1. specific systems
   1. Aerated wastewater treeatment systems
      1. Topic
         1. Treats both black and greywater
         2. Combines physical, biological & chemical processes
         3. Aerobic microorganisms are the key for organic degradation
      2. Catergories
         1. system1 Degrades organic matter Destroys pathogens
            1. Configurations
            2. Step1 Primiary Treatment
            3. Septic tank Solid/liquid separation by settling Solids undergo anaerobic digestion Liquid or septage goes to Step 2
            4. Step 2 Secondary Treatment
            5. Biological reactor + Clarifier Organic matter degraded System allows bacteria to grow Biological solids are separated Clarified effluent is sent to Step 3
            6. Role of Clarifier (or settling chamber)
            7. Detention time should be optimum to: allow proper settling of solids avoid biological activity in the clarifier Continuous skimming is important to remove any floatable solids Continuous removal of settled solids is important
            8. Step 3: Tertiary Treatment
            9. Further organic degradation + disinfection Chemical/UV treatment Treated effluent is stored and recycled for non-potable uses
            10. Types
            11. Based on the type of biological reactor AWTS can be divided into:
            12. Suspended growth systems
            13. Microorganisms are suspended Better process control Compact and uses less space Cannot withstand shock loads Washout/settlement of solids -problem
            14. Topic
            15. Activated sludge process
            16. mostly for BOD / SS removal
            17. Extended aeration process
            18. also reduces ammonia
            19. Septic tank volume
            20. Vp = nSP + twQP
            21. Aeration chamber volume
            22. Va = taQP
            23. Settling chamber or clarifier
            24. Vs = tsQP/24
            25. As = QP/v0
            26. Attached growth systems
            27. Microorganisms are attached Low loading rates High retention of microorganisms Removes organic matter Larger systems Insufficient contact better microorganisms and bacteria
            28. Topic
            29. 1. Single-pass / intermittent sand filters or ISF
            30. Wastewater pumped at a design flow from septic tank at specific intervals
            31. Septic tank Pump chamber Sand filter bed Disinfection chamber Holding / Irrigation tank
            32. ISF: Design Aspects
            33. 1. Filter sand - 0.25 mm to 0.6 mm
            34. 2. Depth of filter bed 450 mm - 1200 mm 500 mm- normal depth
            35. 3. Hydraulic loading rate (HLR) = Flow/Surface area = m3/m2.d or m/d or mm/d Typical loading rates = 40 - 80 mm/d Dosing frequency and Hydraulic application rate
            36. 4. Organic Loading Rate (OLR) = Mass of Organic matter/Surface area = Kg of BOD / Surface area of filter =( mg/L BOD x L/d Flow ) / Surface area of filter Typical = 0.0025 - 0.01 kg BOD/m2.d
            37. 2. Multipass recirculating sand filters (also called as Recirculating aerated sand filter device - RASFD -)
            38. Wastewater recirculated back to the filter after treatment
            39. Septic tank Recirculating effluent chamber Sand filter bed Disinfection chamber Holding / Irrigation tank
            40. (RAFSD): Design aspects
            41. Filter medium - Sand, fine gravel or other
            42. Filter bed depth = 600 mm
            43. HLR = 120 - 240 mm/d
            44. OLR = 0.01 - 0.04 kg BOD/m2.d
            45. Hybrid growth systems
            46. Microorganisms are suspended & as well attached to media can combine +ve aspects of earlier two systems can handle shock loads Require minimum maintenance Process control may be difficult
            47. Design aspects
            48. Primary treatment:
            49. Septic tank design criteria
            50. Secondary treatment: Biological Reactor
            51. Design flow
            52. BOD5
            53. Microorganism concentration in suspended form
            54. Microbial growth on support media
            55. Hydraulic retention time
            56. Organic loading rate
            57. Aeration & oxygen transfer efficiencies
            58. Membrane Bio-reactor: (Microfilatration membranes)
            59. Advanced system May require chemical pre-treatment Requires periodic maintenance Energy intensive High quality treated water Very low organic Almost no suspended solids Very low microorganisms
         2. system2 Both of the above + Removes N + P
2. Purpose of these systems
   1. What is being treated?
      1. combined wastewater
      2. black water and grey water seperately
   2. What are the end-product?
      1. recycled water
      2. compost/soil water
      3. biogas/energy recovery
   3. what is the scale of the system?
      1. for a single home
      2. for a block
      3. for homes+ small scale industry
3. types of systems
   1. Simple systems- modified to complex systems
   2. systems consisting of waterless toilets + grey water treatment systems
   3. systems that combine vermiculture & wastewater treatment in one system
   4. natural systems
   5. systems that use advances such as memebranes.
   6. systems that use advanced disinfection processes
4. design considerations for these systems
   1. Planning & Design for advance systems
      1. is it important to investigate the site?
      2. is it important to investigate the soil?
   2. septic tank capacities for advanced systems
      1. Grey + black
      2. grey only
      3. black only
   3. Disinfection methods
      1. Depends on the use of treated wastewater
         1. Iodine
         2. Ozone
         3. Gamma radiation
         4. Combination of one or two of the above
         5. Chlorination (& dechlorination)
      2. Design considerations
         1. Ease of supply, installation
         2. Contact time
         3. Introduction method
         4. Concentration
         5. Rate of application
   4. Reuse options What are pros & cons?
      1. Agricultural irrigation
      2. Landscape irrigation
      3. Toilet flushing
      4. Preliminary car washing
      5. Laundry use
      6. Potable use
   5. Irrigation design
      1. Subsurface irrigation
         1. Shallow subsurface trenches of 100 mm depth
      2. Surface irrigation
         1. Covered surface drip irrigation – under mulch
         2. Direct application
         3. Open air spray
      3. Topic
         1. Within absorption capacity of soils
         2. Need to follow Design loading rates based on soils
         3. Storage capacity to be provided depending on climate
   6. Regulatory Issues:
      1. Federal
         1. Protection of Environment Operations Act, 1997
      2. Local Government
         1. Local Govt. Act, 1993
         2. Local Govt. (Gen) Regulation, 1995
      3. NSW Health
      4. EPA