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 Table 4.2.1. Total Nitrogen and Total Phosphorus Concentration in
Wastewater Treatment Plant Effluent
Mean Nitrogen
Mean Phosphorus
Treatment Type
(mg/l)
(mg/l)
Activated Sludge
15.8
5.91
Trickling Filter
17.9
7.25
Phosphorus Removal
4
2.85
Primary Settling and
23.8
8.71
Digestion
Oxidation Pond
17.1
6.42
Sand Filter
--
5.02
(after Gakstatter et al. 1978 and Reckhow and Chapra 1983)
Table 4.2.2. Lot Sizes, Percent Impervious Area and Nutrient Export for Various
Land Uses
Lot Size
Land Use
Percent Impervious
(ha)
Rural Residential
2.0
4
Large Residential
0.8
6
Low Density Residential
0.4
12
Low-medium Density Residential
0.2
20
Medium Density Residential
0.1
25
(Adapted from Camp, Dresser and McKee 1988)
4.2-36
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