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Mid-America Transportation Center

Development of a Field Test Method for Total Suspended Solids Analysis

Final Report
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Researchers

  • Principal Investigator: Tian Zhang (tzhang1@unl.edu 402-554-3784)
  • Co-Principal Investigator: John Stansbury (jstansbury2@unl.edu 402-554-3896)
  • Project Status
    Complete
    About this Project
    Brief Project Description & Background
    Stormwater discharges from construction and dewatering sites can carry large sediment loads resulting in highly turbid water. We will develop a vacuum-filtration based method for rapid measurement of TSS in stormwater runoff from construction and dewatethe vacuum-filtration system will consist of an electronic repeating pipette connected to a pipette tip filled with a glass fiber filtration layer. The pipette will produce a repeatable vacuum to allow the consistent extraction of the sample through the tip, and the tip will retain suspended solids (defined as any particles > 2 micrometer) but allow dissolved solids (any particles < 2 micrometer) and water to pass throughring sites. Since standard TSS measurement requires time-consuming laboratory procedures, and since TSS limits are expected for stormwater and dewatering discharges, it is very important to develop this inexpensive, quick field monitoring method.
    Research Objective
    The goal of this proposed research is to develop a vacuum-filtration based method for rapid, cost-effective and reliable measurement of TSS in stormwater runoff from construction and development sites. The specific objectives are to: 1. Make a vacuum-filtration system for TSS measurement; and 2. Test the system for artificial and real stormwater runoff (i.e., with various suspended load characteristics) to establish the method such that it will be usable for various field conditions.
    Potential Benefits
    The proposed method is a membrane- filtration-based method, and it also is based on the former Standard Method in that glass fiber is used to filter the sample TSS. The critical idea is to apply a repeatable vacuum to extract the sample which would allow us to link the filtrate with TSS in the sample. Once the feasibility of the method is proved, it should be easy to standardize/commercialize the system, such as making a simpler pipette to generate vacuum and making disposable, flat-ended pipette tips with a glass fiber layer or even a membrane with a nominal pore size (e.g., ~2 micrometer). It is anticipated that the commercialized system will be much cheaper than any other equipment that can be used for TSS, turbidity or PSD measurement. The proposed research is a significant, initial step in tracking TSS in the field. The method should allow the implementation of a NPDES permit with a TSS-based numeric limit. The method should allow us to address the problems associated with varying site and regional climatic conditions that make the establishment of a uniform turbidity limit unreasonable. The method should be rapid, cost-effective, reliable and easy to be commercialized for large-scale applications.
    Abstract
    Stormwater discharges from construction and dewatering sites can carry large sediment loads resulting in highly turbid water. The USEPA established a NPDES permit for construction-related runoff (i.e., turbidity < 280 NTU) in 2009. However, this limit has subsequently been removed pending further review. On the other hand, many states have issued NPDES permits with TSS limits (e.g., Nebraska requires TSS = 90 mg/L). Since standard TSS measurement requires a time-consuming laboratory procedure, it is imperative to develop a method for rapid, cost-effective, and reliable measurement of TSS in the field.

    The goal of this proposed research is to develop a vacuum-filtration based method for rapid measurement of TSS in stormwater runoff from construction and dewatering sites. The specific objectives (& tasks) are to:

    1) Make a vacuum-filtration system for rapid TSS measurement. The system will consist of:
    a. a pipette tip filled with a layer of glass fiber to retain suspended solids (particles > 2 micrometer) but allow dissolved solids (particles < 2 micrometer) and water to pass through.
    b. An electronic repeating pipette. It can produce a repeatable vacuum so that the sample volume passing through the glass filter will only depend on the properties of the sample (e.g., TSS).

    2) Test the system for artificial and real stormwater runoff to establish the method. Artificial runoff will be made up of silt, clays, and sand of different combinations. Real stormwater will be sampled from several construction sites. We will establish calibration curves of TSS vs. the passed water for different runoff mixtures. The performance, statistics, and cost effectiveness of the method will be evaluated.

    The research is a significant, initial step in tracking TSS in the field. The method should be rapid, cost-effective, reliable and easily commercialized.
    Project Amount
    $ 59,975