Higgins Group Holdings Limited (the applicant) have applied for resource consent to discharge contaminants, being particulate matter 10 (PM10), odour, nitrogen dioxide (NO2), carbon monoxide (CO) and Sulphur dioxide (SO2), to air from the production of asphalt and associated yard activities at 92 Hewletts Road, Mount Maunganui.
The applicant previously held resource consent 63317 to undertake the same activity, this consent expired on 20 September 2020. The applicant lodged a replacement application more than six months prior to the expiry of their previous consent and therefore were automatically afforded the right to continue operating under their previous consent, under section 124(3).
The applicant has generally complied with their previous resource consent with exception to operations in 2011/2012. Emission testing in October 2011 showed a significant non-compliance with the allowed limits of 250 mg/m3 (STP, dry) and 2.5 kg/hr for average concentration and mass emission. In response the applicant upgraded the scrubber and demister which brought the discharge back into compliance. Smoke and odour complaints led to an Abatement Notice and an Infringement Notice in 2022.
The applicant operates a parallel-flow drum mix, diesel-fired asphalt plant, which operates on a continuous basis, with the drum used to both dry and heat aggregate and mix liquid bitumen with hot aggregate to produce hot mix asphalt. The plant has a maximum production capacity of 60 tonnes per hour (tph). The plant is generally run daily from 7.00 am until 6.30 pm to meet average demand, however there are times when the plant runs through the night to meet demand. The annual maximum capacity of the plant production is 75,000 tonnes per year (tpy), whereas the historical maximum annual production has been 50,000 tpy. The applicant proposes to run the operation to have a maximum annual production of 50,000 tpy.
The plant is equipped with a venturi water scrubber to control particulate and other emissions. Combustion gases, dust, bitumen volatile matter and pyrolysis products are drawn by an induced draught fan through the venturi scrubber before being discharged to air via a 13 metre (m) high stack. The proposal is to continue operating at the historical maximum with no additional mitigation measures, meaning that the applicant’s contribution to the individual and cumulative effects of PM10 discharges within the Airshed are not changing from the historical max in 2019 (noting in 2020 and 2021 annual production was between 30,000-40,000 tpy).
Submissions closed on Thursday, 25 May 2023.
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