A gas sensor array consisting of eight metal oxide semiconductor (MOS) type gas sensors was evaluated for its ability for assessment of the selected wastewater parameters. Municipal wastewater was collected in a wastewater treatment plant (WWTP) in a primary sedimentation tank and was treated in a laboratory-scale sequential batch reactor (SBR). A comparison of the gas sensor array (electronic nose) response to the standard physical-chemical parameters of treated wastewater was performed. To analyze the measurement results, artificial neural networks were used. E-nose—gas sensors array and artificial neural networks proved to be a suitable method for the monitoring of treated wastewater quality. Neural networks used for data validation showed high correlation between the electronic nose readouts and: (I) chemical oxygen demand (COD) (r = 0.988); (II) total suspended solids (TSS) (r = 0.938); (III) turbidity (r = 0.940); (IV) pH (r = 0.554); (V) nitrogen compounds: N-NO3 (r = 0.958), N-NO2 (r = 0.869) and N-NH3 (r = 0.978); (VI) and volatile organic compounds (VOC) (r = 0.987). Good correlation of the abovementioned parameters are observed under stable treatment conditions in a laboratory batch reactor.
The possibility of distinguishing different soil moisture levels by electronic nose (e-nose) was studied. Ten arable soils of various types were investigated. The measurements were performed for air-dry (AD) soils stored for one year, then moistened to field water capacity and finally dried within a period of 180 days. The volatile fingerprints changed during the course of drying. At the end of the drying cycle, the fingerprints were similar to those of the initial AD soils. Principal component analysis (PCA) and artificial neural network (ANN) analysis showed that e-nose results can be used to distinguish soil moisture. It was also shown that different soils can give different e-nose signals at the same moistures.
The time domain reflectometry (TDR) method is commonly used for the measurement of moisture content in soil science. In this study, the method is employed for the measurement of moisture profiles in building materials. The practical applications of the method are presented on an example of water penetration into cellular concrete (aerated autoclaved concrete) samples. The measured results are then used for the determination of moisture diffusivity as a function of moisture content.
A system of slope erosion control, consisting of horizontal terraces equipped with drainage ditches filled with sand, was developed in Olszanka, Poland. This system relies on combining two types of erosion control on steep slopes: limiting soil transformations and increasing the infiltration of surface water into the subsoil. The new soil erosion control system is located on a fruit farm in Olszanka. We assessed the functionality and efficiency of the system by calculating the eventual increase in infiltration gained via the drainage ditches. This assessment was performed using the numerical model FEFLOW 5.2. The calculations covered a 74‐d period (summer 2003) and relate to two groups of terraces located on different parts of the slope. The values and directions of groundwater flux and velocity resulting from the calculations were analyzed. We observed a clear increase in infiltration for terraces equipped with sand‐filled drainage ditches under real climatic conditions: 11.69 and 13.6% increases for the base and upper parts of the slope, respectively. The results were empirically verified by comparing measured in situ and calculated values of soil water content; values of R2 = 0.702 to 0.799 (P = 0.05) for four points on two terraces were determined.
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