Four horizontal subsurface flow constructed wetlands (HSFCWs), named HSFCW1 (three-stage, without step-feeding), HSFCW2 (three-stage, with step-feeding), HSFCW3 (five-stage, without step-feeding) and HSFCW4 (five-stage, with step-feeding) were designed to investigate the effects of dissolved oxygen (DO) and step-feeding on nitrogen removal. High removal of 90.9% COD, 99.1% ammonium nitrogen and...

Arsenic pollution in aquatic environments is a worldwide concern due to its toxicity and chronic effects on human health. This concern has generated increasing interest in the use of different treatment technologies to remove arsenic from contaminated water. Constructed wetlands are a cost-effective natural system successfully used for removing various pollutants, and they have shown capability...

The use of constructed wetlands is a relatively new technology but the system is gaining popularity due to its low tech system for treating wastewater (DeBusk, 1999b).Constructed wetlands have found to be effective in treating domestic wastewater where municipalities are concerned with reducing suspended solids, organic matter, phosphorus, nitrogen, and pathogens. Constructed wetlands mimic nat...

The first experiments on the use of wetland plants to treat wastewaters were carried out in the early 1950s by Dr. Käthe Seidel in Germany. The first full scale systems were put in operation during the late 1960s and since then constructed wetland systems have been spreading throughout the world. At present, there are several types of constructed wetlands used for wastewater treatment. Free wat...

Constructed wetlands have been proposed as a potential best management practice (BMP) to mitigate effects of pesticide-associated agricultural runoff. Wetland mesocosms (14 m x 59-73 m) were amended with chlorpyrifos to simulate a storm runoff event at concentrations of 73, 147 and 733 microg/l. Water, sediment and plant samples collected weekly for 12 weeks indicated that chlorpyrifos rapidly ...

During the past decades, the high cost of conventional treatment processes has produced much economic pressure and they are not as natural methods as we expected. Thus, engineers begin to search for some creative, cost effective, and environmentally sound ways to treat wastewaters. Constructed wetland is a man made system which provides us many benefits and it is a very attractive way for many ...