Month: October 2025

Volumetric Substrate Loading Rate

Volumetric Substrate Loading Rate

10/22/25

“How can we quantify the amount of organic matter entering a reactor over a given amount of time and volume?”

Reactors treat water to make it usable for people. We can use the BOD loading rate to quantify how much organic matter is entering a reactor over a given time. However, we also might want to know how much treatment is necessary not just per time but also per volume to make it independent of reactor size. We can simply quantify this using the Volumetric Substrate Loading Rate, which is equal to a reactor’s BOD loading rate divided by its volume.

BOD Loading

BOD Loading

10/21/25

“How can we quantify the amount of organic matter entering a treatment system over time?”

Every day, wastewater treatment plants use microorganisms to break down organic matter in water. Plant operators need to estimate how much organic matter is entering a treatment system over time to design their system properly. But how can we do this? Well, we know that we already have a unit, biological oxygen demand, to estimate organic pollutant concentration. And we know that the influent water stream will contain a certain concentration of organic contaminants. So what if we were to multiply the influent volume flow by its BOD concentration (milligrams of oxygen microorganisms need to use to consume pollutants per liter)? Well, this will give us a variable called BOD Loading, measured in mass of oxygen needed for pollution cleaning per time, that plant operators can use for design calculations.

Sludge Dewatering

Sludge Dewatering

10/20/25

“Why do we need to remove water from sludge?”

Sludge is a mixture of solid waste and water created after an industrial or water treatment process. The more water a body of sludge has, the more volume and weight it will take up, and the more difficult it is to handle. Draining water from the sludge will make it lighter and easier to operate. Sludge Dewatering is an essential tool for sludge operators.

Image credit: https://caryloncorp.com/

Perimeter Runoff Control

Perimeter Runoff Control

10/19/25

“Why do we need to protect the perimeter of our construction site from releasing sediment with stormwater runoff?”

Construction operators are obligated to apply best management practices to prevent stormwater runoff sweeping sediment from their sites from entering water bodies. One of the most important aspects is ensuring the perimeter of the site is controlled. Perimeter Runoff Control strategies keep sediment inside the site. Silt fences and sediment basins are examples of perimeter runoff control. The National Pollutant Discharge Elimination System Construction Stormwater Permit requires construction operators to implement perimeter runoff control before beginning soil disturbing activity as part of their stormwater pollution prevention plans. Construction operators can temporarily dismantle perimeter control infrastructure to allow vehicles to enter the site, as long as the infrastructure is restored as soon as possible.

Image credit: https://cdn.shoplightspeed.com/

Reedbeds

Reedbeds

10/18/25

“What makes areas populated by reeds so special?”

Reeds are wetland-based plants that can successfully populate large swaths of area, making Reedbeds. These reedbeds host special microorganisms in their root systems that clean wastewater by consuming sewage. Reedbeds are often utilized for constructed wetlands due to their wastewater cleansing capabilities.

Electrodialysis

Electrodialysis

10/17/25

“How can we use electric potential to desalinate water?”

Saltwater is much more common than freshwater in the world. Consequently, we could greatly increase our water supplies by converting saltwater to freshwater. But traditional reverse osmosis techniques are incredibly energy-intensive. Is there an easier way to desalinate water? Well, we know that salts have an electrostatic charge. So what if we were to place the water stream between a cathode and an anode and insert an alternating series of membranes that only allow cations or anions to pass? Well, this will create streams of purified water, separated from saltwater. This process, called Electrodialysis, is a smart way to desalinate water and make it useful for people.

Image credit: https://static.wixstatic.com/

Chemical Dissociation

Chemical Dissociation

10/16/25

“Why do some ionic compounds dissolve in water?”

Ionic bonds hold together many compounds. But when placed in water, the water molecules can overpower the bonds and tear apart the compounds. This Chemical Dissociation process is a powerful effect that’s responsible for a plethora of important physical phenomena, ranging from carbonate equilibria to ion exchange.

Reeds

Reeds

10/15/25

“What makes those grass-like plants in wetlands special?”

If you look at pictures of wetlands, you’ll probably see tall grass-like plants. But what are they and what makes them special? Well, these plants are called Reeds. Reeds play a vital role in soil stabilization, waste treatment, nutrient management, and habitat creation. Reeds are a critical part of wetland functioning.

Carbonate Equilibria

Carbonate Equilibria

10/14/25

“How does the interaction between carbon dioxide and water keep pH levels stable?”

Water (H2O) can absorb carbon dioxide (CO2). Some of this CO2 will react with the H2O to form carbonic acid (H2CO3), and some carbonic acid will reversibly decompose into a hydrogen ion (H+) and bicarbonate (HCO3-), and some of the bicarbonate will further reversibly decompose into a hydrogen ion and carbonate (CO3). The more basic a specific body of water is, the more likely these decompositions will occur. At pH levels below ~6.3, carbonic acid predominates. At pH levels between 6.3 to 10.3, bicarbonate predominates. At levels above 10.3, carbonate predominates. This balance is described as the Carbonate Equilibria. The balance of these chemicals holds a massive influence over a water body’s alkalinity and potential for certain treatment methods.