The discharge of water vapour, water droplets and steam at a rate of heat release not exceeding 50 MW maximum capacity is a permitted activity subject to the following conditions:
Explanation and Principal Reasons for Adopting Method 220.127.116.11
Rule 18.104.22.168 is intended only to apply to the discharge of water vapour, water droplets and steam that does not contain volatile contaminants, such as from process waters or condensates.
General permitted activity condition 6.1.8 d) provides for visibility impairment beyond the boundary but special provision is needed where a large scale source is located in the vicinity of an aircraft flight path hence condition c) above. Conditions a) and b) above ensure that the plume will not have nuisance effects from blocking sunlight or fogging and will not result in droplet deposition that could cause icing. Conditions d) and e) relate to the use of biocides that are added to cooling water to control microbial growth and are intended to ensure that hazardous compounds are not released in the discharge.