An evaluation of fresh water mollusc shell sand as an adsorptive media for removing phosphorus in a constructed wetland filter.

摘要

A laboratory study was conducted to investigate the phosphorus (P) retention characteristics of granular mollusc shell media sourced from three freshwater locations in Eastern Ontario, Canada. Batch testing was undertaken to examine the effects of shell source, nominal shell size, pH and influent P concentration on P retention by the shell sands, and to investigate the treatment kinetics and P removal mechanisms of the shell sand materials. Horizontal flow column studies were performed to investigate P retention under simulated field conditions, and to evaluate the use of a solute transport model to describe P retention in a sub-surface flow constructed wetland (CW) filter.; For design purposes, column studies provide better and more realistic estimates of ultimate P retention capacity ( xm Ult ) than do isotherm tests. The 1-D solute transport model approach shows promise as a method of refining CW filter designs and estimating maintenance requirements, though a better understanding of the effects of scaling on filter hydraulics and P retention is required before a such an approach can be used. (Abstract shortened by UMI.)