Industrial and Trade Activity Environmental Management Plan
Appendix C: Bentonite Plant Spill Response Plan Purpose and Objective of Plan The bentonite plant is located within CSA5. This Bentonite Plant Spill Response Plan (BPSRP) relates to the management of spills of liquid bentonite slurry and/or additives from within the bentonite plant. The objective of this BPSRP is to ensure that emergency spills are handled in an appropriate manner to ensure safety of all personnel and to prevent damage to the environment. Bentonite components and additives The fresh bentonite slurry is composed of water from the main fire hydrant and of bentonite and additives (sodium bicarbonate and bentocryl). Mixing of bentonite with water and additives (sodium bicarbonate and bentocryl) to make a bentonite slurry, which will be temporarily stored within the silos before being used in the diaphragm wall construction. Safety Data Sheets for the Bentonil, the Sodium Bicarbonate and the Bentocryl are held at the site office. These additives are not classified under HSNO as hazardous. Irrespective of this, all of these additives will be stored within the bunded bentonite plant area. No other hazardous substances will be required as part of the bentonite plant operation. Structural Controls The entire bentonite plant is bunded to contain any spilt material or bentonite slurry in the event of a pipe or pump failure during transfer of slurry. A surface pump will be used to manually pump any surface water that collects within the bund to an onsite water tank or to the water treatment plant. The bund will be checked on a daily basis for water accumulation, to determine whether pumping is required. Once the water treatment plant has been commissioned, surface water from the bunded area will be pumped to the plant for treatment. This water will be treated prior to discharge to the stormwater system. Washwater At the end of each shift the plant is washed down. Any washwater will be contained within the bunded area and pumped to the onsite water tank or the water treatment plant once commissioned. Contingency Measures To prevent overflow from the silos: • • • • Page 46
• The float switches have been positioned to 2.5 m below the top of the silos, providing extra capacity in the top of the silos in the event of heavy rain • The level alarms have been tested during a trial run • The silos supply circuit has been checked and tested during a trial run • The levels of slurry inside the silos will be lowered down to a minimum level during any long weekend and/or holiday periods (e.g., during Christmas and New Year) | Mt Eden Main Works
