Introduction to Wastewater Treatment
This factsheet is the Wastewater Treatment Tools site.
Wastewater Treatment
This section summarises the appropriate hardware and software tools for treating industrial, domestic or agricultural wastewater. Wastewater treatment may be centralised or take place on an individual level. Wastewater treatment directly influences the quality of water for further use. If wastewater is discharged without treatment, it negatively impacts on the quality of the water available for those downstream. Hence it determines their purification methods, limits the purposes that water can be used for and influences the availability of nutrients for agriculture.
- Hardware
- Software
Creating and Enabling Environment
Creating Policies and a Legal Framework (WWT)
A core governmental role is to formulate policies, through which the government can delimit the activities of all sanitation and water management…
Building an Institutional Framework (WWT)
The term “institutional framework” refers to a set of formal organisational structures, rules and informal norms for service provision. Such a…
Bundling and Unbundling of Functions (WWT)
The clear allocation of functions for the implementation of sustainable sanitation and water management is crucial for its outcomes. Overlapping…
Strengthening Enforcement Bodies (WWT)
Enforcement bodies have a very important role in establishing and ensuring the effective application of other software tools in sustainable…
Decentralisation (WWT)
In order to increase sanitation and water management efficiency and improve equity and justice for local people, a participatory and community-based…
Public Private Partnerships (WWT)
The public sector might not be able to cope with the challenges regarding sanitation and water management and therefore cooperates with the private…
Privatisation (WWT)
“Public sector utilities in developing countries have often not been efficient in providing access to reliable water and sanitation services. [...]…
Nationalisation (WWT)
The nationalisation of sanitation and water management is one option for (local) governments to cope with the increasing problem of lacking…
Developing Human Resources (WWT)
The development of human resources is at the core of sustainable development. People and communities that are empowered with the necessary knowledge…
Integrity Management for Water Sector Organizations
Integrity Management (IM) is a change management approach to reduce unnecessary losses from corruption and bad practice in human resources,…
Introduction
Sanitation Systems
Sanitation systems are a combination of different functional units that together allow managing and reusing or disposing the different waste flows…
User Interface
Pour flush Toilet
A pour flush toilet is like a regular cistern flush toilet except that the water is poured in by the user, instead of coming from the cistern above.…
Urine-Diverting Flush Toilet (UDFT)
The urine-diverting flush toilet (UDFT) is similar in appearance to a cistern flush toilet except for the diversion in the bowl. The toilet bowl has…
Cistern Flush Toilet
The cistern flush toilet is usually made of porcelain and is a mass-produced, factory-made user interface. The flush toilet consists of a water tank…
Low-flush Toilets
A low-flush or low-flow toilet is a flush toilet that is adapted in order to use significantly less water than a full-flush toilet. Low-flush toilets…
Vacuum Toilet
Vacuum toilets are flush toilets that use suction for the removal of faeces and urine resulting in a minimal requirement of water (0.5 to 1.5 litres…
Urinal
An urinal is used only for collecting urine. Urinals are generally for men, although models for women have also been developed. Most urinals use…
Urine Diversion Components
The separate collection of urine allows to reduce water used in toilets for flushing and to collect the nutrients contained in the urine in order to…
Overhung Latrine
An overhung latrine consists of a superstructure and floor built over water. A squat hole in the floor allows excreta to fall directly into the water…
Dry Toilet
A dry toilet is a toilet that operates without flushwater. The dry toilet may be a raised pedestal on which the user can sit, or a squat pan over…
Urine Storage Tank / Container
When urine cannot be used immediately or transported using a conveyance technology (i.e. [8287-jerrycans]) it can be stored onsite in containers or…
Awareness Raising
School Campaigns (WWT)
A school campaign on water and sanitation consists of two main components: one component is the provision of safe water and sanitation facilities in…
SSWM in School Curriculums (WWT)
This tool involves the integration of relevant sustainable water, hygiene and sanitation topics into school education in order to increase knowledge…
Empowering Young People as Promoters (WWT)
Empowering young people as promoters in the field of water and sanitation is a way of assuring that a project or programme has a greater effect and…
Media Campaigns - Internet and Email (WWT)
The media (television, radio, print media, internet and email) play a significant role in spreading information and raising awareness on water and…
Media Campaigns - Posters and Flyers (WWT)
The media (television, radio, print media, internet and email) play a significant part in spreading information on Sustainable Sanitation and Water…
Media Campaigns - Radio (WWT)
The media (television, radio, print media, internet and email) play a significant role in spreading information and raising awareness on water and…
Media Campaigns - Video (WWT)
The media (video, radio, print media, internet and email) play a significant part in spreading information on SSWM and in awareness raising. They…
Creating Information Material (WWT)
Creating appropriate and specific information materials for water and sanitation programmes is of key importance and a way to assure a strong and…
Advocacy - Influencing Leaders (WWT)
"Advocacy is the action of delivering an argument to gain commitment from political and social leaders and to prepare a society for a particular…
Corporate Social Responsibility (WWT)
Corporate Social Responsibility (CSR) is the continuing commitment by businesses to behave ethically and contribute to economic development while…
Social Marketing (WWT)
Social marketing is the use of commercial marketing techniques to promote the adoption of behaviour that will improve the health or well-being of the…
On-site Storage and Treatments
Fill and Cover / Arborloo
To decommission a pit, it can simply be filled with soil and covered. Although there is no received benefit, the full pit poses no immediate health…
Anaerobic Filter
An anaerobic filter is a fixed-bed biological reactor with one or more filtration chambers in series. As wastewater flows through the filter,…
Anaerobic Baffled Reactor (ABR)
An anaerobic baffled reactor (ABR) is an improved [8217-septic tank] with a series of baffles under which the wastewater is forced to flow. The…
Septic Tank
A septic tank is a watertight chamber made of concrete, fibreglass, PVC or plastic, through which blackwater and greywater flows for primary…
Terra Preta Toilets
Urine diversion terra preta toilets are a low cost, dry terra preta sanitation (TPS) systems based on urine diversion and the addition of charcoal…
Biogas Reactor
A biogas reactor or anaerobic digester is an anaerobic treatment technology that produces (a) a digested slurry (digestate) that can be used as a…
Settler
A settler is a primary treatment technology for wastewater; it is designed to remove suspended solids by sedimentation. It may also be referred to as…
Urine Storage
Urine makes up less than 0.5 % of household wastewater but contains most of the essential plant nutrients N, P and K. Waterless urinals or urine…
Urine-Diverting Dry Toilet (UDDT)
A urine-diverting dry toilet (UDDT) is a toilet that operates without water and has a divider so that the user, with little effort, can divert the…
Single Pit
The single pit is one of the most widely used sanitation technologies. Excreta, along with anal cleansing materials (water or solids) are deposited…
Double Ventilated Improved Pit (VIP)
The double VIP has almost the same design as the single VIP with the added advantage of a second pit that allows it to be used continuously and…
Composting Chamber
Composting refers to the process by which biodegradable components are biologically decomposed by microorganisms (mainly bacteria and fungi) under…
Fossa Alterna
The Fossa Alterna is a short cycle alternating, waterless (dry) double pit technology. Compared to the [8239-double VIP] which is just designed to…
The Peepoo
The Peepoo is a self-sanitising biodegradable personal single-use toilet. It is especially suitable for urban slum areas and in emergency relief…
Dehydration Vaults
Dehydration vaults are used to collect, store and dry (dehydrate) faeces. Faeces will only dehydrate when the vaults are well ventilated, watertight…
Twin Pits for Pour Flush
This technology consists of two alternating pits connected to a pour flush toilet. The blackwater (and in some cases greywater) is collected in the…
(Co-) composting (Small-scale)
Composting at the household level is an important method for managing organic waste, which is normally the largest portion of household waste.…
Cesspit
A cesspit, or cesspool is a tank pit used for the temporary collection and storage of sewage or waste. The pit is sometimes lined with bricks or…
Imhoff Tank
The Imhoff tank is a primary treatment technology for raw wastewater, designed for solid-liquid separation and digestion of the settled sludge. It…
Compost Filter
The compost filter is a fairly new method for pre-treating wastewater. There are two different methods: two chamber compost filters or compost filter…
Jerrycan / Tank
Jerrycans are light, plastic containers that are readily available and can be easily carried by one person. When sealed, they can be used to safely…
Single Ventilated Improved Pit (VIP)
The single VIP is a ventilated improved pit. It is an improvement over the [8237-single pit] because continuous airflow through the ventilation pipe…
Command and Control Tools
Standards (WWT)
Standards are requirements based on risk limits. They are often established by authorities to impose levels of pollution control by determining…
Restrictions (WWT)
Restrictions and prohibitions are a part of command & control tools, i.e. which are regulatory instruments that are direct and mandatory.…
(Semi-)Centralised Wastewater Treatments
Advanced Integrated Ponds
Advanced integrated wastewater pond systems (AIWPS), advanced integrated pond systems (AIPS) or advanced integrated ponds (AIPs) are an adaptation of…
Aerated Pond
An aerated pond is a large, mixed aerobic reactor. Mechanical aerators provide oxygen and keep the aerobic organisms suspended and mixed with water…
Waste Stabilization Ponds (WSP)
Waste Stabilization Ponds (WSPs) are large, man-made water bodies. The ponds can be used individually, or linked in a series for improved treatment.…
Fish Pond (Aquaculture)
Fish can be grown in ponds that receive effluent or sludge where they can feed on algae and other organisms that grow in the nutrient-rich water. The…
Anaerobic Filter
An anaerobic filter is a fixed-bed biological reactor with one or more filtration chambers in series. As wastewater flows through the filter,…
Activated Sludge
An activated sludge process refers to a multi-chamber reactor unit that makes use of highly concentrated microorganisms to degrade organics and…
Rotating Biological Contactors
Rotating biological contactors (RBC), also called rotating biological filters, are fixed-bed reactors consisting of stacks of rotating disks mounted…
Upflow Anaerobic Sludge Blanket Reactor (UASB)
The upflow anaerobic sludge blanket reactor (UASB) is a single tank process. Wastewater enters the reactor from the bottom, and flows upward. A…
Anaerobic Baffled Reactor (ABR)
An anaerobic baffled reactor (ABR) is an improved [8217-septic tank] with a series of baffles under which the wastewater is forced to flow. The…
Trickling Filter
A trickling filter, is a fixed-bed, biological reactor that operates under (mostly) aerobic conditions. Pre-settled wastewater is continuously ‘…
Septic Tank
A septic tank is a watertight chamber made of concrete, fibreglass, PVC or plastic, through which blackwater and greywater flows for primary…
Anaerobic Digestion (Large-Scale)
Large-scale anaerobic biogas digesters are reactors used for the conversion of the organic fraction of large volumes of slurries and sludge into…
Settler
A settler is a primary treatment technology for wastewater; it is designed to remove suspended solids by sedimentation. It may also be referred to as…
Retention Basin
Retention basins are among the most frequently implemented storm water management systems. They are used to collect surface runoff and to improve the…
Free-Water Surface Constructed Wetland
A free-water surface constructed wetland aims to replicate the naturally occurring processes of a natural wetland, marsh or swamp. As water slowly…
Horizontal Subsurface Flow Constructed Wetland
A horizontal subsurface flow constructed wetlandis a large gravel and sand-filled basin that is planted with wetland vegetation. As wastewater flows…
Hybrid Constructed Wetland
Different types of constructed wetlands can be combined in order to achieve a higher treatment efficiency by using the advantages of individual…
Vertical Flow Constructed Wetland
A vertical flow constructed wetland is a planted filter bed that is drained at the bottom. Wastewater is poured or dosed onto the surface from above…
Non-planted Filters
A non-planted filter is a box filled with sand and gravel, through which wastewater flows and is filtered. There are several types of non-planted…
Floating Plant Pond
A floating plant pond is a modified maturation pond with floating (macrophyte) plants. Plants such as water hyacinths or duckweed float on the…
Fixed Film Activated Sludge
Integrated fixed film activated sludge (IFAS) is a relatively new technology that describes any suspended growth system that incorporates an attached…
Anammox
Anammox stands for Anaerobic Ammonium Oxidation. The process was discovered in the early nineties and has great potential for the removal of ammonia…
Advanced Oxidation Processes
Hazardous organic waste, widely spread in water by industrial, military and domestic sources, is an emerging issue. Advanced Oxidation Processes (…
Stormwater Management
Stormwater management means to manage surface runoff. It can be applied in rural areas (e.g. to harvest precipitation water), but is essential in…
Adsorption (Activated Carbon)
Activated carbon filtration is a commonly used technology based on the adsorption of contaminants onto the surface of a filter. This method is…
Membrane Filtration
Membranes are thin and porous sheets of material able to separate contaminants from water when a driving force is applied. Once considered a viable…
Ion Exchange
Ion exchange is a water treatment method where one or more undesirable ionic contaminants are removed from water by exchange with another non-…
Ozonation
Ozonation (also referred to as ozonisation) is a chemical water treatment technique based on the infusion of ozone into water. Ozone is a gas…
H2O2
Hydrogen peroxide (H2O2), a colourless water-like liquid, is one of the most versatile, reliable and environmentally friendly oxidising agents. The…
Membrane Bioreactor
Membrane Bioreactors (MBR) are treatment processes, which integrate a perm-selective or semi-permeable membrane with a biological process (JUDD 2011…
Compost Filter
The compost filter is a fairly new method for pre-treating wastewater. There are two different methods: two chamber compost filters or compost filter…
Pre-Treatment Technologies
Pre-treatment is the preliminary removal of wastewater or sludge constituents, such as oil, grease, and various solids (e.g., sand, fibres and trash…
Disinfection and Tertiary Filtration
Depending on the end-use of the effluent or national standards for discharge in water bodies, a post-treatment step may be required to remove…
Economic Tools
Subsidies (WWT)
A subsidy (also known as a subvention) is a form of financial assistance paid to an individual, a business or an economic sector in order to achieve…
Water Charges
Water charges are a widely used economic instrument implied mainly by federal governments to better control water use and water pollution by imposing…
Processes
Terra Preta Sanitation
Terra preta is the name of a carbon and nutrient rich soil, which has been produced by pre-Columbian cultures by the incorporation of manure,…
Struvite
Urine, which contains valuable nutrients like nitrogen and phosphorus, can be applied to soil and used as fertiliser for crops. Though valuable,…
Anaerobic Digestion (General)
Biogas sanitation is the treatment of waste and wastewater by a process called anaerobic digestion. During anaerobic digestion, the organic matter in…
Urine Storage
Urine makes up less than 0.5 % of household wastewater but contains most of the essential plant nutrients N, P and K. Waterless urinals or urine…
Dehydration Vaults
Dehydration vaults are used to collect, store and dry (dehydrate) faeces. Faeces will only dehydrate when the vaults are well ventilated, watertight…
(Co-) composting (Small-scale)
Composting at the household level is an important method for managing organic waste, which is normally the largest portion of household waste.…
Co-Composting
Co-composting is the controlled aerobic degradation of organics, using more than one feedstock (faecal sludge and organic solid waste). Faecal sludge…
Sanitation in Emergencies
Sanitation in Emergencies Overview
The aim of every sanitation system in emergencies is to minimise spread of faecal-oral diseases and to restore a healthy environment. Safe excreta…
Immediate and short-term Emergency Sanitation
Immediate responses to a sanitation crisis caused by an emergency include a wide range of solutions, highly depending on physical conditions on the…
Medium-term Emergency Sanitation and Upgrading
Safe excreta disposal is a high priority task in emergencies. The choice of the optimal sanitation facility depends on different factors such as the…
Greywater
Leach Field
A leach field, or drainage field, is a network of perforated pipes that are laid in underground gravel-filled trenches to dissipate the effluent from…
Soak Pit
A soak pit, also known as a soakaway or leach pit, is a covered, porous-walled chamber that allows water to slowly soak into the ground. Pre-settled…
Vertical Gardens
The term vertical garden refers to any kind of construction and support structure for growing plants in an upwards-directed, vertical way and thereby…
Greywater Towers
A greywater tower is a circular bag, which is filled with soil, ash and/or compost mixture and a gravel column at the centre. It is used to treat and…
Irrigation
To reduce dependence on freshwater and maintain a constant source of water for irrigation throughout the year, wastewater of varying quality can be…
Evapo-transpiration Beds
Evapotranspiration beds are an alternative secondary treatment solution for greywater, pre-treated effluents from septic tanks, anal cleansing water…
Compost Filter
The compost filter is a fairly new method for pre-treating wastewater. There are two different methods: two chamber compost filters or compost filter…
Sludge Treatment
Anaerobic Digestion (Large-Scale)
Large-scale anaerobic biogas digesters are reactors used for the conversion of the organic fraction of large volumes of slurries and sludge into…
Unplanted Drying Beds
An unplanted drying bed is a simple, permeable bed that, when loaded with sludge, collects percolated leachate and allows the sludge to dry by…
Sedimentation/ Thickening Ponds
Sedimentation or thickening ponds are settling ponds that allow sludge to thicken and dewater. The effluent is removed and treated, while the…
Mechanical Dewatering
Mechanical dewatering is normally associated with large wastewater treatment plants and is used to separate sludge (residual sludge from wastewater…
Advanced Nutrient Recovery
Wastewater, municipal sludge or the ash after dried sludge, which is incinerated or disposed of, can be a very rich source for nutrients, in…
Incineration (Small-Scale)
Small-scale incinerators are a useful technology to combust household waste, medical waste, slaughter waste, etc. instead of discharging it in a…
Incineration (Large-scale)
Incineration or burning of non-recyclable solid waste helps to reduce the volume and the health risks related to the waste fraction to dispose.…
Co-Composting
Co-composting is the controlled aerobic degradation of organics, using more than one feedstock (faecal sludge and organic solid waste). Faecal sludge…
Planted Drying Beds
A planted drying bed is similar to an [8223-Unplanted Drying Bed], but has the added benefit of transpiration and enhanced sludge treatment due to…
Solid Waste
Anaerobic Digestion (Organic Waste)
Anaerobic biogas digesters are airtight reactors in which organic waste is decomposed and transformed into biogas by a biological process called…
(Co-) composting (Small-scale)
Composting at the household level is an important method for managing organic waste, which is normally the largest portion of household waste.…
Incineration (Small-Scale)
Small-scale incinerators are a useful technology to combust household waste, medical waste, slaughter waste, etc. instead of discharging it in a…
Incineration (Large-scale)
Incineration or burning of non-recyclable solid waste helps to reduce the volume and the health risks related to the waste fraction to dispose.…
Landfills
A landfill is an engineered pit, in which layers of solid waste are filled, compacted and covered for final disposal. It is lined at the bottom to…
Co-Composting
Co-composting is the controlled aerobic degradation of organics, using more than one feedstock (faecal sludge and organic solid waste). Faecal sludge…