ASABE Technical Library - Abstract
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A RESIDENT’S ROLE IN MINIMISING NITROGEN, PHOSPHORUS AND SALT IN DOMESTIC WASTEWATER
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org
Citation: Paper number 701P0104, . (doi: 10.13031/2013.15834)Authors: R.A. Patterson
Keywords: laundry detergents, nitrogen, phosphorus, sodicity, sodium, wastewater chemistry
The fate of nutrients in domestic wastewater systems cannot be left to the environment to
assimilate and neutralise while the residents bear no responsibility for the quality and quantity of
the waste-water they generate. Other than the quality of the input water, that may be rainwater,
treated water from a reticulated supply or groundwater, all other chemicals and solids are the
result of activities within the house and, therefore, able to be controlled or modified by changes
in individual and household behaviour.
This project reviewed the various chemical inputs to the wastewater stream from the toilet,
kitchen, bathroom and laundry and examined various methods for reducing their entry into the
wastewater stream. While some approaches required the conscious behaviour of each member of
the household, others could be manipulated during the weekly shopping trip and changes in
purchasing strategies. The concentrations of nitrogen, phosphorus and salts can be reduced
through simple, inexpensive activities. The replacement of sink strainers with micro-strainers,
removal of in-sink garbage grinders, collecting and composting of food scraps, and the recycling
of cooking oils will reduce the solids and nutrient loading on the primary treatment system.
A review of one hundred laundry detergents, cleaning agents and kitchen products was carried
out to rank the contribution each made to the wastewater concentration of nitrogen, phosphorus
and salts. Through education of the broader community and the changes to product labelling
codes to reflect the environmental benefits of informed choices, much of the excess chemical
load can be reduced. Most of the benefits can be gained at no additional cost, at no change of
convenience or lifestyle and at significant benefit to the environment, but product manufacturers
beware!