Designers of alternative onsite systems have a very real challenge in states that don’t mandate operation and maintenance. I characterize systems designed in jurisdictions without an O&M mandate as having an owner-operator (mandated areas would have professional operators). As a manufacturer of onsite systems that require periodic O&M, how do I design a system to work in jurisdictions with no mandate so that it is affordable on both the front end (installation) and also over back end (O&M)?

A conventional system has two modes of failure. The wastewater either surfaces or backs up into the house. These are the alarms the owner operator uses to initiate maintenance. If the system contains a pump, a high-level alarm will indicate a possible pump failure. This would be owner-operator compatible. Alternative systems are another matter, however. Because they are designed to overcome limitations of the site where the system will be installed, there are more ways for treatment quality to be compromised. How do we know when the system is not working? What constitutes a failure? Can an owner truly operate the system or does it take a professional?

Designs should be around systems you can fix after they break. When they break, they should not cause irreparable system damage or environmental harm. The starting place for me was to try and make the alternative system act like a conventional system with a pump. If there were a failure, then there would be either a backup into the house or a wet spot in the field or a high-level alarm. The owner would then be expected to call someone to fix the problem. A better conventional system design protocol would be to put a time-dosed pump in every system. Design the pump to discharge the design flow only so excess flow (leaky toilets) would cause a high-level alarm, not a failed drainfield. The designer can then control one more non-compliant event: excess water use.

A low-pressure distribution system can be designed with this philosophy. Once the hydraulic layout has been designed, deliver the wastewater to the network on a time-dosed basis. In the event of clogging, a professional operator would note the loss in capacity and perform necessary maintenance. The owner-operator would have to wait until capacity has been lost to service the facility and a high-level alarm is triggered – and pay a much larger repair bill.

A drip system can be designed with this philosophy. A drip system needs more management than a low-pressure distribution system and care must be taken in design to take advantage of its enhanced benefits. A drip system with solenoids, filters, emitters in addition to a pump, and control should be designed to alert the owner-operator to a problem with the same indicators as a conventional system. For example, in addition to a backup, a wet spot and a high-level alarm for a pump failure, we can design the system to save the drip tubing and the soil treatment with similar alarming. 

Unfortunately, gravity flow-through treatment units cannot be ignored by the owner operator until he gets a backup alarm or wet spot without considerable harm to the system or possible environmental damage. Time dosing to treatment is a considerable enhancement, but until we can affordably monitor and alarm low treatment quality, an owner-operator is not a good solution for many treatment system designs. Designers should only propose designs for owner-operators where treatment quality non-compliance is low-risk and manageable after a long period of non-compliance.

System manufacturers need to provide information to their designers to support O&M either by owners or professional operators. I would assume that systems designed for the owner-operator would be more costly in most cases to provide the appropriate level of operator interface. Each manufacturer would need to make their own case for this utility, but the industry needs to have this discussion.

In all cases, the designer needs to estimate long-term O&M costs. The designer should present owners with adequate information to make the appropriate decision for their budget. It is possible to design for long-term O&M so costs are in line with sewer bills in urban areas.

Time should show which systems are the most manageable for either the owner-operator or the professional. We need to have a better understanding of the expectation of the owner-operator for long-term sustainability. The only way to determine this expectation, in my view, is to first educate them more about what an alternative system is. The challenge continues.