Resource Conservation and Recovery Act (RCRA) Sampling

Resource Conservation and Recovery Act (RCRA) Sampling

Resource Conservation and Recovery Act (RCRA) Sampling

02/28/26

“How do we sample waste to make sure it isn’t hazardous?”

Proper waste disposal is important for keeping the local environment clean. Under the US Resource Conservation and Recovery Act (RCRA), waste generators must determine if their waste is hazardous. If there’s uncertainty about the waste composition, then waste generators must take samples to labs to determine if the waste is ignitable, corrosive, reactive, and/or toxic. Because waste samples can vary widely in contaminants, the waste generator must apply statistical sampling procedures. This means determining the mean, standard deviation, probability of detecting contamination if it truly exists, confidence that our conclusion is correct, the smallest difference from the regulatory standard that we want to detect, and the number of samples needed. Resource Conservation and Recovery Act (RCRA) Sampling is a vital part of determining waste hazards in the U.S.

Suspended Growth Wastewater Treatment

Suspended Growth Wastewater Treatment

Suspended Growth Wastewater Treatment

02/27/26

“How can we treat wastewater with free-floating microorganisms?”

There are many ways to go about wastewater treatment. One of the most common categories is for microorganisms to float freely in wastewater and consume pollutants. This Suspended Growth Wastewater Treatment is an effective way to treat wastewater through mixing the right microorganisms. Activated sludge treatment and aeration lagoons are examples of suspended growth wastewater treatment.

Image credit: https://www.waterandwastewater.com/

Biofilm

Biofilm

Biofilm

02/25/26

“How can microorganisms coalesce into a sticky object?”

Microorganisms are a wonder to behold. They have so many features that their larger-scale cousins cannot even dream of. One of these is that they’re able to coalesce together to create a sticky object called a Biofilm. Biofilms have a three-dimensional structure and are often conceptualized as “cities for microbes”. Biofilms are commonly used in wastewater treatment to extract and digest organic compounds.

Image credit: https://www.biologicalwasteexpert.com/

Curb

Curb

Curb

02/24/26

“How can we delineate the edge of street pavement through elevation?”

It’s useful to have a physical delineation between street and sidewalk in many instances. This could range from limiting cars from hurting pedestrians to routing stormwater through catch basins. This grade-separated delineation is known as a Curb. Curbs have become one of the most ubiquitous urban features in many parts of the globe.

Slow Sand Filters

Slow Sand Filters

Slow Sand Filters

02/23/26

“How can we slowly filter water through sand?”

Sand Filters come in all different shapes and sizes. The earliest sand filters were slow-operating mechanisms. Water would slowly trickle over a large, contained sand bed. Over the course of a few weeks, the sand bed will develop a Schmutzdecke, or thin biofilm derived from the accumulation of suspended organic particles and microorganisms from the water. The schmutzdecke will break down organic contaminants as water passes through it. The sand will then adsorb and retain particles from the water as it passes through. The slow process allows for the creation and operation of the schmutzdecke. These Slow Sand Filters are an electricity and chemical-free way to biologically and physically treat water. Slow sand filters usually have a loading rate of 200 – 400 liters of water per square meter per hour, forcing them to take up large amounts of space for municipal usage.

Image credit: http://www.waterandwastewater.com

Sand Filters

Sand Filters

Sand Filters

02/22/26

“How can we use sand to filter water?”

Sand has many wonderful properties. People can use some of these aspects to filter water. Sand’s small pore size makes it easy for large particles to get trapped, stick to sand particles, or settle down from low velocity. So what if we were to fill a filter with sand, pump water onto the top of the sand bed, and then place pipes near the bottom of the sand to catch the cleaned water at the end of the journey? Well, this is the main idea behind Sand Filters. Sand filters are an excellent way to filter water for your purposes. Some sand filters require backwashing to operate

Image credit: http://www.h2ktech.com

Surface Overflow Rates

Surface Overflow Rates

Surface Overflow Rates

02/21/26

“Why does measuring how much water flows through a tank per area matter for sedimentation tank design?”

Sedimentation tank design involves a lot of variables. One of them includes how much area a settlement tank will need to take up for effective operation. This can be found out by dividing the volumetric flow by the surface area of the tank to obtain the Surface Overflow Rates. The surface overflow rate expresseshow fast the upward velocity of a clarifier is moving. If the particle settling velocity is faster than the surface overflow rate, then it will succeed in removal.

Dissolved Oxygen Depletion

Dissolved Oxygen Depletion

Dissolved Oxygen Depletion

02/20/26

“What depletes dissolved oxygen in water?”

Dissolved oxygen in water is vital for sustaining aquatic life and supporting aerobic microorganisms. However, if there are too many organisms consuming the dissolved oxygen, then it will eventually be depleted. Common culprits of Dissolved Oxygen Depletion include algal blooms from eutrophication, high water temperatures, low aquatic plant activity, low wind speeds, and large numbers of dead organisms. People must take care of water bodies to prevent dissolved oxygen depletion.