![]() In this influent area, sampling equipment is used to collect small portions of the wastewater for analysis. Grit can also plug lines and pipes and does not respond to biological treatment. These items are removed to prevent wear and abrasion on pumps and other mechanical equipment. Grit is comprised of inorganic material such as sand, gravel, eggshells, etc. The next process in preliminary treatment is grit removal. Screenings are removed using a bar screen. These materials need to be removed because they can damage machinery or clog processes. ![]() ![]() Screenings are string like materials, rags and large foreign objects like sticks or perhaps an errant golf ball. Flow monitoring is followed by screenings removal. This involves flow measurement so that the operator can quantify how much wastewater is being treated. Preliminary treatment processes are the first processes that the wastewater encounters as it enters the treatment process. The solids or “sludge” removed from the wastewater stream also needs to be treated. The wastewater then flows to Secondary Treatment where the water passes over a biological filter and chemicals are added to promote the finer particles to settle out. Preliminary Treatment is followed by Primary Treatment where smaller items that either float to the surface or settle to the bottom are removed. Upon reaching the plant, the flow first encounters preliminary treatment where larger items are removed. The wastewater continues to flow through the collection system and eventually reaches the wastewater treatment plant. What happens after collection of the wastewater? Infiltration is usually most severe in the spring when melting snow and rain saturate the ground. All sewer pipes have leaking joints or cracks that allow the groundwater to enter the system to some extent. Infiltration is groundwater that leaks into the sanitary sewer. This program has eliminated approximately 90-95% of the ground water that at one time was pumped into the sanitary sewers. The City of Durand implemented a sump pump and footing drain separation program in 2000. The last of the combined sewers were separated in the late 1970’s. At one time Durand’s storm and sanitary systems were combined they are now separate from one another. Some communities have “combined sewers” that intentionally receive inflow, instead of having separate sanitary and storm sewers. This is relatively clean water that should be discharged to a storm water system. Inflow is rain water that gets into a sewer from surface inlets, holes or leaks in manholes or manhole covers, sump pumps, or roof downspouts. After treatment the water is pumped approximately 3 miles to the Shiawassee River. Durand has four of these pumping (lift) stations.ĭurand’s collection system consists of approximately 15 miles of sewer mains that collect wastewater from approximately 1,500 homes and businesses. Where gravity systems are not practical, pumping stations are used to lift the wastewater and pump it to a point where it will flow by gravity. As the pipes get closer to the treatment facility the pipes become larger in diameter. Durand’s collection system is comprised of sewer pipes ranging in diameter of 8-inches to 24-inches. Sewer collection systems are designed so that the wastewater flows to a centralized treatment location. Additionally, there are many pollutants that could exhibit toxic effects on aquatic life and the public. Waterborne diseases are also eliminated through proper wastewater treatment. Nutrients in wastewater, such as phosphorus, can cause premature aging of our lakes, called Eutrophication. ![]() This biological decomposition of organics could result in fish kills and/or foul odors. For example, organic matter can cause oxygen depletion in lakes, rivers, and streams. If left untreated, these pollutants would negatively affect our water and environment. When water is used by our society, the water becomes contaminated with pollutants. ![]() Pollutants must be removed from the water to protect the environment and public health. After the water has been used, it enters the wastewater stream, and it flows to the wastewater treatment plant. Additionally, industries and commercial enterprises use water for these and many other purposes, including processes, products, and cleaning or rinsing of parts. There are the household uses such as showering, dishwashing, laundry and, of course, flushing the toilet. Wastewater or sewage is the byproduct of many uses of water. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |