Half a century ago, the paper industry was transformed by the introduction of mineral slurries to the manufacturing process. Offering improvements in efficiency, performance, and sustainability, these same value propositions have been transferred to the water treatment market, where high quality mineral slurries are now well established as an effective solution for neutralization and pH adjustment in industrial and municipal wastewater treatment. Now Omya, a leading global manufacturer of high-quality slurries, is bringing the latest technology to the water treatment industry.
Nicholas Nelson, Director Innovation and Technical Marketing Water at Omya, says the development of mineral slurries has come a long way since those early days, but they still present challenges. “The physical properties of the materials involved and the dynamics of formulating them takes a high level of expertise. Omya has a deep understanding of the factors that make the difference, including particle size and density, viscosity control, and dosing parameters. The slurries we are producing today offer high reactivity and efficiency in application, along with unrivalled stability.”
Safe, natural solutions for industrial water treatment
The water treatment industry requires solutions for pH adjustment, acidic neutralization, and metal precipitation. Traditionally, many operators use caustic soda or lime for these applications but, as Nicholas Nelson describes, mineral slurries offer safer, more sustainable solutions. “With high energy costs and a greater focus on the environment, our customers are looking for cost-effective alternatives to traditional chemicals. We have focused on developing a range of slurries offering equal or better process performance that are easier to use, safer for operators, and produced without the high energy consumption required for manufactured chemicals.”
A good example is Omya Neutrasorb S, a ground calcium carbonate (GCC) slurry designed for bulk pH adjustment of acidic wastewaters in the chemical industry and process waters from metal finishing or manufacturing. Nicholas Nelson says customers are realizing the benefit of moving to this natural calcium carbonate product because of its high reactivity. “Omya Neutrasorb S will increase the pH of acidic wastewaters very rapidly, going from as low as 1 or 2 up to 6.5 without aeration or 8 with aeration. This means customers can use it as a direct replacement for caustic soda or powdered lime for a more sustainable solution without compromising efficiency.”
Uniquely stable milk of lime for metal precipitation
In some instances, such as the semi-conductor, automotive or galvanic industries, wastewater contains heavy metals which must be precipitated out by increasing the pH to a much higher level. Omya Neutramaxx is a calcium hydroxide (milk of lime) product which offers a robust solution for metal precipitation as well as for pH stabilization in anaerobic digesters and paper manufacturing processes. “We are seeing heavy demand for Omya Neutramaxx for two main reasons,” says Nicholas Nelson. “Firstly, there are customers who want to replace a much lower quality milk of lime with one that has greater stability and flowability. Milks of lime that are unstable settle quickly and clog tanks and pipes. As Omya Neutramaxx remains stable for up to three months without agitation, it is a game changer for many plant operators. Secondly, there are customers who are currently using caustic soda, which not only has issues with safety and sustainability, but also suffers from volatile pricing. Omya Neutramaxx is not classified as a dangerous good, and because it can be handled easily without settling, it is seen as an ideal substitute for caustic soda.”
Protecting the biological process in activated sludge
Municipal wastewater treatment plant operators have different but equally important needs. “The main focus of a municipal wastewater treatment plant is to meet water quality targets of effluent that is leaving the plant,” explains Nicholas Nelson. “For that to happen, operators must create the optimal environment in terms of alkalinity and pH to allow the effective breakdown of the natural organic content by the bacteria within in activated sludge process. This is where Omya Optical comes in. Omya Optical provides the perfect pH for the nitrifying bacteria to function, to maximize the efficiency of the operation. On top of that, the product cannot be overdosed, as any additional product added to the process will remain as solids particles, and only dissolve when needed as the pH decreases. Furthermore, the surface of the Omya Optical particles provide a nice surface for the growth of bacteria.”
Omya Optical is a high purity, natural calcium carbonate slurry that stabilizes the nitrification process, improves floc formation, reduces sludge bulking, and improves the dewatering of waste activated sludge (WAS). It provides a safer alternative to other chemicals as it can be transported, handled, and stored without special safety measures. Omya Optical is stable for up to four weeks without stirring.
High reactivity for drinking water softening and decarbonization
Mineral slurries also offer highly reactive solutions for the drinking water treatment industry. Omyalime is the most reactive milk of lime on the market, suitable for managing pH in drinking water but also for remineralization of desalinated water and even for maintaining optimal water conditions in aquaculture.
“Omyalime is produced from ultra-pure quicklime, making it highly reactive,” according to Nicholas Nelson. “It is KIWA certified for use in drinking water applications and can be dosed directly into the water stream as a replacement for sodium hydroxide. A key benefit of this product is its stability. The product remains stable in storage over the long term. This is extremely important for our customers.”
Technical support to help customers achieve the benefits
Omya is a leader in developing, manufacturing, and distributing mineral slurries, which is what sets the company apart from competitors. Nicholas Nelson concludes, “Our customers rely on us for not only high-quality slurry solutions available all around the world, but for the technical capability that goes with it. When customers work with Omya, they have access to decades of experience of solving their challenges with mineral slurries. We help them integrate our products into their processes, calculating the savings they will make both financially and in terms of carbon footprint. We want to make sure our customers realize all the benefits of mineral slurries in improving their processes and their sustainability.”