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Monitoring large-scale treatment wetlands is costly and time-consuming, but required by regulators. Some analytical results are available only after 5 days or even longer. Thus, adaptive neuro-fuzzy inference system (ANFIS) models were developed to predict the effluent concentrations of 5-day biochemical oxygen demand (BOD5) and NH4-N from a full-scale integrated constructed wetland (ICW) treating domestic wastewater. The ANFIS models were developed and validated with a 4-year data set from the ICW system. Cost-effective, quicker and easier to measure variables were selected as the possible predictors based on their goodness of correlation with the outputs. A self-organizing neural network was applied to extract the most relevant input variables from all the possible input variables. Fuzzy subtractive clustering was used to identify the architecture of the ANFIS models and to optimize fuzzy rules, overall, improving the network performance. According to the findings, ANFIS could predict the effluent quality variation quite strongly. Effluent BOD5 and NH4-N concentrations were predicted relatively accurately by other effluent water quality parameters, which can be measured within a few hours. The simulated effluent BOD5 and NH4-N concentrations well fitted the measured concentrations, which was also supported by relatively low mean squared error. Thus, ANFIS can be useful for real-time monitoring and control of ICW systems. [ABSTRACT FROM AUTHOR]

Mathematical models are useful for predicting the reactions of watercourses such as rivers due to the entry of contaminants. Some of these models are able to simulate the effects of present and future loadings as well as aid managers and officials in making decisions even if the data are sparse. In other words, river water quality preservation requires more investment in wastewater treatment and/or the installation of collection and control systems; it may also limit activity expansion in the river basin. The conservation of watersheds such as the Maroon and Jarahi basin, which provide water for drinking and for industrial and agricultural use, is socio-economically vital. Therefore, the first stage of managing the conservation of water resources is understanding their qualitative changes. For this purpose, the QUAL2KW mathematical model was utilized to simulate the river water quality in this example region. According to the reported values of water quality parameters and pollutants at monitoring stations, it was established that the river is at a critical condition in terms of biochemical oxygen demand (BOD) pollution due to the discharge of urban and industrial wastewater, as well as high electrical conductivity (EC) due to the drainage of agricultural lands. Based on the statistics calculated during the validation step, the authors concluded that the QUAL2KW water quality model is reliable in the simulation of qualitative parameters and the pollution data of the study area; namely the Maroon and Jarahi river basin located in the south-west of Iran. This will help stakeholders to better manage watersheds with sparse data. This region has been suffering from climate change which has led to droughts and the construction of several dams to retain water. For the second and third stations, the NASH (named after the mathematician John Forbes Nash) values were 0.96 and 0.92, respectively, indicating a relatively high model accuracy. The evaluation using the root mean square errors (RMSE) and NASH showed that the quality of water at the second station was better than the other two stations based on the coefficient of determination R2. Since there were three drains at station number 3, the wastewater entering the Maroon River had a higher level of contamination. [ABSTRACT FROM AUTHOR]

Data collected from five Wildfowl & Wetlands Trust constructed wetland systems offering a range of styles and inflow water types between 2005 and 2009 were examined and compared to identify long-term trends in nutrient removal. Ammonia-nitrogen concentrations were reduced between 31.9 and 96.8%. In contrast, the concentrations of nitrate-nitrogen and total oxidised nitrogen in the effluent exceeded the influent in many of the systems. Reduction in ortho-phosphate-phosphorus and total phosphorous were between −10.5 and 87.6%, and between 6.9 and 92.5%, respectively. Removal efficiencies of biochemical oxygen demand were between 0.0 and 87.3%, and reductions of total suspended solids ranged from −249.3 to 57.6%. Ammonia-nitrogen reduction was effective during summer. Long-term nitrogen removal has been efficient and consistent. However, phosphorous reduction was only sufficient during the early stages of operation, and generally declined as the wetland aged. [ABSTRACT FROM AUTHOR]

Artificial intelligence techniques, such as neural networks, are modeling tools that can be applied to analyze urban runoff quality issues. Artificial neural networks are frequently used to model various highly variable and nonlinear physical phenomena in the water and environmental engineering fields. The application of neural networks for analyzing the performance of combined permeable pavement and earth energy systems is timely and novel. This paper presents the application of back-propagation neural networks and the testing of the Levenberg-Marquardt, Quasi-Newton, and Bayesian Regularization algorithms. The neural networks were statistically assessed for their goodness of prediction with respect to the biochemical oxygen demand (BOD), ammonia-nitrogen, nitrate-nitrogen, and ortho-phosphate-phosphorus by numerical computation of the mean absolute error, root-mean-square error, mean absolute relative error, and the coefficient of correlation for the prediction compared with the corresponding measured data. The three neural network models were assessed for their efficiency in accurately simulating the effluent water quality parameters from various experimental pavement systems. The models predicted all key parameters with high correlation coefficients and low minimum statistical errors. The back-propagation and feed-forward neural network models performed optimally as pollutant removal predictors with regard to these two sustainable technologies. [ABSTRACT FROM AUTHOR]

The impact of hydraulic loading rate (HLR) and seasonal temperature on contaminant removal efficiencies within an integrated constructed wetland (ICW) system of 3.25 ha was assessed. The ICW system was designed to treat domestic wastewater from Glaslough (Ireland). The current loading rate is 800 population equivalents. The system has shown good removal performances (2008 to 2010). Mean concentration removal efficiencies were high: 92% for chemical oxygen demand (COD), 98% for the 5 days at 20°C N-allylthiourea biochemical oxygen demand (BOD), 94% for total suspended solids (TSS), 97% for ammonia-nitrogen (NH-N), 90% for nitrate-nitrogen (NO-N), 96% for total nitrogen (TN), and 96% for molybdate reactive phosphate (MRP). The mean mass removal efficiencies were 92% for COD, 98% for BOD, 96% for TSS, 92% for NH-N, 83% for NO-N, 90% for TN, and 91% for MRP. Loading rate fluctuations were mainly due to high variation in rainfall (0.4 to 400 m day) and in evapotranspiration rate (0 to 262 m day). The influence on the removal efficiencies of the hydraulic loading rate (−0.7 to 15.3 cm day), which was based on overall water balance, was negligible. This implies that the large footprint of the system provides a high hydraulic retention time (92 days). [ABSTRACT FROM AUTHOR]

Abstract: Non-point source pollution such as land-spreading of nitrogen-rich piggery wastewater poses a significant threat to surface waters. The aim was to examine the treatment of anaerobically digested piggery wastewater using four different meso-scale integrated constructed wetland (ICW) systems planted with Glyceria maxima. Four replicates were used for each system to assess differences due to nutrient loading, hydraulic loading and effluent recycling. All systems were effective in removing total organic nitrogen, ammonia-nitrogen, nitrate-nitrogen and molybdate reactive phosphorus. However, ammonia-nitrogen removal was the greatest challenge for high flow rates (>100m3/ha/d). Nitrification was higher in summer than winter. Findings show for the first time that effluent recycling within ICW was beneficial to lower ammonia-nitrogen but was associated with higher operational costs. The cost–benefit ratio based on ammonia-nitrogen removal for standard, recycling, high nutrients and high flow rate treatments was 1.08:1.04:1.06:1.00. It follows that a high flow rate was only marginally more cost-effective. [Copyright &y& Elsevier]

The performances of a new and a mature integrated constructed wetland (ICW) system treating domestic wastewater were evaluated for the first time. The new ICW in Glaslough (near Monaghan, Ireland) comprises five wetland cells, and the mature system in Dunhill (near Waterford, Ireland) comprises four cells. The performance assessment for these systems is based on physical and chemical parameters collected for 1 year in Glaslough and 5 years in Dunhill. The removal efficiencies for the former system were relatively good if compared to the international literature: biochemical oxygen demand (BOD, 99.4%), chemical oxygen demand (COD, 97.0%), suspended solids (SS, 99.5%), ammonia nitrogen (99.0%), nitrate nitrogen (93.5%), and molybdate-reactive phosphorus (MRP, 99.2%). However, the mature ICW had removal efficiencies that decreased over time as the Dunhill village expanded rapidly. The mean removal efficiencies were as follows: BOD (95.2%), COD (89.1%), SS (97.2%), ammonia nitrogen (58.2%), nitrate nitrogen (−11.8%), and MRP (34.0%). The findings indicate that ICW are efficient in removing BOD, COD, SS, and ammonia nitrogen from domestic wastewater. Moreover, both ICW systems did not pollute the receiving surface waters and the groundwater. [ABSTRACT FROM AUTHOR]

Storm water detention devices collect runoff from impermeable catchments. They provide flow attenuation as well as storage capacity, and rely on natural self-purification processes such as sedimentation, filtration and microbial degradation. The aim was to assess the performance of an experimental combined planted gravel filter, storm water detention and infiltration tank system treating runoff from a car park and its access road. Flows were modeled with the US EPA Storm Water Management Model. An overall water balance of the system was compiled, demonstrating that 50% of the rainfall volume escaped the system as evaporation, whereas, of the remaining 50%, approximately two thirds were infiltrated and one third was discharged into the sewer system. These findings illustrated the importance of evaporation in source control, and showed that infiltration can be applied successfully even on man-made urban soils with low permeability. The assessment of the system’s hydrological efficiency indicated mean lag times of 1.84 and 10.6 h for the gravel filter and the entire system, respectively. Mean flow volume reductions of 70% and mean peak flow reductions of 90% were achieved compared to conventional drainage. The assessment of the pollutant removal efficiency resulted in promising removal efficiencies for biochemical oxygen demand (77%), suspended solids (83%), nitrate-nitrogen (32%) and ortho-phosphate-phosphorus (47%). The most important removal processes were identified as biological degradation (predominantly within the gravel ditch), sedimentation and infiltration. [ABSTRACT FROM AUTHOR]

Abstract: A self-organizing map (SOM) model was applied as a prediction tool for the performance of an integrated constructed wetland (ICW) agroecosystem treating agricultural runoff to protect receiving watercourses. By utilizing the SOM model, the time-consuming to measure expensive biochemical oxygen demand outflow concentrations were predicted well by other inexpensive variables, which were quicker and easier to measure. Correct predictions for the outflow biochemical oxygen demand concentrations were between 89% and 100%. This novel approach allows for the real time control of the outflow water quality of the ICW and potentially also of other treatment system applications. Moreover, the missing values and outliers from the large but incomplete ICW data set were replaced accurately by most likely values determined by the SOM model. This was important because the proportions of unusable entries for chemical oxygen demand, suspended solids and biochemical oxygen demand were very high: 41%, 54%, and 61%, respectively. [Copyright &y& Elsevier]

Abstract: The aim of this research was to assess the role of the macrophyte Phragmites australis (Cav.) Trin. ex Steud. in experimental temporarily flooded vertical-flow wetland filters treating urban runoff. For 2 years, hydrated nickel and copper nitrate were added to sieved road runoff to simulate contaminated primary treated urban runoff. During the first year, 5-day biochemical oxygen demand (BOD) removal efficiencies were lower in planted filters than in unplanted filters. However, the BOD removal performances of all filters were virtually similar irrespective of the planting regime during the second year. The nutrient removal performance of planted filters was more efficient and stable throughout the season particularly after the filters matured compared to that of unplanted filters. A substantial amount of nitrogen was also removed by harvesting P. australis, though metals were not, when compared to those retained in the filters. Furthermore, higher concentrations of nickel in the effluent were recorded in the planted filters, despite their ability to take up the heavy metals. P. australis provided undesirable conditions for precipitation of Ni by lowering the pH in the processes. Finally, after applying shock loadings of Cu, higher Cu outflow concentrations were recorded for planted in comparison to unplanted filters. [Copyright &y& Elsevier]

K-nearest neighbors (KNN), support vector machine (SVM) and self-organizing map (SOM) were applied to predict five-day @ 20˚C N- Allylthiourea biochemical oxygen demand (BOD) and suspended solids (SS), and to assess novel alternative methods of analyzing water quality performance indicators for constructed treatment wetlands. Concerning the accuracy of prediction, SOM showed a better performance compared to both KNN and SVM. Moreover, SOM had the potential to visualize the relationship between complex biochemical variables. However, optimizing the SOM requires more time in comparison to KNN and SVM because of its trial and error process in searching for the optimal map. The results suggest that BOD and SS can be efficiently estimated by applying machine learning tools with input variables such as redox potential and conductivity, which can be monitored in real time. Their performances are encouraging and support the potential for future use of these models as management tools for the day-to-day process control. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

Two different chemical recipes comprising various pollutants were selected to create high (HC) and low (LC) levels of contaminated synthetic greywaters (SGW). Remediation in macrocosm–scale floating treatment wetlands (FTW) vegetated with Phragmites australis (Cav.) Trin. ex Steud. (common reed) was investigated under natural weather conditions. The presence or absence of vegetation, short or long contact time of treatment, and low or high contamination loads are the main operational variables in the experimental set-up design of the FTW. The focus on removal processes (other than sedimentation) such as the role of macrophytes in phytoremediation was achieved by agitation of the treated outflow before sampling. To assess the impact of interactions between the experimental operational variables on removal performances of FTW, different approaches of statistical analysis were applied. The results revealed that total suspended solids (TSS) and turbidity values dropped significantly ( p < 0.05) in the presence of vegetation compared with those values from unvegetated wetlands. The presence of vegetation can significantly ( p < 0.05) improve the biodegradation possibility of greywater by increasing the five-day biochemical oxygen demand (BOD) and decreasing the chemical oxygen demand (COD) concentrations. In vegetated FTW, higher removal rates of COD can be achieved when treating HC-SGS compared to LC-SGW. However, no significant differences ( p > 0.05) in the removal of BOD was noted. Significant increases ( p < 0.05) in BOD concentrations have been recorded with increasing contact time of treatment, while high removals of COD have been recorded. The presence of vegetation in wetlands affected significantly ( p < 0.05) the decrease of dissolved oxygen (DO) concentrations in outflow of both types of greywater. If limited sources of organic matter are available, vegetation has significantly ( p < 0.05) enhanced the nutrient balance with increasing nitrate-nitrogen (NO 3 -N) and decreasing ortho-phosphate-phosphorus (PO 4 -P) concentrations in the outflow. Furthermore, significant increases ( p < 0.05) in ammonia-nitrogen (NH 4 -N) and DO were observed with increasing contact time, while TSS, turbidity, and NO 3 -N concentrations significantly decreased ( p < 0.05). In addition, yellow leaves and considerably lower growth rates were observed for the hydroponic plant rhizomes of P. australis , which might be an effect of light-induced fluorescein degradation due to the relatively open water surfaces of the wetlands. [ABSTRACT FROM AUTHOR]

This study compares the performance, design and operation variables of two wetland technologies treating domestic wastewater: an experimental artificial pond system and a mature experimental vertical-flow constructed wetland system. The wetland system planted with Phragmites australis (Cav.) Trin. ex Steud. (common reeds) was operated between June 2011 and October 2015, while the pond system was only operated between July 2015 and October 2015. Three different types of ponds were compared: ponds with wastewater; ponds with wastewater and reeds; and ponds with wastewater, reeds and aeration. Findings regarding the performances of mature wetlands showed that the wetland systems improved the water quality except for ortho -phosphate-phosphorus (PO 4 −P), where the treatment performance reduced slightly over time. In general, the aerated pond systems showed better treatment performances in terms of ammonia-nitrogen (NH 4 −N) and PO 4 −P‎. Both systems were linked with medium to high levels of five-day biochemical oxygen demand (BOD) removal. The highest COD and SS removals were observed for wetlands in comparison to ponds. Moreover, mature wetlands were better in removing NH 4 −N and PO 4 −P than ponds unless the ponds were aerated. The nitrate-nitrogen (NO 3 −N) concentration increased in the aerated ponds reflecting the high oxygen availability. [ABSTRACT FROM AUTHOR]

The overall aim of this research project was to reduce low molecular weight hydrocarbons such as benzene in produced wastewaters. Over 30 months of research was conducted to test the treatment performance in terms of benzene removal in vertical-flow constructed wetlands. Based on an influent concentration of 1gL−1 benzene, the results show mean benzene removal efficiencies between 88.71% and 89.77%, and 72.66% and 80.46% for indoor and outdoor constructed wetlands, respectively. A statistical analysis indicated that the five days at 20°C N-allylthiourea biochemical oxygen demand (BOD5), chemical oxygen demand (COD), nitrate-nitrogen (NO3-N), dissolved oxygen (DO) and electric conductivity (EC) values of the effluent were positively correlated with the effluent benzene concentrations following the order COD>DO>EC>NO3-N>BOD5, and negatively correlated according to the order pH>redox potential (redox)>temperature (T)>turbidity. No strong relationships between benzene and the variables ortho-phosphate-phosphorus () and ammonia-nitrogen (NH4-N) were recorded. [Copyright &y& Elsevier]

Abstract: The aim was to assess the treatment efficiencies of experimental storm water detention (extended storage) systems based on the Atlantis Water Management Limited detention cells receiving concentrated runoff that has been primarily treated by filtration with different inert aggregates. Randomly collected gully pot liquor was used in stead of road runoff. To test for a ‘worst case scenario’, the experimental system received higher volumes and pollutant concentrations in comparison to real detention systems under real (frequently longer but diluted) runoff events. Gravel (6 and 20 mm), sand (1.5 mm), Ecosoil (inert 2 mm aggregate provided by Atlantis Water Management Limited), block paving and turf were tested in terms of their influence on the water quality. Concentrations of five-day at 20 °C ATU biochemical oxygen demand (BOD) in contrast to suspended solids (SS) were frequently reduced to below international secondary wastewater treatment standards. The denitrification process was not completed. This resulted in higher outflow than inflow nitrate-nitrogen concentrations. An analysis of variance indicated that some systems were similar in terms of most of their treatment performance variables including BOD and SS. It follows that there is no advantage in using additional aggregates with high adsorption capacities in the primary treatment stage. [Copyright &y& Elsevier]