how to manage externalities in sewage treatment

How to deal with sewage in rural areas?

In rural areas, households and villages need to deal with disposing of sewage properly on their own, so pathogens do not enter the water supply. There are a few options for on-site systems to manage sewage that should be implemented as soon as possible:

What is secondary treatment of wastewater?

Secondary treatment of wastewater uses bacteria to digest the remaining pollutants. This is accomplished by forcefully mixing the wastewater with bacteria and oxygen. The oxygen helps the bacteria to digest the pollutants faster.

What are the problems with sewage treatment plants?

Failure to control nutrients – treatment standards for sewage treatment plants typically do not require control of excess nutrients such as phosphorus and nitrogen as part of permit limits.

Is there a sustainable way to treat wastewater?

If nature itself can cleanse water, then imitating nature’s processes may be the most effective and sustainable ways of treating wastewater. A great deal of water renewal occurs naturally in wetlands.

How do you manage externalities?

The government can respond to externalities in two ways. The government can use command-and-control policies to regulate behavior directly. Alternatively, it can implement market-based policies such as taxes and subsidies to incentivize private decision makers to change their own behavior.

What are the three main methods to deal with environmental negative externalities?

Dealing With Externalities Command and Control. This is exactly what it sounds like: governments issue commands in order to control the amount of pollution. ... Pigouvian taxes. ... Coasian permit trading.

What are some solutions to solve a positive externality?

Dealing with positive externalities Increasing supply – the government building of council housing to increase the stock of good quality housing. Subsidy to reduce price and encourage consumption, e.g. government subsidy for rural train services.

What are the two main ways to deal with externalities?

When that happens, the government can respond in one of two ways. It can use command-and-control policies to directly regulate problematic behavior, or it can use market-based policies to provide incentives that will lead individuals and firms to solve the problems on their own.

How can positive externalities be corrected?

Positive externalities are corrected by subsidizing consumers, subsidizing suppliers and allowing the government to provide goods.

What are externalities in maintaining sustainability?

An externality is a positive or negative outcome of a given economic activity that affects a third party that is not directly related to that activity. Erosion and chemical runoff caused by building roads, which causes water pollution further downstream, is an example of a negative externality.

What are 3 examples of externalities?

Some examples of negative consumption externalities include:Passive smoking. Passive smoking refers to the inhalation of smoke exhaled by an active smoker. ... Traffic congestion. When too many drivers use a road, it causes delays and slower commuting times for all motorists. ... Noise pollution.

What are the 4 types of externalities?

There are four main types of externalities: positive production, positive consumption, negative consumption, and negative production.

What are some examples of externalities?

Light pollution is an example of an externality because the consumption of street lighting has an effect on bystanders that is not compensated for by the consumers of the lighting.

Which of the following are solutions that governments use to counter overproduction caused by negative externalities?

Which of the following are solutions that governments use to counter overproduction caused by negative externalities? Solar panels provide a benefit those who buy them by reducing their electricity bill, but they also benefit society as a whole by reducing pollution and resource consumption.

What is the role of the city council in sewage treatment?

In urban areas, improving infrastructure for sewage treatment is a question of local government: the city council will be in charge of reviewing the city’s needs and establishing a committee (or whatever sort of organization is needed) to design and construct the system. Here Mission 2017 leaves it up to the city to decide exactly how infrastructure will be improved, rather than force a detailed plan upon them. However, it is highly recommended that all local government analyze their current sewage treatment systems and update their systems to achieve the environmental agency’s newly set out standards.

Why is sewage a transboundary water system?

Because sewage that enters a transboundary water system impacts countries downstream that have no say in the matter, an international agency will be required so different countries can decide upon acceptable levels of pollution; Mission 2017 recommends using the World Health Organization (WHO) drinking water standards. This meeting will be especially beneficial to less-powerful, downstream countries who have to suffer from the effects of the pollution dealt them by upstream countries. As with industrial pollution, this conference must take place immediately, before any national regulations are developed, to ensure that they are in accordance with the international agreement. More information on how these agreements will be reached can be found here.

How to finance a shared latrine?

In rural villages, self supply – where the villagers or household use their own income to finance the project – is an option, albeit not a very likely one, especially in villages building a shared latrine. Microfinancing is another choice, where a small loan of up to $1000 is borrowed from a microfinancing institution. A third option is receiving money from a charity organization, but this is less attractive because the first two choices give the village or household a larger feeling of ownership, since they have paid for and built the latrines themselves; in addition, countries cannot rely on charitable donations as a steady source of income.

How much sewage goes into the water?

According to the United Nations, every day, 2 million tons of sewage is dumped into the world’s waterways. In fact, in developing countries, 90 percent of all wastewater goes into water untreated. As cities outgrow their sanitation systems, wastewater can go straight into rivers, affecting downstream populations [1]. The true danger of sewage is pathogens; untreated wastewater is brimming with bacteria, viruses, and parasites, many of which cause deadly diseases. About five million people die every year from these waterborne diseases [2], and over a billion people rely on unsafe sources of water to live [3]. The most common illness related to untreated sewage water is gastro-enteritis, an infection of the gastrointestinal tract, which can lead to vomiting, diarrhea, and eventually severe dehydration as a result. Open cuts and rashes are also much more likely to become infected when exposed to untreated wastewater [4]. An essential part of water security is ensuring that pathogens from sewage do not contaminate the water. Another reason for improving sewage system is to be able to reuse the water used for waste disposal.

How to flush waste out of a latrine?

Pour flush latrines: Pour flush latrines include a shallow pan cast into the floor where waste collects. One to three liters of water is then used to flush the wastes out of the pan and down a pipe into a pit, where some wastes will decompose and seep into the ground, while some will stay in the pit. Eventually the pit will fill up, at which time a new pit must be excavated.

Why use biochemical water treatment?

The biochemical oxygen demand gives information about the activity of bacterias which are degrading the organic matter present in the water. The higher the biochemical oxygen demand is, the higher the organic content of the water is.

Where do regulations work best?

Regulation will most likely work best in urban areas, where centralized facilities can be inspected can visit and audit treatment facilities often . Rural areas may not even have central facilities to audit – for example, an isolated village with only hand-dug latrines – in which case regulations will not be applicable. There, investing in infrastructure may be the best way to ensure cleaner water.

What are emerging pollutants?

These substances, known as emerging pollutants, include anything from medicines to personal hygiene products and nano-materials, and can reach receiving waters in significant quantities.

What is the control system for biological tanks?

Control of both the aeration supplied to the membranes and the aeration of the biological tanks, using an advanced control system permitting lower air consumption (energy consumption) as well as cutting down on the generation of GH gases (NOx and CO 2 ).

Can water distribution networks affect human health?

Although it has been observed that these compounds can negatively affect aquatic ecosystems, studies on water distribution networks have not been able to demonstrate any adverse effect on human health.

What happens when bio discs are in contact with sewage?

When the discs, also called bio discs, come in contact with sewage, biomass or biological growths become attached to the surface of the discs and eventually form a slime layer over the entire wetted surface area of the discs . The rotation of the discs causes the biomass to be alternately submerged in the sewage to adsorb organic matter and to pick up a thin layer of sewage and then raised out of the liquid and exposed to the atmosphere to oxidize the adsorbed organic matter or substrate and to allow the sewage film to slide down the biomass.

What is an oxidation ditch?

The method of oxidation ditch is essentially an extended aeration activated sludge process. It was developed for the treatment of sewage for small towns in Netherlands. An oxidation ditch consists of an endless ditch for the aeration tank and a rotor for mechanical aeration of the sewage. The ditch is in the form of a long continuous channel usually oval in plan, (see Fig. 15.1).

Where does sewage go?

All the sewage water from household is directed to sewer pipes. The solid waste goes through a series of macerators (cutting blades). This is done to reduce the size of solid waste before it is directed to a lagoon or municipality plant.

What is the process of removing bacteria from municipal sewage?

The plants remove at least 95% of bacteria present in the sewage. The sludge is then subjected to an anaerobic process to ensure that disease-causing microbes are eliminated.

How is waste pumped out of a septic tank?

This method has to be installed properly to allow easy maintenance. The method is challenged in areas with a lot of clay soil because of poor capillarity. In addition, it cannot be installed in areas with a high water table and where flooding is common. In some cases, waste can be pumped out of the septic tanks using submersible sewage pumps . You can buy these pumps from reliable submersible sewage pump suppliers.

What is sewer system?

Houses are built on a plot with each connects to a sewer line. The sewer line collects waste from the toilets, kitchens, and laundry areas. All this waste, including that of your neighbours, is collected in a community wastewater treatment plant. Wastewater flows toward the collection point. Excess water is connected to a river or directed to an irrigation area after treatment.

What happens if waste is not properly managed?

This is very essential to our health. If not properly managed, there can be an outbreak of diseases related to poor hygiene, such as cholera and diarrhoea.

Is sewage waste hazardous?

Sewage comprises water used to flush toilets, in washing, and from general use. The composition of this mixture will be hazardous if not managed and disposed of well. Waste management has become complex with time due to increased population and urbanization.

Can a septic tank be installed in a high water table?

In addition, it cannot be installed in areas with a high water table and where flooding is common. In some cases, waste can be pumped out of the septic tanks using submersible sewage pumps. You can buy these pumps from reliable submersible sewage pump suppliers.

Why is commercial wastewater not sent to public wastewater treatment plants?

Commercial and industrial waste is not sent directly to public wastewater treatment plants, because the public wastewater treatment system cannot effectively remove all of the contaminants. Wastewater from commercial and industrial processes is usually divided into the following four categories and dealt with accordingly:

Why is oxygen important in wastewater treatment?

The oxygen helps the bacteria to digest the pollutants faster. The water is then taken to settling tanks where the sludge again settles, leaving the water 90 to 95 percent free of pollutants. The picture below shows the settling tanks in the Winnipeg Wastewater Treatment Plant.

How to reduce pressure on septic system?

Following some water conservation practices can greatly reduce pressure on your septic system. For more information about conserving water, see the fact sheet about Water Consumption. Here are a few things that you can do to care for your septic system: 1 Do not use your drain or toilet as a garbage disposal; avoid putting dental floss, diapers, coffee grounds and paper towel down the drain, as they can clog up your septic system. 2 Spread your loads of laundry out over the week. When too much water is added to the septic tank, it does not have time to treat wastes, and you could be flooding your drainfield with wastewater. 3 Plant grass on your drainfield, but keep trees and shrubs away from it, because roots can clog the system and cause damage. 4 Do not drive on your drainfield, because this can compact the soil and damage the septic system components.

How is sludge treated?

The sludge that is removed from the settling tanks and the scum that is skimmed off the top during the primary steps are treated separately from the water. Anaerobic bacteria (anaerobic bacteria do not require oxygen) feed off of the sludge for 10 to 20 days at temperatures around 38 degrees Celsius. This process decreases the odour and organic matter of the sludge, and creates a highly combustible gas of methane and carbon dioxide, which can be used as fuel to heat the treatment plant. Finally, the sludge is sent to a centrifuge, like the one shown in the picture below. A centrifuge is a machine that spins very quickly, forcing the liquid to separate from the solid. The liquid can then be processed with the wastewater and the solid is used as fertilizer on fields.

How does wastewater treatment work?

In small communities, wastewater treatment facilities may consist of individual septic systems, simple collection systems that directly discharge effluent to surface waters, or municipal lagoons that are emptied annually. These facilities usually treat and disperse the waste as close as possible to its source, thus minimizing operational costs and maintenance requirements. The longer the waste can sit in a lagoon before being discharged, the less likely it will be to contaminate drinking water sources. Some communities store the waste in lagoons, but others release the waste directly into water sources.

What are the different levels of wastewater treatment?

There are several levels of wastewater treatment; these are primary, secondary and tertiary levels of treatment. Most municipal wastewater treatment facilities use primary and secondary levels of treatment, and some also use tertiary treatments.

Why do cities dump raw sewage?

Some cities choose to dump raw sewage into the oceans and rivers, because it is cheaper than effective treatment . A report published by Sierra Legal found that, of 22 Canadian cities, Victoria, Dawson City, Montreal, Saint John, Halifax and St. John’s dump some or all of their raw sewage directly into water bodies. While not all of the sewage is dumped directly into the oceans, these six cities produce 400 million litres of raw sewage each day! Montreal dumps around 3.6 billion litres of raw sewage into the St. Lawrence River each year, and Victoria is the only large Canadian city to dump all of its waste into the ocean without any attempt to improve the system. The city of Victoria dumps more than 34 billion litres of raw sewage into waterways each year, and still claims that their actions are not harming the environment! Halifax and St. John’s have plans to construct wastewater treatment facilities, but in the meantime, are still discharging 65.7 billion litres and 33 billion litres, respectively, of raw sewage into the Atlantic Ocean. For more information about water pollution, see the Water Pollution fact sheet, or the Operation Water Pollution lesson plans and resources.

What is an emergy synthesis?

The emergy synthesis approach is an integrated evaluation method for ecological-economic systems and has been successfully applied to systems of different scales ( Brown and Ulgiati, 2004 ). Emergy (or embodied energy) is defined as the available energy of one kind previously used up directly or indirectly to make a product or service ( Odum, 1996 ). In emergy accounting, both environmental and economic inputs, including energy, materials, labor and currency, are all converted into solar emergy equivalents. The renewable energy and resources, like sunlight, wind, rain, and tides, which are usually regarded as free externalities of the production process in economics, are included in emergy accounting as significant environmental support. An eMergy synthesis considers the historical accumulation of all the energy used in a production process and provides a universal measure for the different kinds of energy flows in a system network. A system is evaluated through the analysis of energy, mass, information, and currency flows ( Sciubba and Ulgiati, 2005, Bastianoni et al., 2007 ).

What is EYR in energy?

EYR is the ratio of the sum of renewable eMergy ( R) and nonrenewable eMergy ( N) and purchased eMergy ( F) to the purchased emergy ( F ). According to Ulgiati and Brown (2002), EYR values below 5 denote primary materials, such as cement and steel, and secondary energy resources. Primary energy resources usually have an EYR > 5, and processes with an eMergy yield ratio less than 2 do not contribute to as energy sources and are associated to consumables or manufacturing processes. By comparing EYR values, one can understand the competition ability or economic benefit of a resource. Low values of EYR denote weak competition ability and low economic benefit when a resource is developed. On the contrary, high values of EYR denote strong competition ability and high economic benefit.

Background

Solutions

• 1. International Cooperation Because sewage that enters a transboundary water system impacts countries downstream that have no say in the matter, aninternational agency will be required so different countries can decide upon acceptable levels of pollution; Mission 2017 recommends using the World Health Organization (WHO) drinking water standards. T...

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Implementation Case Study: Africa

Financing

Conclusion

References