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water services

all services which provide, for households, public institutions or any economic activity: (a) abstraction, impoundment, storage, treatment and distribution of surface water or groundwater, (b) waste-water collection and treatment facilities which subsequently discharge into surface water.

X-ray fluorescence spectrometric analysis
XRF (X-ray fluorescence spectrometry) is a non-destructive analytical technique used to identify and determine the concentrations of elements present in solid, powdered and liquid samples. The atoms of the analyte are illuminated by X-ray and the excited atoms discharge fluorescent radiation. The energy (wavelength) of the emitted radiation is characteristic to the element, the intensity is proportional to the abundance (concentration) of the element. The analysis is based on a calibration with samples containing known elements. XRF is capable of measuring elements from beryllium (Be) to uranium (U) and beyond at trace levels often below one part per million and up to 100%. The concentration measurement is influenced by the matrix (matrix effect). The XRF spectrometer measures the individual component wavelengths of the fluorescent emission produced by a sample when irradiated with X-rays. Typical environmental applications: at wood treating facilities determination of chromium, arsenic and pentachlorophenol; in numerous other sites toxic metals such as lead, mercury, arsenic and cadmium. XRF is commonly used as a screening tool to identify contaminated areas that must be remedied. Smaller instruments, even hand held devices might be used on site, while higher end instruments are used in the lab. (Source: www.panalytical.com)
xenobiotic

xenobiotics are substances foreign to an entire biological system. They are artificial substances, which did not exist in nature before their synthesis by humans. The term originates from Greek, meaning foreigner, stranger.

zero-waste agriculture (ZWA)

zero waste agriculture is a type of sustainable agriculture which optimizes use of the plants, animals, bacteria, fungi and algae, to produce biodiverse-food, energy and nutrients in a synergistic integrated cycle of profit making processes where the waste of each process becomes the feedstock for another process.

The biogas digester is the heart of most zero waste agriculture (ZWA) systems. It is a 3000 year old anaerobic digestion process, where all organic waste can be converted into biogas, which is used for heating. The residue of anaerobic digestion is utilised for algae production, and agae for growing fish. Microalgae can alternatively be utilised for biodiesel-production. In sunny climates, a one hectare zero waste farm can produce over 1000 litres of oil in a year from the chlorella microalgae grown on biogas digester effluent in a 500 squermeter shallow pond. The nutritive high protein waste from the oil extraction process can be used as animal feed.

The water recycling can also be made complete in such an agricultural system: all the used waters can be naturally treated and reused.

Zero waste agriculture combines ecological or organic farming practices with a complete waste utilisation system.

Zero waste agriculture is optimally practiced on small 1−5 ha sized family owned and managed farms and it complements traditional farming & animal husbandry as practiced in most third world communities. Zero Waste Agriculture also preserves local indigenous systems and existing agrarian cultural values and practices.

Zero waste agriculture presents a balance of economically, socially and ecologically benefits as it:

  1. optimizes food production in an ecological sound manner
  2. reduces water consumption through and recycling and reduced evaporation
  3. provides energy security through the harvesting of biomethane (biogas) and the extraction of biodiesel from micro-algae all of which from as a by-products of food production
  4. provides climate change relief through the substantial reduction in greenhouse gas emissions from both traditional agriculture practices and fossil fuel usage
  5. reduces the use of pesticides through biodiverse farming.

ZWA is a target of the agrarpolitics in many third countries, such as Brazil, India, China, Columbia and South Africa.

Source: http://en.wikipedia.org/wiki/Zero_waste_agriculture