Riveer Environmental uses a variety of filtration technologies to achieve specific filtration goals. When selecting technologies for our systems we always keep our end user in mind. For instance, flocculating water is an excellent way to drop particulates. However, flocculants are designed to work at specific pH levels, temperatures and at specific ratios. In order to work effectively, the user must control all these parameters. We find that our customers are concerned with washing a product, not balancing pH or mixing flocculants.
Depending on your application, we use some or all of the following technologies:
In applications where there is a large volume of suspended solids in the waste stream, settling can play a large and efficient role in the filtration process. Settling can be achieved several ways. Generally the most economical is to provide a settling chamber where solids can be allowed to sink out of the water. If time or space doesn't allow for natural gravity settling, other techniques can be employed to speed the process.
Spin down separation is a common technique to speed the settling process. Centrifugal force is used to simulate gravity forcing the particles that are heavier than water out of the waste stream. This technology has limitation and can have negative effects on other elements of a complete filtration process. Your Riveer sales technician can advise if this technology is appropriate for your application. Specifications
Coalescing is the process that brings oil to the surface of the waste stream. By passing the water through a media that is oleophilic, small oil droplets in the waste water will attach to the media. As more droplets attach to the media, they grow in size to the point that their inherent buoyancy causes them to rise to the surface.
If you select and position your media properly it has the added benefit of encouraging suspended solids to drop to the bottom. This is achieved because of the sheer principal. Every time water changes directions solids in the stream fail to navigate the corner and end up falling out. This principal is easily seen in rivers where sand bars build up on corners.
Floating oil is skimmed off the surface using the same oleophilic technology that coalescing used to bring it to the surface. Because the oil is more attracted to the material of the belt than the water, it grabs on to the belt as it passes through the water and is scraped off into a reservoir that can be easily drained.
The properly designed system needs to collect and trap the oil in a location where it can be skimmed. We use a wall at the end of the coalescing chamber that the water is forced to pass under rather than over. This technique, known as an oil weir, captures all floating oil and other floating contaminants on the upstream side of this wall. This is the most efficient location for the oil skimmer.
We inject Ozone, O3, all through the system to kill bacteria* and breakdown soaps. Ozone has been recognized by the USDA as being more efficient at killing bacteria than chlorine. We generate Ozone electronically with a Corona Discharge ozone generator. This technique for killing bacteria and its associative smell is not only better than chlorine, but it requires no input from you. The water is ozonated 24/7 completely automatically.
After screening and settling solids out, we process the waste water through the first stage of our Micron Filtration. At Riveer Environmental we generally employ at least one high pressure media filter.
This filter holds 7 cubic feet of media and we typically load it with a mixture or fine gravel, sand and Zeolite. The vertical high pressure vessels we use for moderate to heavy mud loads are unbeatable for solids reduction.
Absolute
After processing the waste water through nominal filtration we take the extra step of going through absolute filtration. Where the nominal filter will allow particles to bypass the absolute will not. A 10-micron absolute filter by definition will not allow any particles large than 10-micron to pass. When this filter becomes full, it shuts the system down. Because down stream high pressure pumps are expensive and intolerant to solids, the vast majority of Riveer Environmental filtration systems have at least one absolute filter.
Carbon
Though not a micron filter, we sometimes employ carbon filters to remove VOC's (volatile organic compounds), some metals and pesticides. The carbon can be loaded either into the media vessel or into cartridge filter housings.
These filters all employ the same membrane filter technology the difference being in the tightness of the cells. Ultra filtration can be used effectively to remove water soluble oils from a waste stream. Nano filtration has proven effective at removing pesticides and Reverse Osmosis (RO) removes all salts, soaps and heavy metals.
These filters are relatively expensive to purchase and operate. However, they have applications where they can't be beat. For salt truck washing where water supplies and disposal are difficult, RO can be an integral part of the solution. In tool washing applications where synthetic high temperature oils are used, Ultra filtration can be very effective.
These filters are also used to cleanup incoming water to required washing specifications for aircraft cleaning.
Several companies are pushing bug systems in the market place. And though bugs are very effective in specific applications, they are not the panacea they are presented to be. In a typical equipment wash rack with lots of mud, bugs do nothing. However, when oil is the primary waste, bugs can be an effective component of a complete filtration system.
When evaluating your site your Riveer sales technician may suggest that bugs could be employed effectively in your application, however, in addition to the benefits to you, he will also explain the high recurring costs of bug colonies, the difficulty in keeping them alive, and their filtering limitations.
When Riveer proposes that bugs be incorporated into a filtration system, you can rest assured that all provisions will be made to insure the success of the colony through proper water management, air injection, dwell times and provisions will be made for clean-out.
Evaporation can be employed when there is no economical way to dispose of excess waste water. Forced evaporation is not very common in wash racks as natural evaporation tends to carry away enough water that fresh make-up water is added frequently. However, all closed loop systems need to be drained and cleaned periodically and this is when water disposal becomes an issue.
When large quantities of water need to be evaporated quickly, a gas powered evaporator is the best option. These can evaporate water at rates of a few gallons per hour to hundreds of gallons per hour, depending on size and power.
In some instances more passive evaporators relying on solar energy can be used. Dark colored aerated tanks can effectively evaporate large quantities of waste water over time.
Nominal
Absolute