Dust Controlled During Rapid Gravity Filter Tank Repairs at a Water Treatment Works Plant in Ayrshire, Scotland

Project Overview

Afton Water Treatment Works is located near Cumnock, East Ayrshire. The plant treats raw water sourced from the nearby Afton Reservoir and supplies drinking water to a large part of Ayrshire.

8 rapid gravity filter (RGF) tanks were in need of defect repairs due to rust and corrosion, and George Leslie Limited were the contractors appointed to carry out these repairs.

Challenge

Repair work involved shot blasting inside the tanks before applying steel plates to form a new lining.

Carrying out shot blasting activity effectively would help maximise the durability of repair works reducing the chance of additional and costly repairs in the immediate future. Shot blasting would create optimum conditions on the tank’s inner surface for the subsequent chemical welding work and Acothane coatings being applied.

Although shot blasting maintained the integrity of works, it would also create high volumes of hazardous, airborne dust which, if inhaled, could cause long-term respiratory risks as well as practical challenges for operatives including visibility and ultimately, productivity. These risks were compounded by works taking place in a tank, meaning dust was contained in the work area whilst the work area itself had limited airflow and fresh air entering the space to dilute dust particles being blasted into the atmosphere.

Solution

George Leslie Limited approached RVT Group to recommend engineering controls that would be powerful enough to extract dust from shot blasting activities whilst navigating the limited space around the tanks.

RVT Group supplied a DUSTEX® D4 extraction unit which was installed outside of the tanks with intake ducting capturing dust as close to the shot blasting source as possible. The unit was compact enough to be situated outside of the tanks and the high-pressured, built-in fan providing up to 3,250 m/h airflow meant dust could be extracted and filtered effectively.

The unit’s self-cleaning filter mechanism made it ideal for handling consistently high volumes of dust without clogging up the filters which could be up to HEPA standard if required. The D4 extractor allowed the George Leslie team to focus on the job at hand, knowing they were protected from the airborne dust shot blasting creates and that the integrity of work carried out would be at the highest possible standard.