Supporting info on Green Island noncompliance and issues relating to this.

The Green Island Waste Water Treatment Plant (GIWWTP) receives 3 major sources of industrial wastewater:

1)PPCS Silverstream (Mosgiel) 2)PPCS Burnside 3)Colyer Mair (tannery)

All 3 are pre-treated on-site by the industries in question (pretty crude) before entering the DCC’s sewage system.

2 (Burnside)& 3 (Colyer Mair) go thru GI WWTP but 1 (Silverstream) comes in at the end of the GIWWTP pipeline so you have primary treated meatworks effluent mixing with secondary + disinfected GIWWTP effluent.

1, 2 and 3 have all caused problems (and still do) at various times. The biological system (bacteria which treats the sewage by breaking it down) was killed by high sulphide a few years ago and blood products pushed up ammonia levels big time.

It is Burnside that DCC say they will transfer to Tahuna (not Silverstream) - so yes Silverstream will continue to avoid secondary treatment

The exceedances of effluent quality limits at GI were neither occasional nor minor.

Compliance record at Green Island:

During the January-March 2001 quarter the Faecal coliform concentrations discharged from the Green Island WWTP breached the consent limit set by the Regional Council by 167 times. Ammoniacal nitrogen also breached on many occaisions. Data was collected very week during this time. A letter was sent by the ORC to Gerry Oliphant of the DCC asking for an update on progress to date with local industries to improve trade waste and final effluent quality.

During the April to June 2001 quarter there was an improvement in the faecal coliform discharges with only 7 out of 13 samples breaching the consent conditions! The annual median for faecal coliforms could be calculated at the end of this quarter however and the 50,000/100ml median was 35 times higher than the 14,000/100ml limit. Ammoniacal nitrogen was of concern again. Another letter was sent to Gerry Oliphant.

July-Sept 2001 median for faecal coliforms breached 3.6 times. Ammoniacal nitrogen was of concern again. Another letter sent by ORC to Gerry Oliphant of the DCC.

Oct-Dec 2001: although results were lower than the previous summer Faecal coliforms were still high. The annual median for 28 Dec 2000- 27 Dec 2001 was 1.6 times above the consent condition. Ammoniacal nitrogen was of concern again .Gerry received another letter.

Jan-Mar 2002: still breaches in the consent conditions. Ammoniacal nitrogen was of concern again. An audit report outlined all of the breaches of the consent.

April-June 2002: 7 of the 13 Faecal coliform measurements breached the consent conditions. Ammoniacal nitrogen was 1.3 times above consent conditions. Letter sent to RCH.

July-Sept 2002: 10 of the 13 Faecal coliform readings above the limit. Letter sent again. Ammonical nitrogen exceeded on only 2 occasions. Letter sent.

Oct-Dec 2002: 6 of the weekly Faecal coliform readings above the limit. Ammoniacal nitrogen exceeded on 4 occasions (peak meat processing time).

Overall we can see that the record of non-compliance with consent conditions has been ongoing at the Green Island WWTP. The exceedances are not small/minor and did not occur only a few times.

Issues:

The DCC says that they are going to have the same resource consent conditions at Tahuna as they have at Green Island. This sounds really good as there is secondary treatment at Green Island. However it is cause for concern because the Green Island Plant has trade waste bypassing the secondary treatment to go directly to sea (PPCS Silverstream). The general public is not aware this is happening.

Should the Regional Council have acted to enforce the consent conditions at Green Island rather than just writing letters? This has never been done.

Should the DCC continue to protect a few industries at the cost of the local community? Should the industries be portrayed in a bad light when it is the DCC who is putting there waste out to sea through primary treatment instead of treating it adequately or is it the industries own responsibility?

The public should know that waste at Green Island is not all secondary treated and disinfected. Some bypasses the process (PPCS Silverstream).

Will the waste being directed to Tahuna through the by-pass you reported on a couple of weeks ago have the same effect as the Trade waste at Green Island? We are concerned about the safety of Dunedin’s beaches.

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