scholarly journals Chlorella vulgaris in wastewater treatment processes – practical experience

2020 ◽  
Vol 2020 (2) ◽  
pp. 21-27
Author(s):  
Lesiia Vovk ◽  
◽  
Oksana Matsiyevska ◽  
Oleh Zhdanov ◽  
◽  
...  

Wastewater from human settlements contains a significant amount of organic and biogenic substances. Insufficiently treated wastewater enters surface water and leads to their eutrophication. The usage of microalgae in wastewater treatment has significant advantages in comparison with other methods of removing biogenic substances. Namely: effective and simultaneous removal of nitrogen and phosphorus without reagents management facilities, oxygen formation. Using microalgae in wastewater treatment is a new environmentally friendly biotechnological method. Microalgae grow well in wastewater, from which they absorb pollutants. The purpose of the study is to analyze the work and determine the possibility of intensification of sewage treatment plants in the western region of Ukraine with a population of about 18,900 inhabitants. Productivity of treatment plant is 3400 m3/day. Experimental investigation consisted in adding a concentrate of a living microalgae strain of the species Chlorella vulgaris to the wastewater that was entered to the treatment plant during May-September 2019. During the research, the results of wastewater analyzes conducted by the chemical laboratory of the municipal water supply and sewerage company were used. The results of the survey and analysis of the city's treatment plant indicate an insufficient degree of wastewater treatment. The effectiveness of Chlorella vulgaris at the treatment plant has been experimentally proven. Mathematical dependences of the effect of wastewater treatment (using Chlorella vulgaris) on their temperature according to the indicators: BOD5, COD, concentration of ammonium nitrogen, phosphates and suspended solids were obtained. Dependencies are described by a linear function that characterizes the general behavior of the obtained data. The obtained results made it possible to significantly reduce the negative impact of treatment plants on the environment.

1990 ◽  
Vol 22 (7-8) ◽  
pp. 171-179 ◽  
Author(s):  
G. Bahre ◽  
W. Firk ◽  
M. Gassen

The report describes low-cost development and design of a two-stage wastewater treatment plant for 90,000 PE to achieve the highest possible degree of phosphorus and nitrogen elimination. The receiving water body of the treatment plant is a small watercourse fed almost exclusively by treated wastewater. A significant improvement in the water quality of this watercourse is planned. In particular, the performance of the wastewater treatment plant will need to be enhanced. The plant operator, the Erft River Board, organized a competition to attract solutions for an appropriate development of the plant from several consultants. Apart from embodying the concept of extensive wastewater treatment, designs were expected to preserve the existing infrastructure of the two-stage treatment plant as far as possible. Following selection of the most suitable design, the intended process technology is currently being tested in a pilot-scale plant. Planning envisages advanced wastewater treatment processes, including enhanced biological phosphorus removal, chemical precipitation/flocculation, nitrification and denitrification and combined coagulation/filtration. The pilot-scale investigations are carried out in close co-operation between the water authorities, the plant operators, the consultant, and a university institute of sanitary engineering. The paper presents the design and first results of the pilot-scale investigations in terms of the parameters BOD5, COD, phosphorus, ammonia and nitrate.


2020 ◽  
Vol 6 (11) ◽  
pp. 126-131
Author(s):  
P. Murodov ◽  
O. Amirov ◽  
P. Khuzhaev

The influence of the discharged treated wastewater on the ecology of the Kafirnigan River is considered. The data on the current state of sewage treatment facilities in the city of Dushanbe are given and an assessment of the environmental efficiency of these treatment facilities is given. Preliminary calculations of costs for the construction of a new sewage treatment plant in Dushanbe have been made. The article is devoted to the current problem of cleaning storm sewers. It should be noted that storm water drainage, like wastewater, has a negative impact on the environment. Before the wastewater is disposed of, it is necessary to treat it in a special way, subjecting it to treatment of varying degrees and depths.


2020 ◽  
Vol 21 ◽  
pp. 94-101
Author(s):  
V. Pashnyuk ◽  
O. Myakush ◽  
L. Sysa

Introduction. The quality of wastewater treatment in settlements is an important task of our time. To assess the efficiency of treatment plants in a particular city often use the hydrochemical parameters of the reservoir into which the treated wastewater is discharged. The paper describes the modern sewerage system of the city of Ternopil and the technological process of operation of citywide sewage treatment plants (STP). The purpose of the work is to find out how effectively the Ternopil STP work and whether their activity poses a danger to the Seret River and the inhabitants of coastal settlements. Methods. Hydrochemical parameters of these water samples were studied in the laboratory according to appropriate regulatory methods. Potentiometric, gravimetric, photometric and other methods of chemical analysis were used for research. Results of the research. 2 samples of water from the river Seret were taken for laboratory research. One sample was taken upstream near the outlet of the drain pipes of these structures, the second sample - downstream. Based on the obtained numerical results of the analyzes, the efficiency of the city's treatment facilities was assessed. It is shown that the overall water quality in the Seret River downstream after the discharge of the city's wastewater treatment  plants is satisfactory. The levels of nitrates and phosphates in the studied samples are almost on the border of the MPC, but this is not necessarily due to the poor performance of the city's treatment facilities. There are many agricultural lands on the banks of the river, which often use nitrogen and phosphorus fertilizers. Significant exceeding of the limit value for chemical oxygen consumption can be explained by the warm season (September). At this time, a lot of biological organic matter has accumulated in natural reservoirs. Conclusions. As a result of researches it is established that treatment facil-ities of the city of Ternopil work in a regular mode and provide sufficient sewage treatment. According to open sources, the annual dynamics of the mentioned treatment facilities is shown. As a result, it has been found that since 2017, the efficiency of the city's wastewater treatment at sewage treatment plants remains stable. Such indicators testify to the sufficient efficiency of the treatment facilities of the Ternopilvodokanal utility company.


1987 ◽  
Vol 19 (1-2) ◽  
pp. 107-118 ◽  
Author(s):  
Hans Brix

The present paper describes the theoretical basis of wastewater treatment in the rhizosphere of wetland plants, the so-called “root-zone method”, along with the first working experiences from eight treatment plants in Denmark. Mechanically treated wastewater is led horizontally through the rhizosphere of wetland plants. During the passage of the wastewater through the rhizosphere, the wastewater is cleaned by microbiological degradation and by physical/chemical processes. The wetland plants supply oxygen to the heterotrophic microorganisms in the rhizosphere and stabilize the hydraulic conductivity of the soil. Nitrogen is removed by denitrification and phosphorus and heavy metals are bound in the soil. The first working experiences from Denmark show, that as far as BOD is concerned root-zone treatment plants are very nearly up to conventional secondary treatment standards already from the first growing season (removal efficiency: 51-95%). For the nutrients nitrogen and phosphorus the results vary (total-N removal: 10-88%; total-P removal: 11-94%). The removal efficiencies depended mainly on the composition of the soils and the degree of surface runoff in each treatment plant. It is concluded that root-zone treatment plants seem to be a viable alternative to conventional wastewater treatment technology, especially suitable for single households and small to medium sized communities. There is, however, still very little information on the removal processes for nitrogen (denitrification), on the effect of soil type and on the required surface area to load ratio,


2004 ◽  
Vol 50 (5) ◽  
pp. 29-36 ◽  
Author(s):  
M. Clara ◽  
B. Strenn ◽  
M. Ausserleitner ◽  
N. Kreuzinger

Micropollutants as pharmaceutical active compounds (PhACs), residuals of personal care products or endocrine disrupting chemicals are of increasing interest in water pollution control. In this context the removal efficiencies of sewage treatment plants (STPs) are of importance, as their effluents are important point sources for the release of those substances into the aquatic environment. Activated sludge based wastewater treatment is the worldwide prevalently used treatment technique. In conventional plants the separation of treated wastewater and sludge occurs via sedimentation. A new development is the application of membrane technology for this separation step. The studies focus on the influence of the solids retention time (SRT) on the removal efficiency, as the SRT is the most important parameter in the design of STPs. A conventional activated sludge plant (CASP) and a membrane bioreactor (MBR) were operated at different SRTs. The substances selected are the antiepileptic carbamazepine, the analgesics diclofenac and ibuprofen, the lipid regulator bezafibrate, the polycyclic musks tonalide and galaxolide and the contraceptive 17α-ethinylestradiole. No significant differences in the removal efficiency were detected. Due to the absence of suspended solids in the MBR effluent, substances with high adsorption potential could be retained to slightly higher amounts.


2021 ◽  
Vol 2066 (1) ◽  
pp. 012025
Author(s):  
Yunzhu Liu ◽  
Jinbao Cao

Abstract With the improvement of people’s awareness of environmental protection in recent years, the related problems of water pollution treatment have gradually come into people’s view. As the source of life, water accounts for a huge proportion in our lives, but at the same time, water pollution is quietly spreading in places we don’t know. The continuous discharge of heavy industrial wastewater, agricultural wastewater and domestic sewage leads to increasingly serious water pollution. Sewage treatment(ST) is imperative, and its social benefits are huge, but the corresponding cost is high, and the return on investment is low. Traditional ST methods can not load large-scale ST. How to carry out ST based on artificial intelligence(AI), build ST plant control system, and make ST enter the era of automation is the problem to be solved. The purpose of this paper is to put forward the reform of control system for ST plant based on AI, apply AI into ST, and realize the automation and precision of ST plant. This paper mainly uses the fuzzy self-tuning PID control system algorithm, through the analysis of ST control object, analysis of fuzzy self-tuning PID controller design to complete the ST control system settings. In this paper, the literature review method and data analysis method are used. By collecting relevant data, the control system of ST plant is constructed to simulate ST, and the real-time data of ST is analyzed. The traditional PID control and fuzzy self-tuning PID control are compared. The experimental results show that the wastewater treatment plant system based on AI input, in the aspect of wastewater treatment, the concentration of COD and BOD in the treated wastewater are reduced by a certain proportion, the dissolved oxygen content in the wastewater reaches about 2.0mg/l, which meets the national discharge standard, and its rising time is reduced to 25 seconds, and the adjustment time is saved by 50 seconds.


2018 ◽  
Vol 7 (4.20) ◽  
pp. 310
Author(s):  
Ali Hadi Ghawi

In this study, a sewage treatment plant was designed for the city of Al-Nasiriyah in Dhi Qar governorate in southern Iraq serving 316083 inhabitants. The resulting treated water is suitable for agricultural irrigation and can be discharged to the Euphrates River when needed by adding nitrogen and phosphorus removal units to the wastewater treatment plant. The obtained plant design has been verified and optimized by implementing the proposed plant layout in the GPS-X 5.0 modeling and simulation software (Hydromantis). Where the results of the design showed that the total phosphorus flow is higher than the desired limit of 2 mg / L, due to the excessive release during anaerobic digestion. Control of phosphorus concentration can be controlled by adding chemicals (iron or aluminum salts) in different parts of the wastewater treatment plant. In this case, two different control strategies can be implemented: adding aluminum doses in both water and sludge lines (at Chem1 and Chem2 points) or adding aluminum doses in the water line only (at point Chem2). The second strategy showed that it is the most efficient in controlling the concentration of phosphorus and nitrogen produced, which meets the limits of the Iraqi standard of water used in irrigation.  


1996 ◽  
Vol 33 (12) ◽  
pp. 11-18 ◽  
Author(s):  
I.S. Kim ◽  
J.Y. Ryu ◽  
J.J. Lee

The history of wastewater treatment in Korea began in 1976 with construction of Chongke sewage treatment plant in the city of Seoul. At present, there are 48 large municipal sewage treatment plants for 42 cities with a total treatment capacity of 7,841,000 m3/d. This indicates that the population receiving sewage treatment is 42% of the total national population. The government is planning to extend the population receiving wastewater treatment to 73% by the year 1997. It turned out that activated sludge processes are the most popular type (39 out of 48 plants) for the treatment of municipal wastewater. The present lawful effluent criteria for BOD, COD, and SS from large municipal wastewater treatment plant are changing from 30 mg/l, 50 mg/l, and 70 mg/l, to 20 mg/l, 40 mg/l, and 20 mg/l, respectively, by the year 1996. Regulation of the total concentrations of nitrogen and phosphorus are also added as 60 mg/l and 8 mg/l, respectively. The enactment to control the nutrient concentrations in the lake and pond is inevitable for the protection of drinking water in South Korea.


2020 ◽  
Vol 15 (2) ◽  
pp. 142-151
Author(s):  
Peter Lukac ◽  
Lubos Jurik

Abstract:Phosphorus is a major substance that is needed especially for agricultural production or for the industry. At the same time it is an important component of wastewater. At present, the waste management priority is recycling and this requirement is also transferred to wastewater treatment plants. Substances in wastewater can be recovered and utilized. In Europe (in Germany and Austria already legally binding), access to phosphorus-containing sewage treatment is changing. This paper dealt with the issue of phosphorus on the sewage treatment plant in Nitra. There are several industrial areas in Nitra where record major producers in phosphorus production in sewage. The new wastewater treatment plant is built as a mechanicalbiological wastewater treatment plant with simultaneous nitrification and denitrification, sludge regeneration, an anaerobic zone for biological phosphorus removal at the beginning of the process and chemical phosphorus precipitation. The sludge management is anaerobic sludge stabilization with heating and mechanical dewatering of stabilized sludge and gas management. The aim of the work was to document the phosphorus balance in all parts of the wastewater treatment plant - from the inflow of raw water to the outflow of purified water and the production of excess sludge. Balancing quantities in the wastewater treatment plant treatment processes provide information where efficient phosphorus recovery could be possible. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. There are also two outflows - drainage of cleaned water to the recipient - the river Nitra - 9.9 kg Ptot/day and Ptot content in sewage sludge - about 120.3 kg Ptot/day - total 130.2 kg Ptot/day.


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