**4.2 Chemical treatment**

*Environmental Issues and Sustainable Development*

irrigation, and so on.

*3.2.2 Cleaning wastewater*

toxic thereby needing more care.

**4. Dairy wastewater treatment**

lagoons, or a variation of these.

cal treatment methods [20].

**4.1 Mechanical treatment**

*3.2.3 Sanitary wastewater*

hot water, steam manufacturing, and membrane washing. After the final flushing of bottles and condensates from secondary vapors created in vacuum installations, water from liquid cooling during pasteurization can be used for room washing,

Wastewater purification typically benefits from cleaning machinery within close contact with dairy goods. This involves spillage of milk and substance, whey pressing or brine, malfunctioning of the clean in place effluents, or machinery errors. More than 93% of the organic contents contained in the effluent are partly the remnants of milk, cheese, whey, butter, sugar, honey, and fruit concentrate or stabilizers. These effluents are found in significant concentrations and are extremely

Sanitary wastewater is utilized in washrooms, toilets, etc. Sanitary wastewater has parallels with urban wastewater composition and is typically piped straight to sewage facilities. It may be used as a supply of nitrogen for irregular dairy effluents after a secondary aerobic treatment. Furthermore, by-products from agricultural processes like milk, whey, and their permeate can be classified independently if

For the dairy industry, common wastewater treatment strategies involve grease traps, oil-water separators to remove floatable solids, flow equalization, and clearers to isolate suspended solids. Biological treatment consists of the aerobic and anaerobic methodologies. Anaerobic treatment accompanied by aerobic treatment is also used to minimize soluble organic matter (BOD), and the reduction of biological nutrients (BNR) is used to increase nitrogen and phosphorus levels. Biological aerobic treatment requires cellular destruction in the presence of oxygen. Conventional aerobic treatment of dairy manure includes procedures such as activated sludge, batch sequencing generator, revolving biological contactors, trickling pipes, aerated

Treatment of anaerobic wastewater has emerged as a feasible and inexpensive alternative particularly for high BOD removal over conventional aerobic treatment. Anaerobic methods of treatment involve up-flow anaerobic sludge blanket or UASB, anaerobic batch sequencing reactors or ASBR, continuous-flow reactor, hybrid anaerobic digesters, up/downflow anaerobic filter, and various 2-stage processes that use acid and methane forming bacteria. **Figure 1** shows the sequential treatment of dairy wastewater through mechanical, physical, chemical and biologi-

This is the initial phase of dairy wastewater treatment and this includes grit pool, skimming tank, and main clarifiers. During further effluent processing, the large floating material is removed by screens, in-turn avoiding the chocking of pipes. Chambers are used for extracting heavier inorganic substances like sand, gravel, etc. The aim of installing skimming tanks is to extract oil, grease, pieces

they are segregated individually from other wastewater sources [27, 28].

**102**

Chemical treatment is also recognized as precipitation. This is performed by adding flocculants to wastewater and vigorous mixing with agitators. This method precipitates insoluble phosphate into larger flocks, in the form of small pellets. In pre-sedimentation basins, the greater flocks settle as the main sludge, whereas a clear supernatant fluid overflows into a lake for biological therapies. Sedimentation lagoons are armed with tools to continuously scrape the sediment towards a sump or oblique gutters to keep water away from the clarified surface layers [29].

### **4.3 Biological treatment**

Milk effluent includes organic waste; therefore most viable methods for the elimination of organic content are biological degradation. However, sludge generated may lead to serious and costly problems towards disposal, particularly during the processes of aerobic biodegradation. This can be further worsened due to the tendency of sludge to absorb various organic compounds and poisonous heavy metals also. Nonetheless, biological treatment has the profits of dynamic organic microbial processes and the ability for adsorption of heavy metals effectively. Biological waste management strategies have an immense capacity to incorporate diverse types of biological schemes for selective elimination [30].

#### *4.3.1 Aerobic treatment*

Microorganisms cultured in an O2-rich environment degrade organics by oxidizing matter to CO2, soil, and cellular material. Aerobic treatment methods include activated sludge reactors, rotating biological reactors, conventional filters for trickling, and so on [30].

#### *4.3.2 Anaerobic treatment*

Anaerobic method of treatment is mainly intended for the biological processing of high strength wastewater. It is a process by which microbes are used in the absence of O2 to digest organic matter by converting it to biogas (CH4 and CO2)

and some inorganic contents. 6% of the organic load can be converted into biogas from the wastewater and the rest can be used for cell growth and maintenance. The process reactors are shielded to avoid air obstruction and the release of odors [30].
