Treatment of primary-settled urban sewage in pilot-scale vertical flow wetland filters: Comparison of four emergent macrophyte species over a 12 month period

The treatment of primary treated urban sewage by four emergent macrophytes has been compared over a twelve month period in separate gravel-based vertical flow constructed wetlands (300 litre interstitial volume). Nutrient removal in planted systems was greater than in the unplanted wetland especially for nitrogen and phosphorus and less so for BOD and suspended solids removal. The performance of most planted wetlands (especially Typha orientalis and Schoenoplectus validus) declined into autumn, particularly for nitrogen and phosphorus removal while a decline in plant ET was also observed. Baumea articulata, and to a lesser extent Cyperus involucratus, maintained high ET and nutrient assimilation throughout the trial period. As a consequence of the higher ET, dissolved solids (especially fixed salts) doubled in concentration during flow through wetlands planted with these two species, producing an effluent with a high sodium adsorption ratio and a reduced potential for re-use in irrigation.

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Pilot-scale study of vertical flow constructed wetland combined with trickling filter and ferric chloride coagulation: influence of irregular operational conditions

Water Science & Technology ◽

10.2166/wst.2015.077 ◽

2015 ◽

Vol 71 (7) ◽

pp. 1088-1096 ◽

Cited By ~ 4

Author(s):

B. Kim ◽

M. Gautier ◽

G. Olvera Palma ◽

P. Molle ◽

P. Michel ◽

...

Keyword(s):

Constructed Wetland ◽

Phosphorus Removal ◽

Water Saturation ◽

Oxygen Demand ◽

Pilot Scale ◽

Saturation Level ◽

Vertical Flow ◽

Trickling Filter ◽

Operational Conditions ◽

Vertical Flow Constructed Wetland

The aim of this study was to characterize the efficiency of an intensified process of vertical flow constructed wetland having the following particularities: (i) biological pretreatment by trickling filter, (ii) FeCl3 injection for dissolved phosphorus removal and (iii) succession of different levels of redox conditions along the process line. A pilot-scale set-up designed to simulate a real-scale plant was constructed and operated using real wastewater. The influences of FeCl3 injection and water saturation level within the vertical flow constructed wetland stage on treatment performances were studied. Three different water saturation levels were compared by monitoring: suspended solids (SS), total phosphorus (TP), dissolved chemical oxygen demand (COD), ammonium, nitrate, phosphate, iron, and manganese. The results confirmed the good overall efficiency of the process and the contribution of the trickling filter pretreatment to COD removal and nitrification. The effects of water saturation level and FeCl3 injection on phosphorus removal were evaluated by analysis of the correlations between the variables. Under unsaturated conditions, good nitrification and no denitrification were observed. Under partly saturated conditions, both nitrification and denitrification were obtained, along with a good retention of SSs. Finally, under saturated conditions, the performance was decreased for almost all parameters.

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Small wastewater treatment plants in Flanders (Belgium): standard approach and experiences with constructed reed beds

Water Science & Technology ◽

10.2166/wst.2000.0010 ◽

2000 ◽

Vol 41 (1) ◽

pp. 57-63 ◽

Cited By ~ 7

Author(s):

S. Vandaele ◽

C. Thoeye ◽

B. Van Eygen ◽

G. De Gueldre

Keyword(s):

Wastewater Treatment ◽

Removal Efficiency ◽

Wastewater Treatment Plants ◽

Treatment Plant ◽

Pilot Scale ◽

Surface Flow ◽

Limiting Factor ◽

Vertical Flow ◽

Reed Beds ◽

Reed Bed

In Flanders (Belgium) an estimated 15% of the population will never be connected to a central wastewater treatment plant (WWTP). Small WWTPs can be a valuable option. Aquafin bases the decision to build SWWTPs on a drainage area study. To realise an accelerated construction the process choice is made accordingly to a standard matrix, which represents the different technologies in function of the size and the effluent consents. A pilot scale constructed two-stage reed bed is used to optimise the concept of the reed beds. The concept consists of a primary clarifier, two parallel vertical flow reed beds followed by a sub-surface flow reed bed. The removal efficiency of organic pollutants is high (COD: 89%, BOD: 98%). Phosphorus removal is high at the start-up but diminishes throughout the testing period (from 100% to 71% retention after 7 months). Nitrogen removal amounts to 53% on average. Nitrification is complete in summer. Denitrification appears to be the limiting factor. In autumn leakage of nitrogen is assumed. Removal efficiency of pathogens amounts to almost 99%. Clogging forms a substantial constraint of the vertical flow reed bed. Problems appear to be related with presettlement, feed interval and geotextile.

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