Long term decentralized greywater treatment for water reuse purposes in a tourist facility by vertical ecosystem

Abstract

A horizontal flow wetland (HF) was integrated, in a cascading vertical set-up (vertECO), in a Mediterranean tourist facility for decentralized treatment of real low load greywater streams. 15 different plant species were tested in LECA substrate at three different hydraulic retention times (HRTs: 1.9, 1.4 and 1.0 days) with additional aeration improving degradation processes. Beyond standard parameters, several organic micropollutants (14 pharmaceutical organic compounds and 12 endocrine disruptive compounds) were monitored over a 22 month period. The removal efficiency for standard parameters was very high, on average more than 90% for many parameters (COD, BOD5, TSS, VSS and turbidity) and more than 80% for TOC. BOD5 removal could be correlated with the temperature, while TN, TKN and NH4+-N showed the highest removal efficiency at the lowest HRT. The effluents consistently met the standards for various reuse applications, at all three HRTs, according to Spanish Legislation (RD, 1620/2007) and EU draft. In terms of organic micropollutants, influent greywater was characterized by high concentrations and variability (for example up to 256.1 ± 875.3 µg L−1 for acetaminophen, 88.7 ± 424.5 µg L−1 for ibuprofen). More than 95% of removal by vertECO was achieved for most of the compounds (acetaminophen, ibuprofen, salicylic acid, caffeine, estradiol, progesterone, testosterone, triclosan, methyl-, ethyl- and propylparaben) and more than 80% for diclofenac, atenolol and trimethoprim. On the other hand, hydrochlorothiazide, sulfamethoxazole and salbutamol could not be reduced by more than 30%. Statistically significant differences were found at different HRTs for acetaminophen, atenolol, ibuprofen, ethylparaben, TCPP and TBEP (p < 0.05). Conversely, most of the evaluated micropollutants were consistently removed without apparent influence from temperature