"Wisdom begins in wonder" – Socrates
Category: Biology
Glycolysis
03/10/26
“How do cells break down glucose into energy?”
Glucose (C6H12O6) is the main energy source for cells. Cells will break down glucose into energy and pyruvic acid in a process known as Glycolysis. This is the backbone behind microbial treatment in wastewater engineering.
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
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/
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
Hazard Quotient
01/27/26
“How can we quantify the lethality of exposure to a substance?”
People are exposed to potentially hazardous substances all the time, whether it’s traces of air pollution or bacterial growth on food. We also know that if exposure breaches a certain level, it becomes dangerous. So how can we quantify the lethality of exposure to a substance? Well, what if we divide the exposure level by the reference dose? This is how the Hazard Quotient works, and it is a very useful tool in toxicology.
Noise Dose
01/24/26
“How can we quantify the level of noise someone is exposed to over time?”
Listening to too much loud noise is a well-known safety risk. The constant vibration in your ears can lead to long-term damage if not managed properly. The Noise Dose quantifies how much noise a person has been exposed to for the day, regarding safety levels. We can quantify noise dose by taking the hours someone listened to a certain decibel of noise and dividing it by the maximum number of hours it’s safe to listen to that noise level per day. We can sum this ratio for every noise decibel level heard throughout the day, multiplied by 100% to arrive at the total noise dose. If a noise dose exceeds 100 percent, then the person has breached the healthy recommended daily noise levels.
Chronic Daily Intake
01/23/26
“How can we calculate the amount of contaminant a person is exposed to daily?”
People are exposed to all kinds of substances throughout the day, whether it’s from the food we eat or the air we breathe. Some of these substances are harmful and can lead to health problems. We can measure how much of these contaminants we expose ourselves daily through Chronic Daily Intake. Chronic daily intake is typically expressed as milligrams of substance per kilogram of body weight per day. The US E.P.A uses chronic daily intake as part of health hazard assessment.
Acceptable Daily Intake (ADI)
01/21/2026
“How does the WHO measure how much a certain substance in food or drinking water can be consumed daily over a lifetime without an appreciable health risk?”
NOAELs document how much of a substance an organism can handle before a statistically significant health effect occurs. However, these studies may be conducted in controlled environments or on test animals that may not accurately reflect human conditions. To account for all of these variables, organizations such as the World Health Organization (WHO) and the European Food Safety Authority (EFSA) use Acceptable Daily Intake (ADI). Acceptable daily intake measures the amount of a certain substance in food or drinking water that can be consumed daily over a lifetime without an appreciable health risk to people. This is commonly expressed as milligrams of substance per kilogram of body weight and is applied by regulatory and health authorities all over the world to monitor food additives, pesticides, and much more. Acceptable daily intake is applied to food ingredients similar to how reference dose is applied to environmental toxins.
Reference Dose (RfD)
01/20/26
“How does the U.S. EPA produce recommended daily lifetime exposure limits for substances?”
NOAELs are the highest level of a substance a person can take without any statistically significant effects, according to research. However, this could be much higher than what may actually be safe for long-term use. The U.S. EPA has created the Reference Dose (RfD) in response. Reference does are the maximum acceptable oral dose of a toxic substance that has no adverse noncancer health effects from a lifetime of exposure. Reference doses are commonly found by dividing the NOAEL for a substance by uncertainty factors.
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