Annual report 2006-2007 - Taranaki Regional Council

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Table 14 Summary of performance for Consent 4657-1 to discharge stormwater from galvanising
plant premises into an unnamed tributary of Kahouri Stream
Condition requirement Means of monitoring during period under review Compliance achieved?
1. No discharge of contaminants
other than those in special
condition 2
2. Defines discharge contaminant
limits
Water quality monitoring Yes
Water quality monitoring;
*Zinc above limit – related to historical disposal at this
site.
3. Stormwater management plan Receipt and review by Council Yes
4. Defines no adverse effects on
receiving water after reasonable
mixing
No*
Water quality and biological monitoring Yes
5. Optional review of consent Not exercised Yes
N/A = not applicable
During the year, the Company demonstrated a high level of environmental
performance and compliance with the resource consents. During the year under
review there were two inspections conducted, which indicated that site stormwater
and wastewater were well managed, and operations were undertaken in a manner
that minimises environmental effects.
It is noted that the factory is located in a rural area and is isolated from residences or
other commercial premises. Accordingly, there is no evidence of aerial emissions
from galvanising activities causing adverse effects off-site.
Leachate discharged from the site, as a result of past activities, to a small subtributary
of the Kahouri Stream continues to show measurable concentrations of
zinc, however trends over time suggest that zinc levels are continuing to decrease as
pH of the leachate improves. Despite the elevated zinc, the level of dissolved zinc
was below the detection limit in the stormwater tributary above the confluence with
the Kahouri Stream (TRC site code KHI0000369) and well below the United States
Environmental Protection Agency guidelines for the protection of freshwater aquatic
life in water of hardness similar to the Kahouri Stream (25 g/m 3 CaCO3), and below
the Australia New Zealand (ANZECC) guidelines for 95% protection of aquatic
communities. No adverse effect of the discharge was found in the tributary
downstream, on the basis of chemical monitoring or biomonitoring in conjunction
with other activities in the Stratford industrial area at the headwaters of the
unnamed tributary system.
3.6.4 Recommendations from the 2005-2006 Annual Report
In the 2005-2006 Annual Report, it was recommended:
1. THAT monitoring of air emissions from the galvanising plant of Taranaki
Galvanizers in the 2006-2007 year continue at the same level as in 2005-2006,
including the provision for air deposition gauge monitoring conducted
biennially.