Septic systems

At Cape Cod, USA, a study was carried out by Rudel et al. [18] to investigate the impact of septic systems as a source of APEOs and their degradation products to ground water. In this study NP was detected in all sewage samples at concentrations above 1000 pg L 1. In ground water downgradient of an infiltration bed for secondary treated effluent, NP and OP and ethoxylates were present at about 30 pg L NPEiC and NP/0P(E0)4 were detected in some drinking water wells at concentrations up to 33 pg L-1. 

Behaviour of surfactants in soil after infiltration from septic systems and sewage-infiltration ponds and from surface waters... 

Direct infiltration of (treated) wastewater through sand beds and infiltration of sewage water from laundry ponds or septic systems are among the major contamination sources of surfactants into subsurface and groundwaters. Most studies published on this issue were released by research groups from the USA where these treatment techniques have found some use (Table 6.7.3). 

As an industrial and commercial product, PVA is valued for its solubility and biodegradability, which contributes to its very low environmental impact. Several microorganisms ubiquitous in artificial and natural environments — such as septic systems, landfills, compost and soil — have been identified and they are able to degrade PVA through enzymatic processes. 

The generator must meet the concentration limits of the local sewer authority if discharging the waste to a sewer system is intended, or obtain a groundwater discharge permit from the State Division of Water Pollution Control if the generator discharges to a septic system or other groundwater disposal. If the waste or its pretreated effluent meets silver concentration limits of less than 5 mg/L of silver, the waste or the effluent is not classified as a hazardous waste. 

A mathematical model was developed for the purpose of predicting the fate and transport of down-the-drain household chemicals in septic systems. Model simulations were in good agreement with field data for the laundry detergent builders tartrate monosuccinate (TMS) and tartrate dissuccinate (TDS). The model was also independently verified with phosphate data collected from the study site. Results from this study support that this model is satisfactory as a screening level tool for predicting the fate and transport of household chemicals in septic systems. 

Evidence of the need for continuous action can be found in the massive waste treatment plants in urban areas and septic systems in rural communities. In the developed world, the problem is under nominal control, and this allows us a complacency not evident in the rest of the world. In undeveloped countries, the return of water free of nutrients and bacteria to the enviromnent is a goal to be anticipated and a luxury few can afford. 

Nitrates and phosphates are two important nutrients that have been increasing markedly in natural waters since the mid-1960s. Sources of nitrate contamination include fertilizers, discharge from sewage treatment plants, and leachate from septic systems and manure. Nitrates from fertilizers leach readily from soils, and it has been estimated that up to 40% of applied nitrates enter water sources as runoff and leachate. Fertilizer phosphates, however, tend to be absorbed or bound to soil particles, so that only 20% to 25% of applied nitrates are leached into water. Phosphate detergents are another source of phosphate, one that has received much media attention in recent years. 

Watershed types are based on the primary sources of N to each estuary. Watersheds dominated by urban N sources (e.g., point, septic, and non-point source runoff) were classified as urban, watersheds dominated by agricultural N sources (e.g., fertilization, fixation, and manure) were classified as agriculture, and watersheds dominated by atmospheric N deposition were classified as atmospheric. Effluent from sewage treatment plants in the Barnegat Bay watershed is discharged offshore sewage inputs to the Barnegat Bay estuary are from septic systems in the watershed. Modified from Castro et al. (2003). 

McAvoy, D.C., White, C.E., Moore, B.L. and Rappaport, R.A. (1994) chemical fate and transport in a domestic septic system Sorption and transport of anionic and cationic surfactants. Environ. Toxicol. Chem., 13(2), 213-21. 

Nodax has the benefit of degradation in septic systems, which offer possibilities for application in feminine hygiene products such as wipes and tampon applicators. These flushable products may exist in the form of paper coatings, fibres, films and foams. 

Walczak, M. M. Lantz, J. M. A Case on Septic Systems and Well Water Requiring In-Depth Analysis and Including Optional Laboratory Experiments, J. Chem. Educ. 2004, 81, 218-220. 

Aravena R. and Robertson W. D. (1998) Use of multiple isotope tracers to evaluate denitrification in groundwater case study of nitrate from a large-flux septic system plume. Ground Water 31, 180—186. 

Aravena R., Evans M. L., and Cherry J. A. (1993) Stable isotopes of oxygen and nitrogen in source identification of nitrate from septic systems. Ground Water ll, 180-186. 

Subsurface chemical pollutants also come from septic tanks, which are widely used for the disposal of nonindustrial wastewater in much of suburban and rural North America. The pollutants of concern from septic tanks include pathogens as well as nutrients such as nitrogen and phosphorus. Sometimes, other toxic materials are thoughtlessly disposed of via septic systems in... 

A domestic well is located 30 m upstream from a neighbor s septic system. If domestic use of water is 1000 liter/day, what is the minimum regional flow (bqa) that will just suffice to keep septic effluent from entering the well (easiest to do analytically) ... 

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