Environment Waikato has granted resource consent applications from Watercare Services Limited for a water treatment solids landfill at Trig Rd, Tuakau.
The company had applied to divert clean runoff through a water treatment solids landfill, discharge plant solids onto land, divert and discharge treated water from the operation into a tributary of the Waikato River, clear a hectare of vegetation and disturb up to 9000 cubic metres of soil. Six submissions were received from Waikato District Council, neighbours and a community law centre.
The applicant proposed to remove soft material from the proposed landfill site and place water treatment solids onto land for drying and landfilling. About every 10 years, solids dried in an auxiliary drying area would need to be transferred to the landfill.
The applicant discussed the importance of the project in ensuring the Auckland region had a secure water supply for the next 20 years. Submitters expressed concern about the lack of time they had had to read and respond to the staff report. They were also concerned about the amounts of mercury in the water treatment solids, and dust from the site.
Some also sought compensation should their property be adversely affected by the proposal.
The applicant said review conditions which addressed adverse environmental effects would be more appropriate than compensation. At the Hearing the applicant agreed to add mercury to the parameters to be tested, and to supply monitoring data and reports to interested parties.
Levels of mercury expected in the solids would not be toxic, it said. Groundwater sampling would be done close to the source to detect any unexpected adverse effects as soon as possible.
In making its decision the Committee said that dust was a major concern to submitters. However the method used for drying and landfilling would ensure that dust would not cause any adverse effects as the water treatment solids would be applied to the land wet. The committee considered dust would not cause adverse effects on neighbouring properties or affect the quality of surface or drinking water.
Environment Waikato staff said the technical information contained in the application documents was correct. The Committee was satisfied that water treatment solids would not cause any adverse environmental effects. Although the effects were likely to be minor, appropriate monitoring and review provisions were appropriate to address any effects that may arise.
The Committee said submitters were concerned about the lack of certainty in the staff report, however with any new activity, determining the exact scale of effects with absolute certainty was rare. This was the principal reason for monitoring and review provisions. Under the Resource Management Act, the principle of balance of probabilities was used. Principles such as scientific proof, were not required for decision-making under this legislation, it said.