TABLE 24.8.
General Characteristics of the Three Methods Used for Land Application of Sewage Effluent
| Factor | Application method |
||
|---|---|---|---|
| Low-rate irrigation | Overland flow | High-rate infiltration | |
| Main objectives | Reuse of nutrients and water, wastewater treatment | Wastewater treatment | Wastewater treatment, groundwater recharge |
| Soil permeability | Moderate (sandy to clay soils) | Slow (clay soils) | Rapid (sandy soils) |
| Need for vegetation | Required | Required | Optional |
| Loading rate | 1.5–10 cm/week | 5–14 cm/week | >50 cm/week |
| Application technique | Spray, surface | Usually spray | Surface flooding |
| Land required for flow of 10 6 liters/day | 8–66 hectares | 5–16 hectares | 0.25–7 hectares |
| Needed depth to groundwater | About 2 cm | Undetermined | 5 m or more |
| BOD and suspended solid removal | 90–99% | 90–99% | 90–99% |
| N removal | 85–90% | 70–90% | 0–80% |
| P removal | 80–90% | 50–60% | 75–90% |
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