Lesson 6: Sustainable Water and Wastewater Systems
Lesson 6: Sustainable Water and Wastewater Systems sxr1336.0 Overview
6.0 Overview jls164Overview
When we examine the sustainability profile of a particular community, we always have to look at the water system that sustains that community. Historically, people dwellings were associated with the sources of water: rivers, springs, or lakes. In modern times, the issue of water remains primary. We have more advanced technologies to extract and distribute water resources, and we have other technologies to utilize and treat water. Those technologies become key links in the universal water cycle, which involves both ecological and anthropogenic spheres. This lesson specifically focuses on the technological methods to provide efficiency for water supply and further to provide sustainability of water resources. Such technologies target the two growing problems - water resource depletion and water pollution. After touching on the background of water management systems, this lesson will direct you to the examples of lifecycle analysis, which helps identify the technologies with the higher promise for sustainability.
Learning objectives
By the end of this lesson, you should be able to:
- understand the water cycle, identify the main processes, and explain connections between natural and anthropogenic water paths;
- name and explain the key sustainable technologies in water management and wastewater treatment;
- estimate water use of anthropogenic systems;
- compare different water treatment technologies against environmental metrics and identify pros and cons of new alternatives.
Readings
- EPA Document: USEPA Water Conservation Plan Guidelines, EPA 1998, Appendix A: Water Conservation Measures, pp. 143-155.
- Journal article: Vorosmarty, C.J., Sahagian, D., Anthropogenic Disturbance of the Terrestrial Water Cycle, BioScience, vol. 50, pp.753-763.
- Journal article: Dhinadhayalan, M., Nema, A., Decentralized wastewater management - New concepts and innovative technological feasibility for developing countries, Sustain. Environ. Res., 22(1), 39-44 (2012).
- Journal article: Bonton, A., Bouchard, C., Barbeau, B., Jedrzejak, Comparative life cycle assessment of water treatment plants, Desalination 283, 42-54 (2012).
These articles are available online through PSU Library system - See the "Library Resources" / E-Reserves link in Canvas.
Questions?
If you have any questions while working through this Lesson, please post them to our Message Board forum in Canvas. You can use that space any time to chat about course topics or to ask questions. While you are there, please feel free to post your own responses if you are able to help out a classmate.
6.1 Understanding water cycle
6.1 Understanding water cycle rak189Water is often envisioned as the bloodstream of biosphere. It is a universal medium that is crucial for sustainability of both ecological and human societies. There is no substitute for water. More than 70% of the earth surface is covered by water. However, only 3% of this reserve is fresh water that can be used for human consumption. 90% of the earth's fresh water resources is contained in groundwater and ice, and only 10% is water is contained in surface reservoirs - rivers, lakes, wetlands, and streams. [Girard, 2013].
Although sustaining life is one of the main key purposes of the water, present-day agriculture and many industry branches heavily rely on the abundance of the water resource. For example, water is used as heat transport fluid in thermoelectric energy systems, such as nuclear and fossil fuel fired power plants and concentrating solar power farms. It is used as solvent and raw material in chemical manufacturing. Mining industry utilizes significant amount of water in hydraulic fracturing and oil recovery. Those industries are important parts of modern infrastructure; hence, the water demand must be met to keep the power and food production at the necessary level.
To plan sustainable utilization of water resources, we must understand how the water cycle works at the global and local scales. The amount of water on earth is finite, and the natural water cycle is a system that controls the circulation and redistribution of that resource. You must be familiar with the water cycle concept from your early science classes. But you can get a refresher from the following short video:
Video: Water Cycle | How the Hydrologic Cycle Works (6:46)
PRESENTER: All the water on Earth today, every drop, is all the water there has ever been on the planet. Fresh water is actually, millions of years old. The same water flowing in a continuous loop. Falling as rain and snow from clouds to the Earth's surface. Running in rivers. Pooling in ponds. Flowing from faucets. Irrigating crops. Traveling through plants. Generating power. Eventually, evaporating into the air and condensing into clouds, again.
ANNA MICHALAK: Why is there life on Earth? And the reason there is life on Earth is because Earth has this perfect water cycle.
PRESENTER: The water cycle, so simple even small children understand the basics. Yet, so complex, the most advanced Earth scientists-- hydrologists, geologists, and biogeochemists-- are studying every part and process.
MARTHA CONKLIN: The water cycle is fascinating. It's something that's around us all the time. And yet, we don't really understand it.
PRESENTER: How to summarize what is known about the water cycle? With two words-- flows and stores. The water cycle is a series of flows of water between various water stores, or storages-- clouds in the atmosphere.
TOM HARMON: There's always a little bit of water in the atmosphere. We talk about relative humidity. It's a humid day. It's a dry day. Either way, there's water-- sometimes, a little. Sometimes, a lot.
PRESENTER: There's a lot of water in the ocean-- 70% of all the water on Earth. In the ice sheets and glaciers, 2/3 of all the freshwater on Earth. In the snow packs atop mountains like the Sierra Nevada. In the Great Lakes. In rivers and streams. In reservoirs and watersheds. In wetlands. In the soil. In and on plants and trees rooted in the soil. And beneath the soil, in water tables and underground aquifers like the Ogallala-High Plains, which runs underneath parts of eight states, from South Dakota to Texas. All this storage is temporary. Water in all its forms is always in flux and always moving. And there is a name for every kind of movement in the water cycle, starting with precipitation.
ANNA MICHALAK: Precipitation is the process of water falling onto the surface of the Earth. You could have precipitation in many forms-- rain, snow, hail.
PRESENTER: Rain is falling water in liquid form. Snow, ice, hail, and sleet are falling water in solid or frozen form. Fog and mist, falling water in gas or vapor form. Precipitation that falls directly onto the oceans becomes part of Surface Ocean and can be churned by wave and wind action into ocean currents. Rain and snow that falls directly on rivers and streams becomes one part of stream flow. Rain that falls onto land takes a different path to the river. As does the snow and ice that falls and collects on mountain tops when temperatures warm.
MARTHA CONKLIN: When snow melts, some of it runs through the snow pack and goes into small streams, tributaries that feed into large rivers.
PRESENTER: What about that precipitation that falls on and over land? Some is intercepted by vegetation-- plants and trees. TOM HARMON: Like you might imagine, someone in the game of football intercepting a pass, these are raindrops trying to come to the ground and the leaves on the tree intercept them before they hit the ground.
PRESENTER: And the precipitation that does hit the ground, it can run off if the ground is hardscape, covered with asphalt or concrete, or if the soil is too wet or saturated to absorb more water, like an over-soaked sponge. Otherwise, precipitation infiltrates the soil surface, percolates into the ground.
TOM HARMON: Think of it as the water percolating through your coffee grounds in the morning. Gravity continues to pull it downwards so it will move through.
PRESENTER: Through the topsoil. Into spaces between soil and rock particles. Down to bedrock and further into fractures. Into deep underground aquifers. Even ground water here is moving sideways or laterally, discharging toward a river, lake, or the sea. Generally, the deeper the flow, the slower the flow.
MARTHA CONKLIN: Some of that fractured water might take a very long time-- thousands to millions of years-- to get out.
PRESENTER: And how does water get back out into the atmosphere? It evaporates. It's turned from a liquid into a gas or vapor, by the heat of the sun.
ANNA MICHALAK: If you put a bit of water into a bowl and you set it outside on a sunny day, it's going to disappear. It's still water, it's just in the form of a gas rather than the form of a liquid.
PRESENTER: Water evaporates from every wet surface, even from wet air. Some rain and snow evaporates into the air while falling. Water evaporates through our respiration and perspiration. And from plants through transpiration. Trans means through or across. Plant roots draw up groundwater. And plants pull that water up through their stems into the leaves and then, release them back out through evapotranspiration. Evapotranspiration-- a spelling bee worthy term for evaporation from soil and water surfaces, plus transpiration from plants. Evaporated water molecules are tiny enough to flow into the air. Mix with smoke and dirt particles in the atmosphere. Cool. Condense into visible masses of water vapor-- clouds. Winds move clouds into colder air, water droplets collide and merge, grow bigger and heavier until they are so heavy, they fall again, as rain or snow, sleet or hail. Precipitation, collection, runoff, interception, infiltration, percolation, discharge, transpiration, evaporation, condensation-- the water cycle
This quite general and deceivingly simple concept of water cycle has a number of limitations which are important to understand:
- Capacities of the reservoirs vary dramatically.
- Flow rates between the reservoirs vary dramatically (for example replenishment of a surface stream via precipitation can take days, while replenishment of a deep aquifer may take decades).
- This concept does not directly reflect possible delays or discontinuities.
- Cycle kinetics depends on climate, time of the year, and geographic location.
- This concept does not portray fluctuations in storage zones.
Check out this website!
To add some quantitative information to the picture, please take a look at the US Geological Survey (USGS) website.
If you scroll down and click on any of the components of the water cycle, you will get comprehensive information on that reservoir. Note the dramatic difference in water capacity of different reservoirs. Try to remember at least the order of magnitude of the specific water reserves, since such quantitative perception can be quite useful in sustainability analysis.
Annual evaporation from the ocean is about 80,000 cubic miles versus 15,000 cubic miles from the land. Given the amounts of water evaporated and precipitated are almost equal, the total amount of water exchanged between the atmosphere and the earth surface is about 95,000 cubic miles. Out of the water evaporated and then returned by rainstorms, 24,000 cubic miles fall on land as precipitation. The average annual precipitation over the land is 26 inches, but it is not evenly distributed. Arid locations may get under 1 inch of precipitation, whereas some others can get more than 400 inches. The total annual precipitation in the United States is about 30 inches per year, which accounts for about 4300 billion gallons per day. The total water flow from surface and subsurface sources is about 8.5 inches per year, i.e., about 1200 billion gallons a day. This amount is available for human use, including domestic, industrial, agricultural, and recreational use. Considering that the difference between precipitation and stream flow is -21.5 inches per year (3100 billion gallons per day), this amount is assumed to return to the atmosphere (through evaporation and transpiration). This returned volume roughly accounts for 70 % of the total water supply. [Source: USDA, 2001]
In nature, the hydrological cycle is well-balanced, and fluctuations of environmental water stocks are reversible. But when some of the parts of the system are interfered, resilience of the system may be jeopardized. This can happen when the anthropogenic water consumption cycle is plugged in to the natural water cycle. The main troubles currently experienced because of mismatch of the anthropogenic and natural cycles include:
- groundwater depletion;
- chemical pollution of surface waters and groundwaters;
- lake drying;
- droughts;
- desertification;
- eutrophication
- loss of habitat
- water and food shortages.
While the above-listed factors may have acute local effect, recent research also shows that large-scale hydraulic engineering produces global-scale impact on the earth's water cycle, raising the global sea level.
Reading Assignment:
Read through the following article that discusses the main man-made factors that affect the natural hydrological balance. While you are welcome to read the whole article, put the main focus on Table 1, which quantifies those effects, and sections on "Major classes of water engineering" and "Impacts of Human control...", which explain the specific mechanisms within the cycle.
Journal article: Vorosmarty, C.J., Sahagian, D., Anthropogenic Disturbance of the Terrestrial Water Cycle, BioScience, vol. 50, pp.753-763. (Full article can be accessed via Library e-Reserves in Canvas.)
Some of the things to reflect on in this reading:
- Water management is closely dependent on soil management: overuse of soil, deforestation increase storm water runoff, decreasing absorption to soil and hence decreasing the continental water storage. Water does not have a chance to return to aquifers.
- While no net losses occur in the water cycle ("closed" system), loss of continental (fresh) water from continents to the ocean (salt water), results in shrinking of the usable water reservoirs - e.g., depletion of aquifers.
- Irrigation accounts for over 80% of all 'irretrievable' water consumption. This constitutes ~56% of all water withdrawn from the natural sources in some areas. Loss of water during irrigation is due to intense evaporation and plant uptake.
- Large artificial reservoirs (dammed rivers) have high evaporation rates (compared to unmodified rivers) and therefore can reduce the continental runoff. At the same time, they cause water transfer to the atmosphere and to the groundwater storage.
The idea of sustainability in water management implies matching the natural water cycle and technical (anthropogenic) water use cycle together with minimal damage and maximum mutual support. A new approach to integrated managing water resources is known as total water cycle management, where water supply, stormwater, and wastewater are all considered during the design process.
The diagram in Figure 6.1. presents the water cycle in terms of stocks and flows. It illustrates the connections between different natural processes and reservoirs and also introduces the anthropogenic water paths into the system. The diagram is quite busy, so it would be useful to walk through it step by step. The video embedded below provides commentary to different parts of the diagram and also shows the links where water-treatment technologies must be applied to provide compatibility between the environmental and anthropogenic spheres. While watching, you may need to switch to 'full-screen' and HD quality setting to better see smaller details.
Click on the image to view the large version
Video: Water Cycle Step by Step (8:37)
This animation shows multiple connections within the hydrological cycle, including those with human controlled systems. It gets kinda bulky in the end so I will go step-by-step.
Let's start with ocean. The ocean is the biggest reservoir on the Earth, which accounts for about 96.5% of global water reserve. The ocean exchanges water with the atmosphere. Through evaporation and precipitation. Atmospheric water vapor accounts for only 1000th of a percent of the global water. But because the surface of the evaporating ocean is so huge, they exchange is extremely important as transport mechanism.
Now, let me push this ocean box to the side and clear up space for some other storages and elements of the cycle. We can identify a few main types of continental water storages. Surface water, rivers and streams, lakes, and some snow and ice masses. Snow and ice, by the way, represent quite a significant storage. They contain more water than all other service storage is altogether. Although storages are fed by the precipitation fluxes, rainfall or snow fall, and they also release some water back to the atmosphere. Snow eventually can melt and feed some water to the surface freshwater system. Then surface water flows to the streams and rivers through collection and surface runoff and reverse channel water to the more stationary storage lake or flow directly to the ocean. This is quite well-known schema of natural water exchange, which you may have heard in basic earth science class. But let's go a little bit further and add some more details here.
Some of the rain can be intercepted by plants and that water eventually drips and flows down over with some delay. Plants also release some water to the atmosphere through transpiration and evaporation. Okay, The next step is very important. Considerable amount of surface water infiltrates into the soil from where it can be taken by plants. This process fosters biomass production. The rest of it percolates down to the groundwater and groundwater can actually migrate and exchange with the surface water storage is through the base flow.
Groundwater is another huge reservoir, which may contain either fresh or salty water. Some of the aquifers may have connections to juvenile resources. In other words, the origin of this water can be related to the magmatic processes in the interior. So we put that into the picture. The next link, some of the groundwater in juvenile water reacts with rocks and is present in the mineralized form. For example hydrated minerals. And finally, here we have the geothermal water, which can be connected to both juvenile water pricing or dehydration of minerals on the high temperature and pressure. In some spots, geothermal water can just charge to the surface or to the ocean floor. This closes the loop from the downside. So this is the natural water cycle without humans in the picture.
But what if we put our water utilization system right in the middle here? That includes agricultural, domestic, and industrial use of water. And those can be connected to an artificial water storage. So where does that usable water come from? Can be extracted from the aquifers or taken directly from the surface reservoirs, for example agriculture can use some diverted streams for irrigation. All those users produce some wastewater for sure and that wastewater can be treated and returned to the environment. Can be either discharged to streams or sprayed onto soils, or even can be re-inject it to the aquifers. Some of the treated wastewater can be re-used, which makes it closed recycling loop here. Agricultural irrigation is another way for the water to return to the natural cycle. Now we understand that rain can fall on the human-made environment as well. And after this indirection, we have some stormwater produced. This storm water is also considered some kind of wastewater which can be treated or not treated depending on the locality. But either way, storm water contributes to the discharge flux from the human water utilization system to the nature.
Then we add another discharge curve here, showing that some of the wastewater sometimes goes back to the environment without any treatment. This is not good, but it happens. Can we extract water from other resources if groundwater is not available? Sure. Here we put the additional arrows to show extraction of water from rivers and lakes and exchange fluxes with the ocean certainly also take place. Some locations direct circulation of geothermal water. There's also a viable option. People can use it for heating the homeschool, for example. I'm sure this schematic can be developed further and more storages and fluxes can be identified. But let's stop here. You see this boundary zone here between the naturally balanced part of the cycle and human control part of the cycle is where the potential problems occur. Mismatch in physical and chemical fluxes can throw the system off balance and lead to water shortages, ecological crisis, pollution, and all other negative consequences. So to ensure global and local sustainability of water resources, we need a number of special technologies that would help make these two systems more compatible. Some technologies are used at the extraction phase, for example drinking water purification. Those make sure the water is sufficient and safe for human consumption. Other technologies are used at the discharge path. for example wastewater treatment. Those are designed to mitigate pollution and make sure that we're not depleting our natural reservoirs too soon.
Finally, some technologies help control water loops within the human domain, for example water distribution and collection. The bottom line of this demonstration is that the development of novel technologies for water treatment and monitoring is very important for providing smooth interaction between the sphere of human activity and the environment. The ultimate sustainability goal here is to re-install the water balance locally and globally. And to be sure that this most important and irreplaceable resource is conserved for centuries to come.
As you can see in the diagram in Figure 6.1, the boundaries between the natural and human-controlled water systems are where the sustainable water treatment technologies should come into action. The bottom line is that the role sustainable water technology is to reconcile the natural and anthropogenic cycles and to alleviate mutual harm and system misbalance.
The following list gives you some examples of possible actions that help to keep combined water system sustainable (can vary with location):
Water regime management
- keep the aquifer levels within appropriate range
- prevent flood damage in developed areas
- prevent excessive erosion
Water quality
- minimize the export of pollutants to surface water or groundwater
- minimize waterborne sediment loading
- minimize pollution from sewage protect existing vegetation
Water conservation
- control water extraction and use
- promote the use of rainwater and stormwater where such use does not adversely affect existing environmental values
- promote the reuse of wastewater effluent
- reduce irrigation requirements
- promote opportunities for localized supply
Water value
- enhance water related environmental values
- enhance water related recreational and cultural values
- add value while minimizing development costs
Many of these actions require efficient technologies of water control and water treatment. The following sections of this lesson provide you with some examples and technical details on current practice of water treatment and prospective technologies for the future.
Check Your Understanding
Which of the following continental water storage reserves has the largest global capacity?
Glaciers and snow account for 5,773,000 cubic miles; second largest - groundwater accounts for 5,614,000 cubic miles
Check Your Understanding
What processes in the water cycle are responsible for depletion of continental water storage?
increased evaporation (often observed in artificial reservoirs and on irrigated areas); increased surface runoff (often caused by deforestation, urbanization, and soil damage)
6.2 Water conservation and protection technologies
6.2 Water conservation and protection technologies mjg8Water use statistics
When water is extracted from the natural water cycle, where does it go?
Based on government statistics, a big part of it (~40%) is used for agricultural needs (e.g., irrigation for crops or livestock), around 47% is used for industrial needs (e.g., power generation, mining, etc.), and around 13% is going to public supply (e.g., domestic or commercial) (Figure 6.1). However, these numbers can vary with location. For example, in Minnesota, the majority of the water extracted is used for power generation, while in California, the dominating use is irrigation [USGS, 2015].

Although residential water consumption accounts for a smaller fraction of the whole, domestic water economy is considered an important factor in urban sustainability. The overall domestic water use is expected to grow as world population grows.
According to the U.S. Geological Survey 2015 water census, daily per capita domestic water use in the U.S. was 82 gallons per day, which was an improvement from 88 gallons per day estimated in 2010 census, and 101 gallons per day in 1995 census. This value represents the national average, and the actual local water use can vary broadly - for instance, from 35 gpd in Connecticut to 186 gpd in Idaho [USGS, 2015].
Typical US home water use accounting is:
- Showers - 19.5%
- Washers - 22.1%
- Toilets - 18%
- Dishwashers - 1.5%
- Baths - 2.7%
- Leaks - 8.8%
- Faucets - 23.9%
- Other - 3.4%
One can estimate how much water they use at home with some simple online calculators:
Water Conservation strategies
As the population grows, so does the stress on available water resources. Hence, there are a number of water conservation strategies, with some of the most intuitive approaches being:
- Limiting the consumption: Application of policies, economics, and technologies help regulate the demand. Policies may include restrictions and bans on certain types of water use, standards for fixtures and appliances, enforcement on recycling, etc. Economic measures, such as setting prices for water consumption, typically make people more diligent about their water-related activities. Technological advances may help use less water for the same function (water-economy washers, toilets, etc.)
- Reuse and recycling: Designing systems for reuse and recirculation of water in both domestic and industrial applications are involved in this approach. For example, treated wastewater can be used for irrigation; or water can be recycled in certain types of car wash systems.
- Elimination of losses: Regulation, metering, water-sensitive design, and smart technology are key factors contributing to this strategy. Leak identification systems, smart controllers for water use are some of such conservation technologies.
- Pollution prevention: Less pollution creates more opportunity for water reuse and conserves natural water reserves. Regulatory policies are introduced on water discharging facilities. Also, numerous technologies exist to treat the effluents from domestic and industrial facilities.
Sustainability goals and growing demands for clean water require new solutions in water conservation and use. There are technologies in place; however, many existing methods sometimes have low efficiency and are prone to water losses. Some innovative approaches are overviewed in this Guardian article: "The new water technologies that could save the planet."
The technologies mentioned in this article work out a number of issues, such as scalability, cost, and efficiency. In sustainable development, we want the systems to be affordable and compact, not using too many resources. That makes them easy to implement in both urban and rural settings.
US EPA introduced a set of strategic practices and policies to water promote water conservation. There are three levels of control, which are summarized in Table 6.1 below. Level 1 measures represent the most basic practices, Level 2 measures are intermediate-level controls, and Level 3 lists more advanced strategies for water conservation. When organizations design their water conservation programs, they may start at Level 1 and gradually proceed to Levels 2 and 3:
| Level 1 Measures | Level 2 Measures | Level 3 Measures |
|---|---|---|
| Universal metering | Water-use audits | Replacements and promotions |
| Water accounting and loss control | Retrofits | Reuse and recycling |
| Costing and pricing | Pressure management | Water-use regulation |
| Information and education | Landscape efficiency | Integrated resource management |
Complete the following reading assignment to learn what each of the above-listed measures involves.
Reading Assignment:
The following EPA document will help you to understand the key strategies and driving forces in water demand management and water conservation.
USEPA Water Conservation Plan Guidelines, EPA 1998, Appendix A: Water Conservation Measures, pp. 143-155.
While reading, look through the definitions of the terms listed in the above table and understand them. Implementation of these measures has triple leverage: economics, policy, and technology. As you read, particularly think about the role technologies may play in the effectiveness of these measures.
Check Your Understanding
This question is based on the above reading.
What kind of technologies would play a role in the implementation of the following measures of water conservation? Fill in your ideas in the blank, then click for answers.
Water reuse and recycling
Efficient wastewater treatment technologies are crucial to enable multiple uses of water.
Water accounting and loss control
Accurate water metering technologies, leak detection sensors, monitoring transmission system integrity
Landscape efficiency
Lawn maintenance technologies, irrigation water sensing devices, soil improvement mulching
Retrofits
Low-flow faucets and shower-heads, advanced plumbing materials
6.3 Water treatment systems
6.3 Water treatment systems sxr133Water treatment technologies are designed to eliminate harmful effects of pollutants and natural substances to human health and environment. Within the blended water cycle (considered on page 6.1), these technologies are often placed at the transitions between the environment and human sphere to adapt the water quality.
For example, when water passes from the environmental source to the human consumption system, there is a possible risk to human health from some natural bacteria, chemical elements. Hence, natural water (from either surface or underground reservoir) needs to be purified to a certain standard. On the other end of the system, the water containing waste or substances resulting from the domestic, agricultural, or industrial activity must be cleaned before returning to the environmental pathways. If this is not done, harmful effects of concentrated pollutants can cause significant disturbance to the natural water ecology and escalate damage to both ecosystem and society in the long run. Some common effects of wastewater pollution include eutrophication (biological nutrient pollution; for example, releasing access of nitrogen and phosphorus —"overfeeding ecosystem"); oxygen depletion (due to oxidation of organic compounds); odor and aesthetic damage; proliferation of harmful bacteria, viruses, fungi in drinking water supply.
Centralized water treatment
Centralized water treatment approach implies treating large amounts of water at large rates in a "central" location and distributing that water via networks of pipelines, channels, and intermediate reservoirs. Centralized water treatment is largely implemented and maintained in major urban areas and in most parts of the developed world. Probably most of us primarily use the centralized treatment in our lives (maybe except some travel circumstances).
A couple of videos below describe large-scale water treatment systems that are designed to remove undesired contaminants from water.
This first video shows an example of how water is treated during its transfer from the environmental source to the drinking water supply:
Video: Water Treatment Plant Tour (5:26)
Welcome to our tour of Winnipeg's drinking water supply and treatment system. We use leading edge technology to treat the water as it passes through many stages, including coagulation, flocculation, dissolved air flotation, filtration, and three types of disinfection. Our system protects public health by virtually eliminating the risk of waterborne disease and reducing the level of harmful disinfection byproducts. It also improves the taste, odor, and appearance of our tap water.
Shoal Lake has been our source of water since 1919. It's located 136 kilometers from Winnipeg at the Manitoba-Ontario border and is approximately 92 meters higher than Winnipeg. Water flows downhill from Shoal Lake through an aqueduct into four large reservoirs next to the treatment plant. The aqueduct is a large concrete pipe that carries up to 386 million litres of water per day to the reservoirs. The reservoirs hold up to 8.8 billion litres of water which on average is enough to supply Winnipeg for about 30 days.
Water flows from the reservoirs through two large pipes into powerful pumps that move the water into the plant for treatment. This $300 million state of the art facility features a highly automated system that monitors and controls a wide variety of instruments, mechanical equipment, and electrical equipment, including 40 processors, 140 pumps, 2,300 valves, and 1,400 instruments. It can treat up to 400 million litres of water per day.
In this first step, we add sulphuric acid and ferric chloride as the water flows into the plant. Sulphuric acid lowers the pH of the water and makes this stage of treatment more efficient. Ferric chloride, a coagulant, causes the naturally occurring particles of organic material in the water to attract each other. The water enters flocculation basins where large mixers slowly stir the water, causing the particles to collide and stick together, creating large clumps. Now that large clumps have been formed in the water, the next step is to remove them. We do this in dissolved air floatation tanks. We inject a stream of water, supersaturated with air, into the flocculated water which is flowing into the bottom of the tanks. Tiny air bubbles are released into the water and carry the clumps to the top of the tanks. Skimmers remove the floating clumps from the surface of the water. The clumps are pumped to an area for further processing. The treated water is collected from the bottom of the tanks. The water flows from the dissolved air floatation tanks to chambers where ozone is added. This step called ozonation does three things. It provides the first level of disinfection by destroying most of the harmful bacteria, it improves the filter performance in the next treatment stage, and it improves the taste and odor of the water. We make ozone by applying electricity to liquid oxygen. At the end of the ozone chambers, we add sodium bisulphite to the ozonated water to remove any leftover ozone.
The water now flows into filter tanks containing biologically activated carbon. The filters remove any remaining small particles in the water, including parasites. Good bacteria growing on the filters remove some of the remaining dissolved organic material. This reduces the level of disinfection byproducts in the water. We clean the filters regularly by pumping air and water backwards through them. The backwashed water is pumped to an area for additional processing. The filtered water flows into the chlorine contact chamber for a second round of disinfection. We add chlorine to kill viruses and bacteria such as E. coli that might be in the water. Chlorine is the most widely used drinking water disinfectant in North America and has been used for more than 100 years. We then add sodium hydroxide to bring back the pH of the water close to the original level. The water flows from the chlorine contact chamber into an underground reservoir called the clearwell. We disinfect the water once again using ultraviolet, or UV light. We pump the water through six stainless steel chambers, each containing nine ultraviolet lamps. The lamps are similar to fluorescent bulbs. With only seconds of exposure, the UV light rays penetrate any remaining parasites such as Cryptosporidium, or Giardia. The UV light renders these parasites harmless. After UV disinfection, the water flows into two large pipes where we add fluoride to help prevent tooth decay. We also add orthophosphate to form a protective coating inside water pipes. This coating helps reduce corrosion that may add lead to tap water. The two large pipes carry the treated water to our three reservoirs and pumping stations in the city. We add chlorine again as the water is pumped into the distribution system to ensure that the water remains disinfected until it reaches your tap.
The final stage of treatment is to deal with the materials removed from the water by the treatment processes. The backwash water from the filters is allowed to stand until the solid materials settle. We then send the clean water back to the beginning of the treatment process. We pump the settled out material from the filters and the clumps of particles from the dissolved air flotation process to outdoor settling ponds next to the treatment plant. The pond contents go through natural freeze thaw cycles which separate the liquid and solids. We pump the liquid into Winnipeg's sewer system for wastewater treatment and take the solids to the landfill for disposal.
We test our water each step of the way, from shoal lake to your tap. Our testing program includes over 150 different tests at more than 130 different locations throughout the year. Because water quality is so important, we do more testing than the provincial government requires. Our certified professional team is dedicated to ensuring that our community enjoys safe, high quality drinking water that meets provincial regulatory requirements, and falls well within Health Canada guidelines.
We hope that you've enjoyed this tour of our drinking water supply and treatment system.
This second video illustrates the treatment of the wastewater generated by human activity before it is returned to the environment:
Video: Barry's Wastewater Treatment Tour (5:26)
Have you ever wondered what happens to the water that flows down drains and toilets in your home? Hi. I'm Barry. And today I'm going to show you how wastewater gets treated. The journey begins here in your community. When it rains, snows, or when you wash your car in your driveway, the water runoff is known as stormwater. It flows into these storm drains that you see in your neighborhood streets. Storm drains connect to streams and creeks and eventually lead to Lake Ontario. But something different happens to the water that you use in your home. All the water that goes down drains and toilets in your home is known as wastewater. It's full of food, soap, waste, and more. Wastewater never goes straight into the lake or river. From your basement, wastewater flows into underground pipes that follow the natural slope of the land. So, most of the time, wastewater just flows downhill to the wastewater treatment facility. Now let's go see how we treat it. All of the wastewater from thousands of homes and buildings across Mississauga, Brampton, and parts of Caledon arrives here. It's collected in six big underground pipes directly underneath me. Each pipe is six feet in diameter.
Now let's go see the first step in wastewater treatment. The wastewater flows through these moving screens. The screens trap materials that should never be flushed down your toilet, things like plastics, rags, and dental floss. Everything the screens trap ends up on these conveyors. The conveyors bring all the garbage into large bins in the building next door. The garbage from the conveyors is collected here. When these bins are full, trucks take it away to landfill. Next, let's see where the wastewater goes. After the screening, the wastewater travels into underground grit chambers. Each of the chambers is round and spins wastewater, kind of like swirling water in a cup. As it spins, sand and small rocks are separated, move to the center of the chambers, and are removed. Now that the solid particles and garbage have been removed from the wastewater, it flows into settling tanks, like this one. We call these settling tanks because the wastewater is given time to settle. At the top of the tank, scum floats and is made up of grease, fats, and oils. At the bottom of the tank, sludge sinks and is made up of heavier materials, mainly human waste. Over here, we have an empty settling tank, so you can see how deep it is.
So now we have sunken sludge and floating scum. What happens next? See this large machine across the tank? We call this the bridge. But it doesn't stay in one spot like a regular bridge. The bridge slowly travels the length of the tank. As it moves, it scrapes the sludge along the bottom and skims the scum along the top. It takes 30 minutes for the bridge to travel all the way across the tank. Watch. I'll show you. The sludge and the scum are pushed to the end of the tank where it's collected. The sludge, under water, we can't see. But, at the surface, we can see the scum collecting here. This is a continuous process. The bridge will lift, go back to the far end of the tank, and start over.
Now the journey splits in two. First, we'll see where the sludge and scum go. Then we'll come back and see what happens to the wastewater. The sludge and the scum from the settling tanks, now referred to as biosolids, are pumped into these machines called centrifuges. A centrifuge spins biosolids super fast, like the spin cycle of a washing ma the end of the tank where it's collected. The sludge, under water, we can't see. But, at the surface, we can see the scum collecting here. This is a continuous process. The bridge will lift, go back to the far end of the tank, and start over. Now the journey splits in two. First, we'll see where the sludge and scum go. Then we'll come back and see what happens to the wastewater. The sludge and the scum from the settling tanks, now referred to as biosolids, are pumped into these machines called centrifuges. A centrifuge spins biosolids super fast, like the spin cycle of a washing machine, and remove excess water. Now, getting rid of biosolids, that's when things really heat up. This is one of four biosolids incinerators. And it heats up to over 840 degrees Celsius. The biosolids enter the incinerator with the consistency of cake batter. The incinerator then heats up the biosolids until they turn into ash. For every 10 tons of biosolids, we end up with only one ton of ash.
Now let's go see where the ash ends up. This is a lagoon where the ash is stored. The water is red because of the iron minerals that we added to eliminate phosphates. This is just a little ways away from the incinerators over there. So we add water to the ash to make it easier to pump. And that's how biosolids have turned to ash. Let's go back to where our journey split in two and find out what happens to wastewater from the settling tanks. With the biosolids removed from the wastewater, something interesting happens. Wastewater flows into these aeration tanks. Aeration is a process of pumping oxygen into water. Do you see all those bubbles? That's the oxygen. Aeration allows good bacteria to eat the sludge that didn't sink and the scum that didn't float from the settling tanks. This process is what makes wastewater clear, but it's not clean yet. These are the clarifying tanks. Remember the good bacteria that ate everything to make the water clear? They now sink to the bottom of the tanks and are removed. The water at the top of the tank is now clean, and it will be returned to Lake Ontario. Along the way, we add chlorine as a final disinfectant. It is now time for us to return the treated wastewater back to Lake Ontario. An underwater pipe stretches just over two kilometers out and lies at the bottom of the lake. Before we return the treated wastewater, we remove any excess chlorine.
Now let's go take a look at the control room. Here's where we monitor all the processes we talked about today. Operators ensure that water quality standards are always being followed and that operations throughout the facility, like the aeration tanks and incineration, are functioning properly. Lake Ontario is our most important body of water. It is the home to a variety of fish and plant life. It's the source of our drinking water, and, as we saw today, where stormwater and treated wastewater ends up. Even though our wastewater goes through an intense treatment process, we want to limit our impact on the environment. We can do this by keeping harmful chemicals, like paints, expired medication, and harsh cleaners, out of our sinks, drains, and toilets. Let's all do our part to keep Lake Ontario clean and healthy.
As we can see from these videos, the design of a large-capacity water treatment plant is very complex and involves not one but many steps, each of those utilizing multiple technologies. It is not our goal to learn all of them in detail in one lesson. However, should you have a specific interest in this topic, the US EPA Wastewater Technology Fact Sheets web page can serve as a great resource for obtaining more technical information about them.
Depending on the degree of cleaning and purification, treated water can be reused for:
- irrigation of agricultural crops or landscape irrigation (e.g., schoolyards, golf courses, residential gardens);
- groundwater recharge;
- recreational use (e.g., lakes and ponds, fisheries, snowmaking, marsh enhancement);
- non-potable urban use (e.g., fire protection, air conditioning, toilet flushing);
- potable use;
- industrial use (e.g., cooling, process water).
The main concern in water reuse is to meet the water quality requirements for its intended use. Quality requirements are determined by federal, state, and regional regulatory authorities and may vary. The general guidelines by EPA with regards to the effluent from the wastewater treatment facilities are given in Table 6.2 below:
| Measures | Effluent Limitation | ||
|---|---|---|---|
| Daily maximum | Weekly average | Monthly average | |
| 5-day Biochemical Oxygen Demand (BOD5) | 60 mg/L | 45 mg/L | 30 mg/L |
| 5-day Carbonaceous Biochemical Oxygen Demand (CBOD5) | 50 mg/L | 40 mg/L | 25 mg/L |
| Total Suspended Solids (TSS) | 60 mg/L | 45 mg/L | 30 mg/L |
| pH (instantaneous) | 6.0-9.0 | --- | --- |
Here is an explanation of measures in this table if you are not familiar with the terms:
- BOD5 is the amount of oxygen needed to oxidize organic matter in a water sample. The difference in oxygen content is usually measured over the time span of 5 days (that is the reason for subscript 5). For reference, water from a very clear source may have a BOD of less than 2 mg/L; sewage water may give readings above 100 mg/L; food processing wastes may have BOD of thousands.
- CBOD5 is the amount of oxygen needed to oxidize carbonaceous organic matter (excluding nitrogen compounds)
- TSS is the amount of particulate matter (insoluble) present in a water sample, which is usually determined by filtering the solution and weighing the residue remaining on the filter.
- pH is the measure of acidity of solution in chemistry (defined as pH = -log[H+]). Acidic solutions, such as acid rain, may have pH around 1-2, relatively neutral solutions range within 5-9 (distilled water pH=7), and alkaline solutions have pH 10-14.
These limits determined by EPA are included in the government regulations, published in the Rules of Department of Natural Resources [CSR, 2014]. This document also contains extensive data on limitations imposed on the contents of the toxic element in water before it is reused or discharged in a certain way to the environment. Check Table A for the maximum tolerated concentrations of metals (p.24) and organics (p. 26). The toxicity requirements are especially relevant to industrial water use.
Chemical tests to determine the above metrics are used as controls at any wastewater treatment plant. Various technologies are developed to improve the treatment efficiency and to produce a cleaner effluent suitable for further use.
Engineered ecological systems for water treatment
Traditional water treatment plants accomplish an important function. However, these facilities themselves produce significant environmental impact by consuming energy, producing emissions, by-products, and waste to be disposed of. Later in this lesson, an example is given for a life cycle assessment study which analyzes the way to make these systems more benign.
One of the trends in improving the environmental profile of wastewater treatment facilities is the design of ecological systems that mimic natural processes of neutralizing the pollution.

Here are a couple of examples of the development of such systems:
- Living Machine and Biomatrix systems (see photo above):
- Eco-Machines systems - ecological fluidized bed, or a small constructed wetland
These examples show that ecological treatment systems typically work at the small scale being capable to treat liquid waste from a community of 300-1000 people. This makes them attractive for decentralized treatment for secluded autonomous areas.
Decentralized systems for water treatment
Decentralized systems of water purification often become technologies of choice in developing countries because they do not require huge infrastructure or can be set up quicker when infrastructure is destroyed. Small-scale technologies provide quick response to urgent needs. There are multiple ways to approach the issue. Here is one of them: watch this 10 min video to see an example how small-scale technology can help solve large-scale problems.
Video: How to make filthy water drinkable (9:13)
Good morning, everybody. I'd like to talk about a couple of things today. The first thing is water. Now I see you've all been enjoying the water that's been provided for you here at the conference, over the past couple of days. And I'm sure you all feel that it's from a safe source.
But what if it wasn't? What if it was from a source like this? Then, statistics would actually say that half of you would now be suffering with diarrhea. I talked a lot in the past about statistics and the provision of safe drinking water for all. But they just don't seem to get through. And I think I've worked out why. It's because, using current thinking, the scale of the problem just seems too huge to contemplate solving. So, we just switch off: us, governments and aid agencies. Well, today, I'd like to show you that through thinking differently, the problem has been solved. By the way, since I've been speaking, another 13,000 people around the world are suffering now with diarrhea. And four children have just died.
I invented Lifesaver bottle because I got angry. I, like most of you, was sitting down, the day after Christmas in 2004, when I was watching the devastating news of the Asian tsunami as it rolled in, playing out on TV. The days and weeks that followed, people fleeing to the hills, being forced to drink contaminated water or face death. That really stuck with me. Then, a few months later, Hurricane Katrina slammed into the side of America. "Okay," I thought, "here's a First World country, let's see what they can do. "Day one: nothing. Day two: nothing. Do you know it took five days to get water to the Superdome? People were shooting each other on the streets for TV sets and water. That's when I decided I had to do something.
Now, I spent a lot of time in my garage, over the next weeks and months, and also in my kitchen -- much to the dismay of my wife. (Laughter) However, after a few failed prototypes, I finally came up with this, the Lifesaver bottle.
Okay, now for the science bit. Before Lifesaver, the best hand filters were only capable of filtering down to about 200 nanometers. The smallest bacteria is about 200 nanometers. So, a 200-nanometer bacteria is going to get through a 200-nanometer hole. The smallest virus, on the other hand, is about 25 nanometers. So, that's definitely going to get through those 200 nanometer holes. Lifesaver pores are 15 nanometers. So, nothing is getting through.
Okay, I'm going to give you a bit of a demonstration. Would you like to see that? I spent all the time setting this up, so I guess I should. We're in the fine city of Oxford. So -- someone's done that up. Fine city of Oxford, so what I've done is I've gone and got some water from the River Cherwell, and the River Thames, that flow through here. And this is the water. But I got to thinking, you know, if we were in the middle of a flood zone in Bangladesh, the water wouldn't look like this. So, I've gone and got some stuff to add into it. And this is from my pond.
(Sniffs) (Coughs) Have a smell of that, mister cameraman.
Okay. (Laughs) Right. We're just going to pour that in there.
Audience: Ugh!
Michael Pritchard: Okay. We've got some runoff from a sewage plant farm. So, I'm just going to put that in there. (Laughter) Put that in there. There we go. (Laughter) And some other bits and pieces, chuck that in there. And I've got a gift here from a friend of mine's rabbit. So we're just going to put that in there as well. (Laughter) Okay. (Laughter) Now.
The Lifesaver bottle works really simply. You just scoop the water up. Today, I'm going to use a jug just to show you all. Let's get a bit of that poo in there. That's not dirty enough. Let's just stir that up a little bit. Okay, so I'm going to take this really filthy water, and put it in here. Do you want a drink yet? (Laughter) Okay. There we go. Replace the top. Give it a few pumps. Okay? That's all that's necessary. Now, as soon as I pop the teat, sterile drinking water is going to come out. I've got to be quick. Okay, ready? There we go. Mind the electrics. That is safe, sterile drinking water. (Applause) Cheers. (Applause) There you go, Chris. (Applause)What's it taste of?
Chris Anderson: Delicious.
Michael Pritchard: Okay. Let's see Chris's program throughout the rest of the show. Okay? (Laughter)
Okay. Lifesaver bottle is used by thousands of people around the world. It'll last for 6,000 liters. And when it's expired, using failsafe technology, the system will shut off, protecting the user. Pop the cartridge out. Pop a new one in. It's good for another 6,000 liters.
So, let's look at the applications. Traditionally, in a crisis, what do we do? We ship water. Then, after a few weeks, we set up camps. And people are forced to come into the camps to get their safe drinking water. What happens when 20,000 people congregate in a camp? Diseases spread. More resources are required. The problem just becomes self-perpetuating. But by thinking differently, and shipping these, people can stay put. They can make their own sterile drinking water, and start to get on with rebuilding their homes and their lives.
Now, it doesn't require a natural disaster for this to work. Using the old thinking, of national infrastructure and pipework, is too expensive. When you run the numbers on a calculator, you run out of noughts. So, here is the "thinking different" bit.
Instead of shipping water, and using man-made processes to do it, let's use Mother Nature. She's got a fantastic system. She picks the water up from there, desalinates it, for free, transports it over there, and dumps it onto the mountains, rivers, and streams. And where do people live? Near water. All we've got to do is make it sterile. How do we do that?
Well, we could use the Lifesaver bottle. Or we could use one of these. The same technology, in a jerry can. This will process 25,000 liters of water; that's good enough for a family of four, for three years. And how much does it cost? About half a cent a day to run. Thank you.
So, by thinking differently, and processing water at the point of use, mothers and children no longer have to walk four hours a day to collect their water. They can get it from a source nearby. So, with just eight billion dollars, we can hit the millennium goal's target of halving the number of people without access to safe drinking water. To put that into context, The U.K. government spends about 12 billion pounds a year on foreign aid. But why stop there? With 20 billion dollars, everyone can have access to safe drinking water. So, the three-and-a-half billion people that suffer every year as a result, and the two million kids that die every year, will live. Thank you.
Click on the link below to read about some small innovations that make big difference when applied at the right place at the right time:
6 Water-purifying Devices for Clean Drinking Water in the Developing World
Reading Assignment:
Next, let us get a little bit deeper into the issue. I ask you to read the following paper which analyzes a case study of a decentralized wastewater treatment system in India. It covers enough technical details to understand how the technology works and provides a useful discussion of environmental, economic, and social aspects:
Dhinadhayalan, M., Nema, A., Decentralised wastewater management - New concepts and innovative technological feasibility for developing countries, Sustain. Environ. Res., 22(1), 39-44 (2012). (The full article is accessible via Library e-Reserves in Canvas)
While reading, focus on understanding the pros and cons of the decentralized approach (compared to central distribution system). In your own notes, list three key advantages of decentralized technologies that justify their development and implementation. Also, list three disadvantages that may limit their use in different parts of the world. Can you imagine to use only de-centralized water treatment in your current location? What kind of social impacts might it create?
Check Your Understanding
The BOD is a measure of which type of pollutant in the water?
Organic matter; BOD is the amount of oxygen needed to oxidize the organic compound in a given volume of water.
Check Your Understanding
Which stages in wastewater treatment are designed to decrease BOD of the effluent?
Aerobic biological (bacterial) decomposition. Bacteria in a well-aerated pool are capable of decreasing BOD by over 90%
6.4. Metrics for assessment of water management technologies
6.4. Metrics for assessment of water management technologies djn12Now, as we have a long list and various scales of water treatment technologies, sustainability goals require their careful assessment in terms of environmental, economic, and social effectiveness. LCA analysis is a very common tool to select specific technologies for a particular sustainability system. Note that specific location, hydrological profile, and available infrastructure are pivoting factors in such assessment. LCA cannot be general - it has to be case-specific. Therefore, it would be best for us to consider a specific example that would describe LCA for a particular prospective water treatment technology.
Reading Assignment:
The LCA study referred to below is on a novel membrane-based technology for drinking water treatment. It compares conventional existing practice with a new method using comprehensive lifecycle inventory for both and applying LCA software for data interpretation. This article is a good example to follow when designing an LCA project:
Bonton, A., Bouchard, C., Barbeau, B., Jedrzejak, Comparative life cycle assessment of water treatment plants, Desalination 284, 42-54 (2012). (Full version of this article is accessible via E-Reserves in Canvas.)
This article contains a significant amount of technical details and chemistry data, which some of you may find hard to digest. You do not have to understand it all - your goal will be to follow through the methodology and understand the main steps that lead to authoritative conclusions. While reading, pay attention to the following aspects:
- The goal for this LCA study
- Motivation to consider the new water treatment method. Was there a problem with the existing practice?
- What is "functional unit" and how it is chosen?
- Criteria (metrics) chosen for assessment
- Software used for the analysis
- Results and conclusions: Can you read and explain the diagrams?
This real-life LCA project shows that proper assessment requires a great deal of technical detail and a significant amount of data. As a matter of fact, the authors had to perform an autopsy of system components to enlist all included chemical components with their potential environmental impacts at the stage of system manufacturing. Furthermore, operational data have to be closely tied to the specific demographic and geographic setting and the scale of application.
An additional thought on LCA: The output of LCA is quantified environmental impact, so it is most effectively used to compare alternatives - different products, systems, technologies, or methods. It has much less value when performed for a single product or a single technology since, without a clear reference point (a baseline), it is hard to tell if the impact small, large, or catastrophic, if the alternative brings improvement or makes things worse. Zero impact is probably not a good reference because no such ideal technology possibly exists. LCA also allows identifying the relative magnitude of various impacts. For example, we can determine if there is a particular project has a higher contribution to greenhouse gas emissions or to soil contamination, etc. In turn, this would help direct the mitigation measures - actions to reduce impact by redesigning the system, improving the process, or searching for an alternative.
Here is another example of comparative LCA (in the form of a slide presentation), which is related to three wastewater treatment strategies. This reading is optional, but also provides you with a good illustration of the approach.
Lyons, E et al., Life Cycle Assessment of Three Water Scenarios: Importation, Reclamation, and Desalination (Arizona State University)
Check Your Understanding
Do you remember the main four stages of the technology lifecycle that are typically considered in LCA?
1. Extraction of raw materials 2. Manufacturing 3. Operation / maintenance 4. Waste management / disposal
Do you remember the main four phases of an LCA project?
1. Defining goal and scope 2. Life cycle inventory 3. Impact assessment 4. Interpretation of results
Summary & Activities
Summary & Activities mrs110This lesson drew some connections between the global water resources and human needs for water. With the fast-growing population and fresh water needs, the balance in the hydrologic cycle and pollution of water resources become critical issues. While there are technologies in place to adapt natural water for human use and to adapt the human-used water for environmental use, their capacity and effectiveness are not always sufficient. Water conservation and reuse are other important strategies to complement the combined water cycle. Sustainable water management implies the systematic approach to the water resources and considers anthropogenic water flows and storages as parts of the universal water cycle. Because there is no substitute for water (like, for example, substitutes for fossil fuels), societies will continue demanding water in great amounts. Therefore, water management and treatment technologies will continue being top priority, and innovation in this area will play a key role in sustainability.
While there are many hot topics to review in this area (we did it to some extent and you should feel free to explore more background on your own), our main focus in this lesson is to learn how to evaluate prospective technologies based on the available information. This may be not a simple exercise, but rather a quite complex practical task. That is why it is important to tap into real-world studies and learn from them. Activities in this lesson give you some scenarios to work with and will hopefully provide you with some practice of evaluatory thinking.
| Type | Assignment Directions | Submit To |
|---|---|---|
| Reading | Complete all necessary reading assigned in this lesson. Do not forget to open the links in the text. Although many linked materials are considered supplemental (unless it is marked as "reading assignment"), you will benefit from including those materials in your learning - they give you a more complete story on the topic and contain great examples. | |
| Forum Discussion | Use this online calculator to determine the waste water generation rate at your household. You will need to check all question marks on the house model to supply specific information. In the end go to "Show results", where you get statistics for your water use. Then take a look at your annual water bill (if available) - how does your actual water use compare to the number output by the calculator? (Calculator uses averaged data and assumptions for appliances but does not take into account individual conservation measures, so the results may differ) If you take your water use as an average (per household) in your area, can you estimate the total domestic wastewater generation in your home town or area? How does that compare to the capacity of your local wastewater treatment facility? You may need to check your municipality websites for information such as capacity and the area they serve. | Share your results in the Lesson 6 Discussion Forum. |
| Course Project | This week, peer reviews on the course project outlines are due. Please email your reviews directly to the authors of the presentations you are assigned and also submit them in the designated dropbox in Canvas for grading. Revisit Lesson 12 (Page 12.4) for more guidance on the peer review preparation. | Canvas - Course Project Module |
References for Lesson 6:
Bonton, A., Bouchard, C., Barbeau, B., Jedrzejak, Comparative life cycle assessment of water treatment plants, Desalination 283, 42-54 (2012).
CSR, Rules of Department of Natural Resources, Chapter 7: Water Quality, Code of State Regulations, 2014.
Dhinadhayalan, M., Nema, A., Decentralised wastewater management - New concepts and innovative technological feasibility for developing countries, Sustain. Environ. Res., 22(1), 39-44 (2012).
Girard, J.E., Principle of Environmental Chemistry, 3rd Ed., Jones & Bartlett Learning (2013).
US EPA Water Conservation Plan Guidelines, Appendix A: Water Conservation Measures, pp. 143-155, EPA (1998).
USDA, Conservation and the Water Cycle, Natural Resources Conservation Service, 2001.
USGS, Estimated Use of Water in the United States in 2005, Circular 1344, 2009.
Vorosmarty, C.J., Sahagian, D., Anthropogenic Disturbance of the Terrestrial Water Cycle, BioScience, vol. 50, pp.753-763 (2000).



