How to manage contaminated water on your construction site

Water contamination can happen very easily on site. Here’s how to manage water more responsibly and effectively 

Water sustains life and supports many industries, and it’s also crucial throughout all stages of construction. However, as the driest of all inhabited continents, Australia’s water supply is becoming increasingly scarce. Coupled with growing domestic and industrial demand, it’s important for industries like construction to minimise water consumption and to maintain the quality of the water supply that’s still available. 

Here’s a quick look at why water quality matters and how it can be managed more effectively and responsibly in construction.

How can water become contaminated in construction?

Sediment is one of the greatest threats to water quality in construction. When it rains, the resulting stormwater can pick up sediment from loose and exposed soil and other pollutants as it moves across construction sites. 

Another way that contamination can easily occur is if wastewater isn’t appropriately managed or disposed of during construction activities like painting; wet cutting, drilling and grinding of brick and stone; mixing concrete and grout; and cleaning worksites and equipment. During excavation, the groundwater removed through dewatering can also be contaminated if it’s been exposed to industrial and agricultural discharges, or inappropriate waste disposal in surrounding areas.

Contaminants commonly found on Australian construction sites and in construction wastewater include:

• Soil particles that become suspended in surface water

• Heavy metals from rusting equipment and materials that have been stored outside

• Hydrocarbons in the form of petrol, diesel, kerosene and oils, and other toxic chemicals

• Hazardous chemicals and other toxic materials like lead-based paint, solvents, glue and products like insulation that have been manufactured with harsh chemicals

What impact can water contamination have?

If contaminated water leaves construction sites as untreated groundwater or in the form of run-off, it can introduce dangerous chemicals and other industrial pollutants into the local water supply. Contaminated water can also pollute downstream waterways as it moves out into rivers, reservoirs, wetlands, groundwater and out to sea.  

When contaminated water enters these environments, it poses a significant risk to the health of people, land and marine wildlife. Ingesting toxins through drinking water can lead to severe health issues in humans, while increased nitrogen and phosphorous levels can cause algal blooms that deplete oxygen and suffocate plants and animals, creating ‘dead zones’ in bodies of water.

Water quality can also affect the successful outcome of some construction tasks. For example, when mixing concrete, the presence of impurities like silt and suspended particles in the water can inhibit the hardening process and significantly reduce concrete strength.

Managing water contamination in construction

Know your responsibilities

Understanding your requirements for the management and treatment of construction wastewater is an important first step in preventing contamination and minimising your environmental impact. Whether discharging water is a one-off or a regular occurrence for your business, trade waste permits may be required to ensure that water quality standards can be met. For more information contact your local water authority or environmental protection agency.
 

Preventing water contamination

Preventing water contamination is easier and more effective than remedying it. This can be achieved by: 

• Monitoring the water that you discharge to know when treatment or other action is required

• Limiting the environmental impact of runoffs by collecting and adequately treating wastewater

• Installing silt fencing to minimise silt pollution, or digging cut-off ditches to divert run-off

• Avoiding the re-use of crushed recycled concrete as aggregate, which can elevate water pH

• Disposing of paints, oils and other waste responsibly and never down drains

• Storing materials indoors and above ground that could contaminate stormwater (including paints, solvents, glues, insulation, cements, grease, oils, asbestos, fuels and corrosive metals)

• Avoiding, where possible, the use of toxic substances to control unwanted vegetation and pests

• Providing oil spill kits and refuelling vehicles in designated areas

• Adhering to relevant legal and ethical waste disposal practices in your location

Treating contaminated water

Treatment may be required to remove contaminants before wastewater can be discharged into sewers and local waterways. Outsourcing water treatment can be more cost effective and can provide construction businesses with the confidence that water treatment results will meet all requirements, and stand up to scrutiny.

To support customers, Coates offers detailed laboratory testing to determine water quality and to devise optimal water treatment methodology. When treating groundwater Coates aims to achieve a neutral or beneficial effect (NorBE) on water quality, allowing customers to comply with environmental regulations and have a positive environmental impact. Detailed reports and samples are also made available to customers to confirm discharge water quality.

For advice on how to manage water and contamination on your construction site, contact Coates Engineering Solutions