UCLA

In the western United States and in many arid regions, wastewater reclamation is

becoming a common way of increasing water supplies. More and more wastewater

is being reclaimed for non-potable uses such as irrigation, but indeed reclamation

for potable use is also being practiced. One of the concerns for wastewater

reclamation are the contaminants that are not removed by either the wastewater or

water treatment processes and this is especially for the case of case of potable

reclamation. Radionuclides are rarely a concern in wastewater treatment and

reclamation systems, but the recent accident at Fukushima has focused attention on

the spread of fission and decay byproduct across farmlands and into drinking water

systems.

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In addition, recent wildfires in the abundant territory around Chernobyl caused

release of long-lived fission products to the atmosphere that had previously been

sequestered in the terrestrial system. At this time there is only anecdotal data

available on the impact of the fires on the wastewater radioactivity but it is a

continuing issue.

An important concern is the fate of radionuclides during wastewater reclamation. In

former times, it was assumed that reclamation activities will stop if there is a

contamination problem, but with increasing reliance on reclamation, stopping it may

have important and perhaps severe effects, including the loss of key industries that

use reclaimed water such as petroleum refining. More importantly major cities,

including Los Angeles, have aggressive programs for recycling 100% of its

wastewater to become a main part of its water portfolio. Therefore, in the future any

unexpected interruption in the reclamation programs will have major impacts.

In this dissertation previous observations of the radionuclides in wastewater

treatment plants are reviewed and summarized. As part of this research, a variety of

wastewater sludge samples were analyzed for radionuclides and results are presented

and fate and transport of two radionuclides, 131I and 40K are discussed in detail.