|
Major impacts
Spent biomass and process waste water containing large quantities of nitrogen and phosphorus are the main by-products. Spent biomass is recycled at agronomic rates as fertilizer on crops grown by over 200 neighbouring farmers, and the waste water is used for irrigation of crops on land surrounding the factory.
Breaches of regulatory limit values
The number of irrigation sites exceeding the 10 mg/l limit for nitrates in ground water has been reduced from seven in 1997 to six in 1998 as a result of a number of measures. The most significant was an expansion of the waste water treatment system, which gave a 60-80% reduction in the nitrogen content of the waste water. In 1999, the target for irrigation sites exceeding the standard is no more than four.
Accidental releases
Two accidental releases of waste water into Buffalo Creek occurred in 1998. A total of 270 m3 of evaporator condensate with very low levels of contaminants flowed into the storm water drainage system. Drain piping was modified to correct the discharge problem.
The second release was 9 m3 of treated waste water caused by the overflow of a drain blocked by debris which has since been cleared. Tests showed minimal impact on the water quality of Buffalo Creek from this release.
Complaints
Seven complaints were received about odours from the waste water storage lagoon. On May 1 the improved process waste water treatment system started up and these odours disappeared in less than a week. One odour complaint occurred when the waste water treatment system did not function properly.
Four other complaints resulted when equipment failures on the spent biomass treatment systems caused odours. New procedures have been developed to quickly mitigate such odours and the equipment will be upgraded in 1999 to reduce the risk of further failures.
Three noise complaints were received from one neighbour. In late 1998 noise abatement shielding was installed at nine locations and the outside paging system was decommissioned to eliminate this noise source.
Environmental focus
Efforts have focused on reducing potable water usage as well as process improvements to reduce energy consumption. |
