Supporting Technical Assessments

CTMP Revision 0 If the treated water in the sediment control device is consistently very clear it could indicate overdosing, and the possibility of lowered pH which can present a risk to receiving waters as a result of elevated free aluminium concentration in the discharge. If the treated water is consistently clear the pH of the water in the sediment control device will be tested. Contingencies such as poor treatment performance or consistently very clear treated water should be dealt with as part of the day to day environmental management of the site. Refer to the ESCMP for additional monitoring and maintenance procedures that are to be implemented across the Project. A treatment chemical spill contingency procedure is provided in Section 6.6 below. 6.3 Record Keeping and Reporting A copy of the maintenance record for the chemical treatment system will be kept on site (Appendix C). A copy of the maintenance record for the chemical treatment system will be provided to WRC on request. 6.4 Procedure for Chemical Transportation The use of flocculants will be in accordance with the Project / Site Health and Safety Plan. PAC and Superfloc will be delivered to the site by commercial carriers in accordance with current Hazardous Goods, Traffic and Transport regulation. These chemicals can be requested from the supplier generally in 20 litre containers, 200 litre drums and/or 1,000 litre IBCs. Drums of PAC and Superfloc weigh about 250kg and is most easily moved within the site in a loader bucket. Transport around the site will be via suitable vehicles or machinery and containers will be sealed and secured such that the containers cannot topple over. 6.5 Storage of Chemicals on Site Chemicals will be stored in accordance with the Hazardous Substances procedure. Bulk PAC and Superfloc supplies will be held in secure storage. 200L polyethylene drums or IBCs of PAC and Superfloc will be held beside each chemical treatment shed / floc box, on level ground and secured so that the container cannot topple over. Those drums will be under the overall security and control of the site as a secure workplace. Drums of chemical will always be stored on end with the screw caps uppermost. Topping up of flocculant chemical will be made weekly as part of the regular inspection regime. 6.6 Chemical Spill Contingency Procedure Spills will be manged in accordance with the Emergency Spill Response Procedure. If there is a spill of PAC or Superfloc onto the ground it should be immediately contained using earth bunds to prevent it entering water. The spilt chemical should be recovered if possible and placed in polyethylene containers. If the spilt chemical cannot be recovered, it should be mixed with a volume of soil equal to at least ten times the volume of spilt chemical. This will effectively neutralize the chemical. The soil with which the chemical has been mixed should be buried in the ground a minimum of 0.5 metres below the surface. If there is a spill of chemical into ponded water, discharge from the pond to natural water should be prevented. If there is any spill into flowing water: 1. The Waikato Regional Council should be advised immediately. 2. The volume of the spill should be recorded.

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