Delivered Bulk Bleach vs OSG Bleach

Delivered Bulk Bleach vs On-Site Generated (OSG) Bleach

Water treatment is a crucial aspect of municipal water purification that helps to ensure that people have access to safe and clean drinking water. One important consideration in water treatment is the method used to deliver chlorine, which is the most common disinfectant used to kill harmful microorganisms in the water. Two methods currently utilized that are safer than gaseous chlorine are delivered bulk bleach and on-site bleach generation (OSG). While delivered bulk bleach is more commonly used, OSG has it’s own set of benefits, and there is no ‘one size fits all’ method for disinfection when it comes to water treatment. Whatever your process, both methods are highly effective, and CORECHEM can supply the chemicals needed for each. Here we compare the advantages and limitations of each method.

Delivered Bulk Bleach

Bulk Bleach Delivery

Delivered bulk bleach is a method in which a chemical supplier (such as CORECHEM) delivers liquid Sodium Hypochlorite to a water treatment facility. This bleach is concentrated and sold at an industrial strength of usually between 12 – 15%. The bleach is typically stored in large tanks, and a metering pump is used to inject the liquid Sodium Hypochlorite into the water.

Advantages of Delivered Bulk Bleach

  1. Consistent Quality: Depending on the manufacturer of the bleach, the quality of the product should be higher. CORECHEM currently distributes bleach manufactured by Olin Chlor-Alkali, one of the best chlor-alkali manufacturers in the United States. Additionally, if the bleach is purchased from a reputable chemical supplier that has a high throughput of bleach (such as CORECHEM), it will be both fresh (with minimal degradation), and it will have been tested prior to delivery to ensure that it meets specifications.
  2. Concentrated: Bleach from a chemical supplier is most often sold at between 12 – 15% concentration. This is much stronger than OSG bleach. A higher concentration will mean a lower contact time during the treatment process.
  3. Lower Upfront Cost: Liquid handling equipment must be purchased initially, but this is not as costly as purchasing the OSG manufacturing equipment.
  4. Handling & Maintenance: The plant will have to be equipped to handle the liquid chemical product, but it won’t have an entire bleach manufacturing operation on-site to be maintained as well.
  5. Ease of Operation: Delivered bulk bleach is often a readily available and reliable source of disinfection. OSG equipment may occasionally fail, and plants will have to have a “Plan B” for water disinfection in place.

Limitations of Delivered Bulk Bleach

  1. Degradation: Since bulk bleach is delivered from a chemical supplier (not produced on-site), typically the storage time at the customer’s site is longer. Delivered bleach may commonly be stored up to 30 days on-site as opposed to 1-2 days for OSG-generated bleach. The possibility of degradation, especially in warmer temperatures, must be considered. (Also, the higher concentration of delivered bulk bleach will mean a faster initial degradation rate. For more information, speak to a CORECHEM representative.)
  2. Storage/Handling of Corrosives: Concentrated bleach is corrosive and can pose greater hazards than either salt or the weaker bleach product generated via OSG. Storage and handling of the product may require additional training for employees.

On-Site Bleach Generators

On-site bleach generators produce bleach on-site using salt, water, and electricity. The process involves creating a solution of salt and water, which is then electrolyzed to produce sodium hypochlorite, the active ingredient in bleach. This bleach is often much weaker than delivered bulk bleach, coming at a typical percent of approximately 0.8%.

Advantages of On-Site Bleach Generators

  1. Control Over Chlorine Production: On-site bleach generators provide water treatment facilities with greater control over the production of chlorine. Facilities can adjust the amount of chlorine produced based on water quality and demand.
  2. Stability: Having a low-concentration bleach solution will mean less decomposition. Active chlorine in solution will be readily available.
  3. Price of Raw Materials: OSG production requires salt, a mined mineral product. In the event of economic cycles, salt pricing is far more stable than bleach pricing.
  4. Handling of Materials: Sodium Chloride (table salt) is safer to handle than concentrated Sodium Hypochlorite (bleach). Handling safer raw materials may reduce the need for hazardous materials training or other site-specific concerns.

Limitations of On-Site Bleach Generators

  1. Upfront Investment: On-site bleach generators require an upfront investment in equipment, which can be a barrier for smaller water treatment facilities.
  2. Maintenance Costs: On-site bleach generators require regular maintenance, which can be costly and time-consuming. Often, plants producing their own bleach want to regularly check the quality of bleach being produced. This may be considered a ‘soft cost’ associated with production on-site.
  3. By-Products: Hydrogen Gas is produced in the bleach manufacturing process. Hydrogen Gas quickly becomes a serious hazard if it gets into your plant, as it is highly explosive.

Both delivered bulk bleach and on-site bleach generators have their advantages and limitations, and the choice between the two methods will depend on the specific needs and resources of the water treatment facility. Delivered bulk bleach is a cost-effective and low-maintenance option that provides consistent quality, while on-site bleach generators offer greater control over chlorine production and a low-concentration solution with greater stability.

Other factors to take into consideration? Whichever disinfection method is being used, the overall space available for the necessary tanks and/or equipment should be considered from the beginning of the planning process. Also, transportation costs may vary greatly depending on the location of suppliers, manufacturers, and the end-user of the bleach or salt required for your operation. Regardless of your final choice, the team at CORECHEM is happy to discuss your bulk chemical requirements for water disinfection. Get in touch with a representative to discuss further, today!