Nitrogen elimination from landfill leachates using an extra carbon source in subsurface flow constructed wetlands

Abstract

A three-stage constructed wetland for leachate treatment was monitored on a landfill at a pilot scale. The plant had been designed to achieve at least 75% nitrogen removal. NH4-N input concentration was 240 (median) up to 290 mgl(-1) and COD concentration was 455 to 511 mgl(-1), respectively. A 14 m2 vertical flow sand filter plus a 14 m2 horizontal flow sand filter followed by a 3.3 m2 vertical flow sand filter was chosen. Acetic acid was added to the horizontal flow system for denitrification. The results showed a very stable nitrification rate within the vertical flow system of 94% (median) at NH4-N loading rates of about 10 (median) up to 17 gm(-2)d(-1). Denitrification was mainly dependent on the dosing of acetic acid and could reach a maximum of 98%. One interesting effect was the production of nitrite in the horizontal flow sand filter. This could efficiently be eliminated by the subsequent vertical flow sand filter. The chosen concept proved to be very effective for nitrogen removal. In combination with a final activated carbon filter the COD effluent concentrations could be easily and safely controlled. The design of denitrification reed beds showed a further potential for optimization.

The Efficiency and Reliability of Pollutant Removal in a Hybrid Constructed Wetland with Common Reed, Manna Grass, and Virginia Mallow

“…At the same time, low concentrations of total nitrogen and its aerobic forms at the outflow from the sewage treatment plant indicated that heterotrophic reduction of nitrates had a smooth course. The factor stimulating this process was the high supply of organic compounds [56,57]; however, Zhao et al [58] pointed out that there were exceptions to this rule. This led to the conclusion that the BOD 5 :N ratios allowing optimal denitrification coefficients are, to a large extent, dependent on the individual features of the constructed wetland system, including the configuration of the beds, the plant species used, the accumulation and decay of plant material in the bed or the type of sewage, and the structure of the nitrogen compounds [16].…”

Influence of composition of raw wastewater on removal of nitrogen compounds in multistage treatment wetlands

“…In the recent papers, the key factors supporting proper maintenance of TWs have been discussed. Among others, the load of hydraulic, organics and nitrogen influence the TWs operation, their influence on clogging and pollutants removal have been described [1,18]. In the case of the MTWs analyzed in this work, all above mentioned parameters fulfill the recommended conditions that leads to effective removal of both nitrogen and carbonaceous compounds.…”

“…Reject water (RW) discharged to the pilot MTW Wschód was characterized by the typical composition as for the liquors generated during mechanical dewatering of the digested sludge [16]. Furthermore, the characteristic of the RW was similar to that of landfill leachate from the mature municipal damping site [17][18][19][20]. The share of ammonium nitrogen in TN was 90% in the RW fed to the first tank.…”

METHANE EMISSION POTENTIAL AND INCREASED EFFICIENCY OF A PHYTOREMEDIATION SYSTEM BIOAUGMENTED WITHBACILLUS FIRMUSXJSL 1–10

“…There is limited information on bioaugmentation studies in constructed wetland for waste water treatment. Rustige and Nolde (2007) had performed laboratory experiments with specially adapted biomass that has been added to columns imitating constructed wetlands. In another study by Paredes et al (2007) a subsurface flow constructed wetland was inoculated with anammox biomass and the rate of nitrogen removal was increased by 4-5-fold.…”