Selection of permeable reactive barrier materials for treating acidic groundwater in acid sulphate soil terrains based on laboratory column tests

Abstract

The Shoalhaven region of NSW experiences environmental acidification due to acid sulphate soils (ASS). In order to trial an environmental engineering solution to groundwater remediation involving a permeable reactive barrier (PRB), comprehensive site characterisation and laboratory-based batch and column tests of reactive materials were conducted. The PRB is designed to perform in situ remediation of the acidic groundwater (pH 3) that is generated in ASS. Twenty-five alkaline reactive materials have been tested for suitability for the barrier, with an emphasis on waste materials, including waste concrete, limestone, calcite-bearing zeolitic breccia, blast furnace slag and oyster shells. Following three phases of batch tests, two waste materials (waste concrete and oyster shells) were chosen for column tests that simulate flow conditions through the barrier and using acidic water from the field site (pH 3). Both waste materials successfully treated with the acidic water, for example, after 300 pore volumes, the oyster shells still neutralised the water (pH 7).

In-situ remediation of acid mine drainage using a permeable reactive barrier in Aznalcóllar (Sw Spain)

“…Additionally, Zn was also removed through co-precipitation onto Al-(oxy)hydroxide (and to a lesser extent onto Fe-(oxy)hydroxide where ZVI was used) [23,25]. The occurrence of the combined effect of precipitation as metal (oxy)hydroxides and co-precipitation onto new formed phases as major mechanisms for metal removal under similar conditions has been reported by other researchers [6,10,21,30].…”

“…vegetal-gardening compost and sewage sludge) and ZVI. Limestone (in the form of chips 1-2 cm diameter) was used to raise pH, to precipate some metals as (oxy)hydroxides and to create suitable conditions for SRB [3,21,22]. The organic substrate was added to provide an electron donor to sustain SRB activity [3,6].…”

Remediation of acidic groundwater by way of permeable reactive barrier

“…On 5 October 2006, the pilot-scale PRB, which was 17·7 m long, 1·2 m wide and 3 m deep, was installed parallel to and 15 m from the flood mitigation drain to intersect the zone of maximum groundwater flow. According to the preliminary site characterisation carried out for the same site by Golab and Indraratna (2009), the optimum location for the PRB was chosen …”

“…Only recently, the alkaline PRBs to remediate acidic groundwater generated from ASS terrains have been studied in Australia (Desmier et al, 2002;Indraratna et al, 2010;Regmi et al, 2009). Recycled concrete has been identified as a promising, cost-effective and environmentally friendly material, after batch tests were carried out on 24 alkaline materials by Golab et al (2009). Recycled concrete has proven to be a very good waste material because of its ability to maintain a neutral pH for a considerable time and almost complete removal of dissolved aluminium and iron from the system.…”

Permeable reactive barrier rejuvenation by alkaline wastewater

“…However, this was only a short-term remediation option. A significant advancement was achieved through the installation of a pilot-scale permeable reactive barrier (PRB) (17.7 m length, 1.2 m width, 3.0 m depth) containing recycled concrete as the reactive media (Golab et al, 2009;Golab et al, 2006) at Manildra Group's Environmental Farm in October 2006.…”