Analysis of clogging in constructed wetlands using magnetic resonance

In this work we demonstrate the potential of permanent magnet based magnetic resonance sensors to monitor and assess the extent of pore clogging in water filtration systems. The performance of the sensor was tested on artificially clogged gravel substrates and on gravel bed samples from constructed wetlands used to treat wastewater. Data indicate that the spin lattice relaxation time is linearly related to the hydraulic conductivity in such systems. In addition, within biologically active filters we demonstrate the ability to determine the relative ratio of biomass to abiotic solids, a measurement which is not possible using alternative techniques

Landfill leachate treatment using free water surface constructed wetlands

Nowadays, solid waste management and wastewater treatment are the most important problems that we are facing. The amount of solid waste produced around the world is increasing at high rate as well as in Malaysia. Although there are different alternatives to reduce them or for their treatment and disposition, landfill is still the most common practice in developed and developing countries. However, the landfill method causes generation of leachate Landfill leachate refers to the liquid that seeps through a landfill site and enters the environment. Constructed wetlands emerged as one of the potential treatment alternative that employed emergent plants to remove pollutant from leachate. In this research, a constructed wetland was developed by using Limnocharis flava to treat the landfill leachate. Different leachate concentration (50% and 33%) was studied in the constructed wetland to compare the treatment efficiency in terms of pollutants removal in leachate and the efficiency of the system in different hydraulic retention time (HRT). The result shows a better removal efficiencies at HRT 3 days can be obtained in Cell B where the parameter are NH3-N, PO43-, Mn, Fe, Turbidity, and TSS (83%, 88%, 91%, 92%, 100%, and 98% removal). The highest removal at HRT 6 days are NO3-N, PO43-, Turbidity and TSS (98%, 98%, 100% and 90%) can be obtained in Cell B, while in Cell A the highest removal parameters are NH3-N, COD, Mn, Fe, Tubidity and TSS (93%, 91%, 90%, 94%, 100% and 90%). However, the highest removal of COD can be obtained at HRT 6 days in control unit of 94%. However, the laboratory result shows that the removal efficiencies for HRT 3 days and HRT 9 days have not much different

CONSTRUCTED WETLANDS FOR WASTEWATER TREATMENT

Otpadne vode se moraju pročistiti prije ispuštanja u recipijent. Jedan od načina pročišćavanja otpadnih voda je pročišćavanje biljnim uređajima. Biljni uređaji su kompleksni biološki sustavi koji oponašaju procese u prirodi. Jednostavan su, prihvatljiv i ekonomski opravdan način zaštite voda. U radu su opisani biljni uređaji (umjetne močvare) kroz vrste uređaja, njihove prednosti i nedostatke, osnove projektiranja i hidraulički proračun. Posebno je analiziran biljni uređaj Vinogradci.Waste water must be treated prior to discharge into the recipient. One way of treating waste water is constructed wetland for wastewater treatment. Constructed wetlands are complex biological systems that mimic the processes in nature. These systems are simple, acceptable and economically feasible way of water protection. This paper describes the constructed wetlands through device types, their advantages and disadvantages, the basics of design and hydraulics. Especially analyzed constructed wetland Vinogradci

Fate of silver nanoparticles in constructed wetlands : a microcosm study

Nano-enabled materials are produced at growing volumes which increases the likelihood of nanoparticles being released into the environment. Constructed wetlands (CWs) are likely to receive wastewater containing nanoparticles leaching from products during usage. Therefore, we investigate the retention of silver nanoparticles (Ag-NPs) in microcosms simulating CWs treating domestic wastewater. The effects of aeration and organic matter content on the Ag-NP removal efficiencies are studied in particular. CWs remove most of the Ag (80-90%) and the largest fraction of Ag is found in/on the biofilm. Detailed electron microscopy analyses suggest that Ag-NPs are transformed into Ag2S in all microcosm experiments. The good correlation between total suspended solids (TSS) and the Ag concentration measured in the effluent indicates that Ag-NPs are bound to the solids in the effluent. Aeration of the microcosms does not affect the release of Ag-NPs from the systems but increasing organic matter leads to increased amounts of Ag passing the CWs, correlating with the increased release of TSS from the CWs. These results suggest that Ag-NPs are retained with the (suspended) solids in CWs and that the removal efficiency of TSS is an important factor determining the discharge of Ag-NPs from CWs

Constructed wetlands: Treatment of concentrated storm water runoff (part A)

The aim of this research was to assess the treatment efficiencies for gully pot liquor of experimental vertical- flow constructed wetland filters containing Phragmites australis (Cav.) Trin. ex Steud. (common reed) and filter media of different adsorption capacities. Six out of 12 filters received inflow water spiked with metals. For 2 years, hydrated nickel and copper nitrate were added to sieved gully pot liquor to simulate contaminated primary treated storm runoff. For those six constructed wetland filters receiving heavy metals, an obvious breakthrough of dissolved nickel was recorded after road salting during the first winter. However, a breakthrough of nickel was not observed, since the inflow pH was raised to eight after the first year of operation. High pH facilitated the formation of particulate metal compounds such as nickel hydroxide. During the second year, reduction efficiencies of heavy metal, 5-days at 20°C N-Allylthiourea biochemical oxygen demand (BOD) and suspended solids (SS) improved considerably. Concentrations of BOD were frequently �20 mg/L. However, concentrations for SS were frequently �30 mg/L. These are the two international thresholds for secondary wastewater treatment. The BOD removal increased over time due to biomass maturation, and the increase of pH. An analysis of the findings with case-based reasoning can be found in the corresponding follow-up paper (Part B)

Guidance manual for constructed wetlands.

This Guidance Manual was produced to provide up to date information on the design, costs, construction, operation and maintenance of constructed wetlands used for the treatment of highway runoff. Information is provided on the different types of wetlands and their mode of operation, the design and planting of a wetland system and the retrofitting of treatment structures, the performance and costs of wetlands and their operation and maintenance requirements. The benefits of wetlands in encouraging wildlife and improving the landscape are discussed. The implementation of Sustainable Drainage systems (SuDS) and the use of decision support approaches for selecting SuDS systems are considered. Recommendations are made for future research