Surface Flow Constructed Wetland System Research Articles

Identification of microbial consortia for sustainable disposal of constructed wetland reed litter wastes.

Reed is a typical emerged plant in constructed wetlands (CWs). Its litters were used as raw materials for preparing Fe-C ceramic-filler (Fe-C-CF). The physical and chemical properties of Fe-C-CF were studied under different conditions, including the mass ration of Fe to carbon (Fe/C ratio), sintering temperature, and time, to determine the optimum preparing conditions. Meanwhile, the denitrification performance and CO2 emission flux of the surface flow constructed wetland (SFCW) systems were investigated when using Fe-C-CF as the matrix. The optimum preparing conditions for Fe-C-CF were Fe/C ratio of 1:1, sintering temperature and time of 500°C and 20min, respectively. The SFCW system with Fe-C-CF obtained a higher total nitrogen (TN), nitrate nitrogen (NO3--N), and ammonia nitrogen (NH3-N) removal efficiencies than the control SFCW system without Fe-C-CF. Compared with the heterotrophic denitrification process, the SFCW system with Fe-C-CF decreased CO2 emission by 67.9gm-2 per year. The results of microbial community analysis indicated that addition of Fe-C-CF increased the diversity and abundance of microbial communities in the SFCW systems. The dominant genus of the SFCW system with Fe-C-CF was Bacillus, while Uliginosibacterium was the dominant genus in the system without the filler.

Removal of Fe in well water using surface flow constructed wetland system with Eichhornia crassipes and Pistia stratiotes L.

Removal of Fe in well water using surface flow constructed wetland system with Eichhornia crassipes and Pistia stratiotes L.

The suitable biomass carbon source for improving nitrogen removal in surface flow constructed wetland system: Fresh vs. withered

Plant biomass can be used as a carbon source to enhance the nitrogen removal effect. Related researches mainly focused on withered biomass, while little on fresh biomass. In this study, batch experiments revealed that the carbon release rate (60.5mg TOC g-1) of fresh biomass was significantly higher than that of withered biomass (44.9mg TOC g-1), while the nitrogen release rate showed the opposite trend. Compared with withered biomass, fresh biomass could release more sugar and less refractory humic acid, which means higher bioavailability. After adding fresh biomass, TN removal rate increased from 18.65% to 51.59%. The TN removal in the wetland adding withered biomass increased from 13.59% to 42.25%. The biomass addition had a slight impact on the effluent sensory quality in the first two days. After adding fresh biomass and withered biomass, the relative abundance of denitrifying bacteria like Flavobacterium and Pseudomonas in the system significantly increased. In general, fresh biomass was more suitable as a denitrification carbon source for surface flow constructed wetlands.

Improved denitrification in surface flow constructed wetland planted with calamus

The calamus type surface-flow constructed wetland (SFCW) is widely used for treating low-polluted water bodies, such as effluents from wastewater treatment plants. The calamus biomass is considered a potential carbon source for denitrification, integrating plant biomass into the carbon cycle in SFCWs. This study conducted experiments on the calamus biomass decomposition and evaluated its potential application for denitrification in an SFCW system. We showed that decomposition of the biomass could release a high ratio of total organic carbon (TOC) to total nitrogen (TN), reaching 26.9, 27.7, and 23.6 at biomass doses of 0.1, 0.5, and 1.0 g L −1 . A continuous-flow experiment on the SFCW system revealed that higher TN removal efficiency and load were obtained after the addition of biomass, approximately three times before the biomass addition. Microbial community analysis revealed an increase in heterotrophic denitrifying bacteria (i.e., Flavobacterium , Dechloromonas , and Bacillus ) content throughout the period of biomass addition. This study demonstrated an excellent enhancement of the denitrification efficiency in the SFCW caused by the addition of calamus biomass, suggesting its potential application as an excellent plant carbon source for biological denitrification. • A high C/N ratio (26.9) was released from decomposing 0.1 g L −1 of calamus biomass. • Calamus biomass can be used as carbon source in denitrification processes. • Denitrification efficiency was enhanced by about 200% with the addition of biomass. • Content of denitrifying bacteria was increased by 8 times via adding the biomass.

KINETICS OF PHOSPHATE REMOVAL FROM DOMESTIC WASTEWATER BY CONSTRUCTED WETLAND WITH JOYWEED (Alternanthera sp.)

This study aims to determine the dynamics of phosphate removal process in domestic wastewater through wastewater treatment mechanism of constructed wetland with Joyweed (Alternanthera sp.). The experiment was conducted in batches with a retention time of 12 days, the treatments were designed to evaluate the effect of depth of the water with and without Alternanthera sp. on the ability to remove phosphate in wastewater. After 12 days of operation, all experiments reduced phosphate concentration in the effluent. The highest phosphate removal efficiency is at day 9 (about 69\%). Two kinetic equations of first-order and second-order are used to determine the trend of PO43- removal process in the system. The second-order kinetic equation is more suitable for treating PO43- in domestic wastewater by surface flow constructed wetland system. The results of this study show the potential of domestic wastewater treatment of Alternanthera sp. in the constructed wetland.

Design Methodology of a New Surface Flow Constructed Wetland System, Case Study: East South EL-Kantara Region North Sinai, Egypt

In this paper, a model is developed based on simple equations to design a surface flow constructed wetland system (SFCWL). The hydraulics of the system and the pollutant removal based on first-order plug flow requirements for biological oxygen demand (BOD), Fecal Coli, Nitrogen (N), and total suspended solids (TSS) were considered. The model was applied to design SFCWL of vegetated cells (reed) followed by a storage pond system to treat 6000 m3/day of the degraded agricultural drainage water in the East South EL-Kantara region, North Sinai, Egypt. The model input data are summer air temperature 27 oC, winter air temperature 15 oC, influent concentrations for BOD 120 mg/l, Fecal Coli Number 10000/100 mL, TSS 155 mg/l, Phosphorus 5 mg/l, and Nitrogen 20 mg/l. The model output shows 3.54 days retention time, the total area of the system including a storage pond is 25.7 hectares. The expected overall pollutant removal efficiencies are 83.3 %, 99.5 %, 88.6%, 66%, and 50% for BOD, Fecal Coli, TSS, total Nitrogen and total Phosphorus respectively. The proposed wastewater treatment system as a promising low-cost treatment alternative can change polluted agriculture drainage water into an unconventional water source that can be utilized for irrigation and environment-friendly.

Enhancement of nitrogen removal via addition of cattail litter in surface flow constructed wetland

Abstract: Decomposition of aquatic plant litters is an important process in ecological system, which will significantly affect the water environment and internal organisms. In this study, cattail litter was added into surface flow constructed wetland (SFCW) system to utilize as the additional carbon source for denitrification process. The adding method for the litter was determined by evaluating the influence of different adding methods on the water environment (pH, dissolved oxygen) and the litter utilization efficiency. Then, the change of effluent organic concentration (total organic carbon, TOC) and nitrogen removal efficiency of the system was investigated after the litter addition, meanwhile, the microbial community change was analyzed by high-throughput sequencing. The results showed that cattail litter should be added in batches to the SFCW system with the dosage of 0.1 g L−1 d−1, and the TN removal and loading of the system were significantly increased without obvious increase of the effluent TOC. After the litter addition, summer had higher increasing level of the denitrification efficiency of the system, which was lower in winter. This study could provide suitable method for cycling utilization of aquatic plant litters, and improve the denitrification effect of SFCW system.

Performance assessment of horizontal and vertical surface flow constructed wetland system in wastewater treatment using multivariate principal component analysis

This study aimed to compare the horizontal flow (HFCW) and vertical flow (VFCW) constructed wetland systems in treating dairy wastewater (DWW) and simultaneously harvesting plant biomass from units. The HFCW and VFCW were designed at lab-scale using cattail (Typha angustifolia) and changes in DWW parameters: pH, EC, TSS, NO3-N, NH4-N, PO4−3, SO4−2, Na, K, BOD5, COD and heavy metals (Fe, Cr and Ni) were investigated for 9 months. A setup without plant stand acted as control. The VFCW outperformed to HFCW in terms of removal of NH4-N, PO4−3, BOD5, COD, and heavy metals while NO3-N and SO4−2 showed high removal in HFCW. The principal component analysis (PCA) identified three major components from the 9 major variables accounted for 80.05 and 86.68 of the datasets in HECW and VFCW, respectively. The degree of variance suggested the high performance of VFCW than HFCW. The PCA showed slight variations in functioning of both systems in terms of interdependences of organic and inorganic pollution abetments. The biomass yield of Typha showed great variations between HFCW and VFCW system and relatively the VFCW produced more Typha biomass. The high heating value (HHV) calculated on the basis of proximate and ultimate results indicates that Typha biomass can be used as potential feedstock for renewable energy operations. The Typha based VFCW for dairy wastewater treatment can targets multiple purposes: nutrient capture, habitat restoration, bioenergy, carbon offsets, and water quality credits.

Surface-flow wetland for water reclamation at Batamindo Industrial Park

The reclamation of wastewater as clean water resource is essential in the concept of water conservation. In industries, this will also lead to overall plant operational cost reduction. In this study, a pilot-scale surface-flow constructed wetland system filled with water hyacinth was used to treat effluent from existing sewage treatment plant at Batamindo Industrial Park. The sewage treatment plant effluent with quality fulfilling the regulation of Indonesian Ministry of Environment No.5/2014/XLVII-Group I was treated further to meet the raw water quality standard of Class I defined by Indonesian Government Regulation No.82/2001 as potable water resource. The system was able to maintain high chemical oxygen demand removal efficiency of around 80% from initial value of 100 mg/L in sewage treatment plant effluent despite the change of flow rate from 10 to 40 m 3 /day (corresponding to hydraulic retention time of 2 to 0.5 days in constructed wetland respectively). The constructed wetland could successfully increase dissolved oxygen concentration, remove coliform bacteria and improve clarity (reduce turbidity) of water while maintaining neutral pH and low TSS values. Some additional post-treatments such as simple aeration and ultraviolet irradiation may improve the water quality further to meet the Class I Standard of potable water resource.

An interval steady-state multimedia aquivalence (ISMA) model of the transport and fate of chloridion in a surface flow constructed wetland system treating oilfield wastewater in China

A surface flow constructed wetland (SFCW) system was built up to treat oilfield wastewater after secondary treatment. Chloridion (Cl−) in the wastewater was selected as an indicator to investigate the transport and fate of inorganic salts at high levels in the multimedia environments (air, water, soil, flora, and groundwater) by developing an interval steady-state multimedia aquivalence (ISMA) model. The modeled Cl− profiles were in good agreement with the measured ones, as indicated by the interval average logarithmic residual errors (IALREs) (<0.6 logarithmic units). The modeled results showed that the Cl− accumulated in the soil (70.80%) and was outputted from the environmental system mainly through periodic collection (34.86%) and advection outflow in groundwater (33.03%). It was also proved from imagery interpretation that the saline soil area was reduced 5.52% after wastewater irrigation, indicating that the tertiary treatment of oilfield wastewater through the constructed wetland was contributed to the local ecological restoration.

Study on the Effects of Wastewater Duress on MDA in Constructed Wetland Plants

The study on the wetland plant species and their resistance is the key to ecological wastewater treatment technology. The study on the effects of wastewater duress on the physical and chemical properties of constructed wetland plants and the anti-stress capability of constructed wetland plants can provide theoretical basis and technical support for constructed wetland plant material selection. By adopting surface flow constructed wetland system, the effects are studied on MDA in 4 common plants in Shandong (Phragmites communis, Typha oriental, Arundo donax and Canna generalis) in different wastewater duress time. The results show: All in all, Phragmites communis and Canna generalis have stronger anti-stress capability, while Arundo donax and Typha oriental has weaker anti-stress capability; but as wastewater duress time increases, the anti-stress capability of Phragmites communis decreases, while the anti-stress capability of Canna generalis increases.

Determination of regression model parameter for constructed wetland using operating data

Seven years of performance data from a free surface flow constructed wetland system receiving agricultural runoff were used to determine treatment performance and to develop regression and wetland design models. Removal rates by the wetland were 21–43.6% for 5-day biochemical oxygen demand (BOD5), 49.0–58.1% for total phosphorous (TP), 24.1–46.0% for total nitrogen (TN), and 57.6–77.8% for total suspended solids (TSS). First-order area-based rate constant (k20) values for BOD5 were 15.48 m/year in the early stage of observation and decreased to 12.00 m/year for the stable period. Similar results were found for TP, for which k20 values were 18.72 m/year in the early stage and 14.92 m/year for the stable period. For TN, k20 values in the early stage (21.32 m/year) were slightly lower than those for the stable period (38.02 m/year). Finally, TSS had values of 132.4 and 172.6 m/year in the early and stable periods, respectively. The low k20 for BOD5 was not important for nonpoint source pollution control in the constructed wetland because these kinds of wetlands mainly focus on nitrogen and phosphorus retention. The wetland area and outlet concentration could be approximately predicted using the first-order kinetic model, but the maturity and hydraulic loading rate should be considered for more accurate prediction.

Surface flow constructed wetland for heavy oil-produced water treatment

Heavy oil-produced water from China’ Liaohe Oilfield was purified in a surface flow constructed wetland (SFCW) during a 3-yr field experiment. Treatment showed high mean removal efficiencies of 80%, 93%, 88% and 86% for COD, oil, BOD and TKN, respectively for reed bed #1 and 71%, 92%, 77%, and 81% for COD, oil, BOD and TKN, respectively for reed bed #2. The results also showed that in the third year of the system’s operation, the oil-produced water had mainly positive impacts on the reed’s health parameters. Thus, reed can be used as a feasible wetland macrophyte for treating such wastewater, and this SFCW system can operate for a long time.