ENS-112 Environmental Science Chapter 17 PDF

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Chapter 17 notes from Dr. Adrienne George's lectures for ENS-112 Environmental Science at The University of Tampa...

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Environmental Science 112 FALL SEMESTER 2018 INSTRUCTOR: DR. Adrienne George [email protected]

Chapter 17 Approaches to Waste Management ● Waste refers to any unwanted material or substance that results from a human activity or process ● Waste is divided into several categories ○ Municipal solid waste is non liquid waste that comes from homes, institutions and small businesses ○ Industrial solid waste includes waste from production of consumer goods, mining, agriculture, and petroleum extraction and refining ○ Hazardous waste refers to solid or liquid waste that is toxic, chemically reactive, flammable, or corrosive ○ Wastewater is water we use that we drain or flush ● There are three main components of waste we generate ○ Minimizing the amount of waste we generate ○ Recovering discarded materials and finding ways to recycle them ○ Disposing of waste safely and effectively ● The waste stream is flow of waste as it moves from its sources toward disposal destinations ● Minimizing waste at its source point is called source reduction and is the best way of dealing with the waste stream ● The linear movement of products from their manufacture to their disposal is often described as “cradle-to-grave” ○ The new cradle-to-cradle approach requires that materials from products

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are recovered and reused to create new products

Municipal waste ● Municipal solid waste is commonly referred to as “trash” or “garbage” ○ This includes many different materials, from food scraps to paper, plastic, and glass

Consumption leads to waste ● Waste generation has nearly tripled in the United States since 1960, reflective of the increase in excess packaging and nondurable goods ○ This trend ended around 2005, with source reduction and reuse practices leaving total waste generation flat. ● As developing nations become more affluent, waste production and consumption both tend to increase ○ Many economically disadvantaged people in these countries support themselves by scavenging and selling items from dumps ● Developed countries have improved their waste collection and disposal, and the proportion of waste going to landfills has declined ○ This corresponds to an increase in recycling and composting

Reducing waste is our best option ● Packaging is a major source of waste that can be easily reduced ○ Consumers can buy unwrapped produce or buy food in bulk ○ Manufacturers can switch to packaging that is recyclable or reduce the size and weight of their containers ● Some governments are beginning to tax and restrict the use of plastic shopping bags, because they persist for so long and are often littered

Reusing items helps to reduce waste ● Consumers have many options for reusing items to further reduce waste

Composting recovers organic waste ● Composting is the conversion of organic waste (food scraps, yard debris,etc.) into

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mulch or substrate through the action of bacteria, earthworks, and other detritivores and decomposers ○ This compost is used to enrich soil, mimicking natural cycles of matter and preventing waste from reaching a landfill or incinerator

Recycling consists of three steps ● The first step of recycling is to collect and process used goods and materials ○ Materials recovery facilities (MRFs) - facilities that separate items by weight and size using automated processes including magnetic pulleys, optical sensors, water currents, and air classifiers ● The second step is for the the materials to be used to manufacture new goods ● The last step involves consumers and businesses buying products made from recycled materials

Recycling has grown rapidly ● VArious programs and efforts have increased recycling rates in the United States from 6.4% of the waste stream in 1960 to 25.7% in 2014 ○ One example is “trash audits”, where trash cans are emptied and recyclable materials are removed ● Recycling rates vary greatly from one material to another ● Low commodity prices can make municipal recycling programs unprofitable ○ These market prices do not reflect external costs of not recycling, such as increased greenhouse gas emissions

Financial incentives help address waste ● In “pay-as-you-throw” garbage collection programs, municipalities charge residents for home trash pickup according to the amount of trash they put out ● Bottle bills are laws that have consumers pay a 5-10 cent deposit on recyclable containers that is refunded when the containers are returned to the stores ○ States with bottle bills have recycling rates about 3.5x higher than states without them

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Sanitary landfills are our main disposal method ● Sanitary landfills bury waste in the ground or pile it in large mounds engineered to prevent waste from contaminating the environment ● Municipal landfills must adhere to standards set by the EPA under the Resource Conservation and Recovery Act of 1976 ● Waste placed into landfills is partially decomposed by bacteria and compresses under its own weight to take up less space ● Soil is layered with the waste to speed decomposition and reduce odor and pests ● Liners and collection systems prevent liquid leachate from escaping into the nearby groundwater ● Landfills must be located away from wetlands and earthquake-prone faults, and at least 6 meters above the water table ● Closed landfills are converted into public parks or other uses such as the freshkills Park in New York City

Incinerating trash reduces pressure on landfills ● Incineration, or combustion, is a controlled process in which garbage is burned at very high temperatures ○ Incineration reduces the weight of waste up to 85% and volume by up to 90% ● Emission fro incinerators must be passed through scrubbers that spray liquid that neutralizes acidic gases and a system of filters called a baghouse that physically filters fly ash

We can recycle materials from landfills ● Steel, aluminum, copper, and other metals are abundant enough in some landfills to make salvage operations profitable when market prices for the metals are high enough ● Organic waste from landfills could be mined and composted ● Older landfill waste could also be incinerated in waste-to-energy facilities to produce energy

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Industrial Solid Waste Regulation and economies each influence industrial waste generation ● The federal government regulates municipal solid waste ● State and local governments regulate industrial solid waste, with regulation generally being less strict than municipal solid waste ● Industry bases most of its practices on economic efficiency instead of physical efficiency, where less waste is produced per product

Industrial ecology seeks to make industry more sustainable ● Industrial ecology integrates principles from engineering, chemistry, ecology, and economics to maximize both physical and economic efficiency ○ The goal is to function more like ecological systems, in which organisms use almost everything that is produced ● This involves making several changes to industrial processes ● A life-cycle analysis looks product part generation more efficient, including its origins in raw materials, manufacturing, use, and disposal ○ Waste products from one process are incorporated into other processes ○ Environmentally harmful products are eliminated from industrial processes ○ Design changes are made to increase durability, recyclability, and reusability

Hazardous Waste ● By EPA definition, hazardous waste has at least on of the following characteristics ○ Ignitable: likely to catch fire ○ Corrosive: can corrodes metals in storage tanks or equipment ○ REactive: chemically unstable and readily able to react with other substances ○ Toxic: harmful to human health when inhaled, ingested, or touched ● Industry produces the most hazardous waste, but there are many forms of household hazardous waste as well ○ Paints ○ Batteries ○ Oils 5

○ Solvents ○ Cleaning agents ○ Lubricants ○ Pesticides

Organic compounds and heavy metals pose hazards ● Many synthetic organic compounds are toxic, absorbed through the skin and can act as mutagens, carcinogens, teratogens, and endocrine disruptors ○ They are also persistent, meaning they do not break down easily ● Heavy metals like lad and mercury are fat soluble and break down slowly, making them prone to bioaccumulate and biomagnify

E-waste has grown ● Electronic waste (e-waste) includes obsolete computers, MP3 players, cell phones, and other electronic devices ○ This source of waste has grown substantially due to the short lifespan of these products ● Due to the heavy metals and flame retardants in e-waste, the EPA and many states are beginning to treat it as hazardous waste ● A combination of devices becoming smaller and increase in recycling rates has decreased the amount of e-waste ending up in the waste stream’ ● Electronic devices contain rare and valuable trace metals that can be extracted and sold ○ …

Several steps precede the disposal of hazardous waste ● Under the REsource Conservation and Recovery Act, the EPA sets standards by which states manage hazardous waste ○ Hazardous waste must be tracked “cradle-to-grave” ● FAcilities that generate, transport, or dispose of hazardous waste mist report to the EPA the type and amount of material generated; its location, origin, and destination;

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and the way it is handled ○ This creates high disposal costs, which result in some companies illegally dumping the waste or exporting it to developing countries

We use three disposal methods for hazardous waste ● Landfills can be used for hazardous waste, but they must have several liners and be far from aquifers ● Surface impoundments are shallow depressions lined with plastic and in impervious material that are used to store liquid hazardous waste ○ The water evaporates from the waste, leaving a solid residue that is removed and transported fro permanent disposal ● Deep-Well Injections drill deep beneath the water table into porous rock and waste is injected into it ● Wells pose risks; they can corrode and can leak wastes into soil, contaminating aquifers, and deep-well injection may induce earthquakes

Contaminated sites are being cleaned up, slowly ● In 1980, the U.S. Congress passed the Comprehensive Environmental REsponse Compensation and Liability Act (CERCLA) ○ This created a hazardous waste site cleanup program called the Superfund ● Later laws charged the HPA with cleaning up brownfields, lands that contain hazardous materials ● When a superfund site is identified, scientists prioritize the site on the National Priorities List based on how near the site is to homes, whether wastes are confined or likely to spread, and whether the pollution threatens drinking water supplies ● As of 2017, 1336 Superfund sites remained on the National Priorities List, and only 393 had been cleaned up or otherwise deleted from the list

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