An assessment of a natural wetland receiving sewage effluent

Abstract

An assesstnent of the performance of a wetland dominated by opportunistic weeds in retnoving nutrients from a secondary sewage effluent was carried out at Thredbo in Koseiusko National Park. Water quality sampling of the inflow and outflow showed a reduction in turbidity, pH and conductivity with passage through the wetland. Dissolved oxygen levels also decreased. In summer 1982, the phosphorus toad of 1.8 kgPday' was reduced by 44% as wastewater moved through the wetland, and the nitrogen load of 6.4 kgN day~' by 65%. Winter retentions were 10% and 14% of inflowing loads, respectively. In 1983 there was a net release of phosphorus and reduced retention of nitrogen. This was regarded as being a result of physical disturbance of the wetland. Vegetation downstream of the effluent inflow was dominated by the opportunistic weeds Epilobium sarmantaceum and Rumex crispus. Upstream, Carex gaudichaudiana and Baeckea gunniana dominated. Marked seasonal changes in vigour and biomass were recorded. Plants, but not sediments, downstream of the inflow contained more nutrients than those upstream. Seed bank analysis showed more seeds downstream than upstream. A moist treat-*Present address: Office of the Supervising Scientist, Alligator Rivers Region Researeh Institute, Post Office, Jabiru, NT 5796, Australia.ment promoted more seed germination than a flooded treatment. E. sarmantaceum and to a lesser e.xtent R. crispus dominated in each treatment. In an effort to promote greater water retention and replacement of the weed species, channels in the wetland have been blocked with gravel and planted with Phragmites australis and Schoenoplectus validus.

Fluid activity in the lower crust and upper mantle: mineralogical evidence bearing on the origin of amphibole and scapolite in ultramafic and mafic granulite xenoliths

“…These data suggest derivation of the xenoliths from a significant depth interval encompassing the lowermost crust and uppermost mantle by comparison with the depth to the Moho beneath cone #32 ( Fig. 7) inferred from seismic data (Finlayson, 1968;Dooley, 1980). O'Reilly and Griffin (1985) argued that the seismically defined There is some debate whether PIT estimates based on mineralogical data reflect pre-entrainment equilibrium conditions for the assemblages or past thermal or tectonic events (Fraser and Lawless, 1978;Harte et al, 1981).…”

“…Open circles with tie-lines indicate pressure estimates for felsic granulite assemblages (Newton and Haselton, 1981;Newton and Perkins, 1982) for assumed temperatures of 700 and 800 ~ Other open circles indicate temperatures calculated from coexisting garnet and biotite compositions (Ferry and Spear, 1978). The experimentally deduced stability field for the A12SiO 5 polymorphs is after Holdaway (1971), and the thick dashed line indicates the depth to the Moho beneath cone #32 from Finlayson (1968).…”

“…7) inferred from seismic data (Finlayson, 1968;Dooley, 1980). O'Reilly and Griffin (1985) argued that the seismically defined Wells (1977) and pressures using the method of Harley and Green (1982).…”

Human Impacts on Macrophyte Diversity, W Ater Quality and Some Soil Properties in the Madikane and Dufuya Wetlands of Lower Gweru, Zimbabwe

“…There was a significant difference in the water quality between Madikane and Dufuya as evidenced by the differences in nutrient concentrations of phosphorus and nitrogen. The ability to improve water quality is often high in the presence of species like Phragmites australis and Typha capensis  2011, ALÖKI Kft., Budapest, Hungary (Finalyson et al, 1986;Kadlec and Knight, 1996), which were more dominant in Madikane than in Dufuya. The high concentrations of total nitrogen recorded in water from both dambos ( Table 4) are not an unusual feature as it is a characteristic of water from peat soils.…”

Development of Indices to Predict Phosphorus Release from Wetland Soils

“…Phosphorus is one of the major nutrients that has been identified as having a direct impact on the water quality of a wetland (Bedford et al, 1999; Bollens and Ramseier, 2001; Ewel, 1976; Finlayson et al, 1986; Gusewell et al, 1998; Kadlec and Bevis, 1990; Pauli et al, 2002) and is typically the limiting nutrient for primary productivity in many freshwater systems (North American Lake Management Society, 1992). Although many of the P sorption and retention capacities of wetland soils are similar to the upland soils, there are notable differences that exist.…”