Screening Screening is the first unit operation used at wastewater treatment plants (WWTPs). Screening removes objects such as rags, paper, plastics, and metals to prevent damage and clogging of downstream equipment, piping, and appurtenances. Some modern wastewater treatment plants use both coarse screens and fine screens. Figure 1 depicts a typical bar screen (a type of coarse screen). Coarse Screens Coarse screens remove large solids, rags, and debris from wastewater, and typically have openings of 6 mm (0.25 in) or larger. Types of coarse screens include mechanically and manually cleaned bar screens, including trash racks. Table 1 describes the various types of coarse screens. Fine Screens
About Long Island. Long Island New York is the largest island adjoining the contiguous United States, extending approximately 118 miles east-northeast from the mouth of the Hudson River. It is separated from the mainland on the north by the Long Island Sound and bounded by the Atlantic Ocean on the south and east.
Long Island, in the state of New York, formed from the silt deposited by a melting glacier in North America at the end of the last ice age. Challenge students to investigate islands that have formed in less familiar ways, such as Long Island and barrier islands throughout the world.ow refer to relief maps, a globe, or a world map to show students that the surface of Earth has peaks and valleys and plateaus, some covered by water and others above water. 3. Next, distribute copies of the Background Sheet: Three Ways to Make an Island and review with students the three major ways that islands form.