CART CART-01 Revision 0 Page | 15 tested. Either of these chemicals could be used on site. The recommended chemical to be used on site is PAC, due to its rigorous testing undertaken by the Auckland Regional Council and cost advantage. Taking account of the variability between samples, PAC at a dose rate of 4mg/l Al provided the most consistently high water quality treatment response. An indicative dose rate of 4mg/l Al equates to 62ml PAC / m3 of sediment laden runoff. The pH response to all low to moderate dose rates of PAC and Superfloc were within the acceptable range with respect to background pH and potential toxicity. High dose rates exceeding 8mg/L of Al are not recommended. As stated in Section 1.2, the application and management for chemical at each site will be implemented in accordance with the CTMP and the dosing system setup for each device will be specified in the corresponding SSESCP. Where new soils are encountered, or responses are not as anticipated, additional bench testing will be undertaken in accordance with the GD05 methodology and included in the CTMP.
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