Questions tagged [environmental-engineering]

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Why not use sodium hydroxide to reduce carbon dioxide emissions?

The products of the reaction are useful. Renewables like solar power can be used for the electrolysis of brine. I don't understand why petrochemical companies are not using it as a scrubber?
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what are some books/academic journals which I could read on renewable energy/technology? [closed]

Book suggestions on renewable energy technologies/sources
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How much energy is needed for the USA to only use desalinated water?

What amount of energy would it take to replace the entirety of America's water consumption with desalinated water? And how does it compare with the country's current energy generation capacity? By &...
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Is it possible to avoid the emission of CO2 and other greenhouse gases from thermoelectric plants?

Since the deleterious effects of greenhouse gases are well known, I was wondering if it is possible, for example, for thermoelectric plants to avoid this kind of emissions. More exact, I think it ...
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Air Conditioner for an Acrobat Plane

What kind of Freon air conditioner would work upside down? Or somehow make it cut off and start working again when upright? I have a small cabin so it can be electrically driven. I know they have an ...
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Solar Radiation Environmental Test Duration

I am designing an outdoor sensor and I need to test it for continuous outdoors service. One of the test I wish to perform is a solar radiation test for the actinic effect (like procedure 2 in MIL-STD-...
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Public data re possible estimate of baghouse efficiency. Plus characteristics of chromium emissions. Thanks!

I'm doing an article on a company whose Title V Operating Permit is currently under review by state regulators. (See biographical note below.) See also my specific questions, numbered below. Most ...
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How is the Outlet flow rate in a water system controlled?

The Hardy Cross method for analysis of fluid systems assumes that in inlet flows and outlet flows for the system are known. However, when one constructs such a system in real life, how do we ensure ...
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can submersible pumps be used for leachate from landfill that may have some solid particles of size 15-20mm?

I would like to know if submersible pumps can be used to extract leachate from leachate wells. The leachate is likely to contain solids of size 15-20mm. Further the pump should have diameter less than ...
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Calculating Chronic Daily Intake

I am studying for the FE exam and have come across a question regarding calculating cancer risk. I'm fairly certain that the answer provided has typos, but I'm not 100% sure. Here is the question: ...
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2 answers
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Why is a mining cage called a Mary-Ann?

I apologize in advance if this is off topic - maybe it is more of an English language query... Please feel free to migrate or close if needed :) I have seen mine cages/service lifts referred to as ...
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Referencing for Air Quality Monitoring

I asked the same question in electronics sub, but since it is more general I am asking it here again. I bought the Sharp dust sensor GP2Y1010AU0F. Below are the graph of readings indoor for ~5 minutes,...
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8 answers
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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 ...
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Hazardous waste packaging

I'd like to ask an environemental question which has to do with waste packaging and the EU regulations that enclosure this subject I'd like to package loads of different hazardous wastes in ...
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3 answers
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Mapping of vehicle to its horn sound

From the "meep meep" of the smallest scooter to the "BLLLAAAAAGGGGGHHH" of the largest seagoing container vessel, vehicles seem to have horn sounds that, in an auditory way, seem to indicate their ...
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Adsorption - what models are used for dry scrubbing?

For scrubbing with activated carbon, air is generally brought through a dry adsorption media, where the contaminant is adsorbed onto the media. I would like to know what mathematical model is used ...
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How to retrofit seed starting trays to prevent root circling

I grow plum trees from pits using seed starting trays: Unfortunately, I have a problem where the roots of the seedlings grow in circles around the bottom of the cavities of the trays. The circling ...
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2 answers
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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 (...
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3 votes
1 answer
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Store seeds at 1°C

I have prunus pits that I stratify in a refrigerator during winter. Normally, the seeds germinate in springtime, which is ideal. However, often some of the seeds germinate prematurely. When this ...
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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 ...
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Design review needed for novel ion trap air scrubber / purifier concept [closed]

As a side kick I came up w/ a wet scrubber / air purifier design using trapped charged water droplets. I'm thinking about building a proof of concept but would like the community's feedback. ...
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3 answers
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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, ...
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0 answers
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How to select a smartphone IR camera for VOC monitoring [closed]

I am currently working on a problem involving volatile organic compounds (VOC) source monitoring on some oil and gas transportation environment. I think using infrared (IR) cameras could be a ...
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9 votes
4 answers
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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 ...
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2 answers
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Correlating relative humidity outside and inside an enclosure

I am building a device and I tried to Google an answer to this question but I am an electrical person and lack knowledge in this field. I need to know what the relative humidity inside an enclosure (...
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1 vote
2 answers
379 views

Why not use Sodium Hydroxide mist to precipitate carbon dioxide from hydrocarbon combustion exhaust

Much of the currently used techniques of scrubbing the carbon dioxide from power plant exhaust uses sophisticated amine and other organic compounds. These compounds are then forced to release the CO2 ...
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2 answers
157 views

Do cars that automatically turn off engines at idle save any significant fuel?

There are many new cars now that automatically turn off their engines when stopped at traffic lights. They then automatically turn them on when moving off. These systems have many names along the ...
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2 votes
1 answer
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Difference between surface loading rate and surface overflow rate of sedimentation tanks

Can anyone please explain to me the difference between surface loading rate and surface overflow rate when used during the design calculations of sedimentation tanks in water treatment plants?
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2 votes
2 answers
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Is it better to throw used domestic cooking oil in toilet or within the garbage? [closed]

I recently asked a friend how I should recycle my used deep frying oil because I just don't have enough oil to justify taking my car, drive 20 minutes away to the waste collection site for few liters ...
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1 answer
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How large of an area of the earth's surface would we need to cover in mirrors to negate global warming?

How large of an area of the earth's surface would we need to cover in mirrors to negate current levels of global warming? Let's assume that the reflective component of the mirror is made of aluminium ...
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4 votes
2 answers
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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?
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1 vote
0 answers
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Why have cascading vessels in the 'B' part of the 'AB' wastewater treatment process?

The AB process is wastewater treatment process that works like this: 'A Stage': Wastewater is (after mechanical treatment) subjected to a high load activated sludge process where also a lot of ...
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Can a retention/detention pond and a parking-lot be constructed in the same site foot-print?

Retention/Detention Ponds are often added to a site-design to mitigate storm-water runoff. Enhanced Porosity Concrete (EPC), aka Pervious Concrete, can be used as a parking-lot pavement that allows ...
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Hazardous Chemicals Waste Recycling company & KOH production, ABANDONED the site [closed]

A Hazardous Chemicals Waste Recycling company & KOH production, ABANDONED the site, they cut (looks like with a diamond saw) the concrete floor (25cm height) at about the middle of the warehouse, ...
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1 vote
1 answer
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Thermodynamics of an Arctic Greenhouse

QUESTION For a business project, I'm looking into the viability of a greenhouse situated in Canada's far northern town of Iqaluit. The problem is how to mathematically simulate the internal air ...
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5 votes
1 answer
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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. ...
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3 votes
2 answers
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Nuclear wastegate thermal dissipation systems?

How do shoreline nuclear facilities lower the temperature of wastewater generated by their cooling systems before it enters the ocean?
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8 votes
2 answers
102 views

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 ...
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2 votes
0 answers
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In what ways could coastal cities like New York/Boston/Miami mitigate future sea level rises and maintain current dry land area? [closed]

We've all read articles on rising sea levels and the impact it will have on coastal cities in the coming decades. There are even maps that illustrate how varying levels of rising seas will impact the ...
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What is the relation between the Biological oxygen demand and the depth of water tank? [closed]

I need a relation between Biological oxygen demand and depth. The ultimate [BOD] is known, and I need to calculate a [BOD] at any depth of water tank; temperature is constant. The tank is two meters ...
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9 votes
2 answers
276 views

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 ...
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3 votes
1 answer
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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 ...
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4 votes
1 answer
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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 ...
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3 votes
0 answers
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SBR-like reactors without decanters?

Sequencing batch reactors let sludge settle before drawing off the supernatant. For this, decanter arms are often used. An example is here. The challenge is to draw off the supernatant without ...
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Has large scale mono fermentation of sugar beets been achieved?

Sugar beets are an interesting substrate for biogas production due to their high content of easily digested sugars and starches. However, they lack macronutrients to sustain the bacteria population. ...
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4 votes
2 answers
980 views

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 ...
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4 votes
1 answer
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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 ...
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4 votes
2 answers
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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 ...
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7 votes
2 answers
256 views

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 ...
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