Incidents involving hazardous substances don't just occur on land. Again and again we hear of incidents involving oil spills on water, with serious consequences. It's the sad reality of large scale catastrophes which reach the ears of the general public; tankers run aground, pipeline leaks, oil rig accidents. But seemingly small scale oil leaks can also have catastrophic effects when they affect a local body of water. A single drop of oil can spread in no time at all, contaminating up to 1000 litres of water. But how can companies take precautions? What equipment is needed for an emergency? And what happens when something happens? We answer the most important questions here.
If a company handles water hazardous substances it must use a risk assessment to identify potential hazards. In addition to the corresponding safety measures it must also prepare an emergency plan to deal with leaks. The local circumstances may also mean that the company needs to prepare for incidents involving oil spills on water, for example if there is a body of water on or directly next to the operating site, oil pipelines run near to water or there are drains present into which oil could penetrate by accident.
Oil spills on the water generally need to be reported and are a situation for the fire brigade to handle. However, the emergency plan should not be limited to simply calling 999 and waiting for the professionals to take over. The most treacherous thing about oil spills on water is the speed with which the liquid spreads out on the surface of the water.
Especially in flowing waters, the oil film and the subsequent damage will spread downstream with every second. The fire brigade will take time to arrive on site, meaning valuable time can be lost. To limit the spread of oil, fast emergency measures can be put in place. By doing this companies will not only minimise environmental damage but will also reduce the costs they will have to pay for causing the incident.
Oil spills on water can be expensive. If you allow hazardous substances to enter water and cause damage, you are not only liable to pay damages but will also have to bear the costs for the clean up. Insurers will also keep an eye on things to see if sufficient emergency preparations were made for the corresponding hazards. Companies would therefore be well advised to look at suitable emergency measures as a priority.
It can be useful to cooperate with the local fire brigade when carrying out emergency planning. The relevant fire service may also visit a company themselves if they recognise that there is a potential danger. By working together, both parties can benefit from sharing ideas for preparing an emergency plan and agreeing on suitable emergency equipment. Sometimes the fire service may provide the company special equipment and install this on site. The company can be confident that the right equipment is in the right place if an emergency arises, and the fire brigade will benefit from having the right equipment in place if required.
Determining Suitable Measures and Equipment
Actual emergency measures always depend on the risk assessment, as well as the resources to be procured. If you look at an example emergency plan, you get a good idea of what is important and what is needed.
The response begins with the discovery of the leak. If an oil spill is detected on water or a leak is found that could cause oil to enter water, the fire department should usually be alerted first. Other relevant parties should also be informed such as the water authority or specialists from local companies. If third parties, in particular operators of sewage treatment plants or water supply companies, may be affected, they should also be informed of the dangerous situation.
In an ideal situation, emergency measures will be put in place immediately.
To prevent the leak from spreading the leak should be stopped as soon as possible at its source. This can be achieved by deploying oil barriers on the water. Oil barriers are differentiated into active and passive systems. Passive barriers consist of a submerged guard made of special waterproof fabric with internal buoyancy aids. They are fixed between banks using an anchor system. The lower edge of the guard is weighted down so it does not float on the water. When using the oil barrier, the oil is collected at the water surface while the water flows under the oil spill. The oil can then be pumped away or absorbed with absorbents.
They are filled with highly absorbent polypropylene fleece which absorbs the oil. Active barriers in combination with a passive system work especially well: while the passive system forms the actual oil barrier, the active barrier can take up most of the leaked oil and then be retrieved in one piece using the rope.
If special risk areas are known, the use of oil barriers in emergencies can be prepared as precisely as possible. For example, suitable barrier locations can be determines in advance so that you do not have to drive behind the oil film, but can intercept it at suitable points. Criteria such as favourable flow conditions, safe access routes and sufficient attachment options for the equipment used play an important role in this.
The design of the oil barriers is largely determined by the water conditions. Are they standing or flowing waters? What width, depth and flow rate should be considered?
If oil barriers with diving apron are purchased, the required depth of immersion depends on the depth of the water and the length of the barrier depends on the width of the water. However, at higher flow rates, it is important to keep in mind that the oil barrier should not be installed at a right angle to the shore to reduce the velocity of the approach, thus minimizing the forces on the barrier. For these reasons, the oil barrier should be made longer in individual cases. Practically, here are products that consist of individual elements that can be connected quickly. So you can adjust flexibly to the size of the accident or to different water types. When attaching oil barriers, it is also important not to set the breakpoints on the shore too high, since the barrier can be infiltrated otherwise. Possibly. In addition, binding fleeces should be applied on the shore. Even strong currents can pull oil under the barrier. Here, it is worthwhile, if necessary, to provide a number of barriers which, even at a distance from one another, offer even greater security. Thus, oil that has infiltrated a previous lock may be stopped by the next lock.
Binders for receiving the oil from the water should be kept at the level specified in the risk assessment. Sometimes oil binders are used in granular form, but they have certain disadvantages. Once spread on the oil spill, the binder must also be removed from the water after the absorption process again. This is often difficult and a complete elimination is hardly possible. Depending on the flow conditions, the material is flushed more or less quickly into the bank area and gets caught up in the vegetation. Another disadvantage of the granules is the potential poisoning of the aquatic fauna. The granules, which are partially contaminated with oil, can be falsely identified as food by birds and fish, causing bird and fish extinction, depending on their size. All these negative side effects can be avoided by using oil suction mats, without losing functionality. Floating oil suction mats are made of a non-woven material. They are made of 100% polypropylene and are inherently water repellent (hydrophobic) and oil attractant (oleophilic). They can be easily distributed on the oil spill and collect again without great effort, since they are still buoyant in the saturated state. An elaborate breaking off of the water surface as with the use of granules is eliminated. Suction mats are not only available individually but also on a roll, so that long sections can be used for bank protection. This oil contaminants are absorbed and limited in the embankment. Oil mist and, as previously mentioned, active oil barriers are well-suited to removing residual oil films.
The need for further measures and aids depends on the circumstances. How much staff is needed? Does the staff know the assignment plan? How can the equipment be quickly transported to the job site? Are additional resources such as job boats, anchors, lines, tools or lighting needed? All these questions should be asked in advance in order to respond as quickly as possible in an emergency. You notice: An active contingency planning pays off.
As a rule, follow-up measures follow a successful intervention. In addition to the correct disposal of contaminated materials, the relevant authorities often require monitoring to be carried out to determine possible residual pollution.
The technical information on this page has been prepared carefully and to the best of our knowledge and belief. Nevertheless, DENIOS can not assume any warranty or liability whatsoever, be it contractually, tortiously or in any other way, for timeliness, completeness and correctness neither towards the recipient of this magazine nor to third parties. The use of information and content for your own or other purposes is at your own risk. In any case, observe the local and current legislation.
|Need more information or advice? Call 01952 811 991 to speak to a DENIOS expert.|