Hindcasting of nutrient loadings from its catchment on a highly valuable coastal lagoon: the example of the Fleet, Dorset, UK, 1866–2004

Table 13 Nitrogen and phosphorus loads (kg ca-1 yr-1) produced by domestic sources, and coefficients for removal during sewage treatment (based on [44], [50] and [51]).

Source (kg ca-1 yr-1)	Nitrogen	Phosphorus
Human Load	3.94	0.65
Detergent Load (base year 1988)		0.51
Removal during secondary treatment (%)	n.a	67.22
Total sewage load after secondary treatment†	2.14	0.38

^† based on an original [49] figure of 10.8 g N ca-1 yr-1, equal to an annual loading of 3.942 kg N ca-1 yr-1, receiving primary and secondary treatment as per [48], with retention coefficients of 15% for mechanical treatment, 20% for biological, and 20% for retention by filter beds.