Pollution prevention

When assessing LID options on your site, identifying pollution threats is an important part of the pre-design process. Applying the principles of pollution prevention (P2) the use of processes, practices, materials, products, substances or energy that avoid or minimize the creation of pollutants and waste, and reduce the overall risk to the environment and human health can help eliminate those pollution threats, ensure compliance with regulations and bylaws, and create a safer environment for staff and customers.

P2 is about anticipating and preventing pollution instead of reacting to it after a spill or release has occurred. It is part of an ongoing pollution management approach comprised of prevention, control and clean-up. P2 opportunities can be found throughout any site or operation. For instance, installing different equipment or technology, or changing raw materials or staff routines can result in pollution prevention. The ways in which P2 is achieved varies from one sector to another, but typically there are nine common opportunities:

Opportunities for Pollution Prevention

Dumpster management	Dumpsters can be a major source of pollution that can affect water quality. When dumpster lids are left open, rainwater is able to mix with the trash, resulting in a leaking fluid, or “dumpster juice”, which can contain toxic organic and inorganic materials. If not treated, this dumpster juice can enter the storm drain system, contributing to poor water quality.
Grease management	Restaurants produce grease and other wastes as a by-product of normal food preparation. If grease is dumped or washed into sewers or storm drains, it can cause sanitary sewer overflows or stormwater runoff pollution. Restaurants can implement simple and low-cost P2 practices and train workers to properly dispose of used waste.
Parking lot maintenance	Maintenance operations have the potential to pollute stormwater runoff if sensible P2 practices are not employed. This is particularly true of power washing, which can deliver sediment, nutrients, heavy metals, hydrocarbons and other pollutants into the storm drain system.
Building maintenance	Some building maintenance practices produce polluted wash-water that can directly enter the storm drain system during dry weather, whereas others deposit fine particles or liquids that can wash away into stormsewers during wet weather.
Landscaping and grounds care	Landscaping services are generally performed by a lawn care/ landscaping contractor or an in-house maintenance crew. Poor landscaping practices can create stormwater pollution, particularly in urban areas where soils are compacted.
Outdoor storage	The risk of stormwater pollution is greatest for operations that store large quantities of liquids or bulk materials at sites that are connected to the storm drain system. Protecting outdoor storage areas is a simple and effective P2 practice.
Vehicle maintenance and repair	Often, vehicles that are wrecked or awaiting repair can be a concern if leaking fluids are exposed to stormwater runoff. Vehicle maintenance and repair can generate oil and grease, trace metals, hydrocarbons, and other toxic organic compounds. When vehicles are washed on impervious surfaces, dirty wash water can contaminate stormwater with sediments, phosphorus, metals, oil and grease, and other pollutants that can degrade water quality.
Fuelling stations	Delivery of pollutants to the storm drain can be sharply reduced by well designed fuelling areas and improved operational procedures. The risk of spills depends on whether the fuelling area is covered and has secondary containment.
Snow and ice management	Ontario experiences severe winter weather with large amounts of snowfall. Common snow removal practices include application of de-icer. De-icer is usually made from a urea compound or rock salt. Many property managers apply the products indiscriminately, assuming that more is better. However these de-icers wash into local waterways when the snow starts to melt. The key to de-icer usage is to apply it sparingly, and to remove most of the snow before application. See also salt management.

P2 in practice

Here are three examples of how some P2 techniques have been applied:

Fueling stations and spill containment

If activities on your site include the loading and unloading of product or supplies such as chemicals, fuels, or oils, you should have P2 techniques in place. Spill containment measures temporarily detain any spills, allowing for them to be cleaned and disposed of before reaching storm sewers. This can also reduce the risks of a spill draining into an LID feature, catch basin or drainage swale. Valves can be incorporated into the design of the spill containment so that it can easily be drained of rainwater or liquid.

This spill containment structure in Mississauga prevents sodium hydroxide and potassium hydroxide from leaking into nearby storm drains and natural feautres

A fueling station at a Mississauga business features a catch basin and valve for each cleanups.

Outdoor storage

Outdoor storage can create potential pollution threats as rainfall or runoff comes into contact with product, materials or waste being stored outdoors. Further complications are added when property facilities (i.e. waste bins, recycling bins) are susceptible to illegal dumping. To prevent and manage pollution threats from outdoor storage, there are a variety of P2 strategies that can be employed. Simple strategies can be employed such as storing de-icing salt in a dedicated storage container to prevent continual loss of salt from exposure to precipitation. Other best practices include using large storage containers to protect chemical storage drums, as seen below.

Dumpster management

Dumpster maintenance is often overlooked. As a result, many dumpsters are in poor condition. Cracks in dumpsters will leak toxic organic and inorganic materials into catchbasins and towards waterways. Opportunities for P2 include locating dumpsters on flat concrete surfaces that do not slope toward or drain into the storm drain system, installing a secondary containment system such as a berm or curb around the dumpster, and closing and securing lids properly when the dumpster is not being loaded or unloaded.

Education is a critical component in the implementation of pollution prevention measures. Training your employees on P2 procedures as well as the reasons behind them can change attitudes toward pollution prevention. Employees may be more diligent in following P2 practices if they understand how it effects the quality of their drinking water.

Low Impact Development. A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

Refers to the conditions in which an organism lives and survives or the conditions in which an organism resides. These conditions can be described as aspects of a “physical”, “social” or an “economic” environment, depending on the perspective perceived by the observer.

The portion of water precipitated onto a catchment area, which then flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

Soil, sand and minerals washed from land into water, usually after rain. They pile up in reservoirs, rivers and harbors, destroying fish-nesting areas and holes of water animals and cloud the water so that needed sunlight might not reach aquatic plans. Careless farming, mining and building activities will expose sediment materials, allowing them to be washed off the land after rainfalls.

A hard surface area (e.g., road, parking area or rooftop) that prevents or retards the infiltration of water into the soil.

Soil, sand and minerals washed from land into water, usually after rain. They pile up in reservoirs, rivers and harbors, destroying fish-nesting areas and holes of water animals and cloud the water so that needed sunlight might not reach aquatic plans. Careless farming, mining and building activities will expose sediment materials, allowing them to be washed off the land after rainfalls.

The total mass of a pollutant entering a waterbody over a defined time period.

The net amount of something (e.g. chemical, such as phosphorus), calculated as the product of concentration and volume in a given time. Some BMPs significantly reduce loading of pollutants to the environment by reducing volume more so than concentration.

Ground depression acting as a flow control and water treatment structure, that is normally dry.

Any form of rain or snow.

A compacted earthen wall that diverts runoff or creates shallow ponding of runoff. In some cases, runoff ponds behind the berm and gradually flows through it or is infiltrated.