Nitrogen transformations and balance in constructed wetlands for slightly polluted river water treatment using different macrophytes

2012 ◽  
Vol 20 (1) ◽  
pp. 443-451 ◽  
Author(s):  
Haiming Wu ◽  
Jian Zhang ◽  
Rong Wei ◽  
Shuang Liang ◽  
Cong Li ◽  
...  
2019 ◽  
Vol 79 (9) ◽  
pp. 1639-1647 ◽  
Author(s):  
Lu-ji Yu ◽  
Tao Chen ◽  
Yanhong Xu

Abstract Micro-polluted river water is characterized as having limited biodegradability, low carbon to nitrogen ratio and little organic carbon supply, all of which makes it hard to further purify. Two bench scale constructed wetlands (CWs) with a horizontal subsurface flow mode were set up in the laboratory to evaluate their feasibility and efficiency on denitrification with and without corn cobs as external carbon sources. Micro-polluted river water was used as feed solution. The CW without corn cobs substrates possessed a good performance in removing chemical oxygen demand (COD, <40 mg/L) and ammonia nitrogen (NH3-N, <0.65 mg/L), but less efficiency in removing total nitrogen (TN) and nitrate nitrogen (NO3-N). In marked contrast, the CW with 1% (w/w) corn cobs substrates as external carbon sources achieved a significant improvement in the removal efficiency of TN (increased from 34.2% to 71.9%) and NO3-N (increased from 19% to 71.9%). The incorporation of corn cobs substrates did not cause any obvious increase in the concentrations of COD and NH3-N in the effluent. This improvement in the denitrification efficiency was owing to the released organic carbon from corn cobs substrates, which facilitated the growth of abundant microbes on the surface and pores of the substrate. The open area of the used corn chips is larger than that of the pristine ones, and corn cobs can continue to provide a carbon fiber source for denitrification.


2020 ◽  
Vol 12 (17) ◽  
pp. 7017
Author(s):  
Hossain Md Anawar ◽  
Rezaul Chowdhury

Selection of appropriate river water treatment methods is important for the restoration of river ecosystems. An in-depth review of different river water treatment technologies has been carried out in this study. Among the physical-engineering processes, aeration is an effective, sustainable and popular technique which increases microbial activity and degrades organic pollutants. Other engineering techniques (water diversion, mechanical algae removal, hydraulic structures and dredging) are effective as well, but they are cost intensive and detrimental to river ecosystems. Riverbank filtration is a natural, slow and self-sustainable process which does not pose any adverse effects. Chemical treatments are criticised for their short-term solution, high cost and potential for secondary pollution. Ecological engineering-based techniques are preferable due to their high economic, environmental and ecological benefits, their ease of maintenance and the fact that they are free from secondary pollution. Constructed wetlands, microbial dosing, ecological floating beds and biofilms technologies are the most widely applicable ecological techniques, although some variabilities are observed in their performances. Constructed wetlands perform well under low hydraulic and pollutant loads. Sequential constructed wetland floating bed systems can overcome this limitation. Ecological floating beds are highly recommended for their low cost, high effectiveness and optimum plant growth facilities.


2020 ◽  
Vol 18 (2) ◽  
pp. 224-228
Author(s):  
Luis Sandoval ◽  
José Luis Marín-Muñíz ◽  
Jacel Adame-García ◽  
Gregorio Fernández-Lambert ◽  
Florentina Zurita

Abstract In this study, the effect of Spathiphyllum blandum on the removal of ibuprofen (IB) and conventional pollutants such as chemical oxygen demand (COD), total nitrogen (TN), ammonium (NH4+-N), total phosphorus (TP), and total suspended solids (TSS) is reported; this, through its use as an emergent vegetation in fully saturated (FS) constructed wetlands (CWs) at mesocosm level treating polluted river water. With the exception of TP and COD, it was found that for TN (12%), NH4+-N (11%), TSS (19%), and IB (23%), the removals in systems with vegetation were superior to systems without vegetation (p < 0.05). These findings demonstrate the importance of the species S. blandum, in particular, for the removal of ibuprofen, which is an anti-inflammatory drug commonly found in effluents of wastewater treatment plants. Thus, the results obtained provide information that can be used for the design of future efficient large-scale systems using a new ornamental species, mainly under tropical climatic conditions. This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative.


2006 ◽  
Vol 76 (1) ◽  
pp. 90-97 ◽  
Author(s):  
X. Ruan ◽  
Y. Xue ◽  
J. Wu ◽  
L. Ni ◽  
M. Sun ◽  
...  

2012 ◽  
Vol 518-523 ◽  
pp. 3717-3722
Author(s):  
Jia Wei Hu ◽  
Jun Li ◽  
Yu Chen ◽  
Chang Wen Wang ◽  
Yan Li ◽  
...  

Response surface methodology (RSM) was applied to optimize the magnetic coagulation conditions for micro-polluted river water treatment. Based on single-factor experiment, Box-Behnken central composition experiment design was applied. The poly aluminum Chloride (PAC), magnetic particle, polyacrylamide (PAM), mixing stirring and flocculating stirring revolving speed were chosen as causal factors. RSM was employed to study the effects of these factors on the turbidity removal efficiency. Base on the target value (>95%), the results show that the optimum conditions were PAC 29.31mgL-1, magnetic particle 61.90mgL-1, PAM 0.48mgL-1, mixing stirring revolving speed 288rpm, flocculating stirring revolving speed 6 rpm. The average turbidity removal efficiency in three validation experiments was 95.36%, with the predicted value was 95.19%. The relative error between the measured data and the predicted value was 0.17%. It confirms that RSM was a useful tool to optimize the magnetic coagulation operating conditions for micro-polluted river water treatment.


2011 ◽  
Vol 393-395 ◽  
pp. 1304-1307 ◽  
Author(s):  
En Shi ◽  
Zong Lian She ◽  
Tian Xie ◽  
Jian Wu ◽  
Xiao Hui Fu

The main purpose of this study was to treat organic pollutants, nitrogen and phosphorus in polluted river water by the use of constructed wetland (CW) systems. A laboratory experiment research was conducted on subsurface flow constructed wetland systems operated in vertical flow (VF) and horizontal flow (HF) mode. The systems were unplanted and hydraulic retention times were identically 2.7 days. The average removal efficiencies for HFCW and VFCW were NH+ 4-N 64.9% and 75.2%, NO- 3-N 92.3% and 40.1%, COD 97.5% and 90.1%, TP 94.6% and 96.2%, respectively. The removal of NH+ 4-N and NO- 3-N in the different CW units were in order of VFCW (drained) > VFCW (flooded) > HFCW and HFCW > VFCW (flooded) > VFCW (drained), respectively. When the water level in the VFCW was changed, an obvious fluctuation of the effluent NH+ 4-N and NO- 3-N concentrations was observed.


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