Reliable and efficient water treatment in the offshore industry
Offshore oil and gas platforms consists of giant constructions that are used for drilling and extracting gas and oil from wells, located deep beneath the ocean floors. Depending on the location and the requirements, offshore platforms can either be floating or fixed to the ocean floor. These offshore platforms also have many onsite processing and storage facilities, as well as providing accommodation for the operating crew.
Few industry sectors are as demanding or as hazardous as the offshore industry. The offshore industry is moving forward by grasping new technologies at a faster rate than ever before. This is much thanks to the growing global demand for energy, fall of oil and gas prices, growing competition, and the tighter project budget requirements.
Due to their geographically isolated location, these platforms are designed and built to last for long periods of time in the harshest of environment and need to continuously implement and sustain maintenance-free machinery for reliable operations and minimal production down-time. These key factors can be compromised by unforeseen microbial outbreaks, corrosion of pipes and other process equipment, as well as environmentally hazardous emissions.
Creating engineering solutions for these industries requires an attention to detail and a build quality that exceeds most other applications. Mellifiq offers more than 20 years of experience in implementing advanced oxidation solutions and complementary treatment technologies that can play an integral role in managing the risks of sudden production halts. One issue that must not at any time be overlooked is the safety and health concerns of the oil platform staff.
Our goal is to always offer a more efficient and sustainable air and water treatment solution that helps you improve your business profitability and output quality. By reducing your energy use you will also automatically lower your business’s environmental impact.
Common water treatment challenges in the offshore industry.
Corrosion and clogging are hazards that occur in most engineered systems transporting or storing water. The system’s loss of efficiency and serviceability, because of corrosion and clogging, may entail expensive maintenance service measurements that could cost up to millions of euros. In fact, one of the major maintenance issues facing the offshore industry is the corrosion of the piping systems in closed water circuits such as cooling systems.
The major cause of these problems is the growth of sulfate-Reducing Bacteria (SRB). SRB convert sulfate to sulfite and hydrogen sulfide. Hydrogen sulfide causes severe corrosive attacks on pipes which require heavy maintenance and potentially cause stops in production.
Typically, these problems are counteracted by dosing large volumes of disinfectants such as hypochlorite to prevent the growth of SRB. Ozone treatment presents an alternative to the chemicals with the following benefits to the business. Ozone:
- Is 10-50 times more effective against the proliferation of SRB
- Eliminates handling, transporting and storing chemicals on oil rigs. Ozone is produced in-situ using oxygen as raw material.
- Does not cause accumulation of residual chemicals. Ozone breaks down naturally into its natural component – oxygen.
- Reduces the need for corrosion inhibitors.
- Due to residual free environment, water bleed-off can be reduced by at least 90%.
- Low maintenance. All Ozonetech ozone systems are designed to last for a long time with few mechanical parts. The system requirements and frequency of service and maintenance are low.
More information about corrosion control in cooling systems and cooling towers can be found on the application page. Typically an Ozonetech RENA Vivo B or C series ozone system should be considered for the offshore industry.
Legionella bacteria occur naturally in water from many different environmental sources, but have optimal growth at warm temperatures in stagnant conditions that can be found in engineered environments such as hot and cold water distribution systems, water plants, cooling systems and such.
Wherever there is water and pipes eventually one can find Legionella bacteria causing Legionnaires’ disease. At high enough concentrations and when inhaled, Legionella is a fatal disease in humans when not treated quickly with antibiotics.
Despite major gains in knowledge about the Legionella bacteria, its ecology, its transmission, and Legionnaires’ disease, there remains great uncertainty about how to control Legionella in water systems. Legionella outbreaks can occur in cooling systems, drinking water supply and other buffer tanks used on the oil platform.
Legionella management is a key process in order to prevent the sudden spread of infections by Legionella microbes such as L. pneumophelia. Legionella outbreaks can occur unexpectedly. Careful monitoring of various bacteria must be done to minimize the safety and health risks for humans and the environment and prevent production shutdown. human-environmental safety and health risks and production shutdown.
Mellifiq’s various ozone solutions are very effective for inactivating Legionella microbes and should be considered as a part of the risk management program employed by the offshore industry. As a disinfectant and sanitizing agent, ozone effectively oxidizes the cell walls of all microorganisms like bacteria, algae, spores and protozoa.
Biofilm and scaling prevention
Another problem that occurs in closed water systems is the buildup of biological growth over time, particles and minerals otherwise known as scale. As particles accumulate, microorganisms may find growth-enhancing surfaces. This may reduce heat exchanger efficiency and increase the spread of infections.
The way this problem has been solved in the past has been through the use of chemical agents such as chlorine and chelating agents. While this may serve as an solution to the original problem, the chemicals lead to other problems, such as water reaches a high level of chemical and contaminant concentration. To regulate this, water is bled out of the system, and replaced by fresh makeup water. This bleed-off water can be problematic to dispose of.
The Ozonetech RENA Vivo turn-key ozone system is used for aqueous ozone applications for sanitation to prevent both the growth of bacteria and the use of chemical sanitation agents. In this way, the overall scaling and biofilm effects can be significantly reduced, which will lead to a more maintenance-free operation. Ozone treatment solves the original problem with a vastly reduced number of secondary costs and considerations. As well as being a powerful biocide, killing virus and infectious bacteria, ozone has been proven to have a positive de-scaling effect.
Offshore wastewater treatment
Not only can Mellifiq’s technology be employed using ozone as an effective sanitation agent, with superior characteristics compared to other traditional chemicals, but its oxidizing effects can also be used to treat wastewater streams. This reduces the demand for on-site systems with a high footprint or hauling of waste for external treatment. This will help the industry comply with local regulations for waste handling, treatment and emission requirements.
Mellifiq provides a series of self-contained, complete disinfection solutions and water treatment technology for various sanitation tasks onboard an offshore platform. The Ozonetech RENA CIP™ system is designed to effectively disinfect water and process equipment as well as break-down and oxidation of chemical substances.
Ozone is the most efficient disinfection agent available and replaces traditional chemicals. It offers at least 20 times higher microbial inactivation potential, which means that both concentration and disinfection time can be significantly reduced. Ozone is also very gentle on materials.
The system produces ozone in-situ, and by utilizing an effective air-water mass transfer mechanism, aqueous ozone is generated on demand with extremely low operational costs. After use, the remaining active ozone quickly and naturally decomposes into oxygen, leaving no chemical byproducts behind. The produced ozone cannot be stored which significantly reduces the storage needs at the offshore platform.
Biofouling and corrosion control
Mellifiq’s ozone-based applications overcome biofouling and corrosion problems in circulating water systems thanks to the ozone’s natural oxygen decomposition properties.
- Avoid scaling and corrosion by avoiding hydrogen sulfide formation from SBR and elimination of chemical buildup.
- No pH differential which prevents corrosion.
- Preventive legionella control.
- Eliminate use of other biocides and corrosion inhibitors.
The table below shows a brief comparison of CT values for various disinfectants. Ozone oxidizes effectively organic matter and can be shown to inactivate all types of microorganisms as opposed to traditional means, without causing microbial resistance.
Table 1. CT values (mg/L.min) for 99% inactivation at 5 deg C. (WHO and JG Jacangelo, et. al.)
Brief comparison of CT values for various disinfectants
|Microorganism||Free chlorine||Preformed chloramines||Chlorine dioxide||Ozone|
|G. muris cysts||30-630||1400||7.2-18.5||1.8-2.0|
|L. pneumophelia||4||15||Data not available||0.5|
Lockheed-Martin undertook a comparison study in 1995, where a 600-ton cooling tower system was upgraded to ozone treatment and compared to previous chemical treatment where chlorine gas, biocides and corrosion inhibitors were used. See table 2 below. It was recently proved that ozone completely kills off and is several times more efficient than hypochlorite and formaldehyde – without leaving harmful residues (Akban and Iliyasu, 2015).
In addition to operational cost savings, it was reported that scaling was reduced by 90% and bacterial count was reduced thousand-fold.
Table 2. Annual operating costs after the upgrade to an ozone system, compared to chemical treatment at Lockheed-Martin, Ocala, Florida. (US Department of Energy, 1995).
Annual operating costs after the upgrade to an ozone system
|Item||Chemical treatment (USD)||Ozone treatment (USD)|
Benefits of Mellifq’s technology
Sanitation and disinfection on offshore platforms
Offshore businesses will benefit in multiple ways from Mellifiq’s treatment technology:
- Reduction of scale and corrosion formation
- Deactivation of sulfate-reducing (SBR) bacteria
- Continuous prevention of Legionella outbreaks
- Eliminating the costs of purchasing, handling, transporting, storing and discharging chemicals
- Prolonging the lifetime of the piping systems in closed water circuits such as cooling systems
- Reduced blow-off water in cooling systems
- Comply with regulation pertaining to discharge of water from cooling system blow-off
- Guaranteed sanitized drinking water supply
- Treating wastewater efficiently
- Reduced volumes for freshwater refill – minimizing water consumption
- Maintain transfer efficiency in heat exchangers
- Reducing energy costs
Mellifiq’s solutions will reduce downtime of your operation and the need for maintenance resulting in huge cost savings.
Ozonetech RENA Vivo Series
The RENA Vivo™ system is designed to effectively disinfect water and process equipment as well as removal and oxidation of chemical substances, offering the following operational enhancements:
- Eliminating all disinfection agents used for treatment or sanitation
- Reducing energy requirements by replacing chemicals with ozone sanitation
- Ensuring completely microbial free water
- No handling of chemicals, transport and costs
- Treating complex wastewater substances on site
- Chemical-free feed and process water quality assurance