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

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

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

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

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

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.

Material Toughness

Material Toughness

02/19/26

“How can we measure how much energy a material can absorb before rupture?”

People need materials to absorb energy before rupture. The more energy an item can absorb, the higher its Material Toughness, and the better it will perform for tasks that require heavy resistance to heavy energy shocks. Material toughness is measured by the area under the curve in a stress-strain diagram. Material toughness can be thought of as a combination of hardness and ductility.

Tensile Strength

Tensile Strength

02/18/26

“How can we measure an object’s resistance to being pulled apart?”

Pulling an object exerts stress on its atoms. Different materials will have different amounts of resistance to being pulled apart, summarized by the word Tensile Strength. The largest stress value it can handle before breaking is known as Ultimate Tensile Strength. Tensile is often one of the most important properties engineers must consider in material selection.

Beltpress Dewatering

Beltpress Dewatering

02/17/26

“How can we use a beltpress to dewater sludge?”

Sludge needs to be dewatered to increase solid content. One way to do it is to condition sludge with a chemical flocculant to aggregate suspended particles, transport it onto a mechanical moving porous belt where free water drains out, then squeeze it into a top belt to force more water out, and then move it through rollers to pressure even more water out, and finally discharge it as a cake. This Beltpress Dewatering syste is a common approach for wastewater dewatering worldwide.

Image credit: https://encrypted-tbn0.gstatic.com/