What is an Effluent Filter?

In accordance with the revised edition of the Monroe County Sanitary Code, if your home was built and the septic tank constructed after April 1, 2001, you are required to install an effluent filter in the tank.  The filter works by prohibiting the passage of materials that may damage the long-term use of your on-site wastewater disposal system.  Many filters utilize microbial digestion to assist in filtering out harmful bacteria.  This occurs when a “biomat” of black “slime like” material builds up on the filter.  Within this biomat there are great numbers of bacteria digesting organisms that can reduce the concentrations of harmful bacteria. 

You may wish to consult with your septic installer or local septic tank supplier on the various models available.   The filter will range in price and capabilities, so choosing the right filter is an important step in helping to extend the life of your septic system. 

Assuring Septic System Maintenance Management with Wastewater Filters
By Harry L. Nurse, Jr.

Do wastewater filters solve all the maintenance management problems of conventional on-site systems?

The Spring 1996 edition of Pipeline magazine, published by National Small Flows Clearinghouse, focused on the need for management programs for on-site systems. It reported that state regulators have more confidence in centralized treatment systems than on-site systems because "they have centralized management and oversight and centralized operation and maintenance

Most industry professionals agree there are three keys to managing properly operating on-site systems. These are design, installation and maintenance.

A proper design usually encompasses environmental factors such as a site evaluation - including climatic, topographical and soil conditions, type of use - residential, commercial or industrial, nature and strength of waste, and hydraulic loading of the system.

There are on-site technologic alternatives to properly design a system for most sites. There is also enough systems design know how to determine when an on-site system should not be used. More and more states are putting management programs in place that require designers to pass specific courses and take continuing education seminars to be certified to practice on-site waste-water systems design.

This is not to say that there is complete agreement about this process and it is true many areas of the country lag behind the learning curve required to provide adequate design management. However, that is a program problem that can be solved through proper state and county codes. Good design information is available.

Just as management of the design process is the foundation on which a successful on-site system rests, a competent installation is also necessary to a properly operating system. Good installation is also dependent on training and monitoring installers to assure that the system has been constructed as it has been designed.

Whether it is an advanced design requiring the installation and setting of complex mechanical components or a conventional septic tank and drain field, the system will not provide the designed treatment unless a knowledgeable installer carefully follows the intended design. Again, many states are beginning to require training and certification of installers.

The third leg of this management puzzle is maintenance. It is by far the most difficult of the three to execute. Like designers and installers, service personnel can and should be required to be certified in the skills necessary to monitor and maintain a variety of systems. Some states have already headed down this road with more to soon follow.

The decision to service a system, that is to determine if and when it should be serviced, is usually left to the homeowner. This is the only part of the on-site program dependent on the knowledge and performance of a non-professional. This dependence on the homeowner for service of on-site systems is the greatest contributor to the reluctance of governmental jurisdictions to view economical on-site systems as an attractive alternative to expensive centralized sewer systems.

The industry's failure to provide an adequate approach for the maintenance of the most basic conventional systems has also contributed to the reluctance of states to embrace the more sophisticated on-site technologies. Aerobic treatment units are a case in point. The primary restriction on the acceptance of aerobic treatment units has been the problem of assuring long term maintenance of the system beyond the two years required under NSF Standard 40 certification. Aerobic manufacturers are reluctant to voluntarily increase their required service commitment of two years. They feel it puts them at a cost disadvantage with conventional and other on-site technologies which in most states do not have any enforceable service component.

If periodic monitoring and maintenance is needed for aerobic systems, it is certainly a need for all on-site systems whether it is the more complicated recirculating sand filter or simple conventional systems that usually only require periodic inspection and removal of septage. Although servicing of conventional systems is very straightforward and some would say down right simple, it is also critical in avoiding system failure.

This concern for maintenance management of conventional systems is voiced in seminar after seminar with repeated calls for educating the homeowner about the needs of the system. Simply writing code that says a conventional system should be inspected and serviced every three to five years is not likely to result in the homeowner, who probably doesn't even know the code exists, having the system serviced. Most homeowners have many priorities in their lives other than pumping their septic tank.

When does the homeowner have the system serviced? In seminar after seminar I have conducted, regulators and industry agree, "They have it serviced when it backs up."

Managing the homeowner is the key to managing maintenance! Now, how do we manage the homeowner? Homeowners actually do three things that compound the problem of system performance and interfere with system maintenance management. First, they put things in the tank that don't belong. Second, they hydraulically overload the system. And third, as we said previously they perform system maintenance only when the system backs up.

Depending on the homeowner to act either takes direct regulatory enforcement, which states have been reluctant to do, or depends on homeowner education - an impossibly expensive undertaking that is unlikely to dramatically change homeowner attitudes.

The answer is to manage system maintenance by requiring waste-water filters in all systems utilizing septic tanks as part of the design. Requiring wastewater filters on the outlet of septic tanks manages the homeowner!

If the homeowner discards inappropriate material in the tank, the filter keeps it in the tank. Sanitary products, hair and cigarette butts will also be contained in the tank. If bleach or some other caustic material is discarded, the filter will not remove the offending agent. However, it will protect the field from the excess solids until the tank recovers. If grease is put in the tank, the filter will keep most of the grease out of the field.

If the homeowner overloads the hydraulic flow, not allowing the normal 24 hour retention time, the filter protects the field from solids carryover exacerbated by the flow.

Finally, if the homeowner has maintenance performed only when the system backs up, the filter will protect the field and slow the system down which assures system maintenance before there is a system failure.

Does this mean the system works fine one day and plugs the next causing a messy problem for the homeowner? No! All Zabel filters are designed with a bypass when the body of the filter plugs.

Does the bypass allow unfiltered material to leave the tank? No! The material rises over the outside of the filter, approximately four inches above the outlet invert, causing a gentle slowing of the waste system. The effluent exits through the normal outlet after it has been filtered through the clean reserve portion of the filter.

During the period the system has slowed, the homeowner has ample opportunity and warning to have the system serviced.

Do wastewater filters solve all the maintenance management problems of on-site systems? No. It is in systems utilizing conventional septic tanks and filtered pump vaults that most benefit from this process.

Wastewater filters do not solve problems of poor sitting or poor design. They cannot correct problems caused by poor installation. When the system has been correctly designed and installed, however, the filter is the only passive system that will assure system maintenance prior to an expensive and catastrophic failure caused by overloading of suspended solids.

It will take states time to put in place the programs and training necessary to provide adequate monitoring and management of onsite wastewater system design and installation as well as systems maintenance. However, by simply requiring an inexpensive wastewater filter in every septic tank, conventional onsite systems will no longer be dependent on the homeowner's education or interest in the system's maintenance.

At a lower cost per system than any other design, installation or maintenance management program, requiring a wastewater filter in every septic tank will manage the homeowner assuring septic system maintenance in a timely manner. With conventional system maintenance assured, perhaps state regulators would be more likely to see onsite systems as an attractive and low cost alternative to expensive centralized systems.