Powdered Ceramsite and Powdered Limestone Use in Aerobic Granular Sludge Technology.

Joanna Czarnota,Adam Masłoń,Grzegorz Łagód,Adam Piech,Janusz A Tomaszek

doi:10.3390/ma13173894

Joanna Czarnota, Adam Masłoń + Show 3 more

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https://doi.org/10.3390/ma13173894

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Abstract

The effects of two powdered mineral materials (powdered ceramsite and powdered limestone) on aerobic granulation of sludge were evaluated. The experiment was conducted on a laboratory scale bioreactors treating wastewater for 89 days. Three granular sequencing batch reactors (GSBRs) were operated at the lowest optimal organic loading rate (OLR) of 2.55 g COD/(L∙d). In the control reactor (R1), the mean diameter (d) of the biomass ranged from 124.0 to 210.0 µm, and complete granulation was not achieved. However, complete granulation did occur in reactors to which either ceramsite (251.9 µm < d < 783.1 µm) or limestone (246.0 µm < d < 518.9 µm) was added. Both powdered materials served as a ballast for the sludge flocs making up the seed sludge. Ceramsite particles also acted as microcarriers of granule-forming biomass. The granules in the reactors with added powdered materials had nonfibrous and smoother surfaces. The reactor with ceramsite exhibited the highest average efficiencies for COD, total nitrogen, and total phosphorus removal (85.4 ± 5.4%, 56.6 ± 10.2%, and 56.8 ± 9.9%, respectively). By contrast, the average nitrification efficiency was 95.1 ± 12.8%.

Highlights

The use of aerobic granular sludge (AGS) is a promising and relatively new technology for the treatment of different types of wastewater; it allows for the simultaneous removal of carbon, nitrogen, phosphorus, and other pollutants in a single reactor [1,2,3]
The operating conditions supporting aerobic granulation are strongly determined by various parameters, including the reactor configuration, seed sludge, settling time, organic loading rate (OLR), volume exchange ratio, hydrodynamic shear force, feast–famine regime, cycle time, and other environmental conditions [4,5,6]
(R2) had the most stable sludge volume, as it showed the lowest coefficient of variation for this parameter. The results of this experiment are consistent with, for example, the results reported by Li et al [24], who found that the SVI30 values in a reactor with initial granular activated carbon (GAC)

Summary

Introduction

The use of aerobic granular sludge (AGS) is a promising and relatively new technology for the treatment of different types of wastewater; it allows for the simultaneous removal of carbon, nitrogen, phosphorus, and other pollutants in a single reactor [1,2,3]. The operating conditions supporting aerobic granulation are strongly determined by various parameters, including the reactor configuration, seed sludge, settling time, organic loading rate (OLR), volume exchange ratio, hydrodynamic shear force, feast–famine regime, cycle time, and other environmental conditions (notably, pH and temperature) [4,5,6]. Higher OLR facilitates granule formation [9,10,11,12]. In treatment of wastewater with a lower chemical oxygen demand (COD) concentration, a higher organic load can be obtained by shortening the cycle time [10,16].

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