Environmental Fate and Effects of Cleaning Product Ingredients in Graywater

Household graywater is reused as a means to conserve potable water and to reduce demands on wastewater treatment. Although there are numerous definitions of graywater, a common definition is wastewater generated in the household, excluding toilet wastes, and including wastewater from bathroom sinks, baths, showers, laundry facilities, and in some instances kitchens.

The number of households using graywater is unknown. Estimates of graywater reuse in California have varied from 5-40% of all households. Of those households using graywater, irrigation and direct discharge to soil are the most likely reuse scenarios. Currently, the state of California recommends a graywater system design for irrigation consisting of filtration and below surface distribution. However, the most common reuse of graywater is probably the direct discharge of household laundry waste directly to soil through a garden hose and attached nylon filter. The second most likely reuse scenario for graywater is toilet flushing. Cleaning product ingredients in graywater are not mixed with domestic sewage and therefore are not exposed to the removal processes in domestic sewage treatment systems, such as sorption and biodegradation before discharge to the environment, except when reused for toilet flushing. Since the current trends in graywater reuse appear to be direct discharge to soil and below surface irrigation, the evaluation of graywater in this report focuses on fate and effects in soil.

The composition of graywater is variable and contains a mixture of cleaning product ingredients and other household waste. The concentration of cleaning product ingredients in graywater is estimated to be 2x higher than in domestic sewage.

Based on information obtained for this report, an identified priority data gap is quantitative information on the production, reuse, and discharge of graywater by regions of the United States. The following constituents of graywater also are identified as constituents of environmental interest. These constituents are microorganisms, salts, boron, hypochlorite, organics, and nutrients. Based on climatic data and soil types, 10 water resource regions have been identified as likely candidates for high graywater reuse. This position is supported by significant government activity related to graywater in these regions. Three water resource regions have been identified as potential areas of concern for increased salt and boron concentrations in soils irrigated with graywater (Rio Grande, Upper Colorado, and Lower Colorado). The primary issues and priority data needs related to graywater and the constituents of graywater are further identified and discussed in this report.

Investigation of an Onsite Wastewater Treatment System (OWTS) in Sandy Soil: Part 1: Site Characterization and Fate of Anionic and Nonionic Surfactants

This study reports on the fate of linear alkylbenzene sulfonate, alcohol ethoxylate, and alcohol ether sulfate surfactants in a home septic system near Jacksonville (FL, USA) that has been used since 1976.

Investigation of an Onsite Wastewater Treatment System (OWTS) in a Sandy Soil: Part 3: Predictive Model for Cleaning Product Ingredients

Field monitoring data for three common laundry detergent surfactants were used to test the applicability of a mathematical model that was developed as a screening-level tool for predicting the fate and transport of consumer product ingredients in septic systems.

"

Calculation of Component Chemical Air Emission Factors - Executive Summary

The documents provide an estimate of emissions of seven compounds found in consumer products. These products contain these compounds of interest: isopropyl alcohol, ethanol, methanol, ethylene glycol monobutyl ether, propylene glycol, dipropylene glycol methyl ether, and monoethanolamine. The emission estimates presented were prepared in a systematic and scientific manner using EPA and CARB methodologies. All methodologies provide conservative estimates (overestimation) and should be considered worst case system emissions. The results presented in this report are intended for use in developing regional air emission inventories to establish regulatory priorities."

Calculation of Component Chemical Air Emission Factors: Part II - Emissions from Wastewater Collection and Treatment Systems

Air emission factors are presented for isopropyl alcohol, ethanol, methanol, ethylene glycol monobutyl ether, propylene glycol, dipropylene glycol methyl ether, and monoethanolamine for losses to atmosphere in wastewater collection and treatment systems. For collection systems an equilibrium approach based on a CARB prototype collection system was used. For wastewater treatment plants, the methodology documented in EPA-453/R-94-080A was used. Emission factors (for the complete collection and treatment system) ranged from 2.27% for isopropyl alcohol to 0.0047% for monoethanolamine. These emission factors represent the percent of the material emitted to atmosphere of the original mass of material entering the wastewater system.