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 Wednesday, April 28th
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
rganics
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
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
Photo: Two 3,800m³ anaerobic digesters are used to treat the sludge. Gas collected from the process is used to fire the regenerative thermal oxidizers, as well as the digesters' own heating boilers. F. Wayne Hill Water. Resources Center, Gwinnett County, GA
Methanogenesis

20. Fixed vs. floating cover

22. Belt Filter Press

24. Filter Press http://www. metlabsolutions

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)
Blackish in color
Appox. 80% water (slippery)
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

51. Shouguang City WWTP, PRC

52. Shouguang City WWTP, PRC

53. Shouguang City WWTP, PRC

54. Shouguang City WWTP, PRC

55. Shouguang City WWTP, PRC

56. Shouguang City WWTP, PRC

57. Shouguang City WWTP, PRC

58. Settling Problem in Activated Sludge