Concrete batch plant includes plants that measure, store and transfer concrete constituents in to the truck for transportation to a job site, to central mix drum and to precast products on site. The raw material used includes sand, cement and water. We must seriously consider way to curb Concrete Batching Plant Pollution.
During this process, pollutants which includes the storm water runoff, point of source emissions resulting from materials transfer to the silos, dust sources which includes sand and aggregate transfer, truck and mixer loading, vehicle traffic and also from wind erosion as a result of sand as well as pollutants from cement, aggregate, sand, chemical additives, lubricants and fuel.
The following are some of the prevention measures to be taken during the operation to reduce concrete batching plant pollution:
- Maintenance of the general site operations
- Maintain all the equipments including dust collection equipments to prevent any leaks.
- Identify a buffer zone which surrounds your operations in which you are planning to contain dust generating activities.
- Provide safety, quality and environments management system for the site and plant operations, as well as the delivery system.
- The storage silos
- Check for fabric leaks, cartridge filter system, suctions and shrouds regularly.
- Installation of audible high level arms on the storage silos to avoid over spilling which might damage the filters.
- Store all the dust generating materials inside the silos e.g. cement
- Raw materials
- Avoid using chemical concrete additives since they are more toxic. Instead, use sugar or wood based admixers.
- Avoid using coal fired boiler, bottom ash and cinder for concrete block building and instead, use aggregates.
- Mixer feed operations
- Use the enclosed batch mixer feed as dust prevention and visible emissions.
- Use the spray device to prevent dust emissions.
- Conduct all the mixing operations from an enclosed building to help prevent emission of dust.
- Material handling and storage
- Aggregates less than 5mm or less should be used in open areas. They should be stored in totally enclosed structures such as storage bins.
- The stock pile entrance sides should be covered with a flexible curtain.
- The opening between the storage bins and the materials weighing scale should be totally closed.
- To prevent dust emissions, the belt conveyors should be enclosed with metal board on top and on the two sides.
- All conveyor transfer points should be enclosed by fitting the flexible seals to prevent dust.
- The turning point of all the conveyors should be provided with scrappers to prevent dust collection on the surface belt
- Mixing and loading operations
- Loading concrete trucks should be in such a way that minimizes dust emissions.
- All the air borne dust emission generated by material loading and mixing operations should be vented to fabric filtering system.
- The concrete mixers and other vehicles should be cleaned off after the loading and mixing operations to wash off the mud, dust deposited on the wheels and body.
- Fugitive dust
- Use water sprays or dust suppression agents to reduce dust.
- An air extraction and filtration system for collecting the generated dust should be installed.
- The roof should be extended at least 6 feet beyond the load areas.
- Waste concrete
- Collect the waste concrete in suitable washout pits where it becomes gravel, sludge and sand which can later be reused. The blocks and bricks left overs can be used for ground covers, tracks, walkways, block walls or even curbs.
- Waste water
- Waste and contaminated water should be directed to onsite settling ponds and it can be reused later in for dust control, rinsing trucks exteriors.
The above preventive measures should be taken by the batching plant owners in order to ensure that those people living around the batching plant areas are not affected by any negligence which might turn to be environmental hazard.