Hydrodynamics and phosphorus loading in an urbanized river channel influences response to future managed change: Insights from advection-dispersion modelling.

There is a need to understand what makes certain targeted measures for in-river phosphorus load reduction more effective than others. Therefore, this paper investigates multiple development scenarios in a small lowland polluted river draining an urban area (The Cut, Bracknell, UK), using an advection-dispersion model (ADModel-P). A comparative analysis is presented whereby changes in concentrations and fluxes of soluble reactive phosphorus (SRP) and organic phosphorus (OP) have been attributed to specific transformations (mineralization, sedimentation, resuspension, adsorption-desorption, and algal uptake) and correlated to controlling factors. Under present day conditions the river stretch is a net source of SRP (10.4 % increase in mean concentration) implying a release of previously accumulated material. Scenarios with the greatest impact are those based on managed reduction of phosphorus load in sources (e.g., 20 % increase in afforestation causes an in-river SRP and OP reduction of 1.3 % to 12.6 %) followed by scenarios involving changes in water temperature (e.g., 1 °C decrease leads to in-river SRP reduction around 3.1 %). Measures involving increased river residence time show the lowest effects (e.g., 16 % decrease in velocity results in under 0.02 % in-river SRP and OP reduction). For better understanding downstream persistence of phosphorus pollution and the effectiveness of mitigation measures the research demonstrates the importance of establishing when and where reaches are net adsorbers or desorbers, and whether sedimentation or resuspension is important.

Optimization Method of the Solvothermal Parameters Using Box-Behnken Experimental Design-The Case Study of ZnO Structural and Catalytic Tailoring.

ZnO photocatalysts were synthesized via solvothermal method and a reduced experimental design (Box-Behnken) was applied to investigate the influence of four parameters (temperature, duration, composition of the reaction mixture) upon the photocatalytic activity and the crystal structure of ZnO. The four parameters were correlated with photocatalytic degradation of methyl orange and the ratio of two crystallographic facets ((002) and (100)) using a quadratic model. The quadratic model shows good fit for both responses. The optimization experimental results validated the models. The ratio of the crystal facets shows similar variation as the photocatalytic activity of the samples. The water content of the solvent is the primary factor, which predominantly influence both responses. An explanation was proposed for the effect of the parameters and how the ratio of (002) and (100) crystal facets is influenced and its relation to the photocatalytic activity. The present research laconically describes a case study for an original experimental work, in order to serve as guideline to deal with such complicated subjects as quantifying influence of synthesis parameters upon the catalytic activity of the obtained ZnO.

Dairy wastewater processing and automatic control for waste recovery at the municipal wastewater treatment plant based on modelling investigations.

Based on the calibrated model for an Anaerobic-Anoxic-Oxic (A2O) municipal wastewater treatment plant (WWTP), this research investigated and proposed feasible solutions, control system configurations and optimal operating conditions for the dairy wastewater processing. The steady state study on adding different daily amounts of dairy wastewater in the WWTP water line revealed the most efficient amount to be treated by finding a minimum of the total nitrogen concentration in the water effluent. The dynamic investigations on adding different daily amounts of diary wastewater demonstrated the incentives of the proposed cascade control system configurations, based on the ammonia or nitrates concentration control in the aerated reactors, associated to nitrates and nitrites concentration control in the anoxic reactor. The best periods of time and duration for scheduling the dairy wastewater processing were searched and found. Preliminary results showed the incentives of the additional dairy wastewater distribution during 2 h, at the highest influent concentration moments. Further investigations, relying on the genetic algorithm optimization method revealed that better daily scheduling of the dairy wastewater addition may be obtained. Compared to normal operation, the optimal scheduling program of the dairy wastewater treatment showed an overall performance index improvement of 13.36%, when the daily 1:52 p.m. moment of time and the duration of about 1 h program, found by optimization, were applied. Results demonstrate the dual incentives of the carbon and nutrients recovery, associated to the energy and effluent quality benefits on WWTP operation.

Reducing energy costs of the wastewater treatment plant by improved scheduling of the periodic influent load.

The wastewater treatment plant (WWTP) is a major actor of the water-energy nexus. This study proposes to partially store in available WWTP tank infrastructure the wastewater received during the day-time and schedule the purification of the stored wastewater at night-time. The intended operational approach aims to shift part of the WWTP electrical energy consumption from day-time into the night-time period when the energy has lower prices, also contributing to the balance of the electrical power generation system. This research presents the case study of a Romanian WWTP with Anaerobic-Anoxic-Oxic (A2O) process configuration. A proposed control strategy was implemented and tested on the dynamic calibrated WWTP model, based on the Activated Sludge Model No. 1 and the secondary settler Takács model. Simulations of the proposed scheduling program for the storing and processing time-periods of the influent wastewater, associated to the designed control strategies, demonstrate the reduction of the operational costs and energy savings, while keeping the effluent quality within the requested regulation limits and improving the plant sustainability. In the most favorable case and considering the overall WWTP performance, the operational costs are reduced by 47% and the effluent quality is improved by 25%. To achieve this performance a part of the influent wastewater is stored from 2 p.m. in the available tanks (day-period) while the beginning of the stored wastewater treatment is scheduled at 12 a.m. (night-period). Air flow rate distribution in the nitrification zone and the two water recirculation flow rates are also found by optimization.

Serum tests, liver stiffness and artificial neural networks for diagnosing cirrhosis and portal hypertension.

BACKGROUND: The diagnostic performance of biochemical scores and artificial neural network models for portal hypertension and cirrhosis is not well established. AIMS: To assess diagnostic accuracy of six serum scores, artificial neural networks and liver stiffness measured by transient elastography, for diagnosing cirrhosis, clinically significant portal hypertension and oesophageal varices. METHODS: 202 consecutive compensated patients requiring liver biopsy and hepatic venous pressure gradient measurement were included. Several serum tests (alone and combined into scores) and liver stiffness were measured. Artificial neural networks containing or not liver stiffness as input variable were also created. RESULTS: The best non-invasive method for diagnosing cirrhosis, portal hypertension and oesophageal varices was liver stiffness (C-statistics=0.93, 0.94, and 0.90, respectively). Among serum tests/scores the best for diagnosing cirrhosis and portal hypertension and oesophageal varices were, respectively, Fibrosis-4, and Lok score. Artificial neural networks including liver stiffness had high diagnostic performance for cirrhosis, portal hypertension and oesophageal varices (accuracy>80%), but were not statistically superior to liver stiffness alone. CONCLUSIONS: Liver stiffness was the best non-invasive method to assess the presence of cirrhosis, portal hypertension and oesophageal varices. The use of artificial neural networks integrating different non-invasive tests did not increase the diagnostic accuracy of liver stiffness alone.

Analysis of total phenolic, flavonoids, anthocyanins and tannins content in Romanian red wines: prediction of antioxidant activities and classification of wines using artificial neural networks.

Wine is one of the most consumed beverages over the world containing large quantities of polyphenolic compounds. These compounds are responsible for quality of red wines, influencing the antioxidant activity, astringency, bitterness and colour, their composition in wine being influenced by the varieties, the vintage and the wineries. The aim of the present work is to build software instruments intended to work as data-mining tools for predicting valuable properties of wine and for revealing different wine classes. The developed ANNs are able to reveal the relationships between the concentration of total phenolic, flavonoids, anthocyanins, and tannins content, associated to the antioxidant activity, and the wine distinctive classes determined by the wine variety, harvesting year or winery. The presented ANNs proved to be reliable software tools for assessment or validation of the wine essential characteristics and authenticity and may be further used to establish a database of analytical characteristics of wines.

Counteracting the accidental pollutant propagation in a section of the River Somes by automatic control.

Real-time response to accidental pollution in rivers is a challenging mission that requires efficient on-line monitoring and rapid mitigating systems and calls for automatic control for diminishing or eliminating the pollutant effect. Remediation measures are addressed for cases in which the pollutant concentration can be measured and a neutralising agent can be identified and added to react with the pollutant and transform it by a chemical reaction into less harmful or non-harmful products. Pollution in a section of the River Somes is presented as a case study. Based on the advection-dispersion-reaction processes, a 2D dynamic simulator is developed to investigate and provide accurate predictions of the pollutant distribution. The complex river section geometry, the single and multiple points or spatially distributed sources, and a constant or time-varying release of the pollutant may be handled by the simulator. Furthermore, two control systems are designed and tested. One system involves implementing a feedback control approach, while the other involves applying a feedforward-feedback control structure. System identification of the disturbance and the manipulated variable paths is carried out, and a suitable allocation of the measuring points for both the disturbance and the controlled variable is addressed and demonstrated. The control structures prove to help the proposed polluting counteracting measures by bringing the concentration of the pollutant down to the safe setpoint value. The predictive action of the feedforward-feedback control structure reveals complementary benefits, as the pollutant concentration is promptly forced and maintained below the maximum allowed limit all the time and all over the river region of interest.

Antioxidant activity prediction and classification of some teas using artificial neural networks.

In order to characterise and to classify some teas a simple, rapid and economical method based on composition, antioxidant activity and artificial neural networks (ANNs) is proposed. For these purpose two types of ANN based applications have been developed: one for predicting the antioxidant activity and a second one for establishing the class of the teas. The complex relationship between the total antioxidant activity (AA) depending on the total flavonoids content (F), total catechins content (C) and total methyl-xanthines content (MX) of commercial teas was revealed by the first designed feed-forward ANN. Secondly, using a probabilistic ANN, successful tea classification in various classes (green tea, black tea and express black tea) was also performed.