Several studies made by the Environmental Protection Agency, USA shows that the dirt on the road is just not normal soil but contains hazardous heavy metals. Recent studies have shown that more than 50% of heavy metals and other serious pollutants are attached to particles which measure 60 microns in size and smaller. 

It has been confirmed that even though a street may look clean, there may still be a significant loading of small micron, pollution-laden debris on it. Additionally, from an environmental standpoint, it is exactly this formerly inconsequential material which is now considered most important to remove. The increased emphasis, by the EPA and others, is now being placed upon the removal of small micron debris. 

Contents & Sources of Usual Street Debris: 

What our eyes can see - Dust, Mud, Plastic, Empty Cans & Bottles, Nails Textile, Paper & more… 

What our eyes can’t see but that exists and is more Hazardous 
 

Air Pollution

Approximately, 70% of the dust in the air is created by plying vehicles on the road. Removing this ‘nonpoint source’ pollution, along with the traditional larger debris, has become the newest challenge to sweeping technology. Contaminated air leads to breathing disorders

• Inhaling heavy metals in dust damages the functioning of the brain, lungs, kidney, liver, blood composition and other important organs.
• Long-term exposure leads to gradually progressing diseases such as multiple sclerosis, Parkinson's disease, Alzheimer's disease, muscular dystrophy, cancer of lungs, liver, bladder and skin.

Clogging of Strom Water drain

If the debris is allowed to accumulate in the curb areas on road, this pollution laden dirt run off into stormwater system because of rainfall, and clog the drain lines. 

Storm Line Management - Flood Prevention 
Cleaning of stormwater drain lines is a big cost to municipal corporations.

• Stormwater drain lines carry away the rain water and prevent the flooding of roads and houses.
• These lines run across the entire city and dish out rain water to river or sea.
• These drain lines are provided with a gradient towards the termination point to assist the flow of water.
• Debris on streets and catch basins is pushed by rain water into the main storm drains. The dirt then gets clogged with the main lines.
• Removal of the clogged material in main storm lines requires special equipment and additional manpower

By removing deep sediment buildup and large debris from curb gutters, street sweeping prevents debris entering storm water drain lines to prevent flood.

River/sea Water Pollution

The micro pollutant laden dirt on the road when carried away by rain water, carries heavy metals along with it to sea or river. This impairs the aquatic life in the nearby coastal areas or the rivers. The heavy metals referred as nutrients, directly mixing into the river water is a major cause of algae formation making the water undrinkable. 
Research has shown, improvement in the aquatic life at the coast neighbouring the cities that are regularly swept using sweeping machines.

Mechanical: Make use of 2 side brooms and a large diameter main broom to move the dirt on to the mechanical conveyor which is moving it further to the hopper. Each mechanical sweeper has ability to raise the hopper to unload the material to tractor trolley/tipper. 

Vacuum: Use 2 side brooms and a main broom to move dirt to the front of the appr. 60 cm wide pick up head. Impeller (large dia.) is creating high speed air flow to move dirt from the street to the hopper and the air (after filtration) is exhausted to the atmosphere.

• A vacuum sweeper fan requires at least 140 HP auxiliary engine to operate the sweeping module but a mechanical sweeper requires only 59 HP auxiliary engine.
• Any air leak will affect the vacuum sweeper’s efficiency.
• Buildup of debris on the impeller may cause it to go out of balance. This can cause destruction of the impeller and housing.
• High velocity of air and debris causes high wear rates on parts where the air direction is changed.
• Too much water creates sticky debris which will cling to the walls of the hopper.
• Mechanical sweeper can sweep the 3 mtrs sweeping path at a faster speed and pick-up more debris than a vacuum sweeper.
• Too bulky of material can become plugged in the system
• Normal sweeper cannot sweep the uneven surfaces or reach into gaps and holes in the road.
• Vacuum sweepers emit higher decibel rating than a mechanical sweeper because of the high RPM fan & airflow.

Regenerative: Make use of 2 side brooms and a large pick up head apprx. 2 mtrs long that creates knife edge air blast to displace and lift the dirt from the surface of the road to the hopper. The same air is recirculated again and nothing goes back to atmosphere.

The most effective sweeper for India is mechanical. A hydraulically driven and elevated main broom rotates to flick material onto a squeegee elevator. These work efficiently on unpaved and uneven road surfaces. Other advantages include:

• Very Efficient
• Most Versatile Sweeper
• Better Quality
• Removes Heavy Material
• Sweeps Well Uneven Surfaces
• Easy to maintain

Mechanical sweepers also enable right disposal of debris collected from road.

• Dumping of waste and arranging a truck for lifting it again incurs additional cost.
• Locations used for temporary dumping get polluted because of hazardous elements in the waste.
• In the USA, all mechanical sweepers are equipped with high dump hoppers to empty waste in dumping truck.

Significance: Dust is a major issue for street sweepers, and dust suppression is a major focus for street sweeper manufacturers. Testing under, US-based organization, South Coast AQMD Rule 1186 uses a pass/fail approach to certify a sweepers ability to pick up 80% of material consisting of 90% sand and 10% paint filler, spread over 1000 lbs. The normalized mass of entrained PM10 must be less than or equal to 200 mg/m. PM-10 test is mandatory for all sweepers used in North America and Europe. It guarantees customer, that they not only buy an efficient sweeping machine but also sweeper with the excellent dust control system.

What is PM10 Certification?: Testing, under US-based organization, South Coast AQMD Rule 1186 with a pass/fail approach to certifying the sweepers pick up ability.