Stormwater harvesting strategies

Stormwater Harvesting Strategies (Name of the Student and Student Number)

Treatment Techniques for Harvesting the Stormwater

These are various strategies for effective stormwater harvesting are used. This research focuses on the treatment techniques. The treatment involves Water Sensitive Urban Design Techniques (WSUD) for stormwater and the advanced methods.

1.1 Water Sensitive Urban Design Techniques

The application of WSUD this technique is discussed in the following parts1.1.1 The Physical Processes

Physical Processes describe the devices that are used in WSUD for water treatment devices. The treatment involves hydraulic properties. These techniques include buffer strips, swales, and naturally opened water bodies as well as built water bodies. These processes alone can not provide a major treatment to make the harvested water usable, it only a preliminary treatment which decreases pollutants before the next step. In some cases, the stormwater is directly utilized for the purpose of irrigation, where there is a restriction over public access. Such processes strategically work to reduce the velocities of flow in order to allow the pollutants to settle out from the columns of water. An advantage of using open water bodies is there exposure to Ultraviolet light, which disinfection water to some extent.

The infiltration of stormwater

The collected water from the above physical process is now used in Infiltration method for treatment.

The processes involve permeable and absorbent pavements, trenches, basins, sand filters and the soil, which is biologically treated.

1.1.2 Biofileration Devices

The devices such as; biofilters for Infiltration can combine to the vegetation to treat the water. According Australian studies (Booth et al., 2003), if the previous processes are efficiently designed they can successfully reduce sediment to about 80%, phosphorus about 60%, nitrogen about 80%, heavy metals to about 70%, and greases or oils to about 98% of oils and greases. While the Sand filters have proved to reduce a higher proportion which is 75% to 100%, but a pre-treatment or physical process is required (EPA, 1997). A test was done by Birch et al. (2005) with stormwater of about 450m2 and basin an area of 2.7ha catchment in a park of Sydney. The results proved to be highly effective to remove the contaminants and the metals such as zinc, lead and copper. While the basin found to be ineffective for nitrogen removal. The Design of the method should be efficient, but the maintenance is also an important factor. A survey provided the results as that after four years (Lindsey et al., 1992), only 38% of the basins were performing as they were designed and about 31% were clogged (Schuler et al., 1992).

1.1.3 The Biofilters and the Wetlands method

The natural and the constructed wetlands both use methods of physical and biological treatment. Biofilters has filter for soil which is planted with vegetation, and also contains a number of pipe used to convey water which has filtered to downstream facilities for storage.

There have been some tests to examine the effectiveness of stormwater treatment with biofilters.Biofilters have been tested to be designed in an efficient way can achieve the ...