Gas, odour and dust from the Levin landfill are issues that will not go away, and in the latest compliance report from Horizons Regional Council this remains a significant non-compliance issue.
The absence of any methane surface monitoring in or around the site was deemed so serious it resulted in a fine.
There are over 240 conditions associated with the landfill's five consents.
While the water quality is said to be within the guidelines, several problems have been identified such as rising concentrations in ammonia in bores close to the old unlined landfill as well as 'patterns of rising concentrations in the Hōkio Stream as well as the Tatana Drain, which runs into the Hōkio Stream'.
The report stated that discharge of solid waste to land, diversion of stormwater from around the landfill, discharge of liquid waste on to and into land as well as discharge of stormwater to land and potentially groundwater via ground soakage are fully compliant.
Not supplying enough information, sufficient data, or not doing certain checks are also identified as issues, though these are considered minor and easy to fix.
Minor issues the audit identified are: discharge to air via flared landfill gas and discharge of landfill leachate on to and into land. Horizons considers these non-compliant but as having low risk.
Discharge of leachate is non-compliant due to failure to remediate capping on the old unlined landfill. Further monitoring and an update on all exceedances is asked for.
The flared landfill gas issue has to do with failure to meet certain timeframes and not meeting sampling requirements as well as not including all required information in the operations and management plan.
A significant issue identified here is the failure to undertake any methane surface monitoring, which must be done monthly.
"HDC said it held off until a remedial plan was established and advised that there were health and safety concerns to work through as well as problems resourcing the clay material used to remediate the cap.
"Notwithstanding the comments above, the failure to undertake monitoring has resulted in a significant noncompliance and this sampling must be implemented immediately."
The original consent for the landfill dates from 1998, and covers an old unlined landfill and a new lined landfill.
The community battle to fix ongoing issues began in 2004 when the Parliamentary Commissioner for the Environment, in response to complaints from the community, expressed concern about management and associated environmental effects of the landfill and suggested a review was in order.
This review was completed in 2010. This led to a number of new conditions within the consent. In 2015 the revised consent was put up for consultation.
The decision resulting was appealed in the environment court and on December 19, 2019 a number of amendments were made to the resource consent conditions.
A consultant assessed the recent surface water and groundwater monitoring data. Their report said the quality of the groundwater and the surface water within the Tatana drain could be 'described as adverse'.
The Tatana Drain is privately owned and runs in between the old landfill and the Hōkio Stream at about 100m from the stream and discharges into the Hōkio Stream downstream from the landfill.
Both the drain and the stream run from east to west, while groundwater flows north to west, towards the Hōkio Stream. The consultant deems it likely the drain will intercept shallow groundwater. Groundwater is checked from bores at various depths, but their levels are not recorded at all bores.
Water quality is sampled from a number of locations and includes groundwater bores, surface water within the Hōkio Stream and from the landfill leachate pond.
The groundwater quality concentrations are compared to the drinking water standards in bores in the deep aquifer, and livestock drinking water standards for bores in the shallow aquifer, though it seems unclear what is considered shallow or deep.
Monitoring of the Tatana Drain indicates very high concentrations of ammonia (and other parameters) which is derived from high concentrations in groundwater seepage into the drain. Effects from the old unlined landfill could exceed the guidelines in some circumstances, for example for ammonia, nitrate and DRP in the Hōkio Stream, the consultants' report said.
It also notes there are effects on the Hōkio Stream, but that those are within guidelines. It goes on to urge putting in place actions that can deal with an 'emerging patterns of rising concentrations and potential for effect' on the Hōkio Stream.
The consultants' report said, "Hokio Stream is likely to be the ultimate receiving environment for groundwater discharging from the landfill area. However, the Tatana Drain appears to intercept groundwater and discharges directly into Hokio Stream. Therefore, the Tatana Drain also represents a receiving environment for groundwater discharging from the landfill.
"Water quality within the Tatana Drain is poor, although the data appears to suggest that it improves as water is conveyed downstream towards the confluence with the Hokio Stream.
"Regardless of the improvement, concentrations of parameters such as ammonia are significantly in excess of the toxicity thresholds for aquatic life in the Tatana Drain at the most downstream sampling site.
"Sampling data indicates that discharges from the landfill affect water quality in Hokio Stream, although the effects do not appear to exceed the relevant guideline thresholds.
"Whilst this may be the case based on the current dataset, rising concentrations of ammonia and other parameters in bores located downgradient of the old, unlined landfill are a potential cause for concern, as are the recent breaches of the nitrate thresholds for shallow groundwater in bore B2. Notwithstanding the comments above, we also note that the contaminant mass balance calculations indicate that effects from the landfill could cause effects on Hokio Stream that exceed the guideline values.
"Combined, the pattern of rising concentrations and potential for effects in Hokio Stream should be considered as early warning signs and preparations to manage those effects should be put in place."
Apart from a list of recommendations, such as the request to supply observations to the weekly walkovers and to ensure exceedances are appropriately recorded, Horizons has issued a demand to include monthly methane surface monitoring, lack of which means HDC has failed in complying with several conditions of its consent, the regional council has presented HDC with an infringement notice for an unauthorised discharge to air.
Horizons' annual compliance audit report for the Levin landfill covers the period of December 19, 2019 to December 31, 2020.