Sludge Treatment

1. Sludge Treatment CE 326 Principles of Environmental Engineering Department of Civil, Construction and Environmental Engineering Iowa State University Prof. Tim Ellis Spring 2010

2. Announcements • Monday, April 26th • Course review • Exam review • Wednesday, April 28th • 3rd Exam during lab period (in lab classroom) • Friday, April 30th • No class • A.S. design lab due

3. History • Thomas Crapper • Myth or legend? The World War I doughboys passing through England brought together Crapper's name and the toilet. They saw the words T. Crapper-Chelsea printed on the tanks and coined the slang "crapper" meaning toilet (from : Plumbing and Mechanical, June 1993).

4. Sludge Processes • Thickening • Stabilization • Conditioning • Dewatering • Volume Reduction • Disposal

5. Thickening • c___________ sludge using gravity or f________ methods. Primary sludge can be thickened to a maximum of about 10% solids and secondary sludge to a maximum of about 6% solids. oncentrating lotation

6. Gravity thickener

8. Process flow with recycle:

9. Dissolved Air Flotation (DAF) Thickener

10. Dissolved Air Flotation (DAF) Thickener

11. Stabilization rganics • Converting the o_______ in the sludge to more stable (inert) forms so they can be handled more easily (more d____________, less potential for odors) and used as soil conditioners. • Typically stabilization involves anaerobic or aerobic digestion. • During digestion considerable v______ s_____ destruction occurs ewaterable olatile olids

12. Conditioning • Addition of c_________ to allow better separation of the water and the solids. Ferric c_______ and organic and inorganic p_______ are frequently used for sludge conditioning. oagulant hloride olymer

13. Dewatering • V________, pressure, or drying methods for removing w_____ from the solids. • Typically about 25 to 35% solids can be achieved. acuum ater

14. Volume Reduction • Drying and p__________ for sale as a fertilizer • C__________ • I___________ of sludge with ash residual for ultimate disposal. elletization omposting ncineration

15. Biosolids • Biosolids are t_______ s______; • there are two different classes: • Class A: no detectable levels of p___________ and meets m_____ regulations, requires controlled treatment process involving high pH, temperature, or both; no permit required for land application • Class B: have been t_______ but may contain some pathogens and metals, requires permit for land application • approximately __% of all biosolids are land applied reated ludge athogens etals reated 50

16. Processes for Class A • Processes for generating Class A biosolids: • sludge p___________ • T____________ treatment (55̊C for 24 h) • temperature p______ anaerobic digestion (55̊C digester followed by 35̊C digester) developed at ISU asturization hermophilic hased

17. Anaerobic Digestion

18. Steps in Anaerobic Digestion Hydrolysis Acidogenesis Acetogenesis Methanogenesis

20. Fixed vs. floating cover

22. Belt Filter Press

24. Filter Press http://www.metlabsolutions.com/Shriver%20Press%20-%20side.JPG

25. Centrifuge

28. Land Application

29. Characteristics • Blackish in color • 15% - 90% Solids • Mud-like to granular appearance • Mild to strong odor (musty or swamp like)

30. View of machine used to aerate compost placed in windrows.

31. Overview of windrow composting operation

32. Plants Grow Better with Biosolids

33. Tree Rings Before and After Organic Matter Applied

34. Back River WWTP

35. Back River WWTP

36. Back River WWTP

37. Back River WWTP

38. Abu Dhabi WWTP

39. Abu Dhabi WWTP

40. Abu Dhabi WWTP

41. Abu Dhabi WWTP

42. Abu Dhabi WWTP

43. Budapest WWTP

44. Lake Balaton WWTP

45. Lake Balaton WWTP

46. Lake Balaton WWTP

47. Lake Balaton WWTP

48. Wastewater Treatment in Developing Countries Community Biogas Plant in China

49. Shouguang City WWTP, PRC

50. Shouguang City WWTP, PRC