Treatment of piggery effluent by an aquatic plant filter

Murray-Darling Freshwater Research Centre

MDFRC item.

The ability of Australian native water plants to treat piggery effluent was investigated at a 500-sow piggery. A field experimental treatment system comprising two 20-m trenches, trapezoidal in shape, lined with black plastic and planted with Typha domingensis and Schoenoplectus validus was established. These emergent water plants were selected after a series of growth experiments with piggery effluent in a glasshouse. A further series of comparative experiments with poultry, abattoir and winery effluent, and native and introduced floating plants, was also conducted. The floating plants were not ablt to survive in the concentrated effluents, with the winery effluent being toxic to all species. The field system operated with a 5- or 10-day retention time and was able to remove a proportion of the load of Cl, Na, K, P, COD, Kjeldahl N and suspended solids from the diluted effluent. As the outflow concentrations were still very high, the system was considered to be overloaded and not overly effective for this particular effluent. The treatment or removal that occurred was attributed to physical filtering of the effluent and not plant uptake.