scholarly journals Case study on the dairy processing industries and their wastewater generation in Latvia

2021 ◽  
pp. 1-4
Author(s):  
Basanti Ekka ◽  
Sandis Dejus ◽  
Talis Juhna
Keyword(s):  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Production Quality ◽  
Dairy Wastewater ◽  
Wastewater Management ◽  
Municipal Wastewater Treatment ◽  
Dairy Processing ◽  
Quality Of Water ◽  
High Chemical Oxygen Demand

Abstract The objective of the research presented in this Research Communication was to access the environmental impact of the Latvian dairy industries. Site visits and interviews at Latvian dairy processing companies were done in order to collect site-specific data. This includes the turnover of the dairy industries, production, quality of water in various industrial processes, the flow and capacity of the sewage including their characteristic, existing practices and measures for wastewater management. The results showed that dairy industries in Latvia generated in total approximately 2263 × 103 m3 wastewater in the year 2019. The Latvian dairy effluents were characterized with high chemical oxygen demand (COD), biological oxygen demand (BOD) and total solids (TS). Few dairy plants had pre-treatment facilities for removal of contaminants, and many lacked onsite treatment technologies. Most facilities discharged dairy wastewater to municipal wastewater treatment plants. The current study gives insight into the Latvian dairy industries, their effluent management and pollution at Gulf of Riga due to wastewater discharge.

scholarly journals Hauled liquid waste as a pollutant of soils and waters in Poland

2016 ◽  
Vol 48 (2) ◽  
pp. 111-122
Author(s):  
Agnieszka Karczmarczyk
Keyword(s):  
Rural Areas ◽  
Municipal Wastewater ◽  
System Analysis ◽  
Wastewater Treatment Plants ◽  
Ecological Status ◽  
Liquid Waste ◽  
Point Sources ◽  
Wastewater Management ◽  
Municipal Wastewater Treatment ◽  
Sources Of Pollution

Abstract Hauled liquid waste as a pollutant of soils and waters in Poland. Improperly maintained holding tanks are often underestimated source of contamination of soil, groundwater and surface water. As a rule, wastewater stored in holding tanks, should be transported and treated in municipal wastewater treatment plants (WWTPs). There are 2,257,000 holding tanks in Poland, located mainly in rural areas. The article presents the results of analysis of wastewater management in 20 rural and urban-rural communes, which were chosen at random from the total number of 2,174 communes in Poland. The only criterion of commune selection was total or partial lack of sewerage system. Analysis of the collected data showed that on average only 27% of liquid waste from holding tanks ended at the WWTPs. The median is even lower and amounts to 17.5%. More than 4,000 Mg of P and 26,000 Mg of N is dispersed in the environment in uncontrolled manner. Those diffuse point sources of pollution may be one of the reasons in the difficulty of achieving of good ecological status of rivers and affect the quality of the Baltic Sea.

scholarly journals Improving and upgrading an existing activated sludge with a compact MBBR – disc filters parallel line for municipal wastewater treatment in touristic alpine areas

2020 ◽  
Vol 15 (2) ◽  
pp. 515-527
Author(s):  
L. Desa ◽  
P. Kängsepp ◽  
L. Quadri ◽  
G. Bellotti ◽  
K. Sørensen ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Parallel Line ◽  
Ammonium Nitrogen ◽  
Biofilm Reactor ◽  
Municipal Wastewater Treatment ◽  
Yearly Average

Abstract Many wastewater treatment plants (WWTP) in touristic areas struggle to achieve the effluent requirements due to seasonal variations in population. In alpine areas, the climate also determines a low wastewater temperature, which implies long sludge retention time (SRT) needed for the growth of nitrifying biomass in conventional activated sludge (CAS). Moreover, combined sewers generate high flow and dilution. The present study shows how the treatment efficiency of an existing CAS plant with tertiary treatment can be upgraded by adding a compact line in parallel, consisting of a Moving Bed Biofilm Reactor (MBBR)-coagulation-flocculation-disc filtration. This allows the treatment of influent variations in the MBBR and a constant flow supply to the activated sludge. The performance of the new 2-step process was comparable to that of the improved existing one. Regardless significant variations in flow (10,000–25,000 m3/d) and total suspended solids (TSS) (50–300 mg/L after primary treatment) the effluent quality fulfilled the discharge requirements. Based on yearly average effluent data, TSS were 11 mg/L, chemical oxygen demand (COD) 27 mg/L and total phosphorus (TP) 0.8 mg/L. After the upgrade, ammonium nitrogen (NH4-N) dropped from 4.9 mg/L to 1.3 mg/L and the chemical consumption for phosphorus removal was reduced.

scholarly journals Benchmarking of energy consumption in municipal wastewater treatment plants – a survey of over 200 plants in Italy

2018 ◽  
Vol 77 (9) ◽  
pp. 2242-2252 ◽  
Author(s):  
M. Vaccari ◽  
P. Foladori ◽  
S. Nembrini ◽  
F. Vitali
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Municipal Wastewater ◽  
Energy Savings ◽  
Wastewater Treatment Plants ◽  
Specific Energy Consumption ◽  
Oxygen Demand ◽  
Energy Performance ◽  
High Energy ◽  
Municipal Wastewater Treatment

Abstract One of the largest surveys in Europe about energy consumption in Italian wastewater treatment plants (WWTPs) is presented, based on 241 WWTPs and a total population equivalent (PE) of more than 9,000,000 PE. The study contributes towards standardised resilient data and benchmarking and to identify potentials for energy savings. In the energy benchmark, three indicators were used: specific energy consumption expressed per population equivalents (kWh PE−1 year−1), per cubic meter (kWh/m3), and per unit of chemical oxygen demand (COD) removed (kWh/kgCOD). The indicator kWh/m3, even though widely applied, resulted in a biased benchmark, because highly influenced by stormwater and infiltrations. Plants with combined networks (often used in Europe) showed an apparent better energy performance. Conversely, the indicator kWh PE−1 year−1 resulted in a more meaningful definition of a benchmark. High energy efficiency was associated with: (i) large capacity of the plant, (ii) higher COD concentration in wastewater, (iii) separate sewer systems, (iv) capacity utilisation over 80%, and (v) high organic loads, but without overloading. The 25th percentile was proposed as a benchmark for four size classes: 23 kWh PE−1 y−1 for large plants > 100,000 PE; 42 kWh PE−1 y−1 for capacity 10,000 < PE < 100,000, 48 kWh PE−1 y−1 for capacity 2,000 < PE < 10,000 and 76 kWh PE−1 y−1 for small plants < 2,000 PE.

scholarly journals Initiating Biodegradation of Polyvinylpyrrolidone in an Aqueous Aerobic Environment: Technical Note / Zainicjowanie Biodegradacji Poliwinylopirolidonu W Środowisku Wodno-Tlenowym: Notatki Techniczne

2013 ◽  
Vol 20 (1) ◽  
pp. 199-208 ◽  
Author(s):  
Marketa Julinova ◽  
Jan Kupec ◽  
Roman Slavik ◽  
Maria Vaskova
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Waste Treatment ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Technical Note ◽  
Aerobic Biodegradation ◽  
Municipal Wastewater Treatment

Abstract A synthetic polymer, polyvinylpyrrolidone (PVP - E 1201) primarily finds applications in the pharmaceutical and food industries due to its resistance and zero toxicity to organisms. After ingestion, the substance passes through the organism unchanged. Consequently, it enters the systems of municipal wastewater treatment plants (WWTP) without decomposing biologically during the waste treatment process, nor does it attach (through sorption) to particles of activated sludge to any significant extent, therefore, it passes through the system of a WWTP, which may cause the substance to accumulate in the natural environment. For this reason the paper investigates the potential to initiate aerobic biodegradation of PVP in the presence of activated sludge from a municipal wastewater treatment plant. The following agents were selected as the initiators of the biodegradation process - co-substrates: acrylamide, N-acethylphenylalanine and 1-methyl-2-pyrrolidone, a substance with a similar structure to PVP monomer. The biodegradability of PVP in the presence of co-substrates was evaluated on the basis of biological oxygen demand (BOD) as determined via a MicroOxymax O2/CO2/CH4 respirometer. The total substrate concentration in the suspension equaled 400 mg·dm-3, with the ratio between PVP and the cosubstrate being 1:1, while the concentration of the dry activated sludge was 500 mg·dm-3. Even though there was no occurrence of a significant increase in the biodegradation of PVP alone in the presence of a co-substrate, acrylamide appeared to be the most effective type of co-substrate. Nevertheless, a recorded decrease in the slope of biodegradation curves over time may indicate that a process of primary decomposition was underway, which involves the production of metabolites that inhibit activated sludge microorganisms. The resulting products are not identified at this stage of experimentation.

Removal of hazardous substances in municipal wastewater treatment plants

2020 ◽  
Vol 81 (9) ◽  
pp. 2011-2022
Author(s):  
Vallo Kõrgmaa ◽  
Mailis Laht ◽  
Riin Rebane ◽  
Erki Lember ◽  
Karin Pachel ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Aquatic Environment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Hazardous Substances ◽  
Chemical Pollution ◽  
P Value ◽  
Municipal Wastewater Treatment ◽  
Municipal Wastewater Treatment Plants

Abstract Chemical pollution poses a threat to the aquatic environment and to human health. Wastewater treatment plants are the last defensive line between the aquatic environment and emissions of pollutants. This study focuses on identification of most relevant hazardous substances in Estonian municipal wastewater and their fate in the treatment process. During this study, seasonal wastewater and sewage sludge samples were collected from nine municipal wastewater treatment plants and analyzed for 282 hazardous substances, including EU (n = 45) and Estonian (n = 31) priority substances. Results of this study show that several substances that are subject to international restrictions (e.g. Stockholm Convention) are still present in untreated sewage. Wastewater treatment systems that had a greater level of complexity (TEC >5) were more successful in removing hazardous substances. Statistical analyses showed that removal efficiency of organic hazardous substances had significant (p-value <0.05) linear correlation with removal efficiencies of chemical oxygen demand (COD) and total suspended solids (TSS), but a monotonic relationship with operators' competency. This study showed that operators' competency had a strong influence on the stability of the wastewater treatment efficiency and removal of organic hazardous substances.

Carbon recovery from screenings for energy-efficient wastewater treatment

2017 ◽  
Vol 76 (12) ◽  
pp. 3299-3306
Author(s):  
M. Kaless ◽  
L. Palmowski ◽  
J. Pinnekamp
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Energy Content ◽  
Oxygen Demand ◽  
Weighted Average ◽  
Chemical Energy ◽  
Municipal Wastewater Treatment ◽  
Wastewater Treatment Process ◽  
Washing Water

Abstract The energy content of screenings from six municipal wastewater treatment plants (WWTPs) was examined. Hourly samples of separated screenings were taken over 24 hours at three of the plants to illustrate diurnal variations. To recover the chemical energy, which usually leaves the WWTP with the screenings, a screenings wash press was used to transfer organic matter from the solid into the liquid phase. The chemical energy of raw and compacted washed screenings as well as the chemical energy of washing water were determined by measuring the chemical oxygen demand (COD) for the six WWTPs. A mass weighted average of 1.35 gCOD/gdm (dm: dry matter) was found in the raw screenings of three WWTPs. The overall recovered energy from screenings was found to range from 0.27 to 0.62 gCOD/gdm. This washed-out COD found in the washing water could be sent for anaerobic digestion or to the wastewater treatment process as a carbon source for denitrification.

scholarly journals Effect of sewage sampling frequency on determination of design parameters for municipal wastewater treatment plants

2020 ◽  
Author(s):  
T. Gehring ◽  
E. Deineko ◽  
I. Hobus ◽  
G. Kolisch ◽  
M. Lübken ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Sampling Frequency ◽  
Organic Load ◽  
Design Parameters ◽  
Data Sets ◽  
Municipal Wastewater Treatment

Abstract The uncertainty associated with the determination of load parameters, which is a key step in the design of wastewater treatment plants (WWTPs), was investigated on basis on data sets from 58 WWTPs. A further analysed aspect was the organic load variations associated with variable sewage temperatures. Data from 26 WWTPs with a high inflow sampling frequency was used to simulate scenarios to investigate the effect of lower sampling frequencies through a Monte Carlo approach. The calculation of 85-percentile values for chemical oxygen demand (COD) loadings based on only 26 samples per year is associated with a variability of up to ±18%. Approximately 90 samples per year will be necessary to reduce this uncertainty for estimation of COD loadings below 10%. Hence, a low sampling frequency can potentially lead to under- or overestimation of design parameters. Through an analogous approach, it was possible to identify uncertainties of ±11% in COD loading when weekly average data was used with 4 samples per week. Finally, a tendency of lower COD input loads with increasing temperatures was identified, with a reduction of about 1% of the average loading per degree Celsius.

scholarly journals Excessive greenhouse gas emissions from wastewater treatment plants by using the chemical oxygen demand standard

2021 ◽  
Author(s):  
Zongqing Lv ◽  
Xiaoyu Shan ◽  
Xilin Xiao ◽  
Ruanhong Cai ◽  
Yao Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Wastewater Treatment ◽  
Chemical Oxygen Demand ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Carbon Sink ◽  
Oxygen Demand ◽  
Organic Pollution ◽  
Municipal Wastewater Treatment ◽  
Recalcitrant Organic Matter

AbstractChemical oxygen demand (COD) is widely used as an organic pollution indicator in wastewater treatment plants. Large amounts of organic matter are removed during treatment processes to meet environmental standards, and consequently, substantial greenhouse gases (GHGs) such as methane (CH4) are released. However, the COD indicator covers a great amount of refractory organic matter that is not a pollutant and could be a potential carbon sink. Here, we collected and analysed COD data from 86 worldwide municipal wastewater treatment plants (WWTPs) and applied a model published by the Intergovernmental Panel on Climate Change to estimate the emission of CH4 due to recalcitrant organic compound processing in China’s municipal wastewater treatment systems Our results showed that the average contribution of refractory COD to total COD removal was 55% in 86 WWTPs. The amount of CH4 released from the treatment of recalcitrant organic matter in 2018 could have been as high as 38.22 million tons of carbon dioxide equivalent, which amounts to the annual carbon sequestered by China’s wetlands. This suggests that the use of COD as an indicator for organic pollution is undue and needs to be revised to reduce the emission of GHG. In fact, leaving nontoxic recalcitrant organic matter in the wastewater may create a significant carbon sink and will save energy during the treatment process, aiming at carbon neutrality in the wastewater treatment industry.

scholarly journals Start-up phase of a UASB-septic tank used for high strength municipal wastewater treatment in Mexico

2017 ◽  
Vol 12 (2) ◽  
pp. 287-294 ◽  
Author(s):  
A. L. Santiago-Díaz ◽  
M. L. Salazar-Peláez
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
High Strength ◽  
Upflow Anaerobic Sludge Blanket ◽  
Septic Tank ◽  
Anaerobic Sludge ◽  
Wastewater Management ◽  
Municipal Wastewater Treatment ◽  
Start Up

The objective of this work was to assess the performance during the start-up phase of a Upflow anaerobic sludge blanket (UASB)-septic tank for municipal wastewater treatment in Mexico City. A lab scale UASB-septic tank (62 L total volume, acrylic), consisting of three chambers treated high strength municipal wastewater at ambient temperature (16 °C–24 °C), under 72 h Hydraulic retention time (HRT) during three months. Total and soluble chemical oxygen demand (COD), total biological oxygen demand (BOD5), total solids and total suspended solids (TSS) removals were 75.2 ± 6.5%, 54.8 ± 6.7%, 64.2 ± 4.8%, 25.9 ± 5% and 82.9 ± 5%, respectively. These results are comparable with the removals reported in other works with similar arrangements; and are similar even with average removals of COD, BOD and TSS in UASB reactors installed in Latin America. The good performance obtained showed that it is possible to achieve a short start-up period with UASB-septic tank if it is inoculated with anaerobic sludge. These findings also evidenced the feasibility and reliability of the UASB-septic tank system for decentralized wastewater management in Mexico.

Multi-stage constructed wetland systems for municipal wastewater treatment

2013 ◽  
Vol 67 (7) ◽  
pp. 1590-1598 ◽  
Author(s):  
F. Masi ◽  
S. Caffaz ◽  
A. Ghrabi
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Average Concentration ◽  
Organic Load ◽  
Municipal Wastewater Treatment ◽  
Multi Stage ◽  
Disinfection Process ◽  
Municipal Wastewater Treatment Plants

In the present paper the detailed design and performances of two municipal wastewater treatment plants, a four-stage constructed wetlands (CW) system located in the city of Dicomano (about 3,500 inhabitants) in Italy, and a three-stage CW system for the village of Chorfech (about 500 inhabitants) in Tunisia, are presented. The obtained results demonstrate that multi-stage CWs provide an excellent secondary treatment for wastewaters with variable operative conditions, reaching also an appropriate effluent quality for reuse. Dicomano CWs have shown good performances, on average 86% of removal for the Organic Load, 60% for Total Nitrogen (TN), 43% for Total Phosphorus (TP), 89% for Total Suspended Solids (TSS) and 76% for Ammonium (NH4+). Even the disinfection process has performed in a very satisfactory way, reaching up to 4–5 logs of reduction of the inlet pathogens concentration, with an Escherichia coli average concentration in the outlet often below 200 UFC/100 mL. The mean overall removal rates of the Chorfech CWs during the monitored period have been, respectively, equal to 97% for TSS and Biochemical Oxygen Demand (BOD5), 95% for Chemical Oxygen Demand (COD), 71% for TN and 82% for TP. The observed removal of E. coli by the CW system was in this case 2.5 log units.

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