Biodegradation and nutrients removal from greywater by an integrated fixed-film activated sludge (IFAS) in different organic loadings rates

Hadi Eslami,Hossein Falahzadeh,Mohammad Hassan Ehrampoush,Parvaneh Talebi Hematabadi,Arash Dalvand,Rasoul Khosravi,Abbas Esmaeili,Ali Asghar Ebrahimi,Mahmoud Taghavi

doi:10.1186/s13568-017-0532-9

Abstract

In this study, the efficiency of Integrated Fixed-film Activated Sludge (IFAS) system in synthetic greywater treatment and nutrients removal was studied in duration of 105 days according to different Organic Loadings Rates (OLRs). The study was operated in pilot-scale and OLRs of 0.11–1.3 gCOD/L.d. Scanning Electron Microscope (SEM) image showed that the biofilm with a proper thickness was formed on IFAS reactor’s media. The results indicated that the best removal efficiency of BOD5, COD, and TSS were 85.24, 92.52 and 90.21%, respectively, in an organic loading of 0.44 gCOD/L.d. Then, with the OLR increased, the removal efficiencies of BOD5, COD, and TSS increased as long as the organic loading reached 0.44 gCOD/L.d. But with the OLR increased more, the removal efficiency of these parameters decreased. The ANOVA statistical test results showed that the mean difference of removal efficiency in organic loadings for BOD5 (p ≤ 0.001) and COD (p = 0.003) was significant, while it was insignificant for TSS (p = 0.23). The best removal efficiencies of Total Nitrogen (TN) and Total Phosphorus (TP) were 89.60 and 86.67%, respectively, which were obtained at an OLR of 0.44 gCOD/L.d. By increasing OLR up to 0.44 gCOD/L.d, removal efficiencies of TN and TP increased, while the removal efficiency decreased with the OLR increased more, and this difference was statistically significant (p = 0.021). Finally, the results showed that the IFAS system provided a proper efficiency in treatment of the synthetic greywater and it could be used in a full scale.

Highlights

Nowadays, the shortage of water resources, growing population and increasing water demand, inappropriate distribution of water resources, mismanagement of the available water, and climate changes have steered most of the countries toward the research for new water resources (Abdel-Shafy and El-Khateeb 2013; Khosravi et al 2017; Masi et al 2010; Shahi et al 2013)
The best removal efficiency of BOD5 was at an Organic Loadings Rates (OLRs) of 0.44 gCOD/L.d at the rate of 85.24 ± 3.21%, while
A study by Abdel-Shafy et al (2014) on greywater treatment using a hybrid system showed that the removal efficiency for BOD5 was 70.6%

Summary

Introduction

The shortage of water resources, growing population and increasing water demand, inappropriate distribution of water resources, mismanagement of the available water, and climate changes have steered most of the countries toward the research for new water resources (Abdel-Shafy and El-Khateeb 2013; Khosravi et al 2017; Masi et al 2010; Shahi et al 2013). One. In general, domestic wastewater includes both greywater and black water (Friedler 2004). Domestic wastewater includes both greywater and black water (Friedler 2004) The former contains the domestic produced effluent in places, such as the kitchen, showers, baths, wash basins, and laundry. The latter is an effluent from toilet (Sanchez et al 2010). The greywater contains about 70% of the drinkable water or 60–70% of the domestic produced. The mean BOD5/COD ratio for the greywater has been reported 0.45 ± 0.13 which shows its proper biodegradability potential (Leal et al 2011). The greywater is less contaminated as compared to the black water and is suitable for reuse (Gross et al 2007).With proper treatment of the greywater, the effluent can be used for irrigation, flash tank at homes’ toilet, and other uses (Abdel-Kader 2013)

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