It has been demonstrated that treated bathroom greywater (TBGW) is a useful substitute
for fresh water for non-potable applications in households. Reuse of TBGW for irrigation,
toilet flushing, car washing etc. offers a good opportunity to save drinking water
and meet the sustainable development goals (SDGs). In this study, synthetic bathroom
greywater (SBGW) was compiled in a controlled manner and used as a substitute for
bathroom GW. Detailed statistical analysis also was performed to confirm the similarity
between real and synthetic BGWs. SBGW is suitable for testing efficiency of applied
treatment methods. It was confirmed that coagulation–flocculation with iron(III) chloride
and sand filtration was the most effective method of the tested 7 systems. The best
and affordable treatment combination generates good-quality treated SBGW (TSBGW) (pH
= 7.54 ± 0.29, TURB = 0.54 ± 0.49 NTU, BOD5 = 21 ± 10 mgL−1, COD = 32 ± 11 mgL−1,
and TOC = 12.7 ± 6.7 mgL−1) for different non-potable purposes by complying with the
regulated limit values for reuse. The elemental analysis of raw, TSBGW and tap water
(TW) samples by MP-AES method provided further support for safe recycling. This study
leads to the conclusion that the generation of TBGW by fit-for-purpose treatment can
effectively meet the circular economy goals at household level. The recycling of GW
is of limited importance in the European Union (EU) and legal regulations are not
available in many countries. This study provides novel support for regulating the
reuse of water in Eastern European countries.
