One feature of the hybrid lagoon automatic control system lies in its capacity for organic treatment of various types of wastes, from household waste water and other low-concentration wastes (100-200 mg/liter BOD) to waste water from livestock breeding and food production, human waste and other high-concentration wastes (5,000-10,000 mg/liter BOD).

This versatility is an important feature of the hybrid lagoon automatic control system. As a consequence, this system has the flexibility to meet the changing demands of society for waste treatment. Since waste treatment plants are built for use over extended periods of time, by using this versatility of such facilities, they can immediately after construction be used for treating raw human waste, and then, with the construction of sewage networks, be employed in treating a mixture of human waste and waste water, and be operated as terminal treatment facilities after sewage networks are completed.

In the case of facilities for treatment of raw human waste (600 kliters/day x BOD 13,500 mg/liter), following the guidelines for human waste treatment facilities established by the Ministry of Health and Welfare, the quantity and concentration of human waste treatable may be estimated as follows.

Facilities for treatment of raw human waste (600 kliters/day x BOD 13,500 mg/liter) could begin by treating human waste exclusively, and then, after a period of treating a mixture of human waste and waste water. finally begin operation as a terminal sewage treatment plant, processing 40,500 m3/day x BOD 200 mg/liter.

To convert to equivalent population, if we assume 1.4 liters of human waste per person per day and 200 liters of waste water per person per day, then hybrid lagoon facilities consisting of four basins each 60 m in diameter, with an effective capacity of 12,500 m3, and requiring power for aeration of 175 kW, could begin operation as human waste treatment facilities for 420,000 persons, and subsequently be used for treating waste water generated by a population of roughly 200,000.

1. wastewater
2. microorganism reaction basin
3. microorganism separation basin
4. treated water
5. returned sludge
6. intake
7. discharge of treated water
8. Diagram of single-basin facilities
9. hybrid lagoon basin
10. Cross-sectional diagram
11. Light-loaded state
12. saturated oxygen concentration, mg/liter
13. Properly loaded state
14. aeration process
15. sedimentation process
16. time (reduction of aerated volume)
17. (maintenance of aerated volume)
18. Overloaded state
19. (increasing aerated volume)
20. Changes in dissolved oxygen concentration waveform
21. Block diagram of automatic control and data processing systems
22. unattended operation
23. automatic control instruction
24. instruction
25. sequencer
26. microorganisms
27. measured values
28. conversion equipment
29. recorder
30. selection
31. A/D converter
32. 30 data/sec
33. ?? program creation/modification
34. display
35. memory device
36. on-site supervisor
37. for maintenance/control
38. supervisor's telephone
39. telephone at facilities
40. leased communication circuit (unattended response)
41. telephone at remote location
42. monitoring personnel
43. remote monitoring
44. Performance satisfactory despite the low concentration of activated sludge, and facilities operating smoothly. In future, as amount of sludge increases, should reach planned performance level. Lead, mercury, organic phosphorus compounds, normal hexane extracts, phenol, chrome, arsenic, other impurities not detected .
45. households (generating waste)
46. waste water from rinsing
47. household waste water
48. raw waste
49. (treatment)
50. hybrid lagoon facilities
51. (high-level treatment)
52. (treated water)
53. discharge into public water systems
54. (excess sludge)
55. spring, autumn
56. (sludge reduction processing)
57. dispersion in fields, pastures
58. Basic Design of Newly Installed Human Waste Processing