Home > Online Store

Online Store

 Infiltrative Capacity of Receiving Media as Affected by Effluent Quality, Infiltrative Surface Architecture, and Hydraulic Loading Rate
D. Ryan Walsh, Kathryn Lowe, Dr. John McCray, Dr. Robert Siegrist
Item Number: NRL2006AC-22
Shipping Weight: 0lbs. 0oz.
Price: $20.00
The operational lifetimes of onsite wastewater treatment systems are often directly related to the clogging of the infiltrative surface within the soil treatment unit. Strategies such as pretreatment prior to discharge or installation of gravelless trenches could mitigate clogging. There are economic benefits to increasing the operational lifetime of the soil treatment unit and also minimizing the area required for treatment; however, care must be taken to protect the receiving environment. A one-dimensional column study was conducted at the Colorado School of Mines to evaluate the hydraulic performance as affected by effluent quality, infiltrative surface architecture, and hydraulic loading rate. A replicated factorial design (23) was used to compare two effluent qualities (biofilter effluent and septic tank effluent), two infiltrative surface architectures (open and gravel-laden), and two hydraulic loading rates (20 cm/d and 50 cm/d). The columns were packed with a medium to coarse sand and effluent was delivered daily following a micro-dosing loading regime. Hydraulic parameters were routinely monitored over a period of 144 days including acceptance rate and ponding height. Effluent quality was monitored for parameters such as pH, organic matter, and nutrients. The columns loaded with higher quality biofilter effluent had longer times to continuous ponding (80-113 days) than the columns loaded with septic tank effluent (14-31 days). The higher quality biofilter effluent also resulted in higher final acceptance rates than septic tank effluent within columns with gravelladen infiltrative surface architecture. Open infiltrative surface architecture had higher final acceptance rates than gravel-laden within the columns loaded with septic tank effluent. Infiltrative surface architecture had less of an effect on the final acceptance rates within the columns receiving the biofilter effluent. The 20 cm/d hydraulic loading rate had higher final acceptance rates than 50 cm/d within the columns loaded with biofilter effluent.