Septic tank

In many respects, the commonest rural solution to sewage treatment beyond the reach of sewerage, namely the septic tank, makes use of an intermediate form of land treatment. In the so-called cesspit, a sealed underground tank, collects and stores all the sewage arising from the household. At regular intervals, often around once a month dependent on the capacity, it requires emptying and tankering away, typically for spreading onto, or injection into, agricultural land. By contrast, a septic...

Case Study 91 Engineered Salt Tolerance Rehovot Israel

One area where agrobiotechnological advances could have distinctly environmental applications, in the widest sense, is in the production of transgenic plants. While much of this research has centred on greater productivity, some work has been done to address other issues and one of the potentially most important of these relates to improving salt tolerance. According to some authorities, over half the world's agricultural land is expected to become increasingly saline within the next 50 years....

Examples of developments in plant GE

The purpose of these examples is to illustrate the potential plant genetic engineering could bring to future practical applications in the field of environmental biotechnology. In some cases the intention is to reduce the amount of herbicide and pesticides, or other agricultural chemicals required to produce a given crop yield, in others it is to improve tolerance of harsh conditions or to protect the plants from attack thus reducing wastage. The intention is to note the technical details here,...

Endocrine disrupters

To date, there are chemicals, including xenobiotics, which still resist degradation in the environment. This may be due to a dearth, at the site of contamination, of organisms able to degrade them fully or worse, microbial activity which changes them in such a way that they pose a bigger problem than they did previously. One such example is taken from synthetic oestrogens such as 17a-ethinyloestradiol commonly forming the active ingredient of the birth control pills, and the natural oestrogens...

Plant disease suppression

Intensively reared crops can suffer extensive and expensive losses resulting from plant disease infection. Until the early 1930s, crop rotation and the use of animal manures and green mulches provided the traditional protection regime after this time, chemical fumigation became the favoured method to deal with soil-borne pathogens, which can accumulate heavily in intensive monocultures. Methyl bromide has been the main agent used, its popularity largely attributable to its ability also to...

Extremophiles

As has been previously mentioned, in general the use of biotechnology for environmental management relies on mesophilic micro-organisms which have roughly similar environmental requirements to ourselves, in terms of temperature, pressure, water requirement and relative oxygenation. However, often some of their abilities, which are directly instrumental in enabling their use in this context, arose in the first instance as a result of previous environmental pressures in the species (pre)history....

Fermentation and respiration

The electrons derived from the catabolism of the carbon source are eventually either donated to an organic molecule in which case the process is described as fermentation, or donated to an inorganic acceptor by transfer along an electron chain. This latter process is respiration and may be aerobic where the terminal electron acceptor is oxygen, or anaerobic where the terminal electron acceptor is other than oxygen such as nitrate, sulphate, carbon dioxide, sulphur or ferric ion. Unfortunately,...