Environmental Impacts Associated with New Zealand Cement Manufacture

The environmental impacts associated with the manufacture of cement in New Zealand were investigated, using a similar Canadian study as a base document. Monitoring data for the 1995 year was collected from the three cement plants currently in production Lee Cement Works near Nelson, Golden Bay near Whangarei and Milburn near Westport. Environmental impacts for the first three stages of cement manufacture raw material extraction, transport to the plant, and the manufacturing procedure itself were investigated. To create overall NZ energy and emission values, the values for each of the plants were proportionally weighted to take account of differing plant productions. Only a small portion of the data set which the Canadian study obtained is available for New Zealand. Thus, comparisons between the two nations' cement operations were restricted, although increased monitoring is planned by some New Zealand plants in the near future. From the obtained information: in the extraction of the raw materials, the atmospheric emissions are higher in New Zealand for all the gases measured: C02, S02, NOx, VOC's, CHq and CO. New Zealand's atmospheric emission figures for raw material transportation are similar to Canada's for all gases monitored, with the exception of NOx. This is because of the reliance in some regions of Canada on (diesel-based) long-range rail freight, which results in the emission of high amounts of NO2 compared to other modes of transport. New Zealand's total embodied energy intensity (extraction/transportation/production) for cement is 8% higher than Canada's. Only in the transportation component for New Zealand is the comparative figure lower. The level of other New Zealand cement-related environmental outputs, such as liquid effluents (from quany water, stormwater mn-off and the cement plant) and cement kiln dust. is unknown.