Odour Threshold Investigation 2012 - Bay of Plenty Regional Council

Rotorua District Council also undertakes regular monitoring of H 2 S levels within
Rotorua. This monitoring typically has an indoor or enclosed space focus. The
Council administers the Geothermal Safety Bylaw 44 and provides an advisory role,
which includes testing for the presence of H 2 S gas to ensure as far as possible, the
safety of public from geothermal activity. The levels monitored can be as high as
several hundred ppm on occasions 45 .
4.2.2 Kawerau area
Carter Holt Harvey Pulp and Paper Limited at the Tasman Mill continuously monitor
ambient TRS 46 at Edgecumbe 47 (and also historically at Awakaponga 48 ) (see
Figures 4.3 and 4.4 respectively). This monitoring builds on earlier investigative
monitoring undertaken during 1992 which looked at total sulphur levels 49 where a
H 2 S guideline value of 7μg/m 3 was exceeded for 4.8 percent of the time over the
seven month (mainly winter time) monitoring period. 68
A key issue relating to the Rangitāiki Plains ambient monitoring is that the data
records TRS. These measurements therefore include H 2 S emissions from the
Norske Skog Turbo Alternator 3 electricity generator stack, a number of the Carter
Holt Harvey pulp mill stacks, and the geothermal surface features located in the
Kawerau township and the hills to the west. The percentage contribution made by
H 2 S to the TRS readings is unknown, and may vary from hour to hour depending on
both natural and industrial geothermal emissions.
Figure 4.3 Ambient TRS data frequency from Awakaponga site 50 .
44 Rotorua District Council, 2008, Geothermal Safety Bylaw, Doc No: IT-621891.
45 Pers. Comms Peter Brownbridge, RDC Geothermal Inspector.
46 Total Reduced Sulphur - includes hydrogen sulphide, mercaptans, dimethyl sulphide, dimethyl
disulphide and other sulphur compounds.
47 Resource Consent 60725
48 Resource Consent 61435
49 Bingham, A.G. et al, 1992, Ambient Air Quality Monitoring – Edgecumbe, 1992. Institute of
Environmental Health & Forensic Sciences, NECAL Report S92/837C, 5 August 1992, 27p.
50 Resource Consent 65720 Assessment of Environmental Effects, Chapter 4.
16 Environmental Publication 2012/06–A review of odour properties of H 2 S Odour Threshold Investigation 2012