Department of Civil Engineering, Ahsanullah University of Science and Technology, Dhaka, Bangladesh.
Chemosphere. 2012 Aug;88(9):1065-73. doi: 10.1016/j.chemosphere.2012.04.055. Epub 2012 Jun 5.
This paper reports the pollutant removal performances of a hybrid wetland system in Bangladesh for the treatment of a tannery wastewater. The system consisted of three treatment stages: a subsurface vertical flow (VF) wetland, followed by a horizontal flow (HF) and a VF wetland. The wetlands were planted with common reed (Phragmites australis), but employed different media, including organic coco-peat, cupola slag and pea gravel. In the first stage, experimental results demonstrated significant removal of ammonia (52%), nitrate (54%), BOD (78%), and COD (56%) under high organics loading rate (690 g COD m(-2)d(-1)); simultaneous nitrification, denitrification, and organics degradation were attributed to the unique characteristics of the coco-peat media, which allowed greater atmospheric oxygen transfer for nitrification and organic degradation, and supply of organic carbon for denitrification. The second stage HF wetland produced an average PO(4) removal of 61%, primarily due to adsorption by the iron-rich cupola slag media. In the third treatment stage, which was filled with gravel media, further BOD removal (78%) from the tannery wastewater depleted organic carbon, causing the accumulation of NO(3) in the wastewater. Overall, the average percentage removals of NH(3)-N, NO(3)-N, BOD, COD, and PO(4) were 86%, 50%, 98%, 98% and 87%, respectively, across the whole hybrid system. The results provided a strong evidence to support widespread research and application of the constructed wetland as a low-cost, energy-efficient, wastewater treatment technology in Bangladesh.
本文报道了一个混合湿地系统在孟加拉国处理制革废水的污染物去除性能。该系统由三个处理阶段组成：地下垂直流（VF）湿地，随后是水平流（HF）和 VF 湿地。湿地种植了普通芦苇（Phragmites australis），但采用了不同的介质，包括有机椰糠、冲天炉渣和豌豆砾石。在第一阶段，实验结果表明，在高有机物负荷率（690 g COD m(-2)d(-1)）下，氨（52%）、硝酸盐（54%）、BOD（78%）和 COD（56%）的去除效果显著；同时硝化、反硝化和有机物降解归因于椰糠介质的独特特性，它允许更大的大气氧气转移用于硝化和有机物降解，并提供有机碳用于反硝化。第二阶段 HF 湿地的 PO(4)去除率平均为 61%，主要是由于富含铁的冲天炉渣介质的吸附作用。在第三处理阶段，填充了砾石介质，从制革废水中进一步去除 BOD（78%）耗尽了有机碳，导致废水中的 NO(3)积累。总的来说，整个混合系统的 NH(3)-N、NO(3)-N、BOD、COD 和 PO(4)的平均去除率分别为 86%、50%、98%、98%和 87%。研究结果为在孟加拉国广泛研究和应用湿地作为一种低成本、节能、废水处理技术提供了有力证据。
