Steam vent plumes

The Geysers. The Geysers area was visited on a single day during which several of the steam wells were being vented. Because of the weather, the plumes from the steam well were prominent, and measurements were made both of the ambient level in the area and of the mercury content of individual steam vent plumes. 

Some results of the constant-value pricing system are as foUow generation in a central unit at relatively low pressure, <4.24 MPa (600 psig) tremendous economic pressure to use turbines rather than motors for drives lack of incentive for high efficiency turbines excessively high temperature differentials in steam users tremendous incentive to recover waste heat as low pressure steam and a large plume of excess low pressure steam vented to the atmosphere. 

The ambient levels in the valley to the west of the power development ranged from 5 to 10 ng/meter . At the health resort at the head of the valley near the steam plants, the ambient level was 400 ng/meter. Immediately adjacent to the geothermal steam plant and downwind of specific vents the levels varied from 200 to about 4000 ng/meter. The maximum signal detected was in the plume emitted by a single vent on the north side of the valley it was greater than 28,000 ng/meter. ... 

Both natural phenomena and human activity produce airborne elemental mercury plumes. The naturally occurring plumes are usually associated with mercury mineral deposits and appear to be enhanced by mining activity or the venting of geothermal steam. The man-made plumes are associated with such activities as industry, sewage treatment plants, and refuse fill areas. The dispersal pattern of airborne mercury plumes depends on local conditions of ventilation and perhaps also on local concentrations of other contaminating molecules. 

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