Reuse of treated wastewater and non-potable groundwater in the manufacture of concrete: major challenge of environmental preservation

Abstract

This work concerns the reuse of treated wastewater from Er-Rachidia wastewater treatment plant (WWTP) in the mixing of ordinary B25 concrete, in order to reduce the overexploitation of groundwater, avoid its discharge into watercourses and reduce the risk of environmental pollution due to its mineral and organic matter load. In this respect, Tree types of mixing water were used in this study: Drinking Water (DW), Groundwater (GW) and Treated Wastewater (TW). The results recorded for each type of mixing water, in the fresh and hardened state of concretes, are then compared with the requirements of the standards. The obtained results show that the treated wastewater does not have any adverse effect upon the quality of the concrete; it has shown an improvement of the mechanical resistance from the rst stage, a similar density, setting time and porosity and a slight decrease of the workability compared with the control concrete. A Oneway analysis of variance (ANOVA) at the 5% signi cance level indicated no signi cant difference between concrete samples produced and cured with treated wastewater and control samples at ages 7, 14, 28 and 90 days. Throughout this study the substitution of drinking water by treated wastewater will help to minimize the need for its use. Additionally, it saves drinking water for consumption and makes wastewater treatment plants more economically attractive, together with other similar goals for sustainable development.

Concrete production with domestic and industrial wastewaters—A literature review

“…Abushanab and Alnahhal (2021) used a combination of treated sewage, calcium nitrite, fly ash, and superplasticizer to manufacture concrete samples and it was mentioned that wastewater concrete had markedly higher permeability than that of control samples 68 . Bouaich et al (2022) 69 and Tanli et al (2022) 71 also reported similar results. They indicated that using domestic wastewater with or without recycled plastic could reduce the density of concrete.…”

“…The standards report that pH must be ≥4, 32 ≥6, 43 >5, 35,36 and 6–9 38 . Although the U.S. Environmental Protection Agency reported the maximum amount of BOD 5 should be limited to 30 mg/L, several studies have used wastewater in higher amounts than this number 23,57–59,63,64,66,69 . Unfortunately, there is no standard regarding COD limitations.…”

“…Setting time of manufactured concrete samples with freshwater (W), and treated wastewater (WW); adapted from References 59–61,68–70). …”

“…38 Although the U.S. Environmental Protection Agency reported the maximum amount of BOD 5 should be limited to 30 mg/L, several studies have used wastewater in higher amounts than this number. 23,[57][58][59]63,64,66,69 Unfortunately, there is no standard regarding COD limitations. A high level of COD, however, has been reported that can adversely affect the quality of concrete.…”

Treatment of Mixer Truck Wash Water of a Ready-mix Concrete Batching Plant Using a Low Cost Modified Sand Filter

“…This may be due to pore filling properties of TDS (Aldossary et al, 2020, Zervaki et al, 2013, Vaičiukynienė et al, 2021, which produced higher compressive strength at 3 and 7 days, but about 92% of control (de Matos et al, 2020), higher than control before three months old and similar to control thereafter (Gupta et al, 2020, Klus et al, 2019. Other properties such as workability, initial setting time were reduced but still within the acceptable limit, which may be due to the presence of Cl ion in TDS (Aldossary et al, 2020, Zervaki et al, 2013, Bouaich et al, 2021. However, untreated wash water is not recommended to be used as process water for concrete production due to the low workability and low compressive strength of the concrete produced (Ghrair et al, 2020).…”