ISDS 



process internally. Although the Task Force Report has been circulated under public notice 

 requirements, and by request, it has not as yet been published for widespread public 

 review and evaluation. 



The flndings and recommendations of the Task Force are strongly 

 supported by the flndings of the present research effort, and are supported 

 by the recommendations presented below. The Task Force Report, and 

 attached sets of Subcommittee reports, recommendations, and references, 

 should be considered an essential planning and analytical tool for 

 communities addressing ISDS issues. 



In order to make this valuable planning resource widely available, the fiill Final Report 

 and all Subcommittee Reports should be published in their entirety by DEM and distributed 

 to town officials, building inspectors, and interested citizens. To enhance the accessibility 

 of the Task Force findings and other materials for the use of local officials and project 

 designers, the data should also be organized into a set of tables which could easily be 

 displayed, referenced, or used in the field. 



ISDS AS POLLUTANT SOURCES: ISSUES OF CONCERN 



ISDS pollutant classes of concem, and their effects, are summarized in the following 

 sections. 



Non-Conventional Pollutants 



A 1980 EPA repon identified a total of 23 priority pollutants contained in household 

 wastewater which arc likely to enter septic systems due to disposal of many commonly 

 used household products. In addition to wastewater disposal soiuces, several potentially 

 toxic substances are introduced through the use of septic system cleaners. 



According to data assembled by the State of Connecticut and reported by the ISDS Task 

 Force, two out of three of the types of septic cleaners commonly available are ineffective, 

 and aU pose risks either to the proper functioning of the system, or to the groundwater, or 

 both. In general, additives can affect the capability of the soil to transmit effluent, causing 

 soils to flocculate, clogging leachfield Unes. Biologically-based cleaners (bacteria, 

 enzymes, yeast) are ineffective in the anaerobic environment of the system and contribute to 

 nutrient loading. Similarly, acids and bases interfere with the process of biodegradation 

 which forms the basis of the system's function, while damaging the structure of the tank. 



The third type of cleaner, containing syrithetic organic constituents, is of particular 

 concem, not only from the standpoint of original constituents, but also due to the chemical 

 byproducts of anaerobic reactions in the tank. Of the organic solvents contained in these 

 septic system cleaners, several, including known carcinogens, have been found to present 

 significant health risk to humans exposed at extremely low pan-per-billion levels. Studies 

 conducted in Connecticut and New York have clearly linked use of system cleaners with 

 groundwater contamination, using key contaminants of significance. 



Experimental studies suggest that organics are very ineffectively treated during typical 

 septic tank retention periods. DeWalle et al. (1983) and Tomson et al. (1984 ) sampled and 

 analyzed constituents of distribution boxes and groundwater affected by effluent. Trace 

 levels of several priority pollutants were identified, leading the authors to conclude that 



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