A potential biological approach for sustainable disposal of total dissolved solid of brine in civil infrastructure

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Publisher: Elsevier B.V.
Document Type: Abstract
Length: 7,262 words
Lexile Measure: 1490L

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ABSTRACT

To meet growing water demand, more water is being harvested from nontraditionai sources like brackish water from underground aquifers which contain total dissolved solids (TDS). Drinkable water is produced by separating TDS from water through desalination which typically produces 50-90% potable water and the remaining water (brine) is disposed in evaporation ponds or by injecting it below the ground surface, which is not sustainable. In this study, it was proposed to use TDS partially in place of sand to prepare mortar for possible application in highway infrastructure like fill material in vertical moisture barriers or embankments, etc. Since addition of TDS weakens the integrity of the cement matrix, fly ash and mutated aerobic bacteria were added to the cement matrix. Mortar specimens were subjected to strength and durability tests. Additionally, X-ray diffraction and scanning electron microscope tests were performed on mortar specimens. The preliminary test results indicated that fly ash and microorganism application not only improves the strength and durability, but these also stabilize TDS present in the mortar.

Keywords:

Mortar

Bacteria

TDS

Salt

Compressive strength

Durability

XRD

SEM

1. Introduction

Water is the critical resource for the well-being of humans and the environment. The increase in human populations has increased the water demand (whether for direct or indirect consumption) exponentially. According to Hanjra and Qureshi [1], the water demand gap will be 3,300 cubic kilometers per year to feed the population by 2050 (global population is projected to be 9 billion by 2050). To meet this growing water demand, more water is being harvested from nontraditionai sources like seawater or brackish water from deep underground aquifers. Since both of the sources contain dissolved solids (mainly salts and other minerals), drinkable water is produced by separating total dissolved solids (TDS) from water through a process commonly known as desalination. A typical desalination plant produces 35-50% potable water from sea water and 50-90% from brackish water [2]. However, the desalination process also produces a byproduct commonly known as brine [3], which consists of higher amounts of TDS (more than 7500 mg/L of minerals). To maximize the limited supply of brackish water, inland desalination plants have developed technologies to reduce brine production, which results in the production of brine with even higher concentrations of TDS (more than 10,000 mg/L of minerals). Since concentrated brine is highly corrosive, due to the presence of concentrated sodium, chloride, phosphate, nitrates ions etc., an improper discharge can be detrimental to the environment in which it is disposed. To mitigate environmental damage, common disposal practices include, but are not limited to: evaporation ponds (with proper lining) and injection below the ground surface.

The disposal of such a large quantity of TDS (roughly 145 tons/ day) in an economical and sustainable environmentally friendly manner can be possibly achieved by using the solids as a construction material, and that is the main focus of this research. The most logical place to dispose of TDS can be mortar (consisting of TDS, sand, water, and cement) which can be used in...

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Source Citation   

Gale Document Number: GALE|A405021869