The Process of Water Purification

Saccharomyces is a genus of fungi and it comprises many yeast species.  Most of the species belonging to this genus are very vital in the production of fermented foods. It is also called the brewer’s yeast or baker’s yeast as it is applied in the brewing and baking industry. An example of this species is Saccharomyces cerevisiae, which is applied in the production of wine, bread, and beer. Another example is Saccharomyces bayanus that is utilised in making wine (Rhee et al, 2011).

Lactic acid bacteria

Lactic acid bacteria are vital in the production of various fermented foods such as yoghurt and fermented milk. They are also used in preservation of edible foods through fermentation of other raw-materials like rice wine and beer, cakes, rice, and fish by producing organic acids to control microbes and pathogens. These bacteria provide a conducive environment for the fermentation microbes. They also give desirable flavors in the fermented foods. (Rhee et al, 2011).

Propionic acid bacteria

 Propionic acid bacteria were screened as bio preservatives against food spoilage against molds, yeasts and Bacillus species. It is very effective in preservation of fermented milk and in bakery products (DiGioia D et al., 2011).

Acetic acid bacteria

Acetic acid bacteria are a Gram-negative bacteria that oxidise sugar or ethanol to produce acetic acid during the fermentation process. They are present in environments where ethanol is formed by the fermentation of sugars. Acetic acid bacteria they are known to control the food fermentation processes and are utilized in the production of fermented foods products and beverages. The first step of acetic acid production is the production of ethanol  derived from a carbohydrate by yeasts, and then the oxidation of ethanol to acetic acid carried out by acetic acid bacteria (Raspor and Goranovic, 2018)

Q2 The process of water purification

The goals of the treatment are to remove unwanted constituents in the water and to make it safe to drink or fit for a specific purpose in industrial applications. Various techniques are applied to remove contaminants such as solids, microbes and some dissolved inorganic and organic materials, or environmental pollutants. The choice of a method depends on the quality of the water to be treated, the cost of the treatment process and the quality standards of the water required. The following steps are involved;

1.Sedimentation

The raw water is allowed to enter the sedimentation basin and upon settling , Soil, sand, mineral particles and large particles settle down the basin and are removed(Jacobson,2004).

2.Coagulation and flocculation

After removing the sentiments, the water is then pumped to the coagulation basin. Coagulation and flocculation remove any colour that may be present so that the water is clear and colourless. Clarification is accomplished by causing a precipitate (a solid) to form in the water which can then be removed by using simple physical methods.  Some of the flocculating agents include iron (III) hydroxide, aluminum hydroxide and aluminum potassium sulfate.

3.Filtration

 After the flocculation process, the water is then filtered to remove the remaining suspended particles and unsettled sediments. This is done by passing the water through coarse sand filter or through a mixture of sand, carbon and coal.

4,Disinfection

This is accomplished by filtering out harmful microbes and also by adding disinfectant chemicals in purifying drinking water. Many pathogens are killed by this disinfection step.

Some of the disinfectant agents are Chlorine, Chloramines, Ozone, Hydrogen peroxide, Ultraviolet (UV)

Biochemical Oxygen Demandrganic matter.

this is the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period. This is an important water quality that should be dealt with by minimalizing the dissolved organic matter (Clair et al 2003)

Clair N. Sawyer; Perry L. McCarty; Gene F. Parkin (2003). Chemistry for Environmental Engineering and Science (5th ed.). New York: McGraw-Hill.

Works cited

De Roos J and De Vuyst L.(2018). Acetic acid bacteria in fermented foods and beverages. Curr Opin Biotecahnol. 49:115-119

DiGioia D, Mazzola G, Nikodinoska I, Aloisio I, Langerholc T, Rossi M, Raimondi S, Melero B, Rovira J.(2011). Lactic acid bacteria as protective cultures in fermented pork meat to prevent Clostridium spp. growth.Int J Food Microbiol. 2016 Oct 17;235:53-9

 Jacobsen F.K.(2004). Water Filtration.J. Chem. Educ., 81 (2), p 224A

 Rhee,S.G.,  Lee  J. and Lee C.(2011).

Importance of lactic acid bacteria in Asian fermented foods. Microb Cell Fact. 2011; 10(Suppl 1): S5.

Raspor P; Goranovic D (2018). “Biotechnological applications of acetic acid bacteria”. Critical Reviews in Biotechnology. 28 (2): 101–124