Preventing water pollution during a project is essential for environmental protection, worker safety and regulatory compliance.

According to research conducted by Bimhow, the construction sector contributes to 40% of water pollution[1], a factor likely influencing the recent introduction of unlimited fines by the Environment Agency.

Unfortunately, as regulations become stricter, construction and infrastructure projects are under increased scrutiny as a result. So how do site teams manage water effectively?

The truth is, there is not one correct way to manage water, but there are a number of best practice hints, tips and tricks that you can implement to help alleviate some of the pressure felt on site.

Pre-construction site assessment:

• Carry out ground investigation to understand soil types and assess for contamination
• Identify sensitive receptors such as surface watercourses or aquafers
• Be aware some watercourses are more environmentally susceptible than others
• Understand the water table on site, including the impact of seasonal fluctuations
• Assess specific pollution risks from your construction activities, for instance topsoil stripping, soil stabilisation, piling, concreting, dewatering activities
• Identify your water discharge options
• Sites with nearby surface watercourses or high water tables would benefit from an independent surface water management assessment

Site planning

• Create a clear water management plan that addresses identified risks
• Schedule high-risk activities to minimise pollution risks, for instance minimise exposed clays as much as possible
• Include grading and temporary drainage to direct surface water runoff away from exposed subsoil, excavations and roads
• Perimeter Berms and diversions made from compacted earth, sandbags etc can prevent water from off-site running onto your side and becoming polluted
• Implement dedicated areas for vehicle and tool washing, fuel storage, and chemical handling away from drainage lines

Containment and flow control

• Slowing water flow and trapping sediment at site perimeters by using silt fences, channels and filters
• Sediment basins with inlet/outlet structures, baffles, and sediment forebays to manage water flow

Water collection

• Any site expecting to pump and manage water should establish an attenuation pond to enable storage on site. The larger this is the better, as it provides retention during rainfall or storm events
• Large holding tanks are a good alternative when space or schedule does not permit attention ponds but will be more costly
• Water storage is particularly important whenever on-site treatment is required, providing buffering capacity to prevent the water treatment process from trying to manage sudden fluctuations in flow rates or water quality
• Sumps, pumps and float switches can be established to transfer water automatically around site when permanent or temporary drainage is not available
• Prevent backflow of contaminated water during shutdown and maintenance by using pump isolation valves

Pumps

Whilst there are many types of specialist pumps available, for general excavation, pond dewatering and transferring water around site, electric submersible and diesel centrifugal are the two main pump options. Both can run automatically from float switches and with duty/standby options.

Diesel pumps

Typically used for large earthworks projects where pumping requirements are frequently changing and water has to be pumped long distances or at high flow rates.

Pros:

1. Quick to deploy
2. Easy to set up
3. Self-priming
4. Tolerant of dirty water
5. Positioned on land (accessible)

Cons:

1. Require diesel to run
2. Generate noise

Electric submersible pumps

Typically used for lower flow applications and when water is collected in drainage channels or tanks prior to being pumped out.

Pros:

1. Runs on electric
2. Little to no noise
3. Cheaper to hire and to run

Cons:

1. Requires a power supply
2. Must be positioned in the water body to work (lack of accessibility)
3. Preventing silt being pumped out can be a challenge

Water treatment systems

• Lamella clarifiers, settlement tanks and baffle systems to separate sediment from water being treated
• Oil separation using Lamella tanks or coalescing plate packs
• Automaticchemical dosing systems to treat fine suspended solids, pH imbalanced water or heavy metals
• Full removal of dissolved contamination such as hydrocarbons, nutrients and heavy metals requires extensive treatment methodologies such as activated carbon towers, Reverse Osmosis or Ion Exchange resins. Such systems are not often operated on construction sites and will require extensive support from specialist suppliers during the project

Already know which water treatment system you require for your site? View RVT Group’s full water treatment range for technical specifications >

The key to successful water management can be summarised with proactive planning and knowledge. By organising site layouts, submitting relevant permit applications early and engagement with water treatment experts, you’ll be compliant and well prepared to tackle water management on site.

As part of RVT Group’s water treatment service, we will come to site to see your problem first hand, take relevant measurements and test samples of the water to ensure the treatment option we recommend is best suited for your application.

Our water treatment systems are not only designed to take the pressure off site teams but also give operatives the knowledge required to react to unexpected changes.

Book a free consultation with a water specialist to talk you through how RVT Group can support your water management on site or speak to a member of our team on 0808 281 3150 today.

[1] https://procurepartnerships.co....