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Hand pumps (alias manual pumps or human-powered pumps) are a type of water-lifting device mainly serving community water supplies that can be operated manually. Human-powered pumps also include foot pumps and rope and bucket systems with or without a windlass or shadouf. Synonyms: Hand-Pump, Manual-Pump, Manual Pump, Human-powered Pump
The traditional and still most common method of obtaining groundwater in rural areas of the developing world is by means of dug wells, mostly hand-dug wells. With the prior knowledge that groundwater is present and rather close to the surface, a hole (5-30 metres) is dug until the groundwater level is reached. Inflowing groundwater is collected and can be extracted with the help of pumps or buckets. Synonyms: Dug well
Hardware tools are technical options to optimise your water and nutrient cycle. These are physical solutions that you can see and touch with your hands such as water filters, toilets, treatment systems or technologies to recycle water and nutrients. Usually, you will nee a combination of different hardware and software tools to really make a sustainable impact.
10-25% of health-care waste is regarded as “hazardous” and may pose a variety of environmental and health risks. There are different categories of hazardous health-care waste: sharps waste, infectious waste, pathological waste, pharmaceutical waste, cytotoxic waste, chemical waste and radioactive waste.
Health is of complete physical, mental and social well-being and not merely the absence of disease or infirmity.
Healthcare waste (HCW) is a by-product of healthcare that includes sharps, non-sharps, blood, body parts, chemicals, pharmaceuticals, medical devices and radioactive materials. Poor management of HCW exposes healthcare workers, waste handlers and the community to infections, toxic effects and injuries. Synonyms: HCW
Heat engines, as thermal power plants are physical devices that convert thermal energy to mechanical output (which can be transformed into electricity). The mechanical output is called work, and the thermal energy input is called heat. Heat is transferred from the source, through the working body of the engine, to the sink, and in this process some of the heat is converted into mechanical energy (work) by exploiting the properties of a working substance (usually a gas or liquid).
A parasitic worm, i.e. one that lives in or on its host, causing damage. Some examples that infect humans are roundworms (e.g., Ascaris and hookworm) and tapeworms. The infective eggs of helminths can be found in excreta, wastewater and sludge. They are very resistant to inactivation and may remain viable in faeces and sludge for several years. Synonyms: Helminth eggs
HRP follow the AFP in AIWP systems. Aerobicbacteria break down dissolved organic matter and algae take up nutrients and further BOD. HRPs are designed to promote the symbiosis between the microalgae and aerobicbacteria, each utilizing the major metabolic products of the other. Microalgae grow profusely releasing oxygen from water by photosynthesis. Since at the rapid growth of algae pH can raise to above 9 (because at peak algal activity carbonate and bicarbonate ions react to provide more carbon dioxide for the algae leaving an excess of hydroxyl ions), most pathogens are also killed. Synonyms: High Rate Algal Pond, HRAP, HRP
High-strengthwastewater means it contains greater amounts of organic components (such as fats, oils, and greases) than residential wastewater. It can also mean the effluent contains large quantities of suspended solids or high amounts of certain chemicals, such as disinfectants. Any or all of these components can interfere with the normal biological processes most onsite sanitation systems use. These characteristics vary from day to day, even from hour to hour, and they can have a major impact on how a biological system performs. The major concern of having high organic loading in wastewater is physical clogging. But high organic load may cause anaerobic conditions leading to odour problems and poor performance.
Horizontal learning is an outcome-oriented process that supports the innate human ability to acquire tacit skills through copying the very best of what others do. It is not the traditional top-down learning that takes place in a classroom with a lecturer and students. Much more, people learn from each other by observation, interaction, and
copying. Horizontal learning can hence contribute to promote community empowerment and defends and advances indigenous knowledge.
A horizontal subsurface flow constructed wetland is a large gravel and sand-filled basin that is planted with wetland vegetation. As wastewater flows horizontally through the basin, the filter material filters out particles and microorganisms degrade the organics. Compared to free-water surface flow constructed wetlands, horizontal sub-surface flow constructed wetlands have the advantage of better oxygen transmission reduced risk of mosquito breeding. Synonyms: HF CW, HFCW, Horizontal Flow Constructed Wetland, Sub-surface Flow Constructed Wetland, Sub-surface Horizontal Flow Constructed Wetland
Household-level approaches to drinking water treatment and safe storage are also commonly referred to as managing the water at the “point-of-use”. This term or its abbreviation “POU” typically describe the same procedures as other abbreviations derived from household water treatment, like “HHWT” or “HWT” or “HWTS” (The “S” in “HWTS” refers to safe storage). “Household water management” is also commonly used, and can encompass both treatment and storage. All these terms can refer to a variety of treatment procedures, for example, with chlorine or other chemical disinfectants, sunlight or UV lamps, various filters, or flocculation-disinfection formulations.
Household-level Water Treatment and Safe Storage
Household-level approaches to drinking water treatment and safe storage are also commonly referred to as managing the water at the “point-of-use”. This term or its abbreviation “POU” typically describe the same procedures as other abbreviations derived from household water treatment, like “HHWT” or “HWT” or “HWTS”. (The “S” in “HWTS” refers to safe storage.) “Household water management” is also commonly used, and can encompass both treatment and storage. All these terms can refer to a variety of treatment procedures, for example, with chlorine or other chemical disinfectants, sunlight or UV lamps, various filters, or flocculation-disinfection formulations. Synonyms: HHWT, Household Water Management, Household Water Treatment, HWT, HWTS, Point-of-use Water Treatment
Where there is no or no sufficient supply of fresh or drinking water, nor motorised vehicles to distribute it, water distribution is human-powered. Human-powered water distribution refers to the use of jerry cans and small recipients to fetch water from a centralised distribution point (e.g. river, lake, borehole, shallow well). Either people collect and transport the water themselves or they buy it from mobile vendors that often use small barrels on wheels to transport the water and sell it door-to-door. The effort of ensuring water supply can be high for single families or communities and its price is often higher than that of a well managed public piped distribution system. Synonyms: Humanpowered Water Distribution
Humic acid is a principal component of humic substances, which are the major organic constituents of soil (humus). Humic sub-stances are formed by the microbial degradation of dead plant matter, such as lignin. They are very resistant to further biodegrada-tion. A typical humic sub-stance is a mixture of many mole-cules, some of which are based on a motif of aro-matic nuclei with phenolic and carboxylic substituents, linked to-gether. The functional groups that contribute most to sur-face charge and reactivity of humic substances are phenolic and carboxylic groups. Humic and fulvic acids are commonly used as a soil supplement in agriculture. Organic soil amendments (humus) are beneficial to plant growth due to the release of its constituent nutrient elements into inorganic forms and through its effect on the soil fertility through their water-holding capacity.
Humification describes the process of sludge treatment in planted dewatering/drying beds. The sludge is loaded on the bed and dewatered by percolation in the filter and by evapotranspiration through the plants. The root system of the plants maintains the permeability of the sludge layer. The sludge is be added intermittently. Sludge has to be removed only once every 5 -10 years depending on design. The final product has is very well mineralized and has a soil-like structure. The long solids retention period and pathogen die-off and allows direct reuse of the solids in agriculture. Percolate quality considerably improves by the presence of plant (compared to unplanted drying beds) but may still require a polishing treatment.
Hybrid constructed wetlands combine the high BOD and TSS removal in surface-flow constructed wetlands with the good nitrification due to better oxygen transfer in sub-surface CWs. Depending on the purpose, hybrid wetlands can be either surface flow followed by sub-surface or sub-surface flow followed by surface flow. Synonyms: Combined Constructed Wetland
Permeability in fluid mechanics and the earth sciences (commonly symbolised k). It is the measure of the ability of a porous material (often, a rock or unconsolidated material) to allow fluids (e.g. water) to pass through it. Synonyms: k, k-value
The hydraulic head measures the water pressure expressed in terms of height. For instance the pressure on the bottom of a lake filled with a water column of 10 m, will receive a water pressure of 10 m expressed as hydraulic head. Synonyms: Hydraulic Load
Hydraulic Retention Time
The average amount of time that liquid and soluble compounds stay in a reactor or tank. It is calculated by dividing the volume of a reactor (e.g. m3) by the influentflow rate (e.t. m3/day). In wastewater treatment systems the HRT influence the treatment efficiency and is therefore an important design parameter. Synonyms: Detention Time, HRT, Liquid Retention Time
A cyclone separator parts granular solids from a liquid (e.g. river water) by clustering them through centrifugal force.
Hydrogen peroxide (H2O2), a colourless water-like liquid, is one of the most versatile, reliable and environmentally friendly oxidising agents. The relative safety and simplicity of its uses has led to the development of a number of applications in water treatment such as odour removal, disinfection or metal removal. Hydrogen peroxide is also used in advanced oxidation processes (AOP) and can be combined with catalysts or other oxidisers to produce reactive oxygen species (ROS) able to attack a wide range of organic compounds and microorganisms. The production of hydrogen peroxide is usually performed at industrial scale but can also be done directly in drinking water (or pre-treated wastewater) by electrolysis. Synonyms: H2O2
Hydrolysis describes the cleavage of a chemical compound through the reaction with water. Thereby, a hydrogen atom (H) is added to one part of the split chain, while the remaining hydroxyl group of the water (OH) is added to the other. Hydrolysis is the first step of anaerobic digestion in which insoluble complex molecules such as carbohydrates and fats are broken down to short sugars, fatty acids and amino acids.
Hydroponic means the cultivation of plants in water without soil. Nutrients, essential for the growth of the plants are thereby provided from the water.
When the mechanical energy from flowing or falling water is used to produce energy, this is called hydropower.
Hydropower Small Scale
Hydropower uses the power of moving water (kinetic energy) to generate electricity. Small-scale hydropower produces between 1 and 30 MW. Small-scale hydropower systems can be installed in small rivers, streams or in the existing water supply networks, such as drinking water or wastewater networks. In contrast with large-scale hydropower systems, small-scale hydropower can be installed with little or negligible environmental impact on wildlife or ecosystems, mainly because the majority of small hydropower plants are run-of-river schemes or implemented in existing water infrastructure. Due to its versatility, low investment costs, and as a renewable energy source, small-scale hydropower is a promising option for producing sustainable, inexpensive energy in rural or developing areas. Synonyms: Small Hydropower, Small-scale Hydropower
Hygiene Frameworks and Approaches
To mitigate the effects of lacking hygiene on health, various approaches have been developed that should help people in improving their hygiene. These approaches include guidelines on how to conceptualise, plan and carry out health and hygiene projects.