Non-biodegradable Organic Matter Research Articles

Long-term prediction of algal chlorophyll based on empirical models and the machine learning approach in relation to trophic variation in Juam Reservoir, Korea

This study analyzed spatiotemporal variation and long-term trends in water quality indicators and trophic state conditions in an Asian temperate reservoir, Juam Reservoir (JR), and developed models that forecast algal chlorophyll (CHL-a) over a period of 30 years, 1993–2022. The analysis revealed that there were longitudinal gradients in water quality indicators along the reservoir, with notable influences from tributaries and seasonal variations in nutrient regimes and suspended solids. The empirical model showed phosphorus was found to be the key determinant of algal biomass, while suspended solids played a significant role in regulating water transparency. The trophic state indices indicated varying levels of trophic status, ranging from mesotrophic to eutrophic. Eutrophic states were particularly observed in zones after the summer monsoons, indicating a heightened risk of algal blooms, which were more prevalent in flood years. The analysis of trophic state index deviation suggested that phosphorus availability strongly influences the reservoir trophic status, with several episodes of non-algal turbidity at each site during Mon. Increases in non-algal turbidity were more prevalent during the monsoon in flood years. This study also highlighted overall long-term trends in certain water quality parameters, albeit with indications of shifting pollution sources towards non-biodegradable organic matter. According to the machine learning tests, a random forest (RF) model strongly predicted CHL-a (R2 = 0.72, p < 0.01), except for algal biomass peaks (>60 μg/L), compared to all other models. Overall, our research suggests that CHL-a and trophic variation are primarily regulated by the monsoon intensity and predicted well by the machine learning RF model.

Treatment of hospital wastewater using aerobic granular sludge technology: Removal performance and microbial dynamics

Hospital wastewater contains several contaminants of emerging concern that cannot be removed by conventional treatment processes. Many of these emerging contaminants are pharmaceutical compounds, which are found in hospital wastewater at high loads. The presence of these toxics affects to the performance of biological processes in receiving wastewater treatment plants. This research evaluated the capability of the aerobic granular sludge technology to remove pharmaceutical compounds from hospital wastewater in a single chamber, which to date has not been investigated with real hospital wastewater. Despite the high non-biodegradable organic matter content, COD and BOD5 removal reached 75 % and 100 %, respectively. Nitrogen removal ranged from 70 %–90 %, and phosphate removal was maximum 50 %. The technology was able to efficiently remove antibiotics, antiepileptic and antidepressant drugs, whereas non-steroidal anti-inflammatory drugs were removed and released under oscillating patterns. The granular biomass increased in size, but it reduced the settling velocity. Bacterial and fungal communities were acclimated to pharmaceutical inlet, whereas the archaeal population had a progressive adaptation over time. The aerobic granular sludge technology is therefore a viable approach to enhance the disposal of real hospital wastewater prior to discharge into the urban wastewater network.

Application of iron tailings in the coagulation of landfill leachate by bipolar membrane electrodialysis

Landfill leachate contains large amounts of non-biodegradable organic matter. The recalcitrant substances become more concentrated following the treatment using a combination of biological methods and nanofiltration. In this study, the nanofiltration concentrated landfill leachate (NCLL) was subjected to coagulation treatment using the bipolar membrane electrodialysis (BMED) process with iron tailings. The H+ required for metal leaching and OH− for coagulation are supplemented by water dissociation. The pH value of the NCLL played an important role for coagulation and the suitable pH value was 4. As the resource of the coagulant, a certain amount of iron tailing is needed. The energy consumption (EC) for chemical oxygen demand (COD) removal was about 0.70 kW h/g COD with 10 g tailing. Pretreating the tailing with 0.2 mol/L HNO3 could enhance the coagulation process, resulting in a COD removal ratio of 67.3% within 4 h. Increasing the current density improved the COD removal rate, but consumed more electricity. Employing more treatment units is a viable approach to reduce EC. It decreased to 0.045 kW h/g COD when two treatment units connected together. Humic like acids and fulvic like acids present in the NCLL have been effectively removed. This study provides a way of ‘treating the wastes with wastes’ for NCLL treatment.

Assessing coastal outfall impact on shallow enclosed bays water quality: Field and statistical analysis

Shallow bays, valued for their environmental, economic, and social significance, face increasing threats from anthropogenic stressors, primarily wastewater discharge through coastal outfalls. The slow tidal currents in these bays hinder the effective dispersion of pollutants to deeper waters, exacerbating their impact. This study assesses the spatial effects of wastewater and brine discharges on Sulaibikhat Bay's water quality. The approach combines fieldwork, laboratory analysis, and statistical techniques to identify pollutant types, sources, and concentrations near outfalls, nearshore, and offshore areas. Throughout the study, high water temperatures were observed consistently, exceeding 30 °C in summer and 18.6 °C in winter near most outfalls, with a maximum deviation from the ambient water of 11.1 °C recorded in December. In addition to elevated electrical conductivity (EC) levels peaking at 60,700 μs/cm, these elevated temperatures significantly reduce dissolved oxygen levels and have been linked to fish kill events in the Bay. NH3-N, TSS, COD, BOD5, FC, and FS concentrations exceeded allowable limits in 56.4 %, 92.25 %, 40.30 %, 32.1 %, 70 %, and 63.36 % of samples, respectively, often reaching extreme levels. Also, the BOD5/COD ratios suggest the presence of non-biodegradable organic matter, mainly from industrial sewage, and the FC/FS levels implicate human and animal waste. These results indicate a mix of domestic, industrial, and commercial wastewater discharges and underscore the severe threat coastal outfalls pose to ecosystem health and water quality in Sulaibikhat Bay. Principal Component Analysis (PCA) and Cluster Analysis (CA) delineate two distinct environmental zones with varying characteristics and contamination levels, necessitating expanded monitoring. Finally, substantial field research, numerical modeling, and establishing a sustainable environmental management system are needed to protect this fragile ecosystem. Also, converting outfalls into offshore may mitigate the environmental status of the bay by enhancing pollutant dilution and dispersion.

Rare Earth Doped ZnO Nanoparticles as Spintronics and Photo Catalyst for Degradation of Pollutants.

Antibiotic water contamination is a growing environmental problem in the present day. As a result, water treatment is required for its reduction and elimination. Due to their important role in resolving this issue, photocatalysts have drawn a great deal of interest over the past few decades. When non-biodegradable organic matter is present in polluted water, the photo catalytic process, which is both environmentally friendly and an improved oxidation method, can be an effective means of remediation. In this regard, we report the successful synthesis of pure phased rare earth doped ZnO nanoparticles for tetracycline degradation. The prepared catalysts were systematically characterized for structural, optical, and magnetic properties. The optical band gap was tailored by rare earth doping, with redshift for Sm and Dy doped nanoparticles and blueshift for Nd doped ZnO nanoparticles. The analysis of photoluminescence spectra revealed information about the defect chemistry of all synthesised nanoparticles. Magnetic studies revealed that all synthesized diluted magnetic semiconductors exhibit room temperature ferromagnetism and can be employed for spintronic applications. Moreover, Dy doped ZnO nanoparticles were found to exhibit a maximum degradation efficiency of 74.19% for tetracycline (TCN) removal. The synthesized catalysts were also employed for the degradation of Malachite green (MG), and Crystal violet (CV) dyes. The maximum degradation efficiency achieved was 97.18% for MG and 98% for CV for Dy doped ZnO nanoparticles. The degradation mechanism involved has been discussed in view of the reactive species determined from scavenging experiments.

Short-Term Effects of Forest Fire on Water Quality along a Headwater Stream in the Immediate Post-Fire Period

Changes in water quality were examined during selected rainfall events in a headwater stream severely damaged by a forest fire on 21–23 February 2021. Seven water quality parameters were analyzed: pH, electrical conductivity, biochemical oxygen demand, chemical oxygen demand, total suspended solids (TSS), total nitrogen, and total phosphorous. First-flush effect and event mean concentration analyses were conducted in spring (dry season) and summer (wet season) immediately after the forest fire. In spring, the non-biodegradable organic matter concentrations increased along with pollutants related to ash-enhanced soil water repellency in water affected by first-flush effects. In summer, TSS and nutrient concentrations increased along with pollutants related to fire-induced soil surface disturbances after a series of rainfall events. First-flush analyses indicated that cumulative pollutant loads were greater in the spring than in the summer due to a higher concentration of forest fire ash in the early storm runoff immediately after the forest fire. The event mean concentrations revealed that pollutant loads were associated with both forest fire ash and storm events in the immediate post-fire period. Therefore, this study indicated that water quality along a headwater stream is affected by short-term effects of large and intense forest fires and rainfall seasonality.

Multifunctional in-situ ferrate treatment and its removal mechanisms of membrane bioreactor residual pollutants

Membrane bioreactors (MBRs) integrate the technique of membrane separation with biologically activated sludge and produce high-quality effluent that can be used for water reclamation. However, removal of residual pollutants, including phosphorus, non-biodegradable organic matter, and microorganisms, is necessary for water reuse in areas with high human exposure to water, necessitating further water treatment. In this study, ferrate(VI) was used to remove various residual pollutants that can be contained in the MBR effluents, and the removal mechanisms were studied by comparing with ferric chloride (FeCl3). Optimal ferrate production using the in situ wet oxidation method in the synthetic MBR effluent occurred at pH 7.0 and Fe3+:OCl− = 5, with a ferrate yield of 1.8 mg L−1. Based on the results of the jar test, the optimised ferrate dosage was 7.5 mg L−1, which removed 90% of total phosphorus, 20% of dissolved organic matter, and 90% of microorganisms in the real MBR effluent. Ferrate was more effective than FeCl3 even at a lower dosage (∼25%). The simultaneous oxidising, coagulating, and disinfecting properties of ferrate are expected to reduce the number of post-treatment steps for water reclamation, thus reducing the capital and operational expenses.

Evaluation of Non-Biodegradable Organic Matter and Microbial Community’s Effects on Achievement of Partial Nitrification Coupled with ANAMMOX for Treating Low-Carbon Livestock Wastewater

After the anaerobic digestion of livestock manure, high concentrations of nutrients still remain. Treatment of livestock wastewater through partial nitrification coupled with anaerobic ammonium oxidation (ANAMMOX) could be a useful technology depending on the investigation of microorganism enrichment and partial nitrification coupled with achievement of the ANAMMOX process. The results show 78.4% and 64.7% nitrite accumulation efficiency was successfully obtained in an intermittent aeration sequencing batch reactor and a continuous aeration sequencing batch reactor, respectively, at a loading rate of 0.93 kg ammonium/(m3·d). The main reason for the high nitrite accumulation efficiency was the intermittent aeration strategy which generated a 20–30 min lag reaction for nitrite oxidation and promoted the growth of the dominant ammonium oxidation bacteria (Nitrosomonas). Non-biodegradable organic matter in the effluents of partial nitrification did not have obvious influence on ANAMMOX activity at low loading rates (118 ± 13 mg COD/L and 168 ± 9 mg COD/L), and up to 87.4% average nitrite removal rate was observed. However, with the influent COD concentration increasing to 242 ± 17 mg/L, the potential inhibition of ANAMMOX activity was exerted by non-biodegradable organic matter.

Scaling-Up and Long-Term Operation of a Full-Scale Two-Stage Partial Nitritation-Anammox System Treating Landfill Leachate

(1) Background: Biological treatment of leachate in landfill sites using anaerobic ammonium oxidation (anammox) is challenging because of the intrinsic characteristics of this complex wastewater. In this work, the scale-up and subsequent full-scale implementation of the PANAMMOX® technology (LEQUIA Research Group, Girona, Catalonia, Spain) are presented as a case study to achieve long-term nitrogen (N) removal from mature leachate mostly through a completely autotrophic pathway. (2) Methods: The treatment system consists of two sequencing batch reactors (SBRs) running in series to individually operate partial nitritation (PN) and anammox (A). Following biological treatment, physicochemical oxidation (i.e., Fenton-based process) was used to remove the remaining non-biodegradable organic matter. A cost analysis comparative was conducted in relation to the former technology used on-site for treating the leachate. (3) Results: The scale-up of the process from pilot- to full-scale was successfully achieved, finally reaching an average removal of 7.4 kg N/d. The composition of the leachate changed over time, but especially once the landfill site stopped receiving solid waste (this fact involved a marked increase in the strength of the leachate). The adjustment of the alkalinity-to-ammonium ratio before feeding PN-SBR helped to improve the N-removal efficiency. Values of conductivity above 25 mS/cm in A-SBR could negatively affect the performance of the anammox process, making it necessary to consider a dilution strategy according to the on-line monitoring of this parameter. The analysis of the operational costs showed that by implementing the PANAMMOX® technology (LEQUIA Research Group, Girona, Catalonia, Spain) in the landfill site, savings up to 32% were achievable. (4) Conclusions: Treatment of mature landfill leachate in such a two-stage PN-A system was demonstrated as feasible and economically appealing despite the complexity of this industrial wastewater. Accurate expert supervision of the process was a key factor to reaching good performances.

Study of water quality analysis and evaluation of Hengshui Lake

The water quality of Hengshui Lake in different regions and at different times was analyzed. According to the data analysis results of chemical oxygen demand (COD), biochemical oxygen demand (BOD5), ammonia nitrogen (NH3-N), total nitrogen (TN), total organic carbon (TOC), total phosphorus (TP), calcium ion content, total hardness, chloride ion content, pH value and conductivity of Hengshui Lake water samples, the water quality of Hengshui Lake was evaluated and analyzed. The results showed that the pollution of Hengshui Lake was mainly organic matter pollution, especially non-biodegradable organic matter pollution. The value of TN was higher than the Class III water, which showed that the self purification capacity of Hengshui Lake water body was weaker. The water quality of Hengshui Lake was better, but the treatment of organic pollution should be paid attention to.

Process performance of anaerobic co-digestion of waste activated sludge and aquaculture sludge

The mesophilic anaerobic co-digestion (AcD) performances of waste activated sludge (WAS) and aquaculture sludge (AS) were studied. Mixtures of different compositions (0, 30, 50, 70 and 100 % of AS on the volume basis) were used as AcD substrates and tested via biochemical methane potential assay. The results showed that CH4 production increased with AS/WAS ratio increment, and AS alone used as the substrate showed the maximum CH4 yield, which was 8% higher than that achieved using WAS alone as the substrate. The CH4 yield values were well fitted with the modified Gompertz model. The maximum methane potential (P0) and maximum methane production rate (R0) increased from 66.8 mL CH4/g VSfed to 70.9 mL CH4/g VSfed and from 4.40 mL CH4/g VSfed·d to 5.59 mL CH4/g VSfed·d, respectively, as the AS/WAS ratio increased from 0% to 100 %. In addition, lower levels of free ammonia and non-biodegradable organic matter contributed to the CH4 production increasing with AS/WAS ratio increased.

Biodegradation of Tetracycline Antibiotic by Laccase Biocatalyst Immobilized on Chitosan-Tripolyphosphate Beads

In this study, biodegradation of tetracycline, which is one of the most commonly used antibiotics, was investigated. In order to convert tetracycline into inactive oxidative metabolites, laccase immobilized onto rigid tripolyphosphate-treated chitosan beads was utilized. For immobilization, chitosan surfaces were activated with glutaraldehyde-linker reagents after tripolyphosphate treatment. The glutaraldehyde-linked rigid chitosan beads showed the higher immobilization capacity of laccase, providing thermostability, reusability, and the higher tetracycline transformation activity. Subsequently, synthetic mediators, including 2,2'‑azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and lignophenolic mediators like violuric, syringic and ferulic acids, 1-hydroxybenzotriazole, and vanillin, were investigated to activate laccase as electron mediators with KI assistance. Among them, the immobilized laccase showed highest tetracycline antibiotic inactivation activity when ABTS was used as a mediator. In the presence of KI, violuric and ferulic acids, 1-hydroxybenzotriazole and vanillin functioned as laccase mediators and inactivated tetracycline almost completely, however, the effect was not observed when they did individually. Finally, Vmax of the immobilized laccase was determined as 76.3 ± 4.3 µmoles mg–1 min–1 against tetracycline, which was 2-fold higher than that of the free enzyme. These results will provide novel insights into laccase-based removal of non-biodegradable organic matter.

Sustainable Wastewater Treatment Systems (2018–2019)

An important part of the environmental degradation suffered by the planet is caused by the discharge of untreated or poorly treated wastewater. Industrial, urban, and agricultural wastewater contain many different types of pollutants such as biodegradable and nonbiodegradable organic matter, suspended solids, turbidity, nutrients, heavy metals, pesticides, pathogens, etc. All of these pose a threat to the environment and human health, so the selected treatment techniques must be adapted to their nature in order to optimize their removal. In addition to efficiency, wastewater treatment methods must be sustainable, not only from an environmental point of view, but also economically and ethically. As a result, no technological dependence should be generated in less developed countries or communities. Therefore, this Special Issue deals with improvements in various aspects of wastewater treatment including different aspects of water treatment such as the development of mathematical models, the application of life cycle techniques, or the experimental optimization of wastewater treatment methods. Thirteen articles were accepted covering some of the most relevant fields of wastewater treatment: activated sludge, nanoparticle treatment, constructed wetlands, energy–water nexus, nutrient recovery, eco-friendly sorbents, and reverse osmosis.

Assessment of water quality status of some water bodies in Kolkata

The water quality status of some water bodies in Kolkata were assessed during dry season through the analysis of various physico-chemical and biological components. Studies revealed that water of all the ponds were alkaline with pH value ranging from 7.80 to 8.41 at water temperature between 28.0 and 28.5. Total Dissolved solids (TDS) varied from 310 to 710 mg/L with higher in Science city (710 mg/L), followed by Victoria (366 mg/L), B.B.D.Bag (310 mg/L) and Minto park (250 mg/L). Minimum of 56% dissolved oxygen saturation values were observed in the pond of Science city implying presence of higher oxygen demanding waste and maximum (96%) in B.B.D.Bag indicating lowest level of reducing substances. Lower ratios of BOD/COD ranging from 0.18 to 0.29 implied the presence of comparatively higher level of non-biodegradable organic matter in water. According to National Sanitation Foundation Water Quality Index (NSF-WQI) values, water quality of two ponds (Victoria and Minto park) were classified as good to excellent, one (B.B.D.Bag) is medium to good and another (Science city) is bad which corresponded to the class A, B and C respectively as classified by Central Pollution Control Board (CPCB).

Molecular weight distribution of the recalcitrant organic matter contained in kraft mill effluents and the identification of microbial consortia responsible for an anaerobic biodegradable fraction

The objective of this research was to evaluate the distribution of the molecular weights of the recalcitrant organic matter contained in kraft mill effluents and identify microbial consortia responsible for an anaerobic biodegradable fraction. As a result, the average removal efficiencies of chemical organic demand (COD) and biological oxygen demand (BOD5) during the entire period of operation were 28% and 53%, respectively. The non-biodegradable organic matter was detected at molecular weights less than 1000 Da. However, most of the organic matter was in the molecular weight fraction higher than 10000 Da with 32 ± 11.6% COD as well as color (42.3 ± 8.7%), total phenolic compounds (35.9 ± 7.9%) and adsorbable organic compounds (AOX) (13.0 ± 2.7%). Methanogenic acetoclastic archaea of the genera Methanomethylovorans and Methanosarcina were found in the surface and middle zones of the reactor. Moreover, Methanosaeta and Methanolinea were identified in the low zone of the reactor. In all zones of the reactor, Desulfomicrobium and Desulfovibrio were found to be the most dominant genera of sulfate-reducing bacteria (SRB).

Optimization of electro-Fenton process for the removal of non-biodegradable organic compounds in instant coffee production wastewater using composite Fe3O4–Mn3O4 nanoparticle catalyst

Wastewater from instant coffee production has high organic content. The non-biodegradable compounds of the organic portion, such as caffeine, trigonelline, and diterpene, are difficult to be removed by conventional processes. Electro-Fenton (EF) with particulate catalyst has been found to be a promising method to treat such compounds. Comparing with homogenous Fenton process, EF uses fewer chemicals and generated less sludge. The catalysts can be easily recovered by magnets if they have magnetic properties. In this study, 30–60 nm composite Fe3O4–Mn3O4 nanoparticles were prepared and used as EF catalyst for the treatment of non-biodegradable organic matters in biologically pre-treated wastewater from instant coffee production. These particles were found to contain Fe3O4, γ-Fe2O3, and Mn3O4, which were effective metal sources for Fenton reactions. The correlations between three important operating parameters (i.e., pH, catalyst concentration, and current density) and the treatment efficiency of the non-biodegradable compounds were elucidated by response surface method (Box–Behnken design) via Modde software. An optimal condition was found at a pH of 3.8, a Fe3O4–Mn3O4 concentration of 0.5 g/L, and a current density of 19.6 mA/cm2. After 60 min of treatment at this condition, the highest removal efficiencies of chemical oxygen demand (COD), color, and total organic carbon in the wastewater were 88%, 98%, and 93%, respectively. With this degree of treatment, the COD and color in treated wastewater met the highest treatment level of Vietnam National Technical Regulation on Industrial Wastewater (QCVN 40:2011, column A, 75 mgO2/L for COD, and 50 Pt–Co for color).

A review of the application of sonophotocatalytic process based on advanced oxidation process for degrading organic dye.

Nowadays the use of conventional wastewater treatment methods is becoming increasingly challenging mainly due to the presence of organic matter in wastewater. Therefore, an emerging technology is needed to deal with these highly concentrated and toxic non-biodegradable organic matters. In the last few decades, advanced oxidation process (AOP) has emerged to treat wastewaters discharged from industries. Recently, researchers have shown interest to use the application of ultrasound (US) in photocatalysis, i.e. sonophotocatalysis, to improve the performance of the treatment process in the degradation of organic and inorganic contaminants in aqueous streams. Sonophotocatalysis is the combination of the use of ultraviolet (UV) and US.

Qualitative Assessment and Typology of the Water Resource Used for the Production of Drinking Water in Du&amp;#233;kou&amp;#233;, Western C&amp;#244;te d’Ivoire

The objective of this study was to evaluate the typology of water through physicochemical and bacteriological characterization with the aim of highlighting its vulnerability as a drinking water resource. The methodology adopted was to evaluate the level of pollution by monitoring the spatiotemporal variation of the water pollution indicator levels of Lake Dohou. The sampling frequency is monthly for one year, from November 2017 to October 2018, in order to obtain a fairly representative image of water quality and its seasonal evolution in eight (8) well-defined stations. The parameters were determined using the standard methods defined by the French Association for Standardization (AFNOR). This study shows that the waters are acidic, with an average pH of 5.81 and a low electrical conductivity of between 42.67 ± 4.30 and 59.62 ± 21.84 μS.cm-1. At all stations, seasonal mean water transparencies are low (<1 m). It is also noted that 99.7% of the water samples collected had total nitrogen (TN) levels above the limit of 4 mg.L-1. All of the lake’s waters have non-compliant BOD5 (<3 mgO2.L-1) for raw water intended for the production of drinking water. Sites D6 and D7 have COD/BOD5 ratio greater than 3, which indicates the presence of non-biodegradable organic matter in these areas. Total coliforms, Escherichia coli and Enterococci were present in 100% (28/28) water samples at concentrations ranging from 2300 to 173,000 CFU/100 mL, from 100 to 1650 CFU/100 mL and from 20 to 1140 CFU 1/100 mL respectively. For Salmonella pathogens, they were detected in 50% of the dry season samples and in 100% of the rainy season samples. This almost permanent presence of this pathogenic germ denotes a poor quality of water with reference to this parameter. The presence of total coliform and other microbial contaminants suggests that supplied water is highly contaminated with pathogens and great reservoirs for them. Principal component analysis (PCA) of the physicochemical data set allowed defining three different classes of water on the Dohou Lake. Outside the upstream zone (D6 and D8), water could continue to be used for the production of drinking water.

ANÁLISIS DE TENDENCIAS DE VARIABLES INDICADORAS DE CALIDAD DE AGUA PARA EL RIACHUELO (CUENCA MATANZA-RIACHUELO, ARGENTINA)

El rio Matanza-Riachuelo constituye un ejemplo claro y extremo del “sindrome del rio urbano” y un caso emblematico de contaminacion en Argentina. A partir de los datos generados en el monitoreo de la calidad de agua superficial del Riachuelo (tramo inferior del rio Matanza) que realiza la Agencia de Proteccion Ambiental del Gobierno de la Ciudad de Buenos Aires, se evaluo la evolucion de la calidad del agua (periodo 2008-2016). Para ello, se aplico la prueba estadistica de Mann-Kendall a la serie de datos para cinco variables fisicoquimicas, una microbiologica y la precipitacion acumulada mensual para el area. Los resultados reflejaron condiciones mas favorables en cuanto a contenido y demanda biologica de oxigeno, nitrogeno amoniacal total y ion cloruro aguas arriba de la desembocadura. La abundancia de bacterias Escherichia coli no mostro una tendencia apreciable. Asimismo, la fraccion de materia organica no biodegradable se habria incrementado en todo el tramo al igual que la precipitacion acumulada mensual para el periodo estudiado. El incremento de la escorrentia pluvial habria determinado las tendencias observadas en el intervalo de tiempo considerado. Aun asi, el ecosistema permanecio en un estado altamente degradado con el 50 % de los valores registrados de oxigeno disuelto por debajo de 2 mg/L y el 50 % de los valores de demanda biologica y demanda quimica de oxigeno por encima de 15 y 50 mg O 2 /L, respectivamente. Los numeros de E. coli , por su parte, resultaron similares a los de un efluente cloacal crudo.

Effect of dairy wastewater on changes in COD fractions in technical-scale SBR type reactors.

The annual global production of milk is approximately 630,000 million litres and the volume of generated dairy wastewater accounts for 3.2 m3·m-3 product. Dairy wastewater is characterized by a high load of chemical oxygen demand (COD). In many wastewater plants dairy wastewater and municipal wastewater are co-treated. The effect of dairy wastewater contribution on COD fraction changes in municipal sewage which has been treated with a sequencing batch reactor (SBR) in three wastewater treatment plants in north-east Poland is presented. In these plants the real contribution of dairy wastewater was 10, 13 and 17%. In raw wastewater, SS fraction (readily biodegradable dissolved organic matter) was dominant and ranged from 38.3 to 62.6%. In the effluent, SS fraction was not noted, which is indicative of consumption by microorganisms. The presence of dairy wastewater in municipal sewage does not cause changes in the content of the XI fraction (insoluble fractions of non-biodegradable organic matter). SBR effluents were dominated by non-biodegradable dissolved organic matter SI, which from 57.7 to 61.7%. In raw wastewater SI ranged from 1.0 to 4.6%. Xs fraction (slowly biodegradable non-soluble organic matter) in raw wastewater ranged from 24.6 to 45.5% while in treated wastewater it ranged from 28.6 to 30.8%. In the control object (fourth wastewater plant) which does not process dairy wastewater, the SS, SI, Xs and XI fraction in inflow was 28.7, 2.4, 51.7 and 17.2% respectively. In the effluent the SS, SI, Xs and XI fraction was below 0.1, 33.6, 50.0 and 16.4% respectively.