Sewer mining (or sewage mining) is a concept where municipal wastewater (sewage) is pumped from a trunk sewer and treated on-site to accommodate a range of local, nonpotable water needs. [1] It is a strategy for combating water scarcity. It combines decentralized wastewater management and water reclamation. [1] Since 2012, it is used as a tool for improving water management and promoting reuse of water in Australia. [2]
A sewer mining scheme typically consists of: [3]
One of the advantages of sewer mining is the decrease in transportation costs, since sewage can be treated locally. Another benefit derives from the fact that no further capital costs for sewer infrastructure are needed, because a treatment scheme can be directly linked to the already existing pipeline system. With the combination of new, emerging technologies, such as the membrane bioreactor (MBR), further reduction of operating costs became possible, making the average cost of retrieved water comparable to potable water costs. [3]
Most of sewer mining cases are realised in Australia and involve residential non-drinking uses. More specifically, in Sydney Olympic Park, a large scale sewer mining unit has been installed for using recycled water for irrigational purposes. The retrieved water is being produced in such quantities that substitutes more than 50% of the potable water that would be sustaining green sites in the Sydney Olympic Park and the Newington Estate. Another realisation of sewer mining takes place in Pennant Hills Golf Club, where the recycling scheme produced up to 100 million litres of reclaimed water that is used for irrigating the golf course. [4] In this case, the nutrients from the sewage are used as fertilizer on the golf course rather than being removed in a sewage treatment plant. [5]
In Greece, an example that applies sewer mining as a decentralised wastewater treatment method is the DESSIN Athen's pilot plant, which is implemented under the European Union Seventh Framework Programme. [6] The Athens demonstration site pumps municipal sewage directly from the central sewage network and treats it by the use of a membrane bioreactor, while a reverse osmosis unit assures that the water quality lies within the legislation limits. The treated effluent is used to irrigate a nearby area of 50 square meters. [3]
Greywater refers to domestic wastewater generated in households or office buildings from streams without fecal contamination, i.e., all streams except for the wastewater from toilets. Sources of greywater include sinks, showers, baths, washing machines or dishwashers. As greywater contains fewer pathogens than blackwater, it is generally safer to handle and easier to treat and reuse onsite for toilet flushing, landscape or crop irrigation, and other non-potable uses. Greywater may still have some pathogen content from laundering soiled clothing or cleaning the anal area in the shower or bath.
NEWater is the brand name given to highly treated reclaimed wastewater produced by Singapore's Public Utilities Board. NEWater is produced by further purifying conventionally treated wastewater through microfiltration, reverse osmosis and ultraviolet irradiation. The water is potable quality and can be added to drinking water supply reservoirs where it is withdrawn and treated again in conventional water treatment plants before being distributed to consumers. However, most NEWater is currently used for non-drinking purposes, mostly by industries with production requirements for high purity water.
Wastewater treatment is a process which removes and eliminates contaminants from wastewater and converts this into an effluent that can be returned to the water cycle. Once returned to the water cycle, the effluent creates an acceptable impact on the environment or is reused for various purposes. The treatment process takes place in a wastewater treatment plant. There are several kinds of wastewater which are treated at the appropriate type of wastewater treatment plant. For domestic wastewater, the treatment plant is called a Sewage Treatment. For industrial wastewater, treatment either takes place in a separate Industrial wastewater treatment, or in a sewage treatment plant. Further types of wastewater treatment plants include Agricultural wastewater treatment and leachate treatment plants.
Water reclamation is the process of converting municipal wastewater (sewage) or industrial wastewater into water that can be reused for a variety of purposes. Types of reuse include: urban reuse, agricultural reuse (irrigation), environmental reuse, industrial reuse, planned potable reuse, and de facto wastewater reuse. For example, reuse may include irrigation of gardens and agricultural fields or replenishing surface water and groundwater. Reused water may also be directed toward fulfilling certain needs in residences, businesses, and industry, and could even be treated to reach drinking water standards. The injection of reclaimed water into the water supply distribution system is known as direct potable reuse. However, drinking reclaimed water is not a typical practice. Treated municipal wastewater reuse for irrigation is a long-established practice, especially in arid countries. Reusing wastewater as part of sustainable water management allows water to remain as an alternative water source for human activities. This can reduce scarcity and alleviate pressures on groundwater and other natural water bodies.
The activated sludgeprocess is a type of biological wastewater treatment process for treating sewage or industrial wastewaters using aeration and a biological floc composed of bacteria and protozoa. It uses air and microorganisms to biologically oxidize organic pollutants, producing a waste sludge containing the oxidized material.
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans. This applies to industries that generate wastewater with high concentrations of organic matter, toxic pollutants or nutrients such as ammonia. Some industries install a pre-treatment system to remove some pollutants, and then discharge the partially treated wastewater to the municipal sewer system.
The Hyperion Water Reclamation Plant is a sewage treatment plant in southwest Los Angeles, California, next to Dockweiler State Beach on Santa Monica Bay. The plant is the largest sewage treatment facility in the Los Angeles Metropolitan Area and one of the largest plants in the world. Hyperion is operated by the City of Los Angeles, Department of Public Works, and the Bureau of Sanitation. Hyperion is the largest sewage plant by volume west of the Mississippi River.
Secondary treatment is the removal of biodegradable organic matter from sewage or similar kinds of wastewater. The aim is to achieve a certain degree of effluent quality in a sewage treatment plant suitable for the intended disposal or reuse option. A "primary treatment" step often precedes secondary treatment, whereby physical phase separation is used to remove settleable solids. During secondary treatment, biological processes are used to remove dissolved and suspended organic matter measured as biochemical oxygen demand (BOD). These processes are performed by microorganisms in a managed aerobic or anaerobic process depending on the treatment technology. Bacteria and protozoa consume biodegradable soluble organic contaminants while reproducing to form cells of biological solids. Secondary treatment is widely used in sewage treatment and is also applicable to many agricultural and industrial wastewaters.
Sewage sludge treatment describes the processes used to manage and dispose of sewage sludge produced during sewage treatment. Sludge treatment is focused on reducing sludge weight and volume to reduce transportation and disposal costs, and on reducing potential health risks of disposal options. Water removal is the primary means of weight and volume reduction, while pathogen destruction is frequently accomplished through heating during thermophilic digestion, composting, or incineration. The choice of a sludge treatment method depends on the volume of sludge generated, and comparison of treatment costs required for available disposal options. Air-drying and composting may be attractive to rural communities, while limited land availability may make aerobic digestion and mechanical dewatering preferable for cities, and economies of scale may encourage energy recovery alternatives in metropolitan areas.
Sewage treatment is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable to discharge to the surrounding environment or an intended reuse application, thereby preventing water pollution from raw sewage discharges. Sewage contains wastewater from households and businesses and possibly pre-treated industrial wastewater. There are a high number of sewage treatment processes to choose from. These can range from decentralized systems to large centralized systems involving a network of pipes and pump stations which convey the sewage to a treatment plant. For cities that have a combined sewer, the sewers will also carry urban runoff (stormwater) to the sewage treatment plant. Sewage treatment often involves two main stages, called primary and secondary treatment, while advanced treatment also incorporates a tertiary treatment stage with polishing processes and nutrient removal. Secondary treatment can reduce organic matter from sewage, using aerobic or anaerobic biological processes. A so-called quarternary treatment step can also be added for the removal of organic micropollutants, such as pharmaceuticals. This has been implemented in full-scale for example in Sweden.
Membrane bioreactors are combinations of some membrane processes like microfiltration or ultrafiltration with a biological wastewater treatment process, the activated sludge process. These technologies are now widely used for municipal and industrial wastewater treatment. The two basic membrane bioreactor configurations are the submerged membrane bioreactor and the side stream membrane bioreactor. In the submerged configuration, the membrane is located inside the biological reactor and submerged in the wastewater, while in a side stream membrane bioreactor, the membrane is located outside the reactor as an additional step after biological treatment.
Water resources are natural resources of water that are potentially useful for humans, for example as a source of drinking water supply or irrigation water. 97% of the water on Earth is salt water and only three percent is fresh water; slightly over two-thirds of this is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater is found mainly as groundwater, with only a small fraction present above ground or in the air. Natural sources of fresh water include surface water, under river flow, groundwater and frozen water. Artificial sources of fresh water can include treated wastewater and desalinated seawater. Human uses of water resources include agricultural, industrial, household, recreational and environmental activities.
Water supply and sanitation in Israel are intricately linked to the historical development of Israel. Because rain falls only in the winter, and largely in the northern part of the country, irrigation and water engineering are considered vital to the country's economic survival and growth. Large scale projects to desalinate seawater, direct water from rivers and reservoirs in the north, make optimal use of groundwater, and reclaim flood overflow and sewage have been undertaken. Among them is the National Water Carrier, carrying water from the country's biggest freshwater lake, the Sea of Galilee, to the northern part of the Negev desert through channels, pipes and tunnels. Israel's water demand today outstrips available conventional water resources. Thus, in an average year, Israel relies for about half of its water supply on unconventional water resources, including reclaimed water and desalination. A particularly long drought in 1998–2002 had prompted the government to promote large-scale seawater desalination. In 2022, 85% of the country's drinkable water was produced through desalination of saltwater and brackish water.
Sewage is a type of wastewater that is produced by a community of people. It is typically transported through a sewer system. Sewage consists of wastewater discharged from residences and from commercial, institutional and public facilities that exist in the locality. Sub-types of sewage are greywater and blackwater. Sewage also contains soaps and detergents. Food waste may be present from dishwashing, and food quantities may be increased where garbage disposal units are used. In regions where toilet paper is used rather than bidets, that paper is also added to the sewage. Sewage contains macro-pollutants and micro-pollutants, and may also incorporate some municipal solid waste and pollutants from industrial wastewater.
As Australia's supply of freshwater is increasingly vulnerable to droughts, possibly as a result of climate change, there is an emphasis on water conservation and various regions have imposed restrictions on the use of water.
Degrémont is a company specializing in the production of drinking water, and in the treatment of sewage and sludge. After starting as a family business in France in 1939, it has since become a subsidiary of Suez Environment, employing 4,600 people in 70 countries, and generating annual revenues of €1.520 billion.
Reuse of human excreta is the safe, beneficial use of treated human excreta after applying suitable treatment steps and risk management approaches that are customized for the intended reuse application. Beneficial uses of the treated excreta may focus on using the plant-available nutrients that are contained in the treated excreta. They may also make use of the organic matter and energy contained in the excreta. To a lesser extent, reuse of the excreta's water content might also take place, although this is better known as water reclamation from municipal wastewater. The intended reuse applications for the nutrient content may include: soil conditioner or fertilizer in agriculture or horticultural activities. Other reuse applications, which focus more on the organic matter content of the excreta, include use as a fuel source or as an energy source in the form of biogas.
Water reuse in California is the use of reclaimed water for beneficial use. As a heavily populated state in the drought-prone arid west, water reuse is developing as an integral part of water in California enabling both the economy and population to grow.
The Thomas P. Smith Water Reclamation Facility (TPSWRF) is owned and operated by the city of Tallahassee, Florida. The facility provides sewage treatment services for Tallahassee, Florida and the surrounding areas.
Decentralized wastewater systems convey, treat and dispose or reuse wastewater from small and low-density communities, buildings and dwellings in remote areas, individual public or private properties. Wastewater flow is generated when appropriate water supply is available within the buildings or close to them.