Field Evaluation of the Nutrient Removal Performance of a Gross Pollutant Trap (GPT) in Australia

Abstract

Field testing of a proprietary stormwater treatment device (GPT) was undertaken over a one year period at a commercial site located in Sippy Downs, Queensland. The focus of the study was primarily on evaluating the effectiveness of the GPT device in removing pollution in the form of nutrients (Total Suspended Solids, Total Nitrogen, Total Phosphorus) from stormwater runoff. Water quality analysis was performed on water samples taken from the inflow and outflow of the GPT during 15 natural rainfall events. A new testing protocol was developed to ensure a comprehensive investigation of the stormwater treatment performance of the GPT. Pollution treatment Efficiency Ratios (ER) calculated for the GPT were found to be 49.2% for TSS, 26.6% for TN and 40.6% for TP. Although the nutrient removal rates of the GPT observed in the study were below those specified by Queensland regulations, the results are considered notable for a stormwater treatment device that was not specifically designed to remove nutrients from stormwater.

Statistical Analysis of Field-Based Stormwater Filtration Performance for the Ecosol Litter Basket

“…The mean value of collection efficiencies was evaluated to be 29% for TSS, 40% for TP, 11% for TN, 6% for THM, and 20% for hydrocarbons [10]. In [12], field testing of a gross pollutant trap (GPT) was undertaken over a period of two years at a commercial site located in Queensland, Australia. Approximately 85% of the total catchment area was impervious.…”

“…The catchment contained only residential land use [11]. Field testing of a gross pollutant trap (GPT) was also undertaken over a period of two years at a commercial site located in Queensland, Australia [12]. The catchment drainage area consisted of sealed car parks (50%), building roofs (35%), and approximately 15% open space containing lawns and intermittent impervious paved surfaces (concrete pathways).…”

Embedding Nano-adsorbents Within Gross Pollutant Traps (GPTs): A Review

“…A study made by Nichols and Lucke [14] who used manufactured GPT (Humegard ® ) showed removal of TP, TN and TSS even though the values did not meet the water quality requirement as shown in Table 1. A combination of BMPs such as GPT, bio-retention and pond has been done by Sahrma et al [16] increased the removal of TSS, but it requires extra space and costly due to the multiple installations of BMPs.…”