Settlement basins and retention pond Waste deposition

As we continue the discussion on settlement basins and retention ponds from last month, IKON Environmental Solutions, LP (IKON) thought that we should address one of the most problematic issues associated with the largest jobs IKON performs each year. IKON receives many calls for solutions to help deal with settling basins, retention ponds, stormwater ponds, process ponds, lined ponds, unlined ponds, and everything in between (I’m going to use the term “pond” for now to describe all of these). One of the biggest expenditures of costs, and one of the most debated decisions associated with cleaning out the ponds, is inevitably the disposal of waste (sediment) generated from the cleaning. As with many remediation projects, the waste tends to drive the discussion for nearly everything else.

Regardless of additional issues, when we start talking waste from a pond, we start with the basics: where can the waste go, once generated? That seems like a straightforward question, but waste is a surprisingly complex creature. The first question to address is if the cleaned out material is a waste, or if it is an exempt waste from the Resource Conservation and Recovery Act (RCRA), or if it does not meet the definition of a solid waste. This often hinges on what type of pond and what type of facility the pond is located at. The distinction of industrial versus non-industrial waste is a massive fork in the road. For instance, a detention pond that was being excavated for stormwater retention is often not an industrial waste. Which means that if the soils are unimpacted, they could likely go to other construction projects or fill projects, without environmental oversight, to be reused. Whereas the accumulated sediment in the same detention pond 10 years into the future, when the pond is being cleaned out, likely will have levels of metals, polycyclic aromatic hydrocarbons (PAHs), and total petroleum hydrocarbons (TPH) that might then require environmental oversight and management. Moreover, certainly any pond that is on an industrial facility, falls under the umbrella of industrial waste and requires environmental oversight and management.

So, the facility where the pond waste is generated matters, and the process by which the pond waste is generated also matters in terms of if and how the waste is characterized and profiled for disposal. In a situation of virgin soil from a non-industrial detention pond dig, that sediment might need no oversight, management, or profiling and characterization. For the majority of other situations, some amount of profiling and characterization is required. Those requirements can greatly increase with industrial facilities and with sediments that have potentially come into contact with other materials at a Site.

Profiling and characterization of pond sediments is a process that is codified in Title 40 Code of Federal Regulations (CFR) Part 261. Furthermore, the process is typically delegated to the state environmental regulatory agency, in Texas the Texas Commission on Environmental Quality (TCEQ) oversees the profiling and characterization process of waste under Title 30 of the Texas Administrative Code (TAC) Chapter 335. Similar regulations can be found in other states. The TCEQ has a step-by-step guide to profiling and characterization, but some of this process is still a bit of an “art, not a science”. Many decisions in the decision tree are quite speculative and give definition without providing a definition. For instance, the guide says you must sample your waste. That is pretty easy if you have a drum of sediment contained on the yard; but even that one drum can be complex, is the waste uniform, is it distributed evenly in the drum, does it contain multi-layers? Now imagine a 30-acre pond with 4 feet of sediment with different depositional zones. Was the waste the same 10 years ago as it is today? That waste from 10 years ago is buried by 4 feet of sediment, is it the same today as it was 5 years ago? How many samples should we take to have a representative concentration? Should we grab samples or composite samples? How do we correctly and uniformly sample and devise a representative sample of the waste? Much less, do we sample in place from a barge now, or do we wait until the waste has been removed and sample it in a pile while drying (handling it more, and slowing down removal to a disposal facility)?

Sampling, and how to sample, are just the first of a multitude of questions, in Texas waste is split between industrial and non-industrial waste, but even more, the waste is separated into hazardous waste, non-hazardous Class 1 waste, non-hazardous Class 2 waste, and non-industrial non-hazardous waste. These designations have a great deal to do with where the waste can be shipped and/or sent for final disposal. Additionally, waste can be hazardous by a few different distinctions, they can be hazardous by characteristics. This means by concentration of a certain chemical, their characteristics become hazardous. Alternatively, they can be hazardous just purely by how or where they were processed, how they were derived, or what they came into contact with. These types of hazardous waste are called listed hazardous waste. Hence, when we consider what type of waste, and where the waste can go, we have to consider what classification of the waste, both by concentrations and by process derivation, the waste falls under.

Once we can characterize the waste, then we must also consider the physical state of the sediment for profiling to a facility. Landfills, incinerators, soil recyclers, and all waste disposals in between must meet the criteria for the safe shipping, land filling, burning, or recycling of the sediment. Odor, physical structure, wetness, compressibility, and numerous other physical attributes enter into the equation, much less the chemical constituents and waste classification to determine if the sediment is a good fit for a certain disposal facility. Liabilities can also play into the determination by the generator of the waste.

Where the waste can go for final deposition greatly depends on the facility where the pond waste is generated, the profiled classification of the pond waste, and the process by which the pond waste was generated. Pond waste could have no chemical constituents detected, but if it was generated or came into a contact with a listed hazardous waste, that can make the sediment a hazardous waste. Similarly, you could have benzene detected in a stormwater pond, it could be below the characteristic waste levels for benzene, and yet the sediment might be able to be used as fill material at another Site. Waste rules do not always follow common sense, and generators can get themselves in trouble quickly with incorrectly classified wastes.

There are many applications and uses for settling ponds across many different industries, what remains consistent is that dealing with the waste after removal is usually the most expensive and complex matter for the generator, contractor, and consultant to deal with. The physical and chemical aspects of the sediment can make the sediments difficult to deal with concerning transportation, drying, and disposal. Creative solutions are essential in dealing with sediments, impacted or not, and IKON has those solutions. Join our industry leaders to discuss our upcoming webinar Settlement Basin and Retention Pond: Maintenance, Cleaning, and Disposal. IKON Environmental Solutions invites you to join us for our upcoming webinar on all kinds of ponds at facilities! Register here for the Webinar. For additional information, or for help with settlement basin or retention pond maintenance, contact Greg Blomquist or John Savage.