HOW IS SiC MADE?
Silicon carbide as a material is called upon to perform some pretty difficult tasks From armored vests to high-performance brakes, silicon carbide is used when all others have failed – makes sense to use it for membranes, doesn’t it?
SILICON CARBIDE (SiC) POWDER
Mixed into paste & extruded
Extrusion fired @ >2.200 oC to bond SiC grains
Applied to substrate
SiC ceramic plate
SiC flat sheet membrane
Silicon carbide (SiC) powder is first mixed into a paste and extruded to form the membrane substrate. The substrate is fired at over 2,000 oC to permanently bond the SiC grains to one another. After firing, the substrate is coated with another layer of SiC powder to form the micropores of the SiC membrane. Once coated the substrate is fired again to form a monolithic membrane plate. SiC plates are assembled into modules with the number of plates varying depending on module type and configuration. SiC modules are assembled on top of one another to form stacks or towers. All this is will be done right here in the Ovivo-owned factory in Texas in 2023.
HOW DOES SiC OPERATE?
Solids, pathogens, and other contaminants are blocked by the membrane pores and are retained on the surface. Periodically, water is reversed back through the membranes to dislodge and remove solids that have accumulated on the surface. In some applications, air is bubbled up in between plates to provide a scouring action which further helps keep the membrane clean. Various types of spray washes can be employed to quickly and effectively remove solids from the membrane surface. While this regeneration procedure may sound quite normal for a membrane, SiC is far superior to all others.
WHERE IS SiC USED?
DID YOU KNOW?
Simply put, SiC is resilient. SiC creates new opportunities and solves new problems. SiC Resilience lowers treatment cost. SiC Resilience makes it easier to operate. SiC Resilience has limitless possibilities.
Bottom line is that conventional polymeric membranes lack resilience creating a narrow window of operation. Stray from that window and polymeric membranes can fail and we have all seen that firsthand. Life isn’t perfect and neither is water & wastewater treatment. Process upsets happen. Operational deviations happen. Equipment failures happen. Resilience is a must!
No longer do plant owners have to pay the ultimate price because conditions aren’t perfect. Plant owners now have access to membranes that can respond, without failure, to changing environments no matter how extreme. They now have SiC.
A truly resilient membrane can only be achieved by completely changing the membrane material itself. Polymeric membranes are derived from petroleum oil. SiC is derived from sand. One doesn’t have to be a membrane expert to understand the difference between those materials. With a step change in membrane material, a much wider operational window can be achieved allowing systems to be truly resilient.
It’s true SiC has some pretty impressive properties and operational capabilities. Capabilities such as complete recovery after cleaning, indefinite dry storage, high solids tolerance, resistance to coarse material, and pressure washing capabilities are some of the many capabilities that make life easier for our customers. We even unintentionally froze SiC solid during a pilot study. While the pumps, pipes, and instruments broke, SiC was completely fine.
What are the true costs of a water or wastewater treatment plant? True costs consists of many factors, but for some reason the cost per square foot of membrane gets all the attention, which makes zero sense.
There are costs to construct a plant. There are costs to buy equipment. There are costs to operate a plant. There are costs to expand a plant. There are costs to go in at two in the morning to prevent or correct upsets during a storm. When you think about, the cost per square foot of a membrane pales in comparison to everything else.
Membranes suppliers just want engineers and municipalities to focus on the cost per square foot. They have trained the entire market that this is the only metric you should care about. Nonsense.
Based on this singular metric, membrane suppliers push the limits to see who can operate at the highest flux. Membrane suppliers push the limits of manufacturing to see who can produce a square foot of membrane at the lowest cost. This creates an environment where jobs are won and sold based on who can make a piece of plastic the cheapest and who can convince their customers to operate with the lowest safety factor. They push all the burden to operations. The many difficulties and challenges in operating membrane plants today clearly are the result of this myopic view.
We all know that this is the wrong approach. So let’s change it! Let’s make sure our customers view their plant holistically – and completely. We need to remind them – or even teach them – about the true costs of ownership where the real pain points are. Only SiC allows you to do this.
Let’s not fear this fact: SiC is currently more expensive to make per square foot of membrane compared to polymerics. SiC outperforms polymeric membranes in almost every category but their high cost has slowed market adaptation. However, due to their high flux (small footprint) and longer membrane life, SiC is surprisingly competitive on a dollar per gallon basis. As manufacturing is scaled up to similar volumes as polymeric membranes and the next generation of products are released, the cost of SiC will become even more competitive giving it a significant advantage over polymerics.