Collaborative Reserach: Geotextile Tubes for the Sustainable Dewatering

本研究项目的目的是开发以多糖为基础的合成聚丙烯酰胺衍生聚合物絮凝剂的替代品，并探索以天然纤维为基础的土工布用于脱水应用的可能性。近年来，从港口、湖泊、运河、尾矿池和其他水体中疏浚沉积物吸引了大量公众的兴趣。疏浚的沉积物通常含水量很高，必须以环保和经济可持续的方式处理。这些材料的处理和处置通常需要脱水，即从材料中除去液体以将固体百分比增加到可接受水平的过程。十年前，高含水量物料（1- 10%的干固体）的脱水几乎完全是通过沉降池、机械压榨机和离心机进行的。最近，土工布管已成功地用于脱水高含水量材料的许多行业。由于需要最大限度地保留材料并减少脱水所需的时间，因此在土工布管应用中通常添加合成阳离子或阴离子丙烯酰胺衍生聚合物。虽然这些聚合物已成为土工布管脱水的重要组成部分，但人们对其安全性存在担忧。此外，目前用于评价土工布管材性能的性能指标和测试方法也存在很大差异。该项目将是同类项目中第一个系统研究，旨在开发以多糖为基础的合成聚丙烯酰胺衍生聚合物絮凝剂的替代品，并探索使用天然纤维为基础的土工布用于脱水应用的可能性。采用斑马鱼胚胎毒性试验，对天然高分子絮凝剂和合成高分子絮凝剂的急性毒性进行了研究。该研究还将包括对含粘土矿物和有机物的沉积物进行实验规模和中试规模的模拟测试。将对这些试验进行严格评价，并制定一项新的评价土工织物管脱水沉积物的性能标准。将建立一个结合沉积物、聚合物和土工布基本特性的数学模型，以评估土工布管的长期性能。该项目解决了与疏浚有关的一个重要问题，即以高效、安全和可持续的方式疏浚材料的脱水。将举办网络研讨会，概述土工布管的使用、它们的好处以及本研究的发现。网络研讨会将通过国家组织进行宣传，如北美土工合成学会（NAGS）和美国土木工程师学会（ASCE）。项目负责人将在ASTM D-35年度委员会会议上展示他们的研究成果，并将积极参与制定用于土工织物管脱水评估的实验规模测试的性能标准。两名中学教师将参与这个项目。教师们将与项目负责人合作开发教学模块，用于向中学生传播土工织物管的信息。

The objective of this research project is to develop polysaccharide-based alternatives to synthetic polyacrylamide-derived polymer flocculants, and to explore the possibility of using natural fiber-based geotextiles for the dewatering application. The dredging of sediments from harbors, lakes, canals, tailings ponds, and other bodies of water has attracted a significant amount of public interest in recent years. Dredged sediments are generally high in water content that must be disposed of in environmentally and economically sustainable ways. The handling and disposal of these materials typically require dewatering, the process whereby liquid is removed from the materials to increase the percent solids to acceptable levels. A decade ago, the dewatering of high water content materials (1-10 percent dry solids) was performed almost exclusively with settling ponds, mechanical presses, and centrifuges. More recently, geotextile tubes have been successfully used for dewatering high water content materials by many industries. The need to maximize the retention of materials and minimize the time required for dewatering has led to the common addition of synthetic cationic or anionic acrylamide-derived polymers in geotextile tube applications. While these polymers have become an essential component of geotextile tube dewatering, concerns exist regarding their safety. In addition, there is a wide disparity in the performance indices and test methods that are currently being used to evaluate geotextile tube performance. This project will be the first systematic study of its kind which aims to develop polysaccharide-based alternatives to synthetic polyacrylamide-derived polymer flocculants, and to explore the possibility of using natural fiber-based geotextiles for the dewatering application. The acute toxicity of natural and synthetic polymer flocculants will be tested using the fish embryo toxicity test with zebrafish. The study will also include bench-scale and pilot-scale simulation tests on sediment with clay minerals and organic matter. The tests will be critically evaluated and a new performance standard for the evaluation of geotextile tubes for dewatering sediments will be developed. A mathematical model which incorporates the fundamental properties of sediment, polymers, and geotextiles will be developed to evaluate the long-term performance of geotextile tubes.This project addresses an important problem related to the dredging, the dewatering of dredged materials in an efficient, safe and sustainable manner. Webinars will be developed to provide an overview of the use of geotextile tubes, their benefits, and the findings from this study. The webinars will be advertised through national organizations, such as the North American Geosynthetics Society (NAGS) and the American Society of Civil Engineers (ASCE). The PIs will present their research results at the annual ASTM D-35 committee meetings and will take an active role in developing performance standards for the bench-scale tests used for the dewatering evaluation of geotextile tubes. Two middle school teachers will be involved in the project. The teachers will develop teaching modules, in collaboration with the PIs, which will be used to disseminate information on geotextile tubes to middle-school students.