Hydraulic performance and its evolution over time is a key design parameter for stormwater filter systems. The major impact affecting stormwater filters is the reduction in infiltration rate, or otherwise known as clogging. This paper focuses on the effect of biological clogging of non-vegetated high flow stormwater filters in Australian conditions. An experimental column study was undertaken. Five semi-synthetic stormwater dosing configurations were tested: (i) Typical stormwater (base), (ii) Stormwater with high nutrient load, (iii) Typical stormwater with chlorine tablets, (iv) sterilized stormwater, and (v) potable water. Each configuration had 6 replicate columns, 3 were placed inside under controlled laboratory conditions and 3 were placed outside under normal Australian spring weather conditions, except for the potable water case (v) where it only had 2 replicate columns and both were placed outside. The results found were inconclusive due to the insignificant reduction of the infiltration rate over time and the columns did not clog, which is due to the size of sediment used in this study. It is suggested that further work should be undertaken on investigating the effect of stormwater composition in stormwater filters in real world conditions.
Shrinkage of clay soils during drying can impose significant unfavourable effects on engineering applications. Researchers have attempted to amend drying shrinkage by mixing soil with various additives such as nanomaterials, fibre, geo-polymer etc. This paper discusses the shrinkage characteristics of an expansive clay mixed with nylon fibre and an organic enzyme. As clay is mostly used in compacted form in civil engineering applications, the study was focused on the shrinkage behaviour of compacted clay. Different percentages of nylon fibre, ranging from 0 to 1.2 percent by weight, were mixed with soil. The amount of enzyme added to each mixture was kept fixed at 0.35 g of enzyme per kg of dry soil. Compacted soil blocks were made using standard compaction procedures and cut in to rectangular specimens of size 80 x 60 x 40 mm.Compaction test results indicated that addition of fibre and enzyme can slightly improve the dry density of soil. Rectangular block specimens were allowed to dry without restraints under room temperature. Change in moisture content, linear and volumetric shrinkage and change in void ratio were investigated. Image analysis techniques were used to measure the changes in dimensions.