Septic system design alternatives for sandy soils where percolation rate is too fast for normal soil treatment of septic effluent.

This article includes a master list (links at the ARTICLE INDEX the bottom of this article ) of all alternative septic system designs for difficult building sites such as wet sites, steep sites, rocky sites, limited space, bad soils with no percolation or sandy soils with too fast percolation, sites close to a lake, river or stream, and other difficult site conditions.

Sandy Soil or Beachfront Property Septic System Designs

Here we discuss options for building an acceptable private onsite septic system at beach properties or other areas of sandy soils where the soil percolation rate is too fast for a conventional septic tank and drainfield.

Question: what's the best septic system for beach properties?

2019/04/22 Lucy O'Bryon said:

Which is the best septic system for beach properties?

This Q&A were posted originally at HOME BUYERS GUIDE to SEPTIC SYSTEMS

Reply:

Lucy

That's a great question: best septic system for beachfront properties.

In my OPINION most conventional septic systems may not work properly in a totally-sandy-soil environment. A "septic system" at my parents home at Virginia Beach (8106 Ocean Front) in the 1960s "worked" fine as far as my dad was concerned: the wastewater disposal was successful through a cesspool dug close to the house.

However given the extremely-fast percolation rate of the sand it is unlikely that much successful biological (bacterial) treatment was happening.

Here's a "rule of thumb" about percolation rates for septic drainfield designs:

If it takes less than 5 minutes for the water to drop 1 inch in a saturated hole, the effluent will move too rapidly to be treated properly, such as in sandy soil.

In addition the seasonal high water table probably flooded the cesspool area or at least its lower segment.

Furthermore, cesspools, common in that area at the time, are so deep as to be mostly anaerobic - so their treatment of sewage pathogens is rather limited - or I'd say ineffective.

More likely we were more-or-less peeing into the ocean. (Dad would have argued that dilution was the solution but I'm not sure modern health authorities would agree).

In fact experts have documented environmental contamination by nitrates and viruses from such now-antiquated beachfront septic cesspools. We include example research citations for sandy soil septic systems below.

Septic System Designs for Beach Properties & Sandy Soils

So where does that leave us? The best septic system designs for a sandy beach property might include:

1. Recirculating Sand Bed Filter Septic System - with post treatment disinfection -

see SAND BED SEPTIC SYSTEMS

Also
see MEDIA FILTER SEPTIC SYSTEMS inspectapedia.com/septic/Septic_Media_Filters.php

2. Aerobic septic systems - perhaps a first choice, combined with a post treatment disinfection system.

- see AEROBIC SEPTIC SYSTEMS, ATUs

or depending on what soils and fill are available,

Mound systems or raised bed septic systems

MOUND SEPTIC SYSTEMS

and
RAISED BED SEPTIC SYSTEMS

Onsite mini wastewater treatment systems suitable when there is limited space or unacceptable distance to a body of water or a well are discussed separately

at PACKAGED ONSITE RESIDENTIAL SEPTIC TREATMENT SYSTEMS

Sand Bed Septic Design Regulations & Research

Some of the research cited here explains difficulties in even measuring the percolation rate in sandy soils. ( Barbarick 1976).

• Alexander, Earl B. "Net primary productivity of some California soils compared to those of the Santa Catalina Mountains, Arizona." In Proceedings of the symposium on dynamics and management of Mediterranean type ecosystems (Ed by CE Conrad & WC Oechel), pp. 339-344. 1982. Retrieved from U.S. Forest Service 2019/04/24 original source: https://www.fs.fed.us/psw/publications/documents/psw_gtr058/psw_gtr058_4a_alexander.pdf
• Aravena, Ramon, M. L. Evans, and John A. Cherry. "Stable isotopes of oxygen and nitrogen in source identification of nitrate from septic systems." Groundwater 31, no. 2 (1993): 180-186.
• Barbarick, K. A., A. W. Warrick, and D. F. Post. Percolation tests for septic tank suitability in southern Arizona soils [PDF] Journal of Soil and Water Conservation (USA) (1976). Retrieved from UA Libraries
  Abstract Excerpt:
  
  The percolation rates of nine typical southern Arizona soils varied from 1,75 to 21,5 cm/hr. By use of linear regression, it was determined that a significant linear relationship exists between test hole diameter and percolation rate on Pima cl, Gila vfsl, and Valencia sl soils.
  
  Comparison of rates in 10 and 30 cm diameter test holes indicated tha trates in 10 cm holes were 2,3 times greater than those in 30 cm holes.
  
  Very significant correlations were found between percent sand and clay in subsoil and percolation rates, and a significant correlation was discovered between percent silt in subsoil and measured rates.
  
  By use of existing mathematical theories utilizing matric flux potential, infiltration from point or line sources were used to simulate flow from cylindrical holes or absorption trenches, respectively.
  
  A technique to relate percolation rate to actual flow rates in absorption trenches was established but believed to need improvement.
  
  An attempt to assign a value of alpha to three soils proved to be very difficult usingthe proposed technique.
• Bauman, Bruce John, Soil suitability for on-site sewage treatment in the Flathead Valley, Montana: soil permeability, variability, and ground-water contamination [PDF] PhD diss., Montana State University-Bozeman, College of Agriculture, 1985.
  Abstract & Excerpts:
  
  A field study of in situ soil hydraulic conductivity was conducted in the Flathead Valley of northwestern Montana. Of special interest was interpretation of soil properties in terms of suitability for on-site sewage treatment systems. Thirteen sites were selected, soil profiles described and sampled, and the gypsum crust method used to determine hydraulic conductivity at saturation and in the near-saturation range.
  
  Multivariate statistical techniques were employed for data analysis. Results suggest that soil water movement is strongly influenced by the vertical variability (textural stratification) often noted in soil profiles in the study area.
  
  Complex glacial and proglacial depositional environments are responsible for this variability, which is. also strongly expressed horizontally as lateral variation across the landscape.
  
  Soils formed from similar parent materials (and/or with similar textural properties) generally exhibit similar hydraulic characteristics in the saturated and near-saturated range. Substantial variability within these groups is not uncommon.
• Bender, William Harold. Soils and septic tanks. No. 349. Soil Conservation Service, US Department of Agriculture, 1971.
• Bicki, T. J., and R. B. Brown. "ON-SITE SEWAGE DISPOSAL: THE IMPORTANCE OF THE WET SEASON WATER TABLE." [PDF] Journal of Environmental Health 52, no. 5 (1990): 277-279.
• Cogger, C. G., L. M. Hajjar, C. L. Moe, and M. D. Sobsey. "Septic system performance on a coastal barrier island." Journal of Environmental Quality 17, no. 3 (1988): 401-408.
• McGeorge, William Thomas. FACTORS INFLUENCING THE AVAILABILITY OF NATIVE SOIL PHOSPHATE AND PHOSPHATE FERTILIZERS IN ARIZONA SOILSs [PDF] College of Agriculture, University of Arizona (Tucson, AZ), 1939. Retrieved from U.A. archived 2019/04/24
• New York - Appendix 75-A.9 - ALTERNATIVE SEPTIC SYSTEMS [Regulation and System Design Criteria for Raised Septic Systems, Septic Mound Systems, Intermittent Sand Filter Bed Systems, Evaporation-Transpiration Septic Systems, Evaporation-Transpiration Absorption Septic Systems, and Other Alternative Septic Systems] Effective Date: 12/01/1990
• Ohio - SAND MOUND SEPTIC DESIGN SPECIFICATIONS [PDF] retrieved 2017/10/20, original source: http://www.odh.ohio.gov/
• Ohio - SEPTIC SEPARATION from SEASONAL HIGH WATER LEVEL [PDF] Drainage to manage the level of seasonal water in soils
• Paige, G. B., and P. L. M. Veneman. "Percolation Tests and Hydraulic Conductivity." Soil Horizons 34, no. 1 (1993): 1-3.
• Vaughn, James M., Edward F. Landry, and McHarrell Z. Thomas. "Entrainment of viruses from septic tank leach fields through a shallow, sandy soil aquifer." Appl. Environ. Microbiol. 45, no. 5 (1983): 1474-1480.
• Harman, J., W. D. Robertson, J. A. Cherry, and L. Zanini. "Impacts on a sand aquifer from an old septic system: nitrate and phosphate." Groundwater 34, no. 6 (1996): 1105-1114.
• Scandura, J. E., and M. D. Sobsey. "Viral and bacterial contamination of groundwater from on-site sewage treatment systems." Water Science and Technology 35, no. 11-12 (1997): 141-146.
• SOILS SUITABLE for SEPTIc SYSTEMS - an oldie but goodie from USDA, - original source: naldc.nal.usda.gov/download/CAT87210392/PDF
• TEST PIT PREPARATION for Onsite Sewage Evaluations, State of Oregon Department of Environmental Quality, Portland OR, 800 452-4011. PDF document. We recommend this excellent document that offers detail about soil perc tests, deep hole tests, safety, and septic design. Readers should also see SEPTIC SOIL & PERC TESTS and for testing an existing septic system, also see Dye Tests
• Whelan, B. R., and N. J. Barrow. "The movement of septic tank effluent through sandy soils near Perth. II. Movement of phosphorus." Soil Research 22, no. 3 (1984): 293-302.
  Abstract:
  
  The potential of seven septic tank installations in the Perth (Western Australia) metropolitan area to contribute phosphate to the groundwater was investigated. The phosphate concentration in the soil solution below the soak wells and leach drains was measured using immiscible displacement and compared with the phosphate concentration of the water flowing into the systems.
  
  The phosphate sorbing properties of the subsoils were measured, and these were found to vary up to 100-fold within the same profile. A very strong correlation was established between a laboratory measure of the ability of the soil to sorb phosphate and the phosphate sorbed in the soil profile below leach drains and soak wells.
  
  The correlation held only for those systems for which little further phosphate was removed by reaction with the soil, and the phosphate in the soil solution was at or near the same concentration as the phosphate in the effluent.
  
  For a system receiving water from the bathroom, laundry and kitchen the phosphate concentration was as low as 8 µg P/ml. For a system receiving water from a toilet only, the concentration was as high as 29 µg P/ml. In systems receiving water from both sources the values were intermediate.
  
  For systems that had been installed for more than a few years, the concentration of phosphorus in the soil water down to 6 m below the soak well and leach drain was similar to that in the effluent being discharged into the soil.

...

Continue reading  at AEROBIC SEPTIC SYSTEMS, ATUs or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Sandy Soil Septic System Articles

• AEROBIC SEPTIC SYSTEMS, ATUs - home
• SEPTIC CONSULTANTS, DESIGNERS, ENGINEERS
• BAT MEDIA SEPTIC PLANTS
• BED the SEWER LINE in SAND
• MEDIA FILTER SEPTIC SYSTEMS - home
• SAND BED SEPTIC SYSTEMS
• SAND SEPTIC MEDIA FILTERS
• SAND FILTER SEPTIC DESIGN SPECIFICATIONS
• SANDY SOIL SEPTIC DESIGNS
• SEPTIC MEDIA FILTER CAPACITY & MAINTENANCE
• SEPTIC MEDIA FILTER SOURCE LIST
• SEPTIC MEDIA FILTER SYSTEM OPERATION
• SEPTIC SYSTEM DESIGN ALTERNATIVES - home
• SEPTIC SYSTEM DESIGN BASICS - home
• ALTERNATIVE DESIGN SEPTIC SYSTEM SUPPLIERS
• TYPES OF SEPTIC SYSTEMS - master list

Suggested citation for this web page

SANDY SOIL SEPTIC DESIGNS - home at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to SEPTIC SYSTEMS

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