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In 2006 the WWTP removed 11.9 million pounds of TSS, or 97% of the TSS coming into the plant. Most of these solids are further treated and then hauled away to be used as fertilizer on farm fields. These treated solids are called biosolids. In 2006 the WWTP generated 5,234 dry tons of biosolids. Of that, 2,345 tons were land applied. The remainder was landfilled.
Source: Ann Arbor Wastewater Treatment Services |
What are total suspended solids?
Total suspended solids (TSS) include all particles suspended in water which will not pass through a filter. Suspended solids are present in sanitary wastewater and many types of industrial wastewater. There are also nonpoint sources of suspended solids, such as soil erosion from agricultural and construction sites.
How do total suspended solids affect the environment?
Suspended solids can make waters turbid (cloudy) and cause an increase in stream temperature. As levels of TSS increase, a water body begins to lose its ability to support a diversity of aquatic life. Suspended solids absorb heat from sunlight, which increases water temperature and subsequently decreases levels of dissolved oxygen (warmer water holds less oxygen than cooler water). Some cold water species, such as trout and stoneflies, are especially sensitive to changes in dissolved oxygen. Photosynthesis also decreases, since less light penetrates the water. As less oxygen is produced by plants and algae, there is a further drop in dissolved oxygen levels.
TSS can also destroy fish habitat because suspended solids settle to the bottom and can eventually blanket the river bed. Suspended solids can smother the eggs of fish and aquatic insects, and can suffocate newly-hatched insect larvae. Suspended solids can also harm fish directly by clogging gills, reducing growth rates, and lowering resistance to disease. Changes to the aquatic environment may result in a diminished food sources, and increased difficulties in finding food. Natural movements and migrations of aquatic populations may be disrupted.
Modified from: Michigan DNR
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