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Engineering Stack Exchange

Questions tagged [environmental-engineering]

57 questions
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Why does reducing the amount of emissions control improve the fuel economy of a car?

In addition to power and performance, one of the reasons VW cheated their emissions results was to improve the fuel economy of their cars. Why exactly does this happen? I'm familiar with cars and how cars work so feel free to get technical. And a…
Kevin
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Humidity in home is much higher than outside

We have a two year-old, two-story town house with: fiberglass insulation in the walls; a Tyvek vapor barrier under foam board on the exterior walls; blown cellulose insulation in the attic; stucco outside; and a refrigeration cycle air…
user13416
8
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Inexpensive and moderately accurate (field) method of measuring THC (Total Hydrocarbon Content) in water

I am working in a construction company which is building hydropower plants in Northern Norway. We are monitoring the Total Hydrocarbon Content (THC) of our process waste water. This particularly important during tunneling as the machines are likely…
Mikkel Bue Tellus
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What is a PD pump that I can use as an immersion pump for a slurry?

I need to pump a thick slurry from a tank. The slurry can be pumped, but won't flow well enough that I can use a suction pump from outside the tank. Normally, I'd use a centrifugal immersion pump that can be drawn from the tank for service. But with…
mart
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How can I calculate the evaporation rate for a hazmat spill?

I was given formulas for general evaporation, for a spill calculator I am building. These are formulas, that are supposed to approximate evaporation, are for a number of different chemicals. Molecular weight is pulled from the chemical itself, same…
Duck
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What colour of tarp will let in the least amount of heat?

Source: Low Tunnel Construction: How to Build a Mini Hoop House I have a small greenhouse that I want to keep as cold as possible in the spring. I plan to cover the greenhouse with a polyethylene tarp to shield it's contents from the sun. However,…
User1974
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How do cyclonic vacuum cleaners maintain collection efficiency with constant motion and changes in orientation?

Anyone used to doing housework has probably noticed that vacuum cleaners come in both "bagged" and "bagless" varieties. If you're of a certain age, you may have noticed when these "bagless" vacuums appeared back in the 1990s. Though I didn't…
Air
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Oval aeration tanks - what are they called, what are the key differences in operation to circular tanks?

Consider this overview picture of a WWTP: In the back, you see two oval tanks with bridges and walls, separating an inner from an outer area. These are aeration tanks. Is there a specific reason to build them like this, instead of circular, or is…
mart
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How do wastewater sludge degassing systems work?

There are high-rate anaerobic digestion systems where you remove substrate from the digester, let it settle in a tank, and pump back the settled sludge (possibly not all of it) to ensure a higher sludge retention time. One problem with settling of…
mart
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How to install a wired sensor in a rotating bin without tangling the wires?

I want to insert couple of moisture, temp and humidity sensors in this bin to take readings from the compost. But how do i install it without turning/tangling the wires? Can anyone help me figure a solution I am not an engineer but I am trying…
Vrushabh Chotalia
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Which component of vehicle tailpipe emissions has the greatest social cost?

Emissions Emissions from vehicles have an associated social cost for everyone. We hear a lot about CO2, but CO2 is not the only thing that comes out of a tailpipe. From Wikipedia, emissions components of petrol and diesel engines…
hazzey
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Solving heat loss equation associated with solar trough concentrators

My project is about finding the efficiency of solar trough (cylindrical parabola) concentrator that will boil water in a pipe located at the focus (check picture please). In the process of doing so (of course I made many assumptions, but I think…
Rachid Brah
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Prolong frozen ground conditions (to trick fruit trees into flowering later)

There is a common problem with fruit trees in temperate climates where the trees flower before the last frost. Generally speaking, if the tree has flowered, and the temperature drops below freezing, the flowers die and do not produce fruit. This is…
User1974
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Can solar panels absorb heat for energy?

Solar panels can absorb sunlight and use it for energy, but can they absorb the heat that is generated from their use and use the heat for energy?
Rishi Kavikondala
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Gas cleaning in activated carbon filters - How much moisture is needed and why?

Biogas and sewage (typically around 60% CH4, rest CO2) gas is typically treated in activated carbon (ac) filters to remove H2S and siloxanes. The ac filters need a small amount of oxygen (>0,4%) to work. Additionally, the moisture content needs to…
mart
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