Variation of the element composition of municipal sewage sludges in the context of new regulations on phosphorus recovery in Germany

Environmental Sciences Europe

Table 4 Element contents values of 9 WWTPs compared to averages in ASS and to ordinance limits

		2013–2016 [14] ASS^a	German FO limit [16]	EU FO limit (2019/1009/EU, 2019)	Average of 9 WWTPs	Maximum of 9 WWTPs	WWTP no. with maximum value
As	[mg/kg]		40	40	3	8	e
Pb	[mg/kg]	30–33	150	120	33	77	e
Cu	[mg/kg]	294–309	5000	600	219	521	a
Ni	[mg/kg]	24–26	80	50	22	64	i
Zn	[mg/kg]	773–800	4000	1500	727	1,136	e
Cr	[mg/kg]	31–34			29	56	i
N	[mg/kg]	43,800–45,200			39,020	77,680	g
P	[mg/kg]	25,600–26,600			21,460	27,080	e
K	[mg/kg]	3600–3700			3220	6240	f
Mg	[mg/kg]	5600–5800			5670	9790	b
Ca	[mg/kg]	79,800–84,300			97,760	273,890	d
o.c	[%]	52			57	80	a

ASS agriculturally utilized sewage sludge, FO fertilizer ordinance, WWTP wastewater treatment plant
^aK, Mg and Ca converted from oxide values (K₂O, MgO and CaO as alkaline content). Annual averages from the sewage sludge reports which consider all agriculturally utilized sewage sludges for the respective year