slag as substrates

2015 ◽  
Vol 71 (7) ◽  
pp. 996-1003 ◽  
Author(s):  
Yupan Yun ◽  
Xiaoqin Zhou ◽  
Zifu Li ◽  
Sayed Mohammad Nazim Uddin ◽  
Xiaofeng Bai
Keyword(s):  
Constructed Wetlands ◽  
Phosphorus Removal ◽  
Steel Slag ◽  
Pilot Scale ◽  
Phosphorus Concentration ◽  
Vertical Flow ◽  
Phosphorus Adsorption ◽  
Vertical Flow Constructed Wetlands ◽  
Low Phosphorus ◽  
Set Up

This research mainly focused on the phosphorus removal performance of pilot-scale vertical flow constructed wetlands with steel slag (SS) and modified steel slag (MSS). First, bench-scale experiments were conducted to evaluate the phosphorus adsorption capacity. Results showed that the Langmuir model could better describe the adsorption characteristics of the two materials; the maximum adsorption of MSS reached 12.7 mg/g, increasing by 34% compared to SS (9.5 mg/g). Moreover, pilot-scale constructed wetlands with SS and MSS were set up outdoors. Then, the influence of hydraulic retention time (HRT) and phosphorus concentration in phosphorus removal for two wetlands were investigated. Results revealed that better performance of the two systems could be achieved with an HRT of 2 d and phosphorus concentration in the range of 3–4.5 mg/L; the system with MSS had a better removal efficiency than the one with SS in the same control operation. Finally, the study implied that MSS could be used as a promising substrate for wetlands to treat wastewater with a high phosphorus concentration. However, considering energy consumption, SS could be regarded as a better alternative for substrate when treating sewage with a low phosphorus concentration.

Removal of fluoride and arsenic by pilot vertical-flow constructed wetlands using soil and coal cinder as substrate

2014 ◽  
Vol 70 (4) ◽  
pp. 620-626 ◽  
Author(s):  
Juan Li ◽  
Xinchun Liu ◽  
Zhisheng Yu ◽  
Xin Yi ◽  
Yiwen Ju ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Constructed Wetlands ◽  
Pilot Scale ◽  
Vertical Flow ◽  
Arsenic Adsorption ◽  
Artificial Wetlands ◽  
Arsenic Accumulation ◽  
Vertical Flow Constructed Wetlands ◽  
High Fluoride ◽  
Set Up

This study evaluated the performance of soil and coal cinder used as substrate in vertical-flow constructed wetlands for removal of fluoride and arsenic. Two duplicate pilot-scale artificial wetlands were set up, planted respectively with cannas, calamus and no plant as blank, fed with a synthetic sewage solution. Laboratory (batch) incubation experiments were also carried out separately to ascertain the fluoride and arsenic adsorption capacity of the two materials (i.e. soil and coal cinder). The results showed that both soil and coal cinder had quite high fluoride and arsenic adsorption capacity. The wetlands were operated for two months. The concentrations of fluoride and arsenic in the effluent of the blank wetlands were obviously higher than in the other wetlands planted with cannas and calamus. Fluoride and arsenic accumulation in the wetlands body at the end of the operation period was in range of 14.07–37.24% and 32.43–90.04%, respectively, as compared with the unused media.

Study of oyster shell as a potential substrate for constructed wetlands

2013 ◽  
Vol 13 (4) ◽  
pp. 1007-1015 ◽  
Author(s):  
Zhen Wang ◽  
Jian Dong ◽  
Lin Liu ◽  
Gefu Zhu ◽  
Chaoxiang Liu
Keyword(s):  
Constructed Wetlands ◽  
Phosphorus Removal ◽  
Oyster Shell ◽  
Swine Wastewater ◽  
Vertical Flow ◽  
Flow State ◽  
Phosphorus Adsorption ◽  
Study Results ◽  
Predominant Form ◽  
Potential Substrate

We tested the suitability of oyster shell (OS) as a substrate for phosphorus removal in constructed wetlands (CWs) treating swine wastewater. OS is proven to have a significant phosphorus adsorption capacity; significant phosphorus removal was achieved in vertical subsurface flow constructed wetlands (VSSFs) that were filled with OS and used to treat swine wastewater. In the VSSF system, OS adsorption and precipitation played the greatest role in phosphorus removal, and the phosphorus distribution in the substrate layers was attributed to the vertical flow state of wastewater in the system. Ca–P was the predominant form of phosphorus in the system. Overall, the study results showed that OS could be used for phosphorus removal in CWs. OS also allowed for reuse of a waste substance, making the overall system more environmentally friendly.

Comprehensive evaluation of substrates in vertical-flow constructed wetlands for domestic wastewater treatment

2015 ◽  
Vol 10 (3) ◽  
pp. 625-632 ◽  
Author(s):  
Junmei Wu ◽  
Dong Xu ◽  
Feng He ◽  
Jie He ◽  
Zhenbin Wu
Keyword(s):  
Constructed Wetlands ◽  
Nitrogen Removal ◽  
Phosphorus Removal ◽  
Evaluation System ◽  
Comprehensive Evaluation ◽  
Steel Slag ◽  
Domestic Wastewater ◽  
Vertical Flow ◽  
Substrate Selection ◽  
Comprehensive Evaluation System

Substrates are the important component of constructed wetlands (CWs), which have an effect on construction cost, purification capability and stable operation, so that substrate optimization is the key part of CWs design. The comprehensive evaluation system, including four layers, eleven indicators and nine schemes, for substrates in vertical-flow CWs treating domestic wastewater was established based on analytic hierarchy process. Then combined with Delphi method and fuzzy synthetic evaluation approach, zeolite, anthracite, shale, vermiculite, ceramic filter material, gravel, steel slag, bio-ceramic and combination substrate (isopyknic layered anthracite, bio-ceramic and zeolite) were evaluated from the viewpoints of purification effect, practical performance and economic analysis. The results showed that phosphorus removal, nitrogen removal, chemical stability were the main factors of substrate selection. Combination substrate was the best scheme among nine substrates. Zeolite was ideal substrate for nitrogen removal and biocompatibility, while anthracite and steel slag were ideal substrates for phosphorus removal. The comprehensive evaluation system of substrates was beneficial to comprehensive compare all aspects of performance for different substrates, and could be improved according to the actual situation of engineering applications, so as to provide guidance of substrate selection for CWs design.

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