Performance evaluation of partially saturated vertical-flow constructed wetland with trickling filter and chemical precipitation for domestic and winery wastewaters treatment

Abstract

The use of Vertical Flow Constructed Wetlands (VFCW) is growing rapidly in Europe for domestic wastewater treatment in small communities. In order to improve denitrification and dephosphatation as compared to classical VFCW, the Azoé-NP ® process has been developed. The process line consists of: a biological aerobic trickling filter as a primary treatment stage, ferric chloride (FeCl 3) addition for phosphorus (P) treatment and two stages of partially saturated VFCW. A municipal wastewater treatment plant using Azoé-NP ® process has been monitored during eight years through 44campaigns of 24h time-proportional inlet-outlet sampling followed by analyses of TSS, BOD 5 , COD, TKN, NO 3-N and TP concentrations. The results revealed good performances of the overall treatment. To better characterize the performance of each treatment step, five additional 24h monitoring campaigns were performed with samples taken from four different points along the treatment line. Results showed a good performance in dissolved carbon removal and nitrification by the trickling filter. The main part of the treatment was found to be done by filtration throughout the first filtration stage. Nitrate removal was achieved principally at the second filtration stage. Phosphorus migration through the first stage and its slight retention at the second stage was observed.

Treatment performances of French constructed wetlands: results from a database collected over the last 30 years

“…Most of them are composed of two-stages of vertical flow constructed wetlands (VFCWs) in series, but many configurations exist (association with horizontal flow, pond systems or conventional treatment systems, one stage of vertical flow with recirculation, partially saturated systems, etc.) (Aguilera Soriano et al, 2011;Prost-Boucle and Molle, 2012;Kim et al, 2014;). Current practice usually involves two treatment stages, with three units in parallel on the first stage and two for the second, with successive periods of feeding (3.5 days), and rest periods (7 days at the first stage and 3.5 at the second stage) to maintain permeability, oxygen content and to control the biomass growth (Liénard et al, 1990a, b).…”

Influence of the water saturation level on phosphorus retention and treatment performances of vertical flow constructed wetland combined with trickling filter and FeCl3 injection

“…1. This experimental setup is meant to simulate the operational units of a real-scale AZOE-NP 1 plant but focused only on the first stage of filters as previous studies had shown that the efficiency of the process mainly occurred within the 1st stage (Kim et al, 2014).…”

Study of aggregation in surface sludge deposits from 14 full-scale French constructed wetlands using particle size distribution and dynamic vapor sorption analyses

“…The treatment plants differed by the implementation or not of stages 2 and 3, as detailed in Table 1. The operating conditions of the plants were described in more details in previous articles (Kim et al, 2013;Kim et al, 2014). The selected plants differed not only by the operations in the treatment chain ( Figure 1 and Table 1) but also with respect to other parameters, such as the number of years of operation, the nominal capacity, the peak flow, the total area of VFCW stages (Table 1), and other environmental factors.…”