The RUCK® System
(From Issue 4)
In the RUCK system the household's greywater (washwater) and blackwater (toilet and kitchen sink wastes) are plumbed separately and flow to separate septic tanks (Figure 1). The blackwater flows from the septic tank to the aerobic RUCK filter where it is nitrified and then flows to the anaerobic greywater septic tank for denitrification. The entire system consists of two septic tanks, the RUCK filter, and a conventional leaching facility, all of which are located below the ground surface. In some situations the system may be passive, requiring no pumps or other moving mechanical parts (unless finished effluent must be pumped up to an elevated leaching field to achieve adequate separation to groundwater).
Figure 1. Schemata of a RUCK system.
The treatment process is as follows: blackwater flows to a conventional septic tank where solids settle. The blackwater effluent then flows to the RUCK aerobic filter where it is nitrified. The RUCK filter is composed several layers of in-drains which are overlain by layers of sand and filter cloth. The in-drains are composed of the proprietary material of the RUCK system and provide air to the filter so that it remains aerobic. A schematic diagram of the RUCK filter is shown in Figure 2. The in-drain media and the sand support the growth of nitrifying bacteria. As the effluent trickles through the filter, nitrification occurs. The effluent is collected by a drain at the bottom of the RUCK filter from which it flows into the greywater septic tank. The greywater septic tank is anaerobic and the greywater provides a rich source of carbon which supports the growth of denitrifying bacteria. Denitrification of the effluent is accomplished by passive mixing of the RUCK filter-treated blackwater with the greywater in this septic tank. After treatment in this tank, finished effluent flows to the leaching facility for disposal.
DEP, in its General Approval for the RUCK system, recognizes that the system is capable of producing finished effluent with total nitrogen content of 19 mg N/L. Limited data show that the system may also be capable of approximately 50% removal of phosphorus.
As stated above, there are no moving mechanical parts so the system requires little maintenance other than periodic pumping of the blackwater septic tank. The RUCK filter is designed and sized for minimal maintenance. The RUCK system is designed to operate passively and flow by gravity. However, because of the number of separate components and the necessary drop in elevation between each component the leaching facility will be located at a relatively deep elevation. A 10 foot depth from the land surface to groundwater is required in order for the leaching facility to located deep enough to accommodate gravity flow. If a 10 foot depth to groundwater does not exist, the leaching facility will have to be raised relative to the rest of the system and the finished effluent pumped up to the leaching facility. This requires the installation of a pump chamber and pump.
Figure 2. Illlustration of RUCK filter showing the layering of media.
DEP requires that all RUCK systems be under a maintenance agreement and that a Massachusetts Certified Wastewater Operator will be responsible to oversee operation of the system. Holmes and McGrath, Inc., the designers of the RUCK system, will provide a contract for operation and maintenance. Preliminary maintenance agreements are $800.00 per year which includes $600.00 in water testing fees. DEP requires that influent and effluent from the system be monitored quarterly for pH, BOD, TSS, TKN, nitrate and ammonia.
The cost of installation of a typical RUCK system for a three and four bedroom home is approximately $7250.00 and $9250.00, respectively, above the cost of a Title 5 system. Holmes and McGrath, Inc., 200 Main Street, Falmouth, MA 02540 (800) 874-7373, are the Massachusetts licensed designers and installers of RUCK systems. Local engineers can also be licensed to design RUCK systems and local contractors can be trained to install these systems.