Treatment Wetland Aeration without Electricity? Lessons Learned from the First Experiment Using a Wind-Driven Air Pump

Abstract

Aerated treatment wetlands have become an increasingly recognized technology for treating wastewaters from domestic and various industrial origins. To date, treatment wetland aeration is provided by air pumps which require access to the energy grid. The requirement for electricity increases the ecological footprint of an aerated wetland and limits the application of this technology to areas with centralized electrical infrastructure. Wind power offers another possibility as a driver for wetland aeration, but its use for this purpose has not yet been investigated. This paper reports the first experimental trial using a simple wind-driven air pump to replace the conventional electric air blowers of an aerated horizontal subsurface flow wetland. The wind-driven air pump was connected to a two-year old horizontal flow aerated wetland which had been in continuous (24 h) aeration since startup. The wind-driven aeration system functioned, however it was not specifically adapted to wetland aeration. As a result, treatment performance decreased compared to prior continuous aeration. Inconsistent wind speed at the site may have resulted in insufficient pressure within the aeration manifold, resulting in insufficient air supply to the wetland. This paper discusses the lessons learned during the experiment.

Recent Advances in the Application, Design, and Operations & Maintenance of Aerated Treatment Wetlands

“…Many bench-scale and pilot-scale research studies have investigated the use of intermittent aeration [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65]. Intermittent aeration via windmill-powered air pumps has also been tested [66]. By far, most research studies on aerated wetlands are bench-scale studies operated under controlled steady-state conditions, run for relatively short periods of time (less than one year).…”

Resilience of Micropollutant and Biological Effect Removal in an Aerated Horizontal Flow Treatment Wetland

“…The system is unplanted. It started operation in June 2010, was run with a windmill-powered air pump between August 2012 and July 2014 [29], and was switched back to continuous aeration in 2014. The system has a surface area of 6.2 m 2 , a saturated depth of 1.0 m and was continuously aerated (24 h/d) by two pumps (one in the first half: 1.2 m 3 /h; one in the second half: 1.0 m 3 /h; Mistral 2000, Aqua Medic).…”

Constructed Wetlands for Water Treatment: New Developments

“…The incorporation of forced aeration in CWs is one of the latest trends in CW design, and is highlighted by the submission of four publications on this topic for the present issue [10][11][12][13]. He et al [10] made use of aeration to overcome the limitations of high alkaline stripped effluent.…”

“…The mixing patterns in the bed demonstrated a decrease in volumetric efficiency over time; thus, no significant benefit to the long-term hydraulics of the systems was found [11]. Boog et al [12] report the first experimental trial using a simple wind-driven air pump to replace the conventional electric air blowers of an aerated horizontal subsurface flow CW. The wind-driven aeration system was functional, but treatment performance was lower compared with prior continuous aeration.…”

“…Inconsistent wind speeds at the site were indicated to result in insufficient pressure within the aeration manifold and consequently affect the air supply to the wetland bed. Several practical considerations are discussed for future advances in the topic [12]. Zhai et al [13] report on the operation of a full-scale hybrid CW consisting of a continuously aerated vertical-baffled flow wetlands (VBFWs) followed by horizontal subsurface flow wetlands (HSFWs), used to improve nutrient removal from sewage wastewater.…”