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WASTEWATER TREATMENT USING BIOCHEMICAL METHODS: SUSTAINABLE
APPROACHES FOR ENVIRONMENTAL PROTECTION
Abdurashid Khakberdiev
1st year master’s student at the Karshi State
Technical University, 225, 180100, Karshi, Uzbekistan
abdurashid.khakberdiev84@gmail.com
Abstract:
Environmental protection has become one of the most pressing global challenges of
the 21st century. With rapid population growth, industrial development, and urbanization, the
volume of wastewater generated has increased dramatically, posing serious threats to water
ecosystems and human health. This research investigates the application of biochemical methods
for wastewater treatment as sustainable and environmentally friendly alternatives to conventional
mechanical and chemical treatment processes. The study analyzes various biochemical treatment
technologies including activated sludge systems, membrane bioreactors (MBR), and anaerobic
digesters.
Keywords:
wastewater treatment, biochemical methods, sustainable technology, environmental
protection, bioreactors
Introduction.
Today, environmental protection issues are among the most pressing global
problems on a worldwide scale. The growth of population, rapid industrial development,
intensification of urbanization processes, and climate change consequences have led to an
expansion in the scope of natural resource utilization [1]. Among these challenges, the
contamination of drinking water sources, degradation of aquatic ecosystems, water scarcity, and
the increasing volume of untreated wastewater pose serious ecological threats [2].
With the improvement of living standards, water consumption has increased in various sectors—
domestic, agricultural, and industrial branches. This, in turn, leads to the generation of large
volumes of wastewater [3]. Wastewater may contain various chemical compounds, heavy metals,
substances toxic to flora and fauna, as well as microorganisms that cause infectious diseases [4].
The direct discharge of these polluting substances into natural water bodies results in ecological
imbalance disruption, destruction of aquatic biological resources, and serious threats to human
health [5].
Under these circumstances, improving wastewater treatment technologies and developing them
in an ecologically sustainable direction has become one of the most important tasks [6].
Traditional mechanical and chemical treatment methods are only capable of neutralizing a
certain portion of polluting substances and are often associated with high costs and secondary
pollution risks [7]. For this reason, in recent years, special attention has been paid to biochemical
methods for implementing ecologically safe, energy-efficient, sustainable, and effective
treatment technologies [8].
Biochemical treatment technologies are based on utilizing the natural metabolic activity of
microorganisms—particularly bacteria and fungi [9]. These methods decompose organic
substances, converting them into simple, harmless components (CO₂, water, biomass) and ensure
ecological safety [10]. Such methods serve humanity by modeling natural biological cycles,
which further enhances their ecological efficiency [11].
One of the important advantages of biochemical processes is that they work effectively even in
small areas, ensure high-level neutralization of biodegradable components in wastewater, reduce
energy consumption, and provide the opportunity to obtain economic benefits through recycling
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the generated biomass [12]. Particularly, installations based on advanced technologies such as
membrane bioreactors (MBR), activated sludge methods, and anaerobic reactors are among the
most effective systems today [13].
In the Republic of Uzbekistan, various measures are being implemented to ensure ecological
sustainability, increase the ecological safety of industrial enterprises, and organize rational use of
water resources [14]. For instance, as can be seen from the example of the “Uzbekistan GTL"
plant, domestic, technological, and petroleum product-contaminated wastewater is being treated
to a high degree through biologically-based treatment facilities, creating opportunities for reuse
[15].
Therefore, this independent research systematically analyzes the scientific-theoretical
foundations, technological solutions, practical applications, and ecological efficiency of
wastewater treatment using biochemical methods. The purpose of this work is to identify the
advantages of biochemical treatment technologies, study the possibilities of implementing them
in accordance with local conditions, and develop recommendations aimed at ensuring ecological
safety [16].
Methods.
Biochemical treatment processes can be carried out under both aerobic and anaerobic
conditions. Aerobic processes are conducted with oxygen participation and are mostly
implemented through activated sludge, bioreactors, biofilters, and membrane bioreactors (MBR).
Anaerobic processes occur in oxygen-free conditions and are mainly used for neutralizing high-
concentration organic pollutants and producing energy (biogas).
Biochemical decomposition consists of the following main stages:
1. Hydrolysis
In this stage, high-molecular complex organic compounds (proteins,
carbohydrates, fats) are decomposed into smaller molecules (amino acids, monosaccharides,
fatty acids) under the influence of enzymes. Hydrolysis is considered the initial stage of
anaerobic processes and prepares the necessary substrates for all subsequent metabolic pathways.
2. Acidification (Acidogenesis)
In this stage, simple molecules formed as a result of hydrolysis
are converted into volatile fatty acids (such as acetic, propionic, butyric, and other acids),
alcohols, hydrogen, and carbon dioxide with the participation of acidifying bacteria. Although
this process is not energetically beneficial, it creates the basis for methane formation.
3. Acetogenesis
In this stage, the fatty acids and alcohols formed above are converted into acetic
acid, CO₂, and hydrogen by acetogenic bacteria. The acetogenesis process requires delicate
balance, as excessive hydrogen concentration can weaken the activity of methanogenic bacteria.
4. Methanogenesis
This is the final stage of the biochemical treatment process, where
methanogenic bacteria convert acetic acid and hydrogen into methane (CH₄) and carbon dioxide.
This process is an energy-releasing stage, and the resulting biogas can be used to produce
thermal or electrical energy.
Results and Analysis.
The empirical investigation revealed significant advantages of
biochemical treatment methods over conventional treatment approaches. The study demonstrated
that biochemical systems consistently outperform traditional methods across multiple
performance indicators.
Table 1: Performance Comparison of Treatment Methods
Parameter
Conventional
Treatment
Biochemical
Treatment
Improvement
(%)
BOD Removal (%)
65
88
+35
COD Removal (%)
70
85
+21
TSS Removal (%)
75
92
+23
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Parameter
Conventional
Treatment
Biochemical
Treatment
Improvement
(%)
Energy
Consumption
(kWh/m³)
0.8
0.5
-37
Operational Cost ($/m³)
0.45
0.28
-38
Sludge Production (kg/m³) 0.6
0.3
-50
The results indicate substantial improvements in treatment efficiency with biochemical methods.
BOD removal rates increased by 35%, demonstrating superior organic matter degradation
capabilities. The 37% reduction in energy consumption represents a significant economic and
environmental advantage, while the 50% decrease in sludge production reduces disposal costs
and environmental impact.
In this configuration, the mixed wastewater is recycled to a membrane unit located outside the
bioreactor. Both internal and external wrap membranes can be used in this method. The
necessary pressure is generated by high-velocity flow across the membrane surface. Tubular
membranes are mainly used in external MBR systems (Table 2, Figure 1). The ability of
recirculating and robust polymer membranes to operate at low pressure with high permeate flux
has led to the widespread commercial use of submerged MBRs worldwide.
1 Figure. External MBR system
Table 2: Membrane types used in outdoor MBR systems and their characteristics
No. Type
Membrane
Pore
size
(µm)
Purified
wastewater
Source
1
Tubular Alumina, Zirconium
0.2, 0.05 Utility
24
2
Tubular UF-cellulose acetate, sulfonated polyether
sulfone, hydrophobic polyether sulfone
–
Synthetic
25
3
Plate
UF
–
Distillery
26
4
Tubular UF-ceramics
0.02
Utility
27
5
Tubular MF-ceramics
0.2
Utility
28
6
Tubular Ceramics, Zirconium
0.2, 0.05 Food
(ice
cream)
29
7
Plate
UF-polyacrylonitrile
–
Synthetic
30
8
Tubular Ceramics (Kerasep)
0.1
Utility
31
9
Tubular MF
0.1
Utility
32
10
Tubular UF
–
Synthetic (fuel
oil)
33
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11
Tubular Ceramics (Kerasep)
–
Utility
34
Note:
uses membranes of various types and configurations. These include rotary disc, frame and plate,
hollow fiber, tubular, metallic, microfiltration (MF) and ultrafiltration (UF) membranes made of
organic and inorganic materials.
The pore size of
membranes used in MBR systems ranges from
0.01–0.4 µm.
Filtration flux can range
from
0.05 to 10 m³/m²/day,
depending on the membrane
material and structure.
For
internal casing membranes, the required flux is 0.5–2.0 m³/m²/day
,
For
membranes with an external casing,
it is around
0.2–0.6 m³/m²/day
(at 20°C).
The pressure across the membrane is 20–500 kPa
for membranes with an inner casing
and
10–80 kPa
for membranes with an outer casing. It will be in the range.
Membranes used in MBR systems must meet the above important technical requirements.
Figure 2. Tubular membrane module in an external MBR system
Conclusions.
This comprehensive study demonstrates that biochemical methods represent a
superior approach to wastewater treatment, offering significant advantages in terms of efficiency,
sustainability, and long-term economics. The research findings support the following conclusions:
Biochemical treatment technologies consistently outperform conventional methods, achieving
85% average removal efficiency while reducing energy consumption by 40% and operational
costs by 38%. These improvements stem from the natural metabolic processes of
microorganisms, which provide more complete and sustainable pollutant degradation than
chemical or physical treatment methods.
References
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