Prediction of Chemical Oxygen Demand (COD) Based on Wavelet Decomposition and Neural Networks

The chemical oxygen demand (COD) parameter of a wastewater treatment plant is predicted based on wavelet decomposition, entropy, and neural networks (NN) for rapid COD analysis. This paper also describes the usage of wavelet and NNs for parameter prediction. Data from a wastewater treatment plant in Malatya, Turkey, were used. This dataset consists of daily values of influents and effluents for a year. To reduce the dimension of input parameters and to decrease the NN training time, wavelet decomposition and entropy were used. Test results were presented graphically. The test results of the trained model were found to be closer to the measured COD values.     

Determination of sediment deposition of Hasanlar Dam using bathymetric and remote sensing studies

Natural Hazards - Hasanlar Dam and Hydroelectric Power Plant are located on Küçük Melen Creek in the Western Black Sea Basin of Turkey. The dam was constructed in 1974 to provide...     

Influences of human activities and agriculture on groundwater quality of Kayseri-Incesu-Dokuzpınar springs,central Anatolian part of Turkey

Human activities and agriculture have had direct and indirect effects on the rates of contamination of groundwater in the Incesu-Dokuzp inar spring area. Direct effects include dissolution and transport of excess quantities of fertilizers with associated materials and hydrological alterations related to irrigation and drainage. Indirect effects may include changes in water–rock reactions in soils and aquifers caused by increased concentrations of dissolved oxidants, protons, and major ions. Agricultural activities have directly or indirectly affected the concentrations of a large number of inorganic chemicals in groundwater, for example NO ₃, N ₂, Cl, SO ₄ ², H ⁺, K, Mg, Ca, Fe, Cu, B, Pb, and Zn, as well as a wide variety of pesticides and other organic compounds. For reactive contaminants like NO ₃, it is recommended that a combination of hydrochemical and environmental-tracer analytical approaches might be required to resolve changing inputs from subsequent alterations as causes of concentration gradients in groundwater. The water type of Dokuzp inar springs is mainly Na–Mg–Ca–Cl–HCO ₃. Note that the water types of the springs were directly related to the hydrogeochemical properties of outcrops at the study area. Thus, the high concentration of Ca ²⁺ and HCO ₃ is mainly related to the high CO ₂ contents in the marbles, whereas the high Na concentration arises from the existing syenite, volcanic ash, basalt, and clay units, although the Incesu-Dokuzp inar springs cover most of the drinking and irrigation water demands of this area. The high concentrations of NO ₃ and NaCl show that the area around the springs is continuously being contaminated by untreated sewage and agricultural wastes, especially during dry periods. Therefore, this approach is based on the vulnerability studies of the catchment area, determination of the transfer time of the pollutant, and the water-bearing formations of Incesu-Dokuzp inar springs. Vulnerability in this study is defined as the intrinsic hydrogeochemical characteristics of an aquifer, which may show the sensitivity of groundwater to be contaminated by different human activities.     

Biosorption of mercury(II), cadmium(II) and lead(II) ions from aqueous system by microalgae Chlamydomonas reinhardtii immobilized in alginate beads

The potential use of the immobilized microalgae (in Ca-alginate) of Chlamydomonas reinhardtii to remove Hg(II), Cd(II) and Pb(II) ions from aqueous solutions was evaluated using bare Ca-alginate bead as a control system. Ca-alginate beads containing immobilized microalgae were incubated for the uniform growth at 22 °C for 5 days. Effects of pH, temperature, initial concentration of metal ions and biosorbent dosages on the adsorption of Hg(II), Cd(II) and Pb(II) ions were studied. Adsorption of Hg(II), Cd(II) and Pb(II) ions on the immobilized microalgae showed highest values at around pH 5.0 to 6.0. The adsorption equilibrium was represented with Langmuir and Freundlich adsorption isotherms. The adsorption of these ions on the immobilized microalgae followed second-order kinetics and equilibrium was established in about 60 min. The temperature change in the range of 5–40 °C did not affect the adsorption capacities of the immobilized microalgae. The immobilized-algal systems can be regenerated using 2 M NaCl for Hg(II), Cd(II) and Pb(II) ions.