Characterization of residual sand removed from the grit chambers of a wastewater treatment plant and its use as fine aggregate in the preparation of non-structural concrete

Abstract

This article demonstrates the potential use of residual sand removed from grit chambers, which are used in the primary treatment of Wastewater Treatment Plants (WWTPs), as an alternative material to commercial sand in the production of non-structural concrete in civil construction. The results indicated that the residual sand has a high percentage of total fixed solids (96.9%), high moisture content (14.8%) and significant total coliform [average of 3.84 × 107(100 mL)−1] and fecal coliform densities [average of 5.22 × 105 (100 mL)−1]. The sand cleaning and drying procedure used in the research was effective, since it achieved the following removal efficiencies: about 98.8% of moisture, 67.1% of total volatile solids and 4-log E. coli. After cleaning and drying the residual sand, different amounts of this material were used to prepare the test specimens, which underwent tensile tests. The results of this study confirmed the viable use of residual sand as fine aggregate in concrete for non-structural purposes, and the best performances were verified in tensile and compressive tests (fck) and tensile strength tests (fctk) using 30% (in mass) of the residual sand as fine aggregate (values of 16.6 and 1.60 MPa, respectively).

Characteristics of sand recovered from the municipal wastewater treatment plant

“…The use of sand recovered at the wastewater treatment plant, initially as waste, and after the cleaning processes, obtaining a valuable raw material from it, is a process that has been used for many years and is quite widely described. An example may be the development of sand for specific needs of municipal and communication construction (Warta SA Częstochowa 2011;borges et al 2015). It should be remembered that in order to use such a recovered raw material as a building material, it must be analyzed in terms of strength, porosity, densification ability, and in our climatic conditions, even frost resistance (bieniowski et al 2020).…”

Geotechnical Properties of Washed Mineral Waste from Grit Chambers and Its Potential Use as Soil Backfill and Road Embankment Materials

“…Such a solution improves the final parameters of mineral waste, minimizing or practically completely removing the odor from the waste, reducing the content of organic matter (even to a level below 2%) and the hydration of the waste. Due to the source of the generation of the washed mineral waste from grit chambers, it has a waste code, 19 12 09-"minerals (e.g., sand, stones)", is classified as non-hazardous and inert waste [2,3], and belongs to the group of industrial waste [4]. Due to the predominant Current legislation on managing washed mineral waste recovered from Polish wastewater treatment plants distinguishes three ways of dealing with it [1].…”

“…Moreover, most papers concern only mineral waste characterization and grit chamber performance evaluation, with a significant proportion being site-specific [14]. Hence, the main purpose of studies is usually to optimize the design guidelines of grit chambers for mechanical wastewater treatment and their technological processes [14][15][16][17][18][19]. The papers [15,19] also present an additional purpose, which is to consider the possibility of processing and using mineral waste in construction.…”

“…Hence, the main purpose of studies is usually to optimize the design guidelines of grit chambers for mechanical wastewater treatment and their technological processes [14][15][16][17][18][19]. The papers [15,19] also present an additional purpose, which is to consider the possibility of processing and using mineral waste in construction. The conducted research focuses on determining the physical properties of mineral waste in terms of dry matter content, the content of organic and inorganic substances, granulometric composition, specific density and the settling velocity of particles in grit chambers [14][15][16][17][18].…”

Sand Content Prediction in Urban WWTPs Using MARS

“…The initial pre-treatment phase is of great importance for the proper functioning of WWTP (wastewater treatment plants) [1]; however, as indicated by several authors [2,3], the next steps of these facilities have been studied further given their great impact on water recovery. Parameters such as pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD) and suspended solids (SS) in later stages have been the subject of numerous studies [4][5][6][7].…”