Fig. 2. Time course of pH, dissolved oxygen, five-day biological oxygen demand (BOD₅), and temperature of raw wastewater input and of drainage water from aerated lysimeters (AIR) and lysimeters vented to the leachfield (LEACH). The wastewater loading rate was changed from 12 to 4 cm d^–1 on 21 Apr. 2003. Temperature was not measured on 12 Feb. 2003. Values are means (n = 3). Bars represent one standard deviation. Significant differences between AIR and LEACH treatments (P < 0.05) for a particular sampling date are indicated with an asterisk (*).