What is a RUCK® System?

A RUCK® System is a denitrifying septic system.

What are the major components?

A Traditional RUCK® system is made up of a traditional Title 5 system with an added RUCK® filter, a carbon source unit, a second septic tank and necessary piping and venting.

Why is nitrogen a constituent of concern?

The final constituent of nitrogen reaching the groundwater from on site wastewater disposal systems is nitrate nitrogen. This dissolved form of nitrogen moves readily through the soil with only diffusion providing mitigation of its concentration. In estuarine environments, nitrate is a fertilizer. Excess concentrations of nitrate nitrogen will cause algae blooms, which lead to rapid eutrophication of estuarine systems such as salt-water ponds, harbors and estuaries. Critical concentrations of nitrate nitrogen in certain coastal ponds in Falmouth were determined to be at 0.32 milligrams per liter (mg/l) or PPM (parts per million) in the salt water. The nitrogen loading for each marine system is different based on the particular flushing, shape and depth of the coastal embayment. In general, nitrogen concentrations in groundwater were draining into marine embayments. There only has to be a fraction of the concentration of nitrate nitrogen to be a problem in the receiving salt waters compared to the levels of concentration of nitrate nitrogen that causes a potential for health risks.

The EPA has established a maximum contaminant level of 10 PPM of nitrate nitrogen for drinking water. The Massachusetts DEP has established a total maximum daily load (TMDL) for nitrogen in several estuarian embayments.

What forms of nitrogen exist in wastewater?

Organic nitrogen




What is organic nitrogen?

Organic Nitrogen is nitrogen bound up in the cell walls of the biomass in wastewater.

What is ammonia?

Ammonia is the primary constituent of nitrogen emitted by humans in urine. The formula for urine is NH<sub>3</sub> or NH<sub>4</sub>.

What is nitrite?

Nitrite is an intermediate form of nitrogen and is an unstable compound in the oxidation of ammonia.

What is nitrate?

Nitrate is the final form of oxidized ammonia. This form is stable.

Are there other forms of nitrogen?

Yes, there are many nitrogen compounds. These are the primary compounds. The nitrogen cycle is very complex.

I have heard of Total Kjeldahl Nitrogen. What is it?

Total Kjeldahl Nitrogen (TKN) is a measurement that sums the concentration of Organic nitrogen and ammonia compounds in water.

How is the concentration expressed?

The concentration of all nitrogen compounds is measured in milligrams per liter or parts per million.

Is there a simplified nitrogen cycle?

Yes. View a diagram.

Describe the three steps in the simplified nitrogen cycle

Ammonification: the transformation of organic nitrogen into ammonia. This occurs in septic tanks.

Nitrification: the oxidation of ammonia into nitrite initially and then nitrate. This process takes place in an aerobic environment.

Denitrification: the conversion of nitrate into free nitrogen. This occurs in an anaerobic zone with readily available carbon.

How do these steps take place in the RUCK® system?

The wasrewater from the building flows to the first septic tank (Pre-RUCK filter.) The effluent leaving the first septic tank contains elevated concentrations of ammonia. The organic nitrogen is converted to ammonia in the first septic tank. The effluent is then pressure dosed across the top of a RUCK® filter. The RUCK® filter is a stratified, vented, modified, sand filter. The ammonia compounds are oxidized by bacteria into nitrite initially and then into nitrate. The effluent from the RUCK® filter then flows to the second septic tank (Post-RUCK filterk). There, bacteria convert the nitrate into free nitrogen gas that is vented into the atmosphere. A carbon source, Micro C is mixed with the effluent of the second septic tank to provide an electron donor for denitrification.

Is denitrification a chemical reaction?

No. The nitrogen cycle is microbial. Bacteria drive the cycle.

What happens next?

The refined effluent is discharged to a normal sized soil absorption system.

What other constituents of wastewater are removed in a RUCK® system?

A RUCK® system will store phosphorous and remove pathogens.

What is the removal rate for phosphorous?

Over a four-year test, a RUCK® system in East Falmouth removed 64% of the phosphorus.

What is the removal rate for pathogens?

The removal rate for fecal coliforms ranges from 98% to 99.9996%.

What is unique about the RUCK® filter?

Indrains, a proprietary venting material, are installed in the alternating sand layers to provide greater hydraulic efficiency and promote aerobic conditions in the RUCK® filter. Without the Indrains, the size of the RUCK® filter would have to be much larger.

How is a RUCK® system constructed?

The RUCK® filter is constructed in layers inside a landfill liner. At the bottom of the RUCK® filter is a collection layer composed of crushed stone. The bottom of the filter is sloped to accommodate a collection pipe. Above the collection layer is a twelve-inch layer of sand, then a two-inch layer of crushed stone, then a twelve-inch layer of sand then a two-inch layer of crushed stone, then a twelve-inch layer of sand, then a layer of crushed stone where the effluent is dosed across the top of the filter.

There are vent pipes installed in the vent layers with two vertical pipes installed. One three feet above the ground elevation and one elevated to a roof top elevation. This change in elevation promotes a chimney effect to heighten the capability of the aerobic condition.

How is the filter designed?

The top surface of the filter is proportional to the expected flow. The design of the filter is based on the expected BOD and TSS of the flow. For residential systems, we use standardized areas.

Who owns the designs?

Rein Leak Ph.D. invented RUCK® systems. IRUCKS has an exclusive license to design RUCK® Systems. IRUCKS owns the General Use Certificate for RUCK® Systems in Massachusetts. IRUCKS must conform to DEP requirements for the General Use Certificate.

What does a RUCK® system design include?

At least seven copies of the plans, seven booklets which include copies of the General Use Certificate, copies of a letter clarifying the General Use Certificate, specifications, maintenance agreement and a homeowners information sheet.

View a Typical RUCK® System Layout.