Issue

As TJ Waste expand for the future, they are highly conscious of the environmental issues facing them and want to work with the Environment Agency to ensure that all aspects of the business meet the highest standards in the industry. Some of these issues involve water recycling, dust suppression and emergency fire control, and these also influence the availability and magnitude of the business insurance premiums.

Based on a past excellent working relationship, TJ Waste approached Wright Rain Environmental Ltd to assist with the design of the fire prevention system and a dust suppression system.

Due to the nature of the business, waste is continuously received throughout the day and material remains in the building during the night and weekends. Therefore, a substantial amount of water was demanded to address a potential fire in the building, despite the local fire service being available within a 15-minute call out.

Task

Having established the water requirement to address the fire and the areas at most risk of fire, Wright Rain Environmental Ltd designed a system to fulfil these requirements.

Solution

To enable the system to be completely automated, a 10kw submersible bore hole pump was mounted in the new 10,000l tank, this was then wired into the power supply to be linked in to the automation.

Large diameter PE piping was installed from the tank, along the back of the main building, this then went up to a simple 4 valve manifold assembly. The 7 specially designed deluge fire nozzles are in 3 separate sections and fed from a network of steel pipes mounted in the roof of the building to cover the potential areas of concern and can be individually isolated from the manifold mounted at ground level. Each nozzle covers around 8 metres diameter of floor area.

In order to have easy access to the nozzle control valves, the manifold is mounted on the back wall of the building, with the steel pipes running up the back wall.

The controls were wired into TJ Wastes fire detection equipment.

Some concern was expressed over false activation.
Therefore, a fail-safe system is incorporated involving a variable delay between the fire alarm being activated and the deluge nozzles operating.

Regular testing of the alarm system and pumping system can be carried out with the sprinkler lines isolated and the main bypass valve opened to return the water to the river without deluging the building.

Conclusion

Wright Rain Environmental Ltd are delighted to work with TJ Waste Ltd, who take their Environmental and Health and Safety responsibilities very seriously.

Site

For many years aggregate materials have been delivered, processed, stored and distributed from the depot of Day Aggregates, Station Yard, Purley. Materials are delivered primarily by rail, processed if necessary and stored in a sequence of large concrete bays. From here materials are loaded onto lorries by means of loading shovels and distributed by road.

To improve the efficiency and increase the productivity of their station yard site, Day Aggregates took the decision to completely overhaul their plant, opting for a state of the art rail unloading facility and new storage areas. As part of the improvements to the site and in keeping with their ongoing environmental program, Day Aggregates invited Wright Rain to engineer a system which would reduce the impact of dust created by their operation and automatically add water to selected products whilst moving through their unloading facility, to prevent dust becoming airborne.

Task

Wright Rain has been tasked to design and install an efficient system for, dust suppression at the rail unloading points, Water Addition to materials on the delivery belts. Roadway dust suppression & stockpile dust suppression.

Solution

To prevent dust ‘billowing’ from the underside of the rail wagons whilst being unloaded, a series of sprinklers were installed to create a fine mist curtain on either side of the unloading bay, confining dust to the pit area. This system can be controlled manually from inside the unloading office by means of a simple switch.

Series of ‘Spray Bars’ were installed at specified points along the delivery belts from the rail unloading point to the distribution belt. These spray bars can be operated manually from the rail unloading office so that only required materials are wetted or automated via load sensors on belts. Water is delivered through automatic valves on hydraulic pipelines, hidden on the underside of the plant.

A ‘Halo’ was created from a series of spray bars on each side of the tripper carriage for materials to pass through from the discharge belt to the storage bays. Creating a fine mist, this system prevents dust pluming from materials leaving the belt. Rain gun sprinklers situated on every other bay suppress dust created by wind blowing into the bays. Rainguns soak the top of materials to stop the dust becoming airborne. This system is also used to suppress dust in the additional storage areas around the edges of the yard. These rainguns are designed to overshoot stockpiles and damp roadway areas to reduce dust from vehicle movements. 

Conclusion

This system dramatically reduces the impact of dust both for those working on site and those who inhabit local business and residential properties. Using state of the art pumping and control equipment, Day Aggregates have a dust suppression system which complements the advanced processing equipment on site and has also helped them achieve their overall goal of increased efficiency output and environmental compliance from their Station Yard facility.

Health and Safety and Environmental Issues are two of the major concerns in the modern working environment both internal and external

These may be potentially hazardous to staff and public or a nuisance factor to the local environment, either of which can cause a risk to the operation.

Throughout the year, airborne dust caused by processing, handling and road surface vehicle movements, which could potentially close an operation down if not addressed effectively, and be financially crippling to any organisation.

Most larger organisations are accredited to ISO 14001 which incorporates environmental audits and planning to show that the company is environmentally friendly, reduces wastage and improves the company image. Control of dust emissions are an aspect of this that is taken into consideration.

When companies are making planning applications for new sites or modifying existing permissions, the dust emissions from site form part of the considerations and in many instances, dust monitoring is stipulated as part of the planning consent.

Most of the larger areas around the sites would tend to be controlled using water sprayed onto the roadways and stockpiles by sprinkler and rain gun systems or water bowsers on a regular basis depending upon the type of dust, vehicle movements and exposure to windy conditions.

This dust tends to be a nuisance to both site and neighbours with low levels not of undue concern to health. However, there is growing concern over materials being handled with a higher level of silica content in the dust due to the potential health risks of both site staff and the surrounding areas. In these situations, it is essential that the emissions are taken seriously and control measures retained in perfect working order and staff trained to both minimise dust and to wear the appropriate protective clothing and breathing masks.

Even within the company perimeter or enclosed buildings, dust is particularly unpleasant for employees to work in and the addition of dust masks with protective clothing sometimes makes manual work more difficult or uncomfortable.

Staff also like to know that their health is not at risk and want as good a working condition as possible on site. This helps retain key members of staff for the benefit of both staff and the company.

Wright Rain Environmental specialise in the design, supply and installation of commercial dust suppression systems for the aggregate and waste handling industries for over 20 years and our trained staff are available for system design, breakdowns and service throughout the year.

This is the ideal time to be considering your requirements for this year whilst there is still time to service, install and modify systems ready for the drier weather this Spring.