Wastewater Treatment Engineering

1. Wastewater Treatment Engineering

2. Environ. Engineering Course Sequence Thermo CE3501 Fluids CE3502 P-Chem CE3620 Water Resources CE4506 Regs,P2,3 CE4501 Env.Chem CE4504 Air Quality GE3850 Geohydrol. CE4508, 4507,4509 Drinking & WasteWater ce4505 Surf.Water CE4630 Hydraulic structures CE4620 Open Channel Flow BL4451 Limnology FW4220 Wetlands CE5508: Biogeochem., CE5504: Surf.Water Qual. Modeling

3. Historical Background Public Health Environmental Protection A 1920s, study of the East and Fox Rivers in Green Bay was commissioned because workers in downtown could not open windows in summer due to the stench. Environmental problems plague this system to this day. Investigation of an outbreak of cholera in London in 1854 provided one of the first links between sewage disposal, drinking water supply and waterborne disease.

4. Nature of Wastewater What’s in wastewater? • human feces and urine • food from sinks • soaps and other cleaning agents • runoff from streets and lawns • industrial discharges

5. Nature of Wastewater … and water … lots of it! • Urinal - 1 gallon per flush – 0.4 gal/flush • Toilet - 4 gallons per flush – 2 gal/flush • Shower - 20 gallons per use • Overall - 55 gal/person/day

6. Nature of Wastewater So what’s the problem?

7. Levels of Treatment

8. Clean Water Act of 1972 (since amended) • Technology-based standards (2°) • Water quality-based standards • Fishable-swimmable • NPDES (permitting system) • TMDLs (maximum daily loads) Regulatory Basis

9. Scope of Application On-Site Urban - Municipal Industrial Rural - Municipal

10. Portage Lake Wastewater Treatment Plant RAS 2° Clarifier 1° Clarifier Fe added Fe added UV Disinfection Flow Equalization Aeration Tank 2° Clarifier 1° Clarifier RAS Grit Chamber WAS Recycle Bar Screens 1st Stage Anaerobic Digester 2nd Stage Anaerobic Digester 1°S Supernatant Polymer Added Land Application Sludge Storage Filter Press Lift Station

11. Wastewater Treatment (Preliminary) Bar Racks and Screens Bar racks and screens remove large solids which could clog pumps and pipes in the wastewater treatment plant. Solids are collected and sent to a landfill.

12. Wastewater Treatment (Primary) Settling Tank Settling tanks remove the large solids which remain suspended in the wastewater and about 50% of the oxygen-demanding substances. The solids are sent on for further treatment (sludge digestion) and ultimate disposal.

13. Wastewater Treatment (Secondary) Activated Sludge In the activated sludge process, bacteria and other microorganisms are used to remove small solids and oxygen-demanding substances present in the wastewater. Outflow from this tank undergoes settling and the excess sludge is sent on for further treatment (sludge digestion) and ultimate disposal.

14. Wastewater Treatment (Tertiary) Tertiary treatment refers to any of a variety of biological, chemical, and/or physical methods used to reduce levels of specific pollutants in a wastewater stream. Among these are levels of solids and oxygen-demanding materials, toxic metals and organic chemicals, and algal nutrients such as nitrogen and phosphorus. All wastewater treatment plants (>2 MGD) discharging to the Great Lake are required to remove phosphorus. This is often accomplished through chemical precipitation as described below. Phosphorus removal by precipitation … Ferric chloride, Fe(Cl)3 producing FePO4 and Fe(OH)3 Alum, Al2(SO4)3·18H2O producing AlPO4 and Al(OH)3

15. Wastewater Treatment (Tertiary) Carbon adsorption Carbon adsorption is an incredibly effective means of removing organic chemicals from wastewater … chemicals which would otherwise pass through the plant and enter the environment. This technology is also applied in drinking water treatment, both municipally and with consumer-installed devices.

16. Wastewater Treatment (Disinfection) Ultraviolet Light Disinfection is the most important step in wastewater treatment because it removes pathogens and thus protects receiving waters used for contact recreation and as a drinking water supply. Chlorine is the most commonly used disinfectant. Because of adverse effects on the environment, chlorine is being replaced by other methods such as ozonation and ultraviolet light (the method used a our plant in Houghton.

17. Wastewater Treatment (Sludge) Incineration A variety of means are available for ultimate disposal of sewage sludge. Landfilling and incineration are the most common. Here, the sludge is introduced to the top of a multiple-hearth furnace. The sludge dries and ultimately ignites as it moves down the surface toward the fire. The product is ash (landfilled) and stack gases which are collected for further treatment.

18. Wastewater Treatment (Effluent)

19. Coursework • CE4507 - Wastewater Collection & Water Distribution • CE4508 – Water & Wastewater Treatment and Design • CE4509 – Environmental Process Simulation • CE5501 - Environmental Process Engineering • CE5502 - Biological Waste Treatment Processes • CE5503 – Physical-Chemical Treatment Processes • CE5507 - Sorption and Biological Processes Students have the option of building a ‘concentration’ in water and wastewater treatment as part of the B.S. in Environmental Engineering at Michigan Tech.

20. Employment • Government (MDEQ, City of Detroit) • Industry (GM, Kodak) • Consulting (CH2M-Hill, Montgomery-Watson) • Graduate Study & Research (U.S. EPA, MTU) Check out the web pages of these organizations for professional opportunities.

21. Study Question Where does the wastewater from your home go? What kind of treatment system is utilized? Reading Assignment Take a wastewater treatment plant tour (“Go With the Flow”) courtesy of the Water Environment Federation. http://www.wef.org/publicinfo/#