Routine evaluation of drip distribution systems is crucial in order to keep them working as designed
Drip distribution systems have been around for over two decades, so chances are if you’re a service provider you will encounter these systems, if you have not already. The major systems out there are proprietary, so the first step is to determine which system it is and then follow the listed maintenance items according to that manufacturer. In addition, just like any other system there are some items and conditions that should be evaluated and then a course of action determined.
Here, as in any O&M situation, some of your best tools are your nose and your eyes; they can help determine if the system is operating as it is supposed to or if there is something wrong that will need attention.
Evaluate whether there are any odors around the system. If the venting and the system are operating properly there should be no odor around the headworks or in the dripfield area. If there are odors, the source should be determined. Check all of the connections in the headworks box and check the field area for missing inspection port caps or leaks out of the vacuum breakers. Check the location of the roof vent and whether there are any downdraft possibilities that result in odors coming from the roof vent, depending on wind direction. Look for the presence of tall trees near the house or any other factors that can be identified. Talk with the homeowner about whether they notice the presence of odors and if so under what conditions, and whether the odor is strong or mild.
Use your eyes to evaluate the vegetation in the dripfield area. These systems can be installed around trees and other woody vegetation. If the vegetation over the field is grass, see if the grass seems to be even in height and color as well as evenly distributed across the dripfield. If there are areas where the vegetation is not present or brown, or areas where growth seems to be particularly lush and green, check to see if there are leaks coming to the surface in those areas. In short, if vegetation across the site is not uniform the area should be investigated. In woody areas check for signs of ponding, usually indicated by dead vegetative material and organic staining at the surface.
As discussed earlier, filters to remove solids from the effluent as it is pumped to the dripfield are very important to the operation of the system. These filters need periodic cleaning, generally at least once per year. Line pressures before and after should be measured; this will indicate whether the filter is plugged. Then after shutting the system off, check to see that the filters are in place. Sometimes a homeowner’s solution to a plugged filter is to remove them entirely, not understanding this can cause disastrous consequences for the dripfield itself due to solids plugging.
Filters should be changed or cleaned. Many service providers I have spoken with who take care of these systems on a regular basis carry replacement filters with them to replace the dirty filters, and then take the used back to the shop and clean them there. Make sure that the filters are placed in a container that will keep them from contaminating the truck or trailer with raw sewage. Some systems have automatic cleaning systems which should be checked and run through a cycle during the maintenance visit to make sure it is functioning correctly.
After filters have been checked it is time to look at the distribution system and components.
About the author
Jim Anderson is connected with the University of Minnesota onsite wastewater treatment education program and is an emeritus professor in the university’s Department of Soil Water and Climate. Send him questions about septic system maintenance and operation by email to firstname.lastname@example.org.
This article is part of a series on drip distribution.