What’s in Your Tank?

Pumpers sometimes take septage management and land application for granted. Let’s explore treatment trends and how we can ensure the best disposal options for the future.

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For a number of reasons, there is an increased interest in pumpers' roles in onsite system management — maintenance intervals for different system components and, due to increases in management, what happens to the material we remove from septic and other sewage tanks.

At last month's Pumper & Cleaner Expo, a half-day session was devoted to land application issues and regulations. The session highlighted where pumpers most often run into regulatory problems with the U.S. Environmental Protection Agency and discussed how land application fits into a pumper's business model. It also touched on challenges expected as we move forward.

We often take septage management and land application for granted. It seems every year these issues result in a business owner receiving an audit from the EPA and facing potentially large fines. I will explore some of the definitions and characteristics of the materials pumpers deal with on a daily basis. In future articles, land application and questions about regulatory and technical problems will be addressed.

THE BASICS

Land application of domestic septage is regulated by the EPA regulation 40 CFR, part 503. Some states have their own programs to implement and oversee the federal requirements as well as their additional standards. The EPA defines septage as "liquid or solid material removed from a septic tank, cesspool, portable toilet, Type III marine sanitation device or similar treatment works that receives only domestic sewage. Domestic sewage does not include liquid or solid material removed from a septic tank, cesspool or similar treatment works that receives either commercial or industrial wastewater and does not include grease removed from a grease trap at a restaurant."

As I go around the country, I frequently hear stories where a pumper has taken something onto their truck that they shouldn't have and then wonders, "OK, now what do I do with it?" So making sure you know what is allowable and what is not is important. This may seem like common sense, but you only have to make the mistake once to know it can be painful
and expensive.

Commercial wastes are any liquid or solid materials from septic tanks, holding tanks or similar treatment works that receive either commercial or industrial wastewater. Waste is not commercial if it is only from sanitary facilities within the plant or business. Commercial wastes include waste from small slaughterhouses, pretreatment wastes from a food processing facility, and waste from a flammable trap at a car wash. Land application of non-hazardous waste is regulated at the federal level under a different set of rules, 40 CFR, part 257.

TRENDS IN TREATMENT

Septage is managed in a variety of ways across the country. The most common methods have been the transfer of septage to municipal treatment plants for treatment, land application and landfilling. A trend involves private facilities that separate water and solids (dewatering), and then deal with treating the water and solids separately. The water can be delivered to a treatment plant for a fee and with solids removed and the BOD reduced. Treatment plants are more likely to accept the water, while the solids can be landfilled. The water can be applied as irrigation water where appropriate. The solids can be land-applied. More options are available, and the choice usually comes down to a more economically viable approach.

In metropolitan areas, it is most common and cost-effective for septage to be discharged into the municipal treatment plant, becoming part of the city waste stream and treated and managed as a part of its biosolids. There are potential issues to be aware of. Smaller municipal plants can have a treatment plant operation disrupted by the addition of high-BOD septage and therefore often refuse to accept the waste. In these areas, the waste usually ends up being land-applied.

LAND APPLICATION

About 10 years ago, Minnesota estimated that about 300 million gallons of septage was pumped annually, with 200 million gallons being land-applied. The other third went to municipal treatment plants for treatment. Your state will have its own unique amounts and proportions.

One important aspect of septage management involves properly locating and managing a land application site. Just as with other parts of an onsite system, the goal is to protect human health and the environment while handling the waste being generated.

The federal requirements are somewhat hazy on how these goals are to be met. There is no particular guidance on how to prevent runoff or groundwater contamination, but it does say you need to do it. So a part of any land application plan needs to take into account site suitability factors — in terms of setback distances from wells, buildings, people and surface waters — and detailed site management plans.

A friend in the industry told me he always knew what was headed his way in terms of land application requirements by paying attention to manure handling in his neighborhood. That is probably good advice. You could also watch requirements for managed biosolids sites from the municipal plants. The same runoff, nutrient management and site separation distance requirements often serve septage land application sites well.

Because the quality of septage varies from load to load, an average septage analysis is currently used to calculate allowable rates of land application in a nutrient management plan. One answer is to mix loads to produce a more consistent product. For reference, septage supplies about 5 pounds of nitrogen and 2 pounds of phosphorus per 1,000 gallons. We will look at how that affects application levels in future columns.



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