Performances of constructed wetlands for municipal wastewater treatment in rural mountainous area (original) (raw)
Related papers
Water Science & Technology, 2012
One of the limits for the application of constructed wetlands (CWs) in mountain regions (such as the Alps) is associated with the considerable land area requirements. In some mountain areas, the treatment of domestic wastewater at popular tourist destinations is particularly difficult during the summer, when the presence of visitors increases hydraulic and organic loads. This paper aims to evaluate whether a hybrid CW plant designed on the basis of the resident population only, can treat also the additional load produced by the floating population during the tourist period (summer, when temperatures are favourable for biological treatment), without a drastic decrease of efficiency and without clogging problems. The research was carried out by considering two operational periods: the first one was based on literature indications (3.2 m2/PE in the VSSF unit) and the second one assumed higher hydraulic and organic loads (1.3 m2/PE in the VSSF unit). The removal efficiency in the hybrid...
Performance of two small subsurface flow constructed wetlands treating domestic wastewaters in Italy
The performance of a vertical and a horizontal subsurface flow wetland (v-SSF and h-SSF), designed for treating domestic wastewater from a single family, was investigated by monitoring total nitrogen (TN), nitrate nitrogen (NO3-N), ammonium nitrogen (NH4-N), total phosphorus (TP), chemical oxygen demand (COD) and the dissolved oxygen (DO) content of the influent and the effluent wastewater of each system during the first two years of operation. The growth of Phragmites australis in each system was recorded by measuring the height and observing their general conditions. The treated domestic wastewater presented similar chemical–physical characteristics in the two systems which operated in analogous environmental conditions. The median influent characteristics were: TN 81.9 mg L−1, NO3-N 0.19 mg L−1, NH4-N 33.5 mg L−1, TP 11.9 mg L−1 and COD 354.5 mg L−1. During the whole monitoring period median reductions in the v-SSF were TN 71%, NH4-N 94%, TP 27% and COD 92% whereas in the h-SSF they were TN 59%, NH4-N 21%, TP 52% and COD 70%. Internal production of NO3-N was observed, mainly in the v-SSF probably due to the difference in oxygen availability in the medium and the design of the system. DO concentration increased in the effluents in both years, with higher values measured in v-SSF than in h-SSF. The reduction performance increased in the second year, particularly in v-SSF, whereas no statistical differences were observed between spring–summer and autumn–winter periods. P. australis reached maximum development at the end of summer in both systems and maintained a stable height during autumn–winter. In h-SSF the vegetation located close to the influent showed lower growth than in the rest of the bed.
Linnaeus Eco-Tech, 2019
The efficiency of pollution removal from municipal sewage in two vertical flow constructed wetlands consisting of gravel filters with surface area 4 x 5 m, depth 60 cm, covered by reed was evaluated over a period of two years. The flow of wastewater was about 50 mm per day. Wastewater underwent only mechanical treatment before reed bed B, but reed bed A was supplied with wastewater after biological treatment with activated sludge. Sewage was sampled before and after filtration every IO days. Measurements were made of sewage supply and discharge, precipitation and wastewater temperatures. The main indicator of efficiency was the elimination of suspended solids, carbon, nitrogen and phosphorus from the wastewater during filtration. The elimination of the pollution load was 2-25 g per square meter per day for the BOD 5 and 0-3.5 g per square meter per day for total nitrogen. Rates of pollution removal were between 2 and 4 times as high in bed B as in bed A. The rate ofBOD 5 removal and the coefficient k for BOD5 were strongly dependent on temperature for reed bed B; less so far for bed A. The difference between summer and winter indicates that the surface area of constructed wetland B should be 3 times bigger during winter to obtain the summer rate ofBOD 5 pollution removal in the climatic conditions ofNorth Poland (54a° N).
Ecological Engineering, 2014
Four constructed wetlands with horizontal subsurface flow situated 500 m a.s.l. were surveyed in order to evaluate long-term treatment efficiency. The results revealed that treatment performance of all surveyed constructed wetlands is excellent for organics and suspended solids and varied between 88% and 94% for BOD 5 , 67% and 85% for COD and 74% and 96% for TSS. Removal of NH 4 +-N in CWs Zásada has improved over the time of operation and average treatment efficiency amounted to 53%. There was no difference between summer and winter NH 4-N outflow concentrations. Average removal of TP amounted to 59% and the removal efficiency was very stable over the 18 years of operation.
Water Science & Technology, 2011
The paper presents the detailed design and some preliminary results obtained from a study regarding a wastewater treatment pilot plant (WWTPP), serving as a multistage constructed wetland (CW) located at the rural settlement of 'Chorfech 24' (Tunisia). The WWTPP implemented at Chorfech 24 is mainly designed as a demonstration of sustainable water management solutions (low-cost wastewater treatment), in order to prove the efficiency of these solutions working under real Tunisian conditions and ultimately allow the further spreading of the demonstrated techniques. The pilot activity also aims to help gain experience with the implemented techniques and to improve them when necessary to be recommended for wide application in rural settlements in Tunisia and similar situations worldwide. The selected WWTPP at Chorfech 24 (rural settlement of 50 houses counting 350 inhabitants) consists of one Imhoff tank for pre-treatment, and three stages in series: as first stage a horizontal subsurface flow CW system, as second stage a subsurface vertical flow CW system, and a third horizontal flow CW. The sludge of the Imhoff tank is treated in a sludge composting bed. The performances of the different components as well as the whole treatment system were presented based on 3 months monitoring. The results shown in this paper are related to carbon, nitrogen and phosphorus removal as well as to reduction of micro-organisms. The mean overall removal rates of the Chorfech WWTPP during the monitored period have been, respectively, equal to 97% for total suspended solids and biochemical oxygen demand (BOD 5 ), 95% for chemical oxygen demand, 71% for total nitrogen and 82% for P-PO 4 . The removal of E. coli by the whole system is 2.5 log units.
To foster the practical development of the constructed wetlands used for water quality enhancement in Turkey, 2 vertical subsurface flow pilot-scale constructed wetlands were implemented on the METU campus, Ankara, Turkey. Both of the wetlands were planted with Phragmites australis and operated identically at a flowrate of 3 m3.d 1 and a hydraulic loading rate (HLR) of 0.100 m.d 1, intermittently. The main objective of the research was to quantify the eect of dierent substrates (gravel and blast furnace granulated slag) on the nutrient removal performance of the constructed wetlands in the prevailing climate of Ankara. According to the monitoring study (July 2002-January 2003), concentration based average removal eciencies for the slag and gravel reed beds were as follows: TSS (64% and 62%), COD (49% and 40%), NH+ 4 -N (88% and 58%), TN (41% and 44%), TP (63% and 9%) and PO3 4 -P (60% and 4%). In general, the treatment performance of the slag system was better than that of the grave...
Constructed Wetlands as a Sustainable Solution for Wastewater Treatment in Small Villages
Biosystems Engineering, 2004
With the aim of solving the wastewater treatment problem in small villages, treatment performance of a pilotscale subsurface-flow constructed wetland (SFW) was evaluated for removal efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total and faecal coliform and faecal streptococci bacteria from raw municipal wastewater. Studies of the composition and thermal behaviour of the harvested biomass were achieved in order to assess their possible utilisation as a fuel.
Desalination, 2007
Performance and behaviour of a subsurface-horizontal flow constructed wetlands (SSF-h CW) used for sewage post-treatment behind an upflow anaerobic reactor under Moroccan climate conditions are reported. The experimental setup included three parallel beds of 28 m 2 , each receiving 9.5 m 3 d −1 of pre-treated sewage corresponding to a hydraulic loading rate of 0.34 m(m 2 d) −1 and a COD loading rate of 0.15 kg (m 2 d) −1 . Beds 1 and 2 were planted with Phragmites australis and Arundo donax, respectively, and bed 3 was kept unplanted (control). Average data reported here coincided with a plant age going from 12 to 18 months and covered an entire cold season and the early part of the hot season. Average water losses by evapotranspiration amounted 40 and 57 mm d −1 , respectively, for Arundo and Phragmites, while evaporation did not exceed 7 mm d −1 for the unplanted bed. Percentage of losses given as the ratio of lost flow/applied flow, amounted 11, 17 and 2%, respectively, for Arundo, Phragmites and the control.
REMOVAL EFFICIENCY OF CONSTRUCTED WETLAND FOR TREATMENT OF AGRICULTURAL WASTEWATERS
Constructed wetlands were proven to be the efficient method for treatment of agricultural wastewaters in last two decades. In this study, the performance of a constructed wetland for treating wastewater from small farm was tested. The constructed wetland for 75 PE with horizontal subsurface flow at Chrámce, Central Bohemian Uplands, Czech Republic, was built in 2011. A hybrid constructed wetland combining the horizontal (HF), vertical filter (VF) and horizontal (HF) filter stages has been designed to treat wastewater from the agriculture production (processing of fruits, sheep, pigs, production of jams, spirits and wine, etc.). The mechanical pretreatment consists of two accumulation tanks (for different wastewater types) from which the wastewater is intermittently pumped into a settling tank. The treatment system consists of two horizontal flow beds and one vertical flow bed with intermittent feeding. The filters are planted with Phragmites australis, Phalaris arundinacea, Iris pseudacorus, Iris sibirica, Glyceria maxima and Lythrum salicaria. For tertiary treatment, three shallow ponds with littoral vegetation were designed. During the feed batch operation the inflow values up to 25.400 mg/L COD and 2.640 mg/L BOD 5 were reduced by up to 99%. The volume of each feed batch was applied at one to five day intervals. Also, the effect of discharged water on the littoral zone of aquatic biotopes has been evaluated. This knowledge is necessary for the design of a stable, artificial water system.
Turkish Journal of Engineering and Environmental Sciences, 2004
To foster the practical development of the constructed wetlands used for water quality enhancement in Turkey, 2 vertical subsurface flow pilot-scale constructed wetlands were implemented on the METU campus, Ankara, Turkey. Both of the wetlands were planted with Phragmites australis and operated identically at a flowrate of 3 m 3 .d −1 and a hydraulic loading rate (HLR) of 0.100 m.d −1 , intermittently. The main objective of the research was to quantify the effect of different substrates (gravel and blast furnace granulated slag) on the nutrient removal performance of the constructed wetlands in the prevailing climate of Ankara. According to the monitoring study (July 2002-January 2003), concentration based average removal efficiencies for the slag and gravel reed beds were as follows: TSS (64% and 62%), COD (49% and 40%), NH + 4-N (88% and 58%), TN (41% and 44%), TP (63% and 9%) and PO 3− 4-P (60% and 4%). In general, the treatment performance of the slag system was better than that of the gravel system.