Businesses

1. Eliminate non-stormwater discharges – avoid and reduce

The first step is always to ensure stormwater does not get contaminated. The aim is to prevent pollutants entering the stormwater system at source and not incur the costs of clean up. Stormwater drains must only carry stormwater runoff, and not wastewater, washdown water, rubbish, chemicals or any other contaminant that can be reasonably prevented from entering the system.

It is more cost effective and far more preferable to reduce, and where possible eliminate the causes or sources of stormwater pollution than treat the effects somewhere else on the site. These may be through simple changes in practice or engineered features (structural measures). One of the most effective methods is to structurally separate work areas from other areas of the site. 

2. Stormwater runoff is a resource – reuse and recycle

Stormwater runoff should be managed as a valuable water resource and used as an alternative source of water supply. By using the water onsite it helps reduce the volume of runoff. Ensuring it is free of pollutants increases the value of the resource and the potential number of uses. Remember, once pollutants contaminate stormwater they reduce the capacity for that stormwater to be recycled or increase the costs associated with treating the stormwater, minimising its economic viability for reuse.  

3. Treat stormwater

Treatment is the least preferable method for dealing with stormwater pollution and can be very costly. Treatment to remove any residual pollutants must be undertaken before any discharge of stormwater to the public stormwater network is allowed.  

Assessing the risk of pollutants potentially entering the stormwater system from the business activities will assist in minimising stormwater pollution. The activities and site should be separated into areas of potential risk of stormwater pollution. As a guide, divide the site into areas or risk, with each area being treated according to the level of risk of listed pollutants entering the stormwater system.

As a minimum the business site or activity may be divided into 3 basic risk areas. This will, however, vary depending on the activities of the business site. A more complex site with many different activities may have many risk areas:

• Generally water from the roof is cleaner than most stormwater runoff provided it does not come in contact with work areas, roadways and car parks. It can be collected, and reused or discharged. It is not always completely free of contaminants however. For example, for sites that emit high levels of dust or air pollutants, even the roof runoff is likely to be contaminated and will require suitable management. If water is discharged from the site then it must be sent directly to the street infrastructure without passing over work areas and preferably via a treatment system such as a bio-filtration raingarden or other suitable WSUD features.
  
  Where discharge is to street stormwater infrastructure, you must check with the relevant authority, usually the council, on its requirements.
   
• Some areas of the site may be less at risk from contamination because none of the more polluting activities occur in or on them. For example, administration areas, roads or carparks outside work areas. Provided this stormwater does not traverse work areas, this runoff water may be suitably collected and treated prior to reuse or discharge provided it can be demonstrated that the discharge will comply with the Environment Protection (Water Quality) Policy 2015 and all reasonable and practical measures have been taken to minimise pollution.  
  
  WSUD techniques may be used here and will assist in treating the water and managing flows. Spill management (containment) may also need consideration. Runoff from these areas should not be allowed to mix with runoff from work areas.
   
• Stormwater from bunded areas and all work areas is considered wastewater and must be collected and treated accordingly. Work areas are any areas where the business activities occur or where listed pollutants are produced, used, accessed or stored. How these areas are managed will vary depending on the activity being undertaken on the site. Different work areas of the site may require different management depending on the activities being undertaken on each work area.

Once a risk assessment has been undertaken, a suite of management actions should be developed and incorporated into a plan in the form of a site (or activity) stormwater pollution prevention plan. The complexity of the plan will depend on the activities the business undertakes.

A mobile business for example, may have a set of procedures it will follow at each site to prevent stormwater pollution.

At a large industrial site the stormwater pollution plan will be more complex and is likely to include a range of non-structural and structural measures, both those that prevent stormwater pollution and those that treat stormwater pollution.

The SPPP must clearly stipulate how stormwater from the different risk areas of the site is managed to avoid discharge of pollutants off site. Offsite release to the public stormwater system is possible only if it can be demonstrated that the discharge will comply with the Environment Protection (Water Quality) Policy 2015 and all reasonable and practical measure have been taken to minimise pollution. Pre-development flows offsite should also be maintained. 

Many councils have a regional or catchment stormwater management plan and other requirements that must be met for discharge to the street infrastructure. The site pollution prevention plan must comply with any of these obligations. It is essential that you check with the relevant authority on any requirements they may have for discharge. 

Management of stormwater for pollution prevention will vary depending on the activity being undertaken on the site. Some measures will be non structural controls, designed to prevent or minimise pollution entering stormwater.

Development of a stormwater pollution prevention plan, maintenance practices, operational procedures, training and education programs are all forms of non-structural controls. These controls should be reviewed regularly for improvements and modified accordingly.

Structural controls may also be implemented to manage the quality and quantity of stormwater runoff.  These are often engineered systems and must have a maintenance & inspection program to ensure functioning at optimal design at all times.

A treatment train approach is encouraged where combinations of measures, both structural and non structural, may be implemented to achieve best practice management of stormwater. It is also key that these systems are maintained on an ongoing basis.

Work areas are most at risk of contamination. There should be structural separation of the work areas from other areas of the site with the ability to shut down and contain each area in the event of spillage. Separating work areas is one of the most fundamental of structural controls. Structural separation may be achieved by roofing work areas.

Under no circumstances should drainage inside roofed areas connect to the stormwater system. If roofing is not practical, structural separation may be achieved through techniques such as grade separation, diversion banks, kerbing, and bunding. Inspect the uncovered areas of your workplace when it rains and ask will runoff become contaminated and pass to a stormwater drain? If the answer is yes, it is essential to manage these areas and disconnect any direct connections to the stormwater system.

Ensure runoff from relatively clean areas such as the roof is kept separate and not allowed to pass over work areas (structural separation).

• Collect and use all roof and other runoff where feasible.
• All areas where pollutants including chemicals, waste and wastewater are produced, stored, accessed or used must be isolated from the stormwater system. If they are not roofed, any wastewater that collects in these areas must be collected and managed so that it does not discharge to the stormwater system (structural separation). Treatment will be dependent on the pollutants from the business activities.
• Good housekeeping and staff awareness are critical; clearly identify all stormwater drains and management procedures; implement education programs.
• The floor drainage of any covered and roofed work areas must be isolated from the stormwater system.
• All sites must consider how spills will be managed and have an emergency spill response plan that clearly stipulates procedures and responsibilities to be followed. Spills must not be washed into the stormwater system under any circumstances. Ideally configure the stormwater management system onsite to allow for shut-down and containment in the event of an emergency spill.
• Chemical storage and handling areas must be located in sealed secondary containment areas based on the EPA Guideline Bunding and spill management.
• All waste chemicals and solvents must be collected and stored in a secondary containment area and disposal to a suitably licensed liquid waste depot.
• Washdown water from cleaning plant and equipment or process water must be collected and disposed to sewer (with appropriate approvals) or to a suitably licensed waste depot.
• Vehicle washing should be only in approved wash bays
• Business that have a high risk of contamination from fuel/petroleum products will need to have a suitable treatment for hydrocarbons and ensure all fuel storage areas are adequately bunded
• All solid waste bins should have lids
• Ensure vehicles exiting the site do not deposit materials (eg sediment) on the roads. Consider a wheel wash or other means to clean vehicle wheels before exiting the site.
• All treatment systems used to treat runoffmust bemaintained to the manufacturers or design specifications. They should have a regular maintenance program and all maintenance procedures should be documented. 

In summary the stormwater pollution prevention plan, based on risk assessment must document:

• How the different work areas of the site are structurally separated
• All pollution controls for the different risk areas of the site, both structural and non-structural
• Other management procedures to minimise pollution including;
• how spills will be managed
• how pollution control and treatment systems will be managed and maintained.
• All reuse options
• Discharge points off site.

Water-sensitive urban design (WSUD) promotes the sustainable use and reuse of water integrating water from all sources. WSUD is an approach to urban planning and design that integrates the total water cycle into the urban development process.

WSUD is:

• integrated management of groundwater, stormwater, drinking water and wastewater to protect water related environmental, recreational and cultural values
• the storage, treatment and use of stormwater
• treatment and reuse of wastewater
• the use of vegetation for treatment purposes, water efficient landscaping and enhancing biodiversity
• using water-saving measures within and outside domestic, commercial, industrial and institutional premises to minimise requirements for drinking and non-drinking water supplies.  
  Source: WSUD Technical manual for Greater Adelaide, NWC.

WSUD techniques can reduce stormwater flows and improve the water cycle so it mimics a more natural water cycle.

When WSUD is implemented appropriately it can greatly reduce the impacts of urbanisation including those from stormwater. A range of WSUD measures may be used to reduce the impacts of stormwater pollution and changed flow regimes, depending on site circumstances as illustrated.  

Some WSUD techniques are outlined below. For a more comprehensive overview see WSUD Technical Manual Chapter 1 Introduction to WSUD.

WSUD in your business

WSUD can effectively be applied to the non-work areas of commercial, industrial or retail sites to minimise impacts on the natural water cycle. It may not be suitable for work areas, but could form part of a treatment train, depending on the activities being undertaken. 

Separation of work areas from other parts of the site is key to ensure pollutants from the activities do not contaminate the stormwater. If this is done robustly it will isolate the industrial pollutants potentially minimising the cost of treatment. By roofing work areas it removes large volumes of water which can be used for other purposes and reduce the demand for potable water. 

Although at risk of some contamination from vehicle movements, sediment and litter, the further separation of areas such as carparks, administration areas and some roadways from both water from the roof and work areas mean that these areas can usually be treated similarly to other urban stormwater, using a range of best practice WSUD measures. 

Bio-retention may be suitable for driveway areas of commercial and industrial sites.

WSUD measures

Bio-retention (biofiltration) systems are systems that improve stormwater quality through vegetation and filtration through a prescribed filter media. Treated flows are either infiltrated to underlying soils, or collected in an under-drain system to the stormwater system. They may be located in carparks, along roadways or in median strips and hence are usually suitable for these locations on a commercial or industrial site. The surface area should be sized at a minimum 2% of the contributing catchment size.

Further design and technical information on biofiltration systems refer to:

• Adoption guidelines for stormwater biofiltration systems
• WSUD Greater Adelaide Technical Manual – Chapter 10

Constructed wetlands are shallow, extensively vegetated water bodies that allow settling of sediment particles, fine filtration and biological processes to remove pollutants. Constructed wetlands may be useful where runoff contains high concentrations of soluble material but this will require careful design with large macrophyte zones and extended residence time.

• WSUD Greater Adelaide Technical Manual Chapter 13
• Melbourne Water 2010, Constructed wetland design manual

Pervious pavements are load-bearing pavements that are permeable to water. They include a permeable surface layer that allows water to penetrate to an underlying storage layer. The storage layer consists of crushed stone or gravel which is used to store water before it infiltrates to the underlying soil (or it may be discharged towards a piped drainage system). Infiltration to the ground assists in reducing runoff, recharging groundwater and there is some removal of sediment and any attached pollutants through the gravel layer. The suitability or otherwise of pervious pavements will depend on the activities of the business.

Further information on the range of pervious pavements see WSUD Greater Adelaide Technical Manual Chapter 7.

Water efficiency in your business can help reduce costs and your environmental footprint. Rainwater tanks designed to capture and store water from a roof of a building can be employed and captured water may be used for a range of purposes within the business. Depending on the size and how they are utilised they can greatly reduce the runoff from a business.

Reducing runoff assists in reducing changes to the flow regimes that urban waterways and coastal waters, usually experience, thereby reducing impact. Use of captured rainwater may be one of the demand reduction strategies employed by the business.

SA Water can provide assistance to business in developing water efficiency plans and have a Water efficiency toolkit available.   

Concrete waste and brick, bitumen or concrete cutting wastewater must not enter the stormwater system.

When cutting concrete and bitumen many fine particles of waste are released. Wastewater contains chemicals and waste materials, sediment, metals.

• Surround the cutting area with portable bunds to contain all waste and wastewater.
• Surround the nearest stormwater drains with portable bunds.
• As concrete is cut use a wet vacuum system to collect waste material.
• To minimise the amount of wastewater use a system to recycle the wastewater.
• Collect all solid and liquid waste and transport in sealed containers to a licensed disposal depot.
• Follow the general requirements for all mobile operators.  

Motor vehicle servicing or repairs waste, oil, grease, lubricants or engine coolant, solvents must not go to the stormwater system.

• All solid and liquid wastes must be collected and removed for proper disposal at licensed disposal facilities. Wastes may include coolants, grease, oil, metals, brake fluids, lubricants, wastewater from engine degreasing, batteries, oil filters.
• Place a spill mat with bunded side under the vehicle to capture or leaks and spills
• Ensure your spill response kit is readily available.
• Ensure all containers for either new or used liquid product are sealed and have secondary containment so that if the containers are accidently knocked when in use or transit the liquid is captured.
• Capture wastewater from equipment and dispose with other liquid waste.
• Capture wastewater from greasy hands and dispose with other liquid waste or wash them over a sink connected to the sewer.
• The base from which the mobile service operates must have suitable waste and containment facilities for both solid and liquid waste.

Wastewater and detergents from washing of vehicles must not go to the stormwater system.

• If washing vehicle exteriors, provided there is no likelihood of chemicals or oil, do so on grassed or garden areas only where the water can soak into the ground. Make sure the area is far enough away from stormwater entry points and use portable bunding to ensure it stays in areas where it can soak into the ground.
• Alternatively, particularly if there is any risk of chemicals or oil, wash on a fully bunded spill mat and capture the wastewater in a sealed container for appropriate disposal in the sewer (subject to SA water requirements) or a licensed waste facility.
• Follow the general requirements for all mobile operators.

Wastewater and detergents from washing of vehicles must not go to the stormwater system. Carpet or upholstery cleaning waste, paint and paint scrapings, solvents must not go to the stormwater system.

• If there are any materials such as paint scrapings, solvents or other chemical used in the detailing process, then washing must occur on a mat with bunded sides so that all wastewater can be captured and removed in a suitable sealed container for disposal at a licensed facility. Paint, solvents and other chemicals may contaminate soil and leach into groundwater. Washwater with these materials cannot be allowed to soak into the ground.
• When washing vehicles and no chemicals have been used ,it is possible to do so on grassed or garden areas where the water can soak into the ground. Make sure the area is far enough away from stormwater entry points and use portable bunding to ensure it stays in areas where it can soak into the ground.
• All vacuum and solid waste must be collected and disposed of at a licensed facility.
• Follow the general requirements for all mobile operators.  

Animal faeces and washdown water from cleaning animals or animal enclosures must not go to the stormwater system.

• Use washing units in an area where wastewater can soak into the ground or garden.
• Alternatively using a washmat with inflatable sides or portable bunding to collect the water and take away to dispose at a licensed liquid waste disposal facility.
• Similarly all wastewater from cleaning animal enclosures be disposed to a suitably managed soakage area or taken away for disposal at a licensed facility.
• Avoid using cleaning solutions with flea rinse. Such solutions are pesticides and should be used sparingly so they do not run off into the stormwater system. Even biodegradable ones can cause environmental harm if they enter stormwater systems, streams, rivers and ultimately the ocean.
• All waste products, such as dog hair or fur, nails, dirt and sediment associated with washing and grooming must be collected and disposed into solid waste bins or licensed waste facilities and not the drains or gutters.
• Similarly solid waste from cleaning animal enclosures must be disposed to licensed waste facilities.
• Follow the general requirements for all mobile operators.  

High pressure water waste and roof cleaning waste must not go to the stormwater system.

• If using a high pressure cleaner, ensure that all wastewater is directed to a soakage area such as the garden or lawn. Alternatively use portable bunding to direct it to an area where it can be collected and taken away for disposal.
• If cleaning rooves ensure the downpipes are disconnected. All wastewater from cleaning should be collected and disposed through a licensed waste contractor or directed to a suitably managed onsite soakage area.
• Do not undertake these activities on windy days when spray drift may carry pollutants into the stormwater system.
• Do not hose down the driveway or any paths into the gutter. Sweep instead.
• Follow the general requirements for all mobile operators.  

Pool backwash water and pool chemicals must not go to the stormwater system.

• Under no circumstances should the waste water from cleaning a cartridge filter or swimming pool filter backwash water enter the stormwater system.
• Cartridge filters that are hosed down should be done so that the wastewater flows into a soakage or garden area or the sewer system or use portable bunding to direct it to an area where it can be collected and taken away for disposal.
• In areas connected to the sewerage system, backwash water from all swimming pools can be directed to a sewerage drainage point (new pools are subject to the necessary approvals). Check with the property owner.
• In unsewered regions, backwash water or cartridge washwater is to be discharged to a grassed, vegetated or garden area.
• Any surface run-off resulting from the discharge should be contained within the property boundaries and salt tolerant plants are recommended for saltwater chlorinators.
• Follow the general requirements for all mobile operators. 

Garden waste such as lawn, plant clippings and leaves must not enter the stormwater system.

• Under no circumstances should garden waste be swept, blown or hosed into the street gutters.
• Instead rake or sweep garden waste, use it as mulch, compost it or place in the green organics bin or take it to a licensed composting facility.

Pesticides, herbicides and fertilisers must not be used near any stormwater drains.

• This is a particularly important around driveways and pathways that may flow into the stormwater drain.
• Excess use of pesticides, herbicides and fertilisers is likely to runoff into the stormwater system. Use these chemicals sparingly and do not use them during periods of rain or when rain is forecast in the next 24 hours.
• Do not spray under windy conditions; the wind may transport the spray to the stormwater system.
• Further information on using pesticides, herbicides and fertilisers wisely:
• Guidelines for responsible pesticide use
• Safe and effective pesticide use: a handbook for lifestyle landholders
• Safe and effective pesticide use: a handbook for commercial spray operators
• Safe and effective herbicide use: a handbook for near-water applications
• Follow the general requirements for all mobile operators.