Jolanta Dąbrowska

Optimisation of Operational Parameters for Nonwoven Sheaths of Water Absorbing Geocomposites in Unsaturated Soil Conditions

of Water Absorbing Geocomposites in Unsaturated Soil Conditions. FIBRES & TEXTILES in Eastern Europe 2016; 24, 3(117): 110-116. DOI: 10.5604/12303666.1196620 110 Optimisation of Operational Parameters for Nonwoven Sheaths of Water Absorbing Geocomposites in Unsaturated Soil Conditions Krzysztof Lejcuś1, Jolanta Dąbrowska1, Joanna Grzybowska-Pietras3, Daniel Garlikowski1, Iwona Lejcuś2, Andrzej Pawłowski1, Michał Śpitalniak1

Swelling Behaviour of Superabsorbent Polymers for Soil Amendment under Different Loads

One of the most important among the numerous applications of superabsorbent polymers (SAPs), also known as hydrogels, is soil improvement and supporting plant vegetation in agriculture and environmental engineering. Currently, when water scarcity involves water stress, they are becoming still more commonly used for water retention in soil. As it turns out, one of the major factors influencing the superabsorbent polymers water retention capacity (WRC) is the load of soil. The study presents test results of absorbency under load (AUL) of SAPs. The object of the analysis was cross-linked copolymer of acrylamide and potassium acrylate, of a granulation of 0.50–3.15 mm. The authors analysed the water absorption capacity of the superabsorbent polymers under loads characteristic for 3 different densities of soil (1.3 g∙cm−3, 0.9 g∙cm−3, 0.5 g∙cm−3) and three different depths of application (10 cm, 20 cm, and 30 cm). Soil load and bulk densities were simulated by using weights. The experiments were conducted with a Mecmesin Multitest 2.5-xt apparatus. The obtained results demonstrate a very significant reduction in water absorption capacity by SAP under load. For a 30 cm deep layer of soil of bulk density of 1.3 g∙cm−3, after 1 h, this value amounted to 5.0 g∙g−1, and for the control sample without load, this value amounted to more than 200 g∙g−1. For the lowest load in the experiment, which was 0.49 kPa (10 cm deep layer of soil of a bulk density of 0.5 g∙cm−3), this value was 33.0 g∙g−1 after 60 min. Loads do not only limit the volume of the swelling superabsorbent polymer but they also prolong the swelling time. The soil load caused a decrease in the absorption capacity from 338.5 g∙g−1 to 19.3 g∙g−1, as well as a prolongation of the swelling time. The rate parameter (time required to reach 63% of maximum absorption capacity) increased from 63 min for the control sample to more than 300 min for the largest analysed load of 3.83 kPa. The implications of soil load on superabsorbent polymer swelling are crucial for its usage and thus for the soil system. This knowledge might be employed for the more effective usage of superabsorbent polymers in agriculture and environmental engineering, in which they are commonly used to retain water and to support plant growth.

Mściwojów Reservoir – study of a small retention reservoir with an innovative water self-purification system

The study presents the characteristics of the Mściwojow Reservoir equipped with a unique pre-reservoir structure that supports the process of self-purification of waters. The authors present more than ten years of studies, focusing mainly on the issues of water quality and the concentration of phosphorus, which is considered as the main factor influencing water eutrophication process. Quite a high concentration of phosphates was noted in the outflow from the main reservoir, in spite of a lower concen tration of these compounds in the water leaving the pre-reservoir. Basing on the conducted analyses, the catchment of the reservoir was qualified as group 4, being very prone to the movement and supply of material to the reservoir. The negative value of the retention coefficient of phosphorus obtained for the main part of the reservoir points to the existence of an internal source of phosphorus supply to the reservoir. During over 10 years of studies, new directions of the development of the rural areas were determined. Future works should be extended so as to cover all elements of the ecosystem of the reservoir. In a longer term it seems natural to extend the research works to cover the whole catchment of Wierzbiak River.