Water Treatment

Site Layout And engineering Controls

322 Views

Site Layout And engineering Controls - Water treatment Plant

Abstract

There is no doubt that, when the waste material is improperly discarded can cause considerable ecological damage even when disposed of in accord with conventionally accepted criteria, it must be recognized that it has the potential to introduce a number of hazardous species into atmosphere e.g. heavy metals, and post-combustion chlorinated species.

Waste material should be disposed of so that they don’t contaminate drainage systems, water ways and in accordance with local legislation.

It is important to control the waste disposal within Raslanuf, if not random disposal will grow and cover big area of land and it will be too difficult to control in future. 

It is time to create an organization and legislation to control the waste disposal within Raslanuf.

This report highlights the basis which should be considered and followed in scrap yard and waste disposal.

Site Layout And engineering Controls

The manner by which a hazardous waste is managed will, to a large extent, affect the health and safety of not only personnel who work at the site, but also surrounding environment at a site where evidence indicates it is needed.

Since on-site activities at hazardous waste sites usually include investigation, handling, and movement of hazardous materials; personnel, equipment, and previously uncontaminated areas may become contaminated by spilled toxic materials or harmful airborne dusts and vapors if proper control is not established and maintained.

Contaminant must be made harmless or contained and hazards must be eliminated or isolated to protect workers and others from injury, illness, or death, and to protect surrounding environments.

So, site management is related to 1) site layout, and 2) engineered controls.

Site Layout :

The manner in which the site is physically arranged and laid out to accomplish the remedial objectives is one of the most important aspects of site management.

A properly laid out and managed site, such as one having excellent materials handling operations and control over entry and exit of all personnel, equipment, and materials, can significantly increase the health and safety of personnel on-site and contribute to successful remedial actions.

 

A site must be controlled to reduce the possibility of :

1-exposure to any contaminants present.

2-their transport by personnel or equipment from the site.

The possibility of exposure or translocation of substances can be reduced or eliminated in number of ways, including :

*Setting up security and physical barriers to exclude unnecessary personnel from the general area.

*Minimizing the number of personnel and equipment on-site consistent with effective operations.

*Establish work zones within the site.

*Establish control points to regulate access to work zones.

*Conducting operations in a manner to reduce the exposure of personnel and equipment and to eliminate the potential for airborne dispersion.

*Implementing appropriate decontamination procedures.

The shape and topography of the site and existing physical facilities, such as buildings, pits, tanks, stacks of barrels, fences, roads, overhead power lines, ponds, etc., that are located on-site or adjacent to the site should be identified and mapped as part of the initial site investigation. This information is vital for planning the best physical arrangement for activities and functions at each particular site.

Similarly, information on the types and locations of existing and potential hazards should be known so that a safe layout can be accomplished. This information should be included on a site map and used as the basis for developing the master control plan.

In addition to identifying the on-site location of all waste piles, physical barriers, hazards, and special problems on site map, working areas must also be identified. Such areas are needed for sampling, staging, detoxifying, storing, processing, bulking, decontaminating, functions. Some of these activities, like detoxification and staging can take place in areas that are not free of contamination. Other activities, like storing containers of decontaminated materials or most support functions, must take place in areas that are clean and free from contamination. All such areas must be identified and considered in the site layout plan.

One key to successful site operation is total control of the entrance and exit of materials, equipment, and personnel. The site map should therefore show the location of existing and potential routes for entering and leaving the site, especially emergency access routes. Separate routes for personnel and equipment must some times be included. The site map is a very important tool to be used both in planning and in executing the control plan. It is a visual tool to compliment written plans or orders and must be updated as changes occur. Clear plastic overlays can be used to easily make changes and show current information on all posted maps.

The site map must be easily understood by all personnel and visitors if it is to be of maximum value. Every efforts should be made to assure that the information contained on the map is both current and accurate.

One recommended method to prevent or reduce the transfer of contaminants and maintain control is to delineate zones or specific areas on the site where prescribed operation occur. The site must then be operated to insure that only those operations which are prescribed occur within a designated zone. Control of access points for entrance and exit to each of the zones or specific areas is the key to site-control. Movement of personnel and equipment between zones and onto the site itself are then limited to the access points. This should help keep contaminants within specific areas on-site and thus reduce the potential for spreading contamination. Three zones or control areas are usually designated for each site, see figure (1):

*Zone 1: Exclusion Zone.

*Zone 2: Contamination Reduction Zone.

*Zone 3: support Zone.

The use of three-zone system, access control points, and exacting contamination reduction procedures provides a reasonable assurance against the translocation of contaminating substances and is highly recommended. A description of the purpose and layout of each zone follows:

Zone 1 : exclusion Zone

the exclusion zone is laid out to include all of the areas on-site where contamination is known or suspected to occur, and all of the areas where the processing of hazardous wastes is planned. The boundaries are initially established from information obtained during preliminary site investigations. Such information should include site records, visual observation indicating the presence of possible contaminants. Organic or inorganic vapors or gases, harmful particulates in air, combustible gases, and the results of water and soil samples are used as indicators of the presence of possible contaminants. Other factors to consider when locating exclusion zone boundaries include the distance needed to prevent fire or explosion from affecting personnel and equipment outside the zone.

Once the boundaries have been determined, they should be physically secured and well-defined by visible landmarks. It is recommended that physical barriers such as fences, earth-berms, ditches, or barricades be erected around this zone to designate its location and to help control access to and from it. Signs must be posted and the use of bright-colored flagging or other visual material to subsequent operations, the location of zone boundaries may be moved or modified as required to meet program, operational, or environmental changes. Zone boundaries must be made to serve the purpose of the remedial actions taking place on-site.

When there is sufficient distance between the exclusion zone boundary and the work areas within the zone to protect entering personnel from unexpected venting of materials such as during a fire or explosion, thehotlineor warning line for this zone should be established along the outer boundary of the zone. Otherwise, the hotline should be established up-wind of operations and separated from the exclusion zone by sufficient distance to account for such unexpected occurrences. It must also be marked so as to be readily recognized.

As the name implies, all personnel and equipment are to be excluded from this zone unless they have specific permission of the on-site coordinator or site manager and properly protected by the prescribed level of personnel protective equipment. Prescribed levels are based on site-specific conditions which include type of work to be done, the hazards that might be encountered, the physical condition of the workers, and environment conditions such as weather. An entry and exit point must be established at the periphery of the exclusion zone to regulate the flow of personnel and equipment into and out of the zone and to verify that the procedures established to enter and exit are followed.

Hazardous wastes at uncontrolled sites are either treated and disposed of on-site or are prepared for safe shipment to an approved disposal site. In either case, the work of opening, sampling, emptying, bulking, mixing, detoxifying, treating, solidifying, filling, staging, and associated handling of hazardous materials, is done within the exclusion zone. Liquid and solid residues from the decontamination processes located in the contamination reduction zone, and any other contaminated material from the site, are brought to the exclusion zone for treatment and disposal. If the wastes are to be properly confined so as not to spread contaminants, then all such functions must be controlled and contained within this zone.

The exclusion zone must be laid out to allow multiple operations. Some remedial functions will occur simultaneously and others will occur sequentially. For example, there may be be drum sampling, drum moving…

Zone 2 : Contamination Reduction Zone

The contamination reduction zone is laid out to surround the exclusion zone and provide a buffer or isolation area to separate contaminated areas from uncontaminated or clean areas. This zone provides transition area to assure that the physical transfer of contaminating substances on personnel and equipment does not occur, or is limited to acceptable levels. This is accomplished by a combination of factors including control of access, decontamination procedures, distance between zones, work functions, and zone restrictions.

If all on-site contamination is contained within the exclusion zone boundaries, then the contamination reduction zone will remain begin and remain a noncontaminated area. As operations proceed, the contamination reduction zone will remain free from contamination only if it is properly maintained and managed. Some minor contamination may occur, but on a relative basis, the amount of contaminants should decrease from the hotline and not be detected at the support zone boundary. Any contamination that does occur should be removed and returned to the exclusion zone for treatment.

At the boundary between the exclusion and the contamination reduction zones decontamination stations are established for personnel and equipment as required. The decontamination stations serve as control points to contain the contamination within the exclusion zone. Decontamination, outlines requirements and procedures on setting up and operating decontamination stations should be prepared and followed.

Access to the contamination reduction zone from the support zone must also be controlled. Personnel and equipment must be allowed to enter only through designated control points and only when authorized . Personnel entering the contamination reduction zone from the support zone must wear the personnel protective equipment prescribed for this zone. The decontamination area always requires some levels of protection. They should leave any contaminated protective equipment at the decontamination station when leaving the decontamination reduction zone. Personnel and equipment entering this zone from the exclusion zone will go through the decontamination stations and will leave all contaminated equipment and clothing at the stations. They must still mention the specified level of protection required for this zone while passing to the support zone.

This means that the control or safety plan must address all activities and functions that take place at remedial site and prescribe the personnel protective equipment that will be used for each activity or function. The planning and execution of the plan to assure compliance are important steps to ensure that the operation will be conducted safely commensurate with the actual problems of each function or activity.

Zone 3 : support Zone

The support zone is located in clean or noncontaminated areas outside of the contamination reduction zone (see figure 1), usually in the outermost portions of the site and sometimes in areas separated from the site. The support zone is generally located within established site security perimeter, however some support activities such as personnel vehicle storage and some emergency care facilities may be located outside of the security perimeter. Since support functions may be located in several different parts of the site, security must be mentioned at required areas of the support zone.

Support functions such as the command post, equipment trailer, equipment storage, or first aid facilities cannot ore are not located elsewhere, but only indicates that the support zone is set up to provide support functions in a clean area.

The location of the command post and other support facilities in the support zone depends on a number of factors. They include ;

-accessibility, topography, open space available, location of highways, or other limitations.

-Wind direction, preferably the support zone facilities should be located up-wind of the exclusion zone. Shifts in wind direction and other conditions may dictate that the initial selection of certain support functions was not correct and they may have to be moved to a greater distance from work areas than was originally anticipated.

-resources such as telephone and power lines, water, adequate roads for moving materials and equipment, and shelter.

Other functions that may be located in the support zone include the communication area, the staging area for supplies and equipment, a wind direction indicator visible to all.

The location and operation of all functions at such sites is dictated largely by what the function does or is supposed to do. If it is a clean operation or must be kept clean, it should be located in the support zone. If it is an operation that involves sampling or handling of contaminated materials it should be located in either the exclusion zone or contamination reduction zone.

Area Dimensions

The distance between various on-site functions must all be sit-specific. The size of each zone or work area must also be based on the conditions at each site and not on some standard formula. Considerable judgment is needed to assure that the distances between zone boundaries and distances between activities within zones are large enough to provide room for the necessary operations. The distances must also be great enough to prevent the spread of contaminants and eliminate or significantly reduce the possibility of injury due to explosion or fire.

Contamination Control

The on-site coordinator is responsible for control of all on-site activities. The safety officer only assists, but should have the authority to stop the operation if it is found to be life-threatening .

A site will only be as safe as those who are in control are willing to make it, and contamination will only be contained if control measures are planned and implemented.

Procedures must be established to assure that the clean zone remains clean. This is done through utilizing proper clean-up and mitigation methods in the exclusion zone and proper decontamination methods in the contamination reduction zone. It is also done by controlling entrances and exits of all zones as indicated earlier, and in providing the facilities and separation necessary to safely accomplish the work.

-----------------
About Author: Ahmed Eltayef is an Operation Engineer (Technical Coordinator) at Qatar Petroleum (QP) Qatar. He has more than 20 years of experience in petrochemical complex operation and cooling water systems process. He has wide experience in Oil and Gas companies operations including plant projects and studies, planning and scheduling, management reporting, manpower planning, strategic planning, corporate plans / business plans, systems and procedures, QMS, contracts, budgets, coordination with existing / new customers etc. His other articles can be seen here 
Support
Please feel free to submit your feedback below
Feedback

CAPTCHA
Image CAPTCHA
Enter the characters shown in the image.