Quantifying Airflow Passively Generated by the Differential Venting of Onsite Systems

Abstract. As practitioners of onsite wastewater contemplate the opportunity of providing reclaimed water, this paper tries to remind them of what is unique about onsite systems. Onsite systems are appreciated for their cost-effective simplicity and ease of maintenance. These attributes are a result of seeking out passive and natural processes for treatment unit processes whenever possible. Passive components described in detail in the paper are septic tanks, bell siphons, gravity-fed soil absorption systems, soil capillarity and differential venting. Field data from Florida and New Hampshire document the improvement in air flow with the Presby Advanced Envrio-Septic^® system using differential venting. Onsite system designers are encouraged to confirm that every active unit process employed in their design is required to achieve the desired outcome while simultaneously considering the cost-effectiveness of the system for the consumer.