How to use the characteristics of each growth stage of microbial batch culture to carry out sewage b

There are four stages of microbial growth: retardation, logarithmic growth, stability, and decay.

Generally, the sewage treatment system will control the microorganisms in the stable period, because the microbial activity at this time is good, and it is not easy to produce sludge expansion.

Sewage treatment is to take advantage of this feature.

Microbial batch culture treatment sewage treatment is mainly applied to the characteristics of microorganisms in different periods

For the intermittent culture of microorganisms, in order to avoid the occurrence of the slow phase in the process of sewage biological treatment, it is generally considered to use sludge in the logarithmic growth period or vigorous metabolism for inoculation, and increasing the inoculation amount and using sludge inoculation of the same type of reactor can greatly shorten the effect of the slow period.

However, if the growth of microorganisms is maintained in the growth rate rising stage (logarithmic phase), the microorganisms reproduce quickly, the vitality is very strong, and the ability to treat sewage is bound to be higher, but even so, it does not mean that the treatment effect must be the best, because the stronger the microbial activity, the easier it is to coagulate and precipitate, and to make the microorganisms grow in the logarithmic phase, sufficient food is required, that is, the organic matter in the sewage must maintain a higher concentration, in this case, relatively speaking, the concentration of organic matter contained in the treated sewage must be higher, Therefore, it is actually difficult to obtain better effluent for biological treatment of sewage at this stage.

In the stable phase, the growth rate of microorganisms decreases, and the cells begin to accumulate storage and metachromatic particles, liver sugar, etc. Spore microorganisms also form sore at this stage, and the metabolic activity and flocculation and sedimentation performance of sludge in the stable stage are good, and the traditional activated sludge method is generally operated in this range. You can log in.

The following statement about the cultivation and utilization of microorganisms is incorrect (a).

a.The urea solid medium can quickly kill other microorganisms, while retaining the microorganisms that use urea.

b.When preparing the medium, the pH of the medium should be adjusted according to the type of microorganisms

c.Yeast cannot directly use glutinous rice starch fermentation to obtain glutinous lead source divine rice wine.

d.Acetobacterium acetate can be activated by the appropriate concentration of alcohol with a split front.

A. The urea solid medium is based on urea as the only nitrogen source, can not kill other microorganisms, the reason for screening out urea decomposition bacteria is that only microorganisms that can synthesize urease can decompose urea, obtain nitrogen source, in order to survive in this medium, the rest of the microorganisms due to the inability to decompose urea, lack of nitrogen source eventually die, a error.

The culture technology and application of microorganisms include aerobic culture and anaerobic culture.

The application is to continuously discover and which bucket history is widely used in various antibiotics, the study of bacterial cells and viruses has reached the level of submicroscopic structure, so as to further understand their activity rules, further elucidate the nature, composition and mechanism of action of bacterial endotoxins and exotoxins, significantly improve the isolation and culture technology, and greatly improve the positive rate of isolating Campylobacterium or bacteroides from patient specimens.

Aerobic culture is also called aerobic culture. That is to say, when this kind of microorganism is cultivated, it needs to be added with oxygen, otherwise it will not grow well. In the laboratory, bevel culture is obtained from the outside world by means of a cotton plug.

The liquid culture of the triangular flask is mostly shaken by shaking the shaker, so that the outside air enters the bottle continuously.

Microbial culture techniques.

Anaerobic culture is also called anaerobic culture. These microorganisms do not require oxygen to participate in the cultivation. One of the most important aspects of the culture of anaerobic microorganisms is the removal of oxygen from the medium.

Research and development of new microorganisms with good immunogenicity and small size, and develop specific, sensitive, simple and rapid microbiological diagnostic methods and technologies.

The role of this curve in the biological treatment of wastewater is to understand the degree of sewage treatment in real time.

The growth law of microorganisms is generally reflected by the growth curve. According to the growth rate of microorganisms, its growth can be divided into four growth periods, stagnation period, logarithmic phase, quiescent phase, senescence phase, sewage biological treatment, microorganisms are the main organisms that decompose organic matter, understanding the microbial growth curve can help operators control the number and activity of microorganisms, control and optimize the number and vitality of microorganisms, so as to improve sewage treatment efficiency and reduce treatment costs.

For example, when evaluating a wastewater treatment program, the microbial growth curve can determine the optimal long stages and conditions to maximize the decomposition of microorganisms. Reviewing microbial growth curves can also determine when new microorganisms are added in order to maintain a particular bacterial number and viability, maintaining a good state of biological equilibrium during treatment.

Which growth stage of microorganisms is used in conventional activated sludge method (You Jian).

a.Stasis period.

b.Logarithmic growth phase.

c.Quiescent period.

d.The period of decay and death.

Correct answer: B

1 Shorten the lag period.

In industrial fermentation and scientific research, the lag period will prolong the production cycle and reduce the utilization rate of the equipment, and certain measures are usually used to shorten the lag period:

Genetic methods were used to change the genetic characteristics of the strain, so that the delay period of the strain was shortened.

The use of inoculation and culture of robust strains in the exponential growth period can shorten or even eliminate the lag period.

Try to make the composition of the fermentation medium close to the seed medium, and appropriately rich, or add the components of the fermentation medium to the seed medium, and the experiment has confirmed that the microorganisms inoculated into the nutrient-rich natural medium are shorter than those inoculated into the nutritionally monotonous combination medium.

Appropriately increase the inoculation amount, the fermentation industry usually uses V seeds:V medium 1 20, up to 1 10, and the use of a larger inoculation amount to shorten or even eliminate the delay period.

2 Grasp the logarithmic period.

During the logarithmic phase, the number of bacteria increases the fastest and the growth rate is the largest, and in the fermentation industry, the growth rate of the bacteria can be increased with the increase of nutrient concentration by continuous flow addition or supplementation of fermentation raw materials, and more bacteria can be obtained.

3 Extend the stabilization period.

The length of the stable period of microorganisms is related to the characteristics of the strain and environmental conditions, and in order to obtain more bacteria or metabolites in the fermentation industry, the stable period can also be extended by feeding the material, adjusting the pH value, temperature or ventilation capacity. Continuous culture is a culture method in which nutrients are added to the fermentation system and metabolites are removed.

The process by which microbial fermentation forms products does not always coincide with the process of microbial cell growth. It is generally believed that the primary metabolism of microorganisms is the process of releasing biological energy and generating intermediate products, and the intermediate products generated by primary metabolism are called primary metabolites, such as amino acids, nucleotides, ethanol, etc., which are necessary for the survival of microorganisms, and various microorganisms produce similar types of primary metabolites, and the formation of these products is often synchronized with the formation process of microbial cells. In the process of microbial batch culture, the stable period of microbial growth is the best time to harvest these products.

There are also some metabolites that are not related to the survival, growth and reproduction of microorganisms, called secondary metabolites, such as antibiotics, growth hormones, alkaloids, vitamins, pigments and toxins. The formation of these metabolites is often out of sync with the microbial cell growth process. In batch cultures, they tend to peak late in the stabilization phase of microbial growth or in the decay phase.

Through continuous culture and other methods, the stabilization period can be extended and the yield of secondary metabolites can be increased.

4 Monitor the period of decay.

In industrial fermentation, try to prevent the arrival of the decay period, but the decay period is inevitable, once the decay period is entered, the accumulated microbial metabolic poisons may react with metabolites or affect purification, and the fermentation must be ended at the right time.