Characterising caravan and recreational vehicle wastewater from dumpsite holding tanks: possible implications for rural wastewater management

The caravan and recreational vehicle (RV) industry is rapidly expanding in Australia, with increasing use of self-contained vehicles fitted with blackwater tanks. In rural regions without sewerage infrastructure, wastewater is emptied into dumpsite holding tanks and trucked to community treatment plants. However, little is known about the quality of this wastewater. This study is the first to characterise RV dumpsite wastewater in Australia, with samples collected across three rural South Australian sites over three seasons. Compared with traditional wastewater treatment plant inlets, RV wastewater was markedly stronger: suspended solids averaged 450 mg L⁻¹ versus 105 mg L⁻¹, ammonium 1321 mg L⁻¹ versus 83.1 mg L⁻¹, nitrate 8.2 mg L⁻¹ versus 0.2 mg L⁻¹, phosphate 108.7 mg L⁻¹ versus 13.1 mg L⁻¹, and BOD5 2597 mg L⁻¹ versus 210 mg L⁻¹. E. coli abundance was similar across sites. These elevated concentrations highlight risks of hydraulic and biological stress for rural treatment systems.