Wireless Network Sensing of Urban Surface Water Environment Based on Clustering Algorithm

To improve the wireless sensing image extraction technology of urban surface water environment, a regional FCM clustering method combined with water index was proposed in this paper. The normalized water index (NDWI) was obtained by calculating the fusion multispectral wireless sensing image. Through the combination with normalized water index, fuzzy clustering results were obtained by RFCM algorithm proposed in this paper. The optimal threshold was selected to defuzzify the fuzzy clustering results, and finally, the extraction results of urban surface water were obtained. The accuracy of the proposed algorithm was compared with that of the traditional surface water extraction algorithm. The experimental results showed that the size of different neighborhood regions affected the water extraction accuracy. In W city, the kappa coefficient of MFCM16 was 0.41% higher than that of MFCM8, and the overall classification accuracy of MFCM16 was 1.33% higher than that of MFCM. In G city area, the kappa coefficient of MFCM16 was 1.81% higher than that of MFCM8, and the overall classification accuracy of MFCM16 was 1.7% higher than that of MFCM. Comparing the RFCM algorithm with other algorithms, the RFCM algorithm obtained the best experimental results, to reduce the “salt-and-pepper phenomenon” effect.

Permeable Reactive Concrete Using Recycled Waste Materials for Nutrient Contamination Removal in Urban Surface Runoff

In recent years, stormwater control measures (SCMs) such as permeable concrete pavement have been experimentally investigated and used to manage hydrologic and water quality impacts of stormwater runoff. Research revealed the potential of permeable pavement in reducing and delaying peak flow rate, reducing runoff volume, and capturing heavy metals and other particulate-bound pollutants from stormwater runoff. However, few studies have evaluated the effects of permeable pavement on nutrients in stormwater runoff. This research aims to produce permeable reactive concrete (PRC) from waste fly ash, waste gypsum board and waste coco peat and to investigate its effectiveness in removing nutrient contamination present in stormwater or urban surface runoff. The raw materials underwent through granulation process to produce granulated filtering media (GFM). Cylindrical samples of PRC were then made and subjected to various physical and water quality tests. The use of GFM as partial coarse aggregates of PRC for urban surface runoff management and nutrient contamination removal has been tested and evaluated. After performing all the tests, the researchers concluded that GFM as partial coarse aggregates of PRC is effective due to the significant increase in infiltration rate of the entire sample compared to the traditional permeable concrete that has an average infiltration rate of 2-6 mm/s. The results in the water quality test revealed that PRC with GFM as partial coarse aggregates lessen the nitrate, phosphate, and ammonia that are present on urban surface runoff.