ABSTRACT

This chapter is concerned with some of the pollutants and ancillary chemicals found in treatment marshes that are not principal targets for design. Chlorine is not present in runoff waters but may be present in disinfected tertiary effluents that reach treatment marshes. Treatment marsh source water hydrogen ion concentrations are typically circumneutral, and so are the marsh effluent waters. The annual trends in marsh effluent pH are typically quite weak. Because of these weak annual trends, marsh pH behavior can be adequately described by an annual mean and the associated standard deviation. Treatment marshes may therefore be regarded as functioning at circumneutral pH, with the caveat that open water near the outlet may foster algal growth and attendant diurnal cycles of pH that include high values. Carbon compounds interact strongly with marsh ecosystems. Treatment marshes operate in a different processing environment, in which rate coefficients display seasonal dependence rather than temperature dependence.