Resource recovery goes further than just the management of waste. Life-cycle analysis
(LCA) can be used to compare the resource recovery potential of
different treatment technologies. Improvements to administration, source separation and collection, reuse and recycling are important. For example, organic materials can be treated with anaerobic digestion and turned into energy, compost or fertilizer.
Resource recovery can also be an aim in the context of sanitation. Here, the term refers to approaches to recover the resources that are contained in wastewater and human excreta (urine and feces). The term "toilet resources" has come into use recently. Those resources include: nutrients (nitrogen and phosphorus), organic matter, energy and water. This concept is also referred to as ecological sanitation. Separation of waste flows can help make resource recovery simpler. Examples include keeping urine separate from feces (as in urine diversion toilets) and keeping greywater and blackwater separate in municipal wastewater systems.
Resource recovery can also be an aim in the context of sanitation. Here, the term refers to approaches to recover the resources that are contained in wastewater and human excreta (urine and feces). The term "toilet resources" has come into use recently. Those resources include: nutrients (nitrogen and phosphorus), organic matter, energy and water. This concept is also referred to as ecological sanitation. Separation of waste flows can help make resource recovery simpler. Examples include keeping urine separate from feces (as in urine diversion toilets) and keeping greywater and blackwater separate in municipal wastewater systems.
Materials used as a source
Solid waste
Steel crushed and baled for recycling
Recycling is a resource recovery practice that refers to the
collection and reuse of disposed materials such as empty beverage
containers. The materials from which the items are made can be
reprocessed into new products. Material for recycling may be collected
separately from general waste using dedicated bins and collection
vehicles, or sorted directly from mixed waste streams.
The most common consumer products recycled include aluminium such as beverage cans, copper such as wire, steel food and aerosol cans, old steel furnishings or equipment, polyethylene and PET bottles, glass bottles and jars, paperboard cartons, newspapers, magazines and light paper, and corrugated fiberboard boxes.
PVC, LDPE, PP, and PS (see resin identification code)
are also recyclable. These items are usually composed of a single type
of material, making them relatively easy to recycle into new products.
The recycling of complex products (such as computers and electronic
equipment) is more difficult, due to the additional dismantling and
separation required.
The type of recycling material accepted varies by city and
country. Each city and country have different recycling programs in
place that can handle the various types of recyclable materials.
Wastewater and excreta
Valuable resources can be recovered from wastewater, sewage sludge, fecal sludge and human excreta. These include water, energy, and fertilizing nutrients nitrogen, phosphorus, potassium, as well as micro-nutrients such as sulphur and organic matter. There is also increasing interest for recovering other raw materials from wastewater, such as bioplastics and metals such as silver.
Originally, wastewater systems were designed only to remove excreta and
wastewater from urban areas. Water was used to flush away the waste,
often discharging into nearby waterbodies. Since the 1970s, there has
been increasing interest in treating the wastewater to protect the
environment, and efforts focused primarily on cleaning the water at the
end of the pipe.[citation needed] Since around the year 2003, the concepts of ecological sanitation and sustainable sanitation have emerged with the focus on recovering resources from wastewater.[citation needed]
As of 2016, the term "toilet resources" came into use, and encouraged
more attention to the potential for resource recovery from toilets.
The following resources can be recovered:
- Water: In many water-scarce areas there are increasing pressures to recover water from wastewater. In 2006, the World Health Organization, in collaboration with the Food and Agriculture Organization of the United Nations (FAO) and the United Nations Environment Program (UNEP), developed guidelines for safe use of wastewater. In addition, many national governments have their own regulations regarding the use of recovered water. Singapore for example aims to recover enough water from its wastewater systems to meet the water needs of half the city. They call this NEWater. Another related concept for wastewater reuse is sewer mining.
- Energy: The production of biogas from wastewater sludge is now common practice at wastewater treatment plants. In addition, a number for methods have been researched regarding use of wastewater sludge and excreta as fuel sources.
- Fertilizing nutrients: Human excreta contains nitrogen, phosphorus, potassium and other micronutrients that are needed for agricultural production. These can be recovered through chemical precipitation or stripping processes, or simply by use of the wastewater or sewage sludge. However, reuse of sewage sludge poses risks due to high concentrations of undesirable compounds, such as heavy metals, environmental persistent pharmaceutical pollutants and other chemicals. Since the majority of fertilizing nutrients are found in excreta, it can be useful to separate the excreta fractions of wastewater (e.g. toilet waste) from the rest of the wastewater flows. This reduces the risk for undesirable compounds and reduces the volume that needs to be treated before applying recovered nutrients in agricultural production.
Other methods are also being developed for transforming wastewater into valuable products. Growing Black Soldier Flies in excreta or organic waste can produce fly larvae as a protein feed. Other researchers are harvesting fatty acids from wastewater to make bioplastics.
Organic matter
An active compost heap.
Disposed materials that are organic in nature, such as plant
material, food scraps, and paper products, can be recycled using
biological composting and digestion processes to decompose the organic matter. The resulting organic material is then recycled as mulch or compost for agricultural or landscaping purposes. In addition, waste gas from the process (such as methane) can be captured and used for generating electricity and heat (CHP/cogeneration)
maximising efficiencies. The intention of biological processing is to
control and accelerate the natural process of decomposition of organic
matter.
There is a large variety of composting and digestion methods and
technologies varying in complexity from simple home compost heaps, to
small town scale batch digesters, industrial-scale enclosed-vessel
digestion of mixed domestic waste (see mechanical biological treatment). Methods of biological decomposition are differentiated as being aerobic or anaerobic methods, though hybrids of the two methods also exist.
Anaerobic digestion of the organic fraction of municipal solid waste (MSW) has been found to be more environmentally effective, than landfill, incineration or pyrolysis. Life cycle analysis
(LCA) was used to compare different technologies. The resulting biogas
(methane) though must be used for cogeneration (electricity and heat
preferably on or close to the site of production) and can be used with a
little upgrading in gas combustion engines or turbines. With further
upgrading to synthetic natural gas it can be injected into the natural
gas network or further refined to hydrogen
for use in stationary cogeneration fuel cells. Its use in fuel cells
eliminates the pollution from products of combustion. There is a large
variety of composting and digestion methods and technologies varying in
complexity from simple home compost heaps, to small town scale batch
digesters, industrial-scale, enclosed-vessel digestion of mixed domestic
waste (see mechanical biological treatment). Methods of biological decomposition are differentiated as being aerobic or anaerobic methods, though hybrids of the two methods also exist.
Recovery methods
In many countries, source-separated curbside collection is one method of resource recovery.
Australia
In Australia, households are provided with several bins: one for recycling
(yellow lid), another for general waste (usually a red lid) and another
for garden materials (green lid). The garden recyclinc bin is provided
by the municipality if requested. Some localities have dual-stream recycling,
with paper collected in bags or boxes and all other materials in a
recycling bin. In either case, the recovered materials are trucked to a materials recovery facility for further processing.
Municipal, commercial and industrial, construction and demolition
debris is dumped at landfills and some is recycled. Household disposal
materials are segregated: recyclables sorted and made into new products,
and unusable material is dumped in landfill areas. According to the Australian Bureau of Statistics
(ABS), the recycling rate is high and is "increasing, with 99% of
households reporting that they had recycled or reused within the past
year (2003 survey), up from 85% in 1992".[citation needed]
In 2002–03 "30% of materials from municipalities, 45% from commercial
and industrial generators and 57% from construction and demolition
debris" was recycled. Energy is produced is part of resource recovery as
well: some landfill gas
is captured for fuel or electricity generation, although this is
considered the last resort, as the point of resource recovery is
avoidance of landfill disposal altogether.
Sustainability
Resource recovery is a key component in a business' ability to maintaining ISO14001
accreditation. Companies are encouraged to improve their environmental
efficiencies each year. One way to do this is by changing a company from
a system of managing wastes to a resource recovery system (such as
recycling: glass, food waste, paper and cardboard, plastic bottles etc.)
Education and awareness in the area of resource recovery is increasingly important from a global perspective of resource management. The Talloires Declaration is a declaration for sustainability concerned about the unprecedented scale and speed of environmental pollution and degradation, and the depletion of natural resources. Local, regional, and global air pollution; accumulation and distribution of toxic wastes; destruction and depletion of forests, soil, and water; depletion of the ozone layer
and emission of "green house" gases threaten the survival of humans and
thousands of other living species, the integrity of the earth and its biodiversity,
the security of nations, and the heritage of future generations.
Several universities have implemented the Talloires Declaration by
establishing environmental management and resource recovery programs. University and vocational education are promoted by various organizations, e.g., WAMITAB and Chartered Institution of Wastes Management. Many supermarkets encourage customers to use their reverse vending machines
to deposit used purchased containers and receive a refund from the
recycling fees. Brands that manufacture such machines include Tomra and Envipco.
In 2010, CNBC aired the documentary Trash Inc: The Secret Life of Garbage about waste, what happens to it when it's "thrown away", and its impact on the world.
Extended producer responsibility
Extended producer responsibility
(EPR) is a pricing strategy that promotes integrating all costs
associated with a given product throughout its life cycle. Having the
market price also reflect the "end-of-life disposal costs" encourages
more accuracy in pricing. Extended producer responsibility is meant to
impose accountability over the entire lifecycle of products, from
production, to packaging, to transport and disposal or reuse. EPR
requires firms that manufacture, import and/or sell products to be
responsible for those products throughout the life and disposal or reuse
of products.
