Existing evidence related to soil retention of phosphorus from on-site wastewater treatment systems in boreal and temperate climate zones: a systematic map

Table 3 Method to evaluate P retention in soil/sand filters within facility

General approach	Method	Number of studies
Determining dissolved P in influent and leachate	Dissolved total phosphorus, TP, in septic tank effluent and after filter	32
	Dissolved PO₄-P + TP in septic tank effluent and after filter	11
	Dissolved PO₄-P in septic tank effluent and after filter	8
Comparing accumulated P with cumulative P load	TP and oxalate-P in filter compared to control	3
	Oxalate-P in filter compared to control	1

ISSN: 2047-2382