Time for a New Onsite System Additives Study?

It's been 15 years since the U.S. EPA did a comprehensive study on the impact of additives in septic tanks. A more recent study helps, but perhaps it's time for some fresh facts.
Time for a New Onsite System Additives Study?
Some professionals argue that biological additives may have some — minor — benefits and could be useful in systems with high-sodium drinking water or in areas with hard water supplies.

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The debate of the efficacy of septic tank additives rages on. The U.S. Environmental Protection Agency’s most recent study on chemical or biological additives in septic tanks was 15 years ago. The results? The EPA neither recommends nor prohibits the use of additives — of biological composition — citing inconclusive evidence in widespread usage.

Some professionals argue that biological additives may have some — minor — benefits and could be useful in systems with high-sodium drinking water or in areas with hard water supplies. Chemical additives, however, could have possible adverse effects on groundwater quality, system components and soil structure.

Taking sides

“Bioremediation isn’t for everyone,” says Rick Howe, owner and president of Cape Cod Biochemical Company. “Some contractors would much rather dig than remediate. Some feel that replacement rather than remediation is much more guaranteeable. But there are those situations where the customer, for whatever reason, would prefer not to excavate their yard.”

Chemical additives — sulfuric acid and hydrogen peroxide — were originally used to restore drainage in onsite systems. However, both have since been prohibited in most areas due to their environmental impacts.

A mechanical treatment (pneumatic soil fracturing) was introduced to solve soil issues — compaction, saturation, improper drainage — without disturbing the ground surface. Aerators also converted anaerobic septic tank systems into aerobic units by adding oxygen. Hence the argument that bacteria, combined with oxygen, can break down biomat and reduce sulfides.

“Both worked to restore drainage in many cases,” Howe says.

Biological restoratives, designed to remove buildup from drainfield lines, are the main concern among onsite professionals because a thousand-plus off-the-shelf products can make it difficult for homeowners to determine which are beneficial and which could be detrimental.

Combined with jetting or pneumatic soil fracturing, however, product manufacturers argue that these additives can help restore drainage to sluggish drainfields.

Additives are designed to extend the life of septic systems, but not replace regular — and necessary — maintenance and pumping.

Of course, excessive or improper use of any type of biological or chemical additives could potentially cause long-lasting damage to system components and drainfield performance. Regardless of which side you’re on, be sure to educate homeowners on the proper system maintenance, including the proper use of off-the-shelf products if they choose to use them without your approval.

Fresh facts

A more recent two-part study conducted by onsite professionals and soil scientists and published by the Journal of Environmental Health inspected the impact of three biological additives on 48 full-scale, functioning septic tanks. The tanks ranged from poorly maintained to highly maintained.

Part 1 of the study examined solids accumulation in septic tanks — sludge depth, scum thickness and total solids. The results were more or less the same as the 15-year-old study from the EPA.

“No significant, positive long-term additive treatment effects occurred across all maintenance levels,” says the study. “Separate analyses of variance, however, indicated that at high prior-maintenance sites, significant treatment effects occurred on sludge depth, scum thickness and total solids.

“We conclude that our study does not indicate any long-term, statistically significant effects on solids digestion in septic tanks for additives as a collective group. Our study also does not support using bacterial septic tank additives or as a substitute or to reduce septic tank pumping frequency.”

Part 2 examined septic tank effluent quality and overall additive efficacy. The study looked at 20 well-maintained, full-size, functioning septic tanks. Units were treated with one of the three biological additives or a control. Again, the results are probably as expected.

“Our study highlights some newly understood potentially positive efficacies of biological additives on septic tanks at well-maintained sites where septic tanks have been recently pumped,” says the study. “No positive effect occurred overall for additives as a collective generic grouping.

“The general public could benefit from a national and international additive testing and certification program.”

While this two-part study only examined three of the 1,200-plus available septic tank additives, the results still offer insight into the impact of these additives — and endorse the need for more research.

How do you recommend the U.S. EPA study the impact of additives in septic tanks? Post a comment below. 


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