Block · one region of the page, as the scanner read it. It may hold a whole story, part of one, several, or an advertisement; stitching blocks into articles is the next step. Text is supplied OCR.
Page 6 · column 3 of 6 · from the scan, no model involved
Water
From Page A1
from the air to be absorbed into •the water and used to precipitate metals out of solution. Iron and manganese are prevalent in local water sources.
One of the main drawbacks of this type is the large size of the pond needed. Another is that oxidation lowers the pH of the water even more. Lime .must be added, either as expensive powdered lime, or through the use of an open or closed limestone trench.
The limestone trench contains chipped limestone that gradually dissolves, raising the pH over time. Sometimes, the water is diverted into a well so that the water must fall and agitate the limestone, causing it to dissolve more quickly.
It is important that the pH of the water be maintained at a high enough level to support aquatic life. In highly acid water, neither the microbes that feed fish nor the fish themselves can survive.
Reducing wetlands perform exactly the opposite process as oxidizing wetlands. Organic sewage material on the bottom of the pools, with bacteria in the water, creates a chemical reaction that removes oxygen atoms from the metals in the water.
98.4%