Why do we prefer to call secondary waste water treatment as biological treatment?
Secondary waste water treatment is called biological treatment because microorganisms are involved in the breakdown of organic matter in this phase of waste water treatment.
The primary effluent is passed into large aeration tanks where the organic matter in it is consumed by aerobic microbes which are later themselves digested by anaerobic bacteria and fungi in anaerobic sludge digesters.
What for nucleopolyhedro viruses are being used now a-days?
Several methods of biological control are being used in the pest management to keep the pollution-free environment and yield clean, non-toxic and good quality products for human consumption.
Baculoviruses are a group of viruses used as biological control agents that occur naturally and are specific to some insects. Most of the baculoviruses belong to the genus Nucleopolyhedro virus.
These viruses are excellent candidates for species-specific, narrow spectrum insecticidal applications. They have been shown to have no negative impacts on plants, mammals, birds fish or even on non-target insects.
This is especially desirable when beneficial insects are being conserved to aid in an overall Integrated Pest Management (IPM) Programme or when an ecologically sensitive area is being treated.
How has the discovery of antibiotics helped mankind in the field of medicine?
Antibiotics produced by microbes are regarded as one of the most significant discoveries of the twentieth century and have greatly contributed towards the welfare of the human society.
Anti is a Gk. word that means 'against' and bio means 'life', together they mean 'against life' (in the context of disease causing organisms); whereas with reference to human beings, they are 'pro life' and not against. Antibiotics are chemical substances, which are produced by some microbes and can kill or retard the growth of other (disease-causing) microbes.
Antibiotics have greatly improved our capacity to treat deadly diseases such as plague, whooping cough (Kali khansi), diphtheria (Gal ghotu) and leprosy (Kusht rog), which had killed millions all over the globe. Today, we can not imagine a world without antibiotics.
Why is distillation required for producing certain alcoholic drinks?
Depending on the type of the raw material used for fermentation and the type of processing (with or without distillation) different types of alcoholic drinks are obtained.
Wine and beer are produced without distillation whereas whiskey, brandy and rum are produced by distillation of the fermented broth.
Distillation increases the alcohol content in alcoholic drinks. That's why for producing certain alcoholic drinks, distillation is required.
Write the most important characteristic that Aspergillus niger, Clostridium butylicum, and Lactobacillus share.
Their common characteristic is that they produce organic acids as part of their metabolism and are therefore, used for commercial and industrial production of the same.
(i) Aspergillus niger (a fungus) for citric acid.
(ii) Clostridium butylicum (a bacterium) for butyric acid.
(iii) Lactobacillus (a bacterium) for lactic acid.