How Are The Sewers Designed?

Posted on November 29, 2019 in Blogging Local News

Sewer system designs start with an engineering consultation, which will try to finalise the conceptualization of ideas and produce environmental impact assessments. Usually, engineering consultants forecast the population growth rate of communities that need new sewer systems. Since residents will form a connect of sewer pipes, civil engineers need to plan for wastewater-related emergencies. 

A civil engineering group must think about every aspect of the construction process. Along with the ethics of the structure itself, engineers also must consider a bit of land’s capability to handle water flow in the event of a major storm or flooding. Even ancient builders realized that. In fact, as it has been said, the first streets appeared some 3500 years ago, and even these early predecessors to the highway took drainage into consideration. We could see then that drainage mattered to the people of ancient times. And if the people of the past put this into consideration, we should expect that we, equipped with the knowledge that is passed down from the ancient times, to utilise it and develop them into better forms that would further benefit the society.

Water could be the planet’s life force, but it can cause lots of problems if allowed to sit down on sidewalks or roadways. Without proper drainage analysis, a structure runs the danger of flooding, foundational damage, and in worst-case situations erosion and even sinkholes.

Apart from laying new sewer pipes, the old sewer system in your municipality might be due for an upgrade. This reconstruction of the sewer system also needs superior designs that guarantee durability. Here are some techniques that ensure the right design methods of sewer systems.

Types of Sewer Systems 

Sewage systems include pipes that transport wastewater from houses, factories, and other buildings to treatment plants. Other components include lateral pipes, outfall, trunk, and sub-main pipes that carry sanitary sewage. Normally, these pipes are different from the types that collect surface runoffs (stormwater) from rainfall. While designing sewer systems, civil engineering professionals consider a range of factors.

• The Combined Sewer System

In the combined sewer system, both stormwater and sanitary sewage flow through the same pipes. Usually, municipalities discharge sludge from the combined sewage system without proper treatments. Most times, poor town planning methods leave engineers without any alternative to the combined sewage pipe installation. When the roads are too narrow, it might be difficult to install separate sewer pipes for both stormwater and wastewater.

• The Separate Sewer System

In the separate sewer system, one pipe collects storm and roof drain. Another pipe collects wastewater from homes and industries to treatment plants. Normally, the design of stormwater pipes ensures that street wash and surface runoffs flow to lakes and rivers. Also, sanitary sewage gets to the treatment plant through outfall sewer pipes.

Factors That Affect the Design of Sewer Pipes

Before laying sewer pipes, civil engineers consider the distance to the water table, environment factors, temperature, and pressure of wastewater. They also consider how the city’s treatment plant for sludge should be designed before it receives these wastes.

There are more pollutants from industrial wastewater. Since the production of goods might require special raw materials, we expect industrial wastewater to have more pollutants. Since it’s the same sewer system that transports all types of wastewater, civil engineers must consider a range of characteristics.

• The Temperature Factor

The average temperature of wastewater varies between 10 and 20O degrees (Celsius). Since wastewater contains effluents and microbial activities, these chemical reactions will increase the internal temperature of sewer pipes. The atmospheric temperature has a negligible (slight) influence on the temperature inside sewer pipes. 

Generally, potable water supply pipes have lower temperatures than sewer pipes. Also, residents use warm water to bath and prepare meals. So, the temperature of wastewater is affected by what the pipes receive and the weather condition of that area.

However, temperature is an important factor in designing wastewater pipes. Engineers often use sewer pipe materials that can handle this range of temperatures. When biochemical reactions increase the temperature of wastewater, it also makes oxygen is less soluble. During the summer months, heat increases the temperature of wastewater pipes and bacteria that produce methane gas. Using the right type of plumbing would also help to avoid problems down the road, which means fewer chances to repair the drains every other month or so.

• The Density Factor

The density of wastewater is an important parameter that influences the design of sewer pipes. Density is calculated by comparing the mass per unit volume of any material (kg/m3). Normally, density currents depend on the concentration of solid particles in the wastewater. Also, treatment plant operators consider this characteristic of wastewater.

Apart from gases (carbon, sulphur, hydrogen, nitrogen, and oxygen), the chemical compounds in wastewater include organic and inorganic matters. The composition of organic matter has fewer filterable solids than its suspended solids. Other organic pollutants in wastewater include fats, proteins, urea, and oils. They form complex structures that increase the density of wastewater and in some cases, may create sewer blockage if these substances accumulate without getting treated.