Question 1

What can escape and contaminate ground or surface waters if the soil below and above a landfill is permeable?

Accepted Answer

Leachates, which are liquids that have passed through the landfill and picked up pollutants and contaminants, can escape and contaminate ground or surface waters if the soil around the landfill is permeable. Pollutants, contaminants, and carcinogens are all possible components of leachate, but the specific substances will depend on the waste that is present in the landfill.

Question 2

Pollutants escape from improperly designed landfills in all of the following ways except

Accepted Answer

Rodents burrowing into the landfill for shelter do not constitute a way pollutants escape from landfills. Instead, they are a consequence of the landfill's presence, potentially leading to other issues, but not a direct pathway for pollutants to escape.

Question 3

Wastes dumped in the oceans at present are mainly

Accepted Answer

Dredge spoils are the most common type of waste currently dumped in the oceans, as they result from dredging activities to maintain navigable waterways and ports.

Question 4

Organic matter can be beneficial by a process known as

Accepted Answer

Composting is the process of breaking down organic matter into nutrient-rich soil that can be used as a natural fertilizer for plants. Composting reduces waste and can improve soil health, making it a sustainable and eco-friendly way to dispose of organic matter. Incinerating destroys organic matter and can release harmful pollutants into the air, while harvesting involves collecting crops or resources, which is not a process that applies to organic matter in general.

Question 5

For a landfill,which of the following techniques provides an incomplete solution to reducing space?

Accepted Answer

Incineration reduces the volume of waste, thus saving space in a landfill, but it does not eliminate the need for landfills entirely. Some residue from incineration processes still requires landfilling, and not all materials are suitable for incineration.

Question 6

If a septic system is to be used for sewage disposal,

Accepted Answer

The soil should be unsaturated, containing sufficient air (oxygen) to permit aerobic breakdown of wastes. In a septic system, the wastewater is treated and disposed of on-site, mainly with the use of bacteria that break down the organic material in the wastewater. Oxygen is necessary for the bacteria to perform aerobic digestion, which is the most effective method of breaking down the organic material. Therefore, the soil should be unsaturated to allow for oxygen to be present for the aerobic bacteria. The other options are incorrect as high population density is not required for efficient operation, and not all potential pollutants may be decomposed in normal operation. The surrounding soil does not necessarily have to be impermeable, but it should be able to allow for proper drainage.

Question 7

The problem of solid waste disposal

Accepted Answer

The problem of solid waste disposal has been reduced by increasing recovery, recycling and reusing (such as composting, waste exchange programs and reuse of scrap materials). The other options are not true - population growth and aging buildings contribute to the problem, and the EPA has not eliminated the problem entirely.

Question 8

Incineration can provide energy as a by-product.Another waste-disposal method that can supply useful fuel is

Accepted Answer

Sanitary landfill is the only waste-disposal method listed that does not involve burning or directly utilizing waste as fuel. However, some landfills can also capture methane gas produced by the decomposition of organic waste and use it as a source of energy. This process is known as landfill gas-to-energy and provides an additional benefit to the environment by reducing greenhouse gas emissions.

Question 9

On-site disposal of food waste using an in-sink garbage-disposal unit is detrimental for all of the following reasons except

Accepted Answer

On-site disposal of food waste using an in-sink garbage-disposal unit is beneficial for reducing the impact on local landfills, but it requires electricity and water, adversely affects the performance of septic systems, and increases the volume of solids that must be treated by municipal wastewater treatment plants.

Question 10

In terms of volume,the largest liquid-waste disposal problem is

Accepted Answer

Sewage accounts for the largest volume of liquid waste generated worldwide. It includes domestic wastewater, industrial effluents, and agricultural runoff. While toxic industrial chemical waste and high-level liquid radioactive waste may have more severe environmental impacts, they are generated in smaller volumes compared to sewage. Wastewater from mineral-processing activities is also significant, but it is generated in smaller volumes compared to sewage waste.

Question 11

In the United States,the major share of municipal soil wastes end up in

Accepted Answer

Sanitary landfills are the most common method of disposing of municipal solid waste in the United States. According to the Environmental Protection Agency (EPA), there were 1,738 active municipal solid waste landfills in the U.S. in 2018. Incineration facilities are a less common method of waste disposal and are generally used for hazardous waste rather than municipal solid waste. Open dumps are illegal and have been phased out in most places in the U.S. Finally, the dumping of municipal solid waste in oceans is illegal under the Marine Protection, Research, and Sanctuaries Act.

Question 12

The difficulties in recycling where materials are recovered from the municipal refuse requires

Accepted Answer

Source separation is the process of separating recyclable materials from general waste at the time of disposal. This is essential for effective recycling as it helps to improve the quality and purity of the material, making it easier to process and reuse. Source assessment, source provenance, and source assimilation are not directly related to the process of recycling where materials are recovered from municipal refuse.

Question 13

If one were practicing the dilute-and-disperse approach to disposal of liquid hazardous wastes,one might consider using

Accepted Answer

The dilute-and-disperse approach to disposal of liquid hazardous wastes is not an environmentally responsible approach. It can have negative impacts on water quality and human health. Therefore, switching to an alternate, more environmentally responsible approach is the best choice. Options such as recycling, proper disposal at hazardous waste facilities, or treating the wastes to remove hazardous components are preferable alternatives. Options A, B, and C are not appropriate methods for disposing of hazardous liquid wastes.

Question 14

In a landfill,

Accepted Answer

Controlling moisture content in a landfill can optimize methane production and waste decomposition while minimizing leachate. Too much moisture can result in anaerobic conditions that produce harmful gases and leachate, while too little moisture can slow down decomposition. Therefore, the goal is to maintain optimal moisture levels for efficient landfill operation.

Question 15

After aerobic waste decomposition in a landfill has stopped,

Accepted Answer

Anaerobic decomposition, which occurs after aerobic decomposition has ceased in a landfill, produces various gases, including methane, due to the activity of anaerobic bacteria breaking down organic waste in the absence of oxygen.

Question 16

The use of plants in the cleansing of water includes all of the following except

Accepted Answer

The use of plants in the cleansing of water can involve many methods, such as constructed wetlands, plant-laden ponds, and gravel-filled basins with wetland plants. However, removing oil from groundwater is not typically a process that involves the use of plants. Instead, oil is often removed from groundwater through physical and chemical methods such as filtration and absorption using materials like activated carbon.

Question 17

The thickness and __________ of soil are key factors in determining site suitability for a septic system.

Accepted Answer

Permeability is crucial for septic systems as it determines how well water can move through the soil, affecting the system's efficiency and preventing contamination.

Question 18

Volumetrically,the two principal sources of solid waste in the United States are wastes from livestock and from

Accepted Answer

Mineral extraction and processing, along with wastes from livestock, are the two principal sources of solid waste in the United States when measured by volume. This is because the processes involved in mineral extraction and processing generate large quantities of overburden and tailings, while livestock produce significant amounts of manure and other agricultural wastes.

Question 19

Each of the following is true about the recycling of paper except

Accepted Answer

Recycling paper reduces the demand on local landfills as it diverts waste from them. Therefore, option C is not true. Options A, B, and D are all correct statements about paper recycling.

Question 20

Conventional waste incineration,at moderate temperatures,

Accepted Answer

Conventional waste incineration, at moderate temperatures, is particularly effective for paper and similar flammable materials. It does not completely destroy toxic organic chemicals and produces harmful gases. Therefore, option B and C are incorrect.

Quiz 16: Waste Disposal