Abstract

This study proposes a methodology to prevent excessive and misuse of polymers in dewatering applications. In this study, to determine the optimum conditions some measurement were performed such as zeta potential measurements to arrange the pH of the slurry, flocculation tests to reduce turbidity and settlement time, particle size distribution analysis to enhance floc size, and Fourier-Transform Infrared Spectroscopy (FTIR) analysis to limit the level of trace elements that can be discharged into the sea. For the study area, Golden Horn located in Istanbul of which contaminated sea bottom sediments are dredged periodically was selected. 11 anionic and 2 cationic varieties of polyacrylamides were used considering the zeta potential observations on the slurries arranged at pH = 3–9. Anionic polymers performed better than cationic ones at the intended dosage. 30 ppm concentration of AA4 polymer enhanced the mean floc size D₅₀= 0.06–0.12 mm, and increased the settlement rate up to 4.4 cm/min, so 121 NTU turbidity (99.7% yield) was achieved. The remaining water was polymer-free and was suitable for discharge to the marine environment. So, further investigations on polymer selection will be optimized dewatering process and lead to environmental sustainability and economic savings.

摘要

本研究提出了一种防止在脱水应用中过度使用和滥用聚合物的方法。在这项研究中，为了确定最佳条件，进行了一些测量，例如 zeta 电位测量以安排浆液的 pH 值、絮凝测试以减少浊度和沉降时间、粒度分布分析以提高絮体大小，以及傅里叶变换红外光谱(FTIR) 分析以限制可排放到海中的微量元素水平。研究区选择位于伊斯坦布尔的金角湾，定期疏浚受污染的海底沉积物。考虑到对 pH = 3-9 排列的浆料的 zeta 电位观察结果，使用了 11 种阴离子和 2 种阳离子聚丙烯酰胺。在预期剂量下，阴离子聚合物的性能优于阳离子聚合物。30 ppm 浓度的 AA4 聚合物提高了平均絮体尺寸 D₅₀ = 0.06–0.12 mm，并将沉降速率提高到 4.4 cm/min，因此达到 121 NTU 浊度（99.7% 产率）。剩余的水不含聚合物，适合排放到海洋环境中。因此，对聚合物选择的进一步研究将优化脱水过程并导致环境可持续性和经济节约。