Contaminated Soil Remediation in Hervey Bay

In Hervey Bay, remediation of contaminated soil follows strict protocols under AS 1726 and the National Environment Protection (Assessment of Site Contamination) Measure. The city's coastal geology, with shallow groundwater tables at 2–4 m depth near the Esplanade, creates migration pathways for hydrocarbons and heavy metals. We have managed over 40 sites in the region, from the former gasworks at Pialba to light-industrial lots on Torquay Road. Our NATA-accredited laboratory (ISO 17025) provides quantitative analysis for BTEX, PAHs, and TRH. For sites requiring deeper understanding of lateral spreading, we integrate resistividad eléctrica SEV to map contaminant plumes non-invasively.

Shallow groundwater and permeable sands in Hervey Bay make contaminant migration a real risk — proactive remediation avoids plume expansion toward the Great Sandy Strait.

Service characteristics in Hervey Bay

Hervey Bay sits on Quaternary sands and estuarine clays, with an average rainfall of 1,100 mm per year. The high infiltration rate — up to 10⁻⁴ m/s in dune sands — accelerates leaching of contaminants into the aquifer. Our remediation strategy combines three core methods: biopiles for aerobic degradation of petroleum hydrocarbons, soil vapor extraction (SVE) for volatile compounds in the vadose zone, and chemical oxidation using Fenton's reagent for recalcitrant chlorinated solvents. At a recent site on Boat Harbour Drive, we treated 2,500 m³ of TPH-contaminated soil to below Tier 1 ESLs. Pre-treatment characterization always includes ensayo Proctor for compaction control during backfill. Post-treatment verification follows a 5-point grid per 500 m², with duplicate samples for QA/QC.

Contaminated Soil Remediation in Hervey Bay – Geotechnical Solutions

Parameter	Typical value
Contaminants treated	TPH, BTEX, PAHs, chlorinated solvents, heavy metals
Treatment depth	0–6 m bgl (extendable via SVE wells)
Remediation duration	4–16 weeks per batch (biopiles)
Laboratory accreditation	NATA ISO 17025 (soil + groundwater)
Post-treatment criteria	Tier 1 ESLs, ASC 2010 guidelines
QA/QC frequency	1 duplicate per 10 primary samples

Critical ground factors in Hervey Bay

A construction site near Urangan Boat Harbour encountered diesel contamination from a former fuel depot. The sand aquifer here has hydraulic conductivity of 3×10⁻⁴ m/s, meaning a 1 m³ spill can spread 50 m down-gradient in a single tidal cycle. Without intervention, the plume would have reached the marine park within six months. We installed a perimeter SVE system with 12 extraction wells, reduced TPH from 4,800 mg/kg to 280 mg/kg in nine weeks. The lesson: delay in remediation multiplies liability exponentially in coastal sands like those in Hervey Bay.

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Applicable standards: AS 1726:2017 — Geotechnical site investigations, ASC NEPM 2013 (Schedule B1 — Guideline on Investigation Levels), AS 4482.1:2005 — Guide to the investigation and sampling of potentially contaminated soil, USEPA SW-846 — Test methods for evaluating solid waste

Our services

We deliver two specialized remediation services tailored to Hervey Bay's hydrogeology and regulatory framework.

On-site Biopile Remediation

Aerobic treatment of petroleum hydrocarbons in engineered biopiles. Each pile contains 200–400 m³ of contaminated soil mixed with 15% organic amendment (compost or wood chips). Aeration via perforated HDPE pipes at 0.5 m spacing, with continuous moisture monitoring. Achieves 85–95% reduction in TPH within 8 weeks, verified by NATA-accredited GC-MS analysis.

Soil Vapor Extraction (SVE) System

Designed for volatile contaminants in the vadose zone. Extraction wells screened at 2–5 m bgl, connected to a regenerative blower (1,200 m³/h capacity). Vapor treatment via granular activated carbon (GAC) canisters. We have installed SVE systems at three former service stations in the region, achieving compliance with QLD DERM closure criteria within 12 weeks.

Frequently asked questions

What is the typical cost range for contaminated soil remediation in Hervey Bay?

For a standard 500 m³ site with TPH contamination, costs range between AU$4,690 and AU$17,680 depending on contaminant type, depth, and chosen technology. Biopiles are usually at the lower end of that range; SVE with GAC treatment sits at the higher end. A detailed site investigation is required to give a fixed quote.

How long does remediation take before the site is usable?

Biopile treatment typically runs 8–16 weeks for TPH reduction to Tier 1 levels. SVE systems can achieve target concentrations in 6–12 weeks of continuous operation. Post-treatment verification sampling adds another 2–3 weeks for laboratory turnaround. Total project duration from mobilization to closure is usually 3–5 months.

Which regulations apply to contaminated soil remediation in Hervey Bay?

The primary framework is the ASC NEPM 2013 (National Environment Protection Measure) and the QLD Environmental Protection Act 1994. Site investigations follow AS 1726:2017, and laboratory analysis must be NATA-accredited. For sites near the Great Sandy Strait, additional approvals under the Marine Parks Act may be required due to potential runoff.

Can you treat mixed contamination (hydrocarbons plus heavy metals) in one process?

Yes, but the approach is sequential. We first treat organic contaminants via biopiles or SVE, then address metals through soil washing or stabilization. For a recent site in Pialba with lead (180 mg/kg) and diesel (2,300 mg/kg), we combined biopiles with phosphate-induced immobilization. Treatment took 14 weeks and met both Tier 1 ESLs for organics and health-based criteria for lead.