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

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.

Simulating the impact of piers on hydrodynamics and pollutant transport: A case study in the Middle Yangtze River

It is known that channel engineering, including the construction of piers, will change the river hydrodynamic characteristics, which is a significant factor affecting the transport process of pollutants. With this regard, this study uses the well-validated and tested hydrodynamic module and transport module of MIKE 21 to simulate the hydrodynamics and water quality under various pier densities in the Wuhan reach. Hydrodynamic changes around the piers show spatial differences, which are similar under different discharges. The range and amplitude of hydrodynamic spatial variations increase with the increase in pier density. However, there is a critical value of 1.25 to 2.5 units/km. When the pier density is less than this critical value, this type of cumulative effect is the most significant. Additionally, greater changes can be found in chemical oxygen demand concentrations, which also show spatial and temporal variations. The area with high chemical oxygen demand concentration upstream and downstream from the engineering area exhibits the distribution characteristics of “decrease in the downstream area and increase in the upstream area” and “increase in downstream the area and decrease in the upstream area” respectively. In the reach section of the engineering area, the area with high chemical oxygen demand concentration increases in the front area near the piers and decreases near the shoreline. Furthermore, the concentration shows attenuation actions with a longer residence time owing to the buffering effect of pier groups. These results have significant implications on shoreline planning and utilization. Moreover, they provide scientific guidelines for water management.

How Physicochemical Parameters of Water Change with Distance in a Lake: Case Study Lake Bunyonyiinkigezi

Pollution resulting from unsustainable agricultural and urbanization activities in the Ruhezamyenda and Bunyonyi catchments are threatening lake Bunyonyi. These have led to high chemical oxygen demand (COD), electrical conductivity, turbidity, pH, iron (II) concentration and low dissolved oxygen (DO5). In this study we have investigated the how COD, turbidity, pH, concentration of iron, total suspended solids, total nutrients and DO5 of water changed with distance in lake. Water sampled from different distances in the lake filtered using Whatman paper at ambient temperatures was tested for COD, electrical conductivity, turbidity, total nutrients, iron, hardness and DO5. COD was 20.8±.0.03mg/L to 16 ± 0.03mg/L; total hardness was 16.5±0.2 mg/L to 18.6 ± 0.3 mg/L total nitrate was 103.5± 2 mg/L to 88 ± 3 mg/L; total phosphate was 100.8 ±.2.5 to 87± 3 mg/L; high TSS values from 3.4 ± 0.1 mg/L to 2.5 ± 0.1 mg/L showed contamination of water. As pH decreased from 8.3 ± 0.03 to 7.6 ± 0.04 revealed that bases were getting removed. The turbidity dropped from 25.7 ± 0.3 NTU to 20 ± 2 NTU due settling down of sediments. Iron (II) concentration ranging from 1.1± 0.1 to 0.8± 0.1 mgL-1 . Dissolved oxygen decreased from 7.9 ±0.3 mg/L to 4.8 ± 0.2 mg/L indicating surface water can uphold life of aquatic organisms. Total hardness ranged from 0.22± 0.05 to 0.19± 0.05 mg/L Electrical conductivity was high and ranged from 130± 5 to 150± 5 µS/cm indicating presence of electrolytes. Lake Bunyonyi water is not greatly polluted, but requires to be safe guarded against poor unsustainable agricultural practices, sewage draining from towns, schools and hotels in nearby settlements.

High Cod and Turbidity Removal in The Treatment of Polluted Pond Water Using Low Dosage of Pineapple Leaf Coagulant: A Preliminary Study

Coagulation process using low dosage of plant-based coagulant to remove high chemical oxygen demand (COD) and turbidity is important for water treatment. This study presents the treatment of pond water using plant-based pineapple leaf coagulant to achieve high COD and turbidity removal. The coagulation was performed using a jar test experiment of pond water at different pH followed by different dosages of pineapple leaf coagulant. It was found that the highest COD and turbidity removal ranged between 94.1 – 94.6 % and 88.3 – 88.4 % at pH 8 respectively, using low dosage (50 mg L-1) of pineapple leaf coagulant. The final COD and turbidity values ranged between 7.3 – 8.0 mg L-1 and 17.7 – 17.8 formazin turbidity unit (FTU) respectively, which are lower compared with results from other studies that used high dosage coagulants. Moreover, the final pH, COD, turbidity, dissolved oxygen (DO), and total suspended solid (TSS) values of the treated pond water were below the standard limits set by the National Water Quality Standards for Malaysia (NWQSM) class IIB, which represents water bodies suitable for recreational use with body contact (DOE, 2016). Therefore, it is expected that the newly-formulated waste utilisation of pineapple leaf coagulant can reduce the usage of chemical coagulants and can further be used for different types of water.

Modeling the Performance of Full-Scale Anaerobic Biochemical System Treating Deinking Pulp Wastewater Based on Modified Anaerobic Digestion Model No. 1

The deinking pulp (DIP) is a main resource for paper making, and the wastewater from DIP process needs to be treated. Anaerobic biochemical technique has been widely applied in DIP wastewater treatment, due to the remarkable capability in reducing high chemical oxygen demand (COD). In this study, a mathematical simulation model was established to investigate the performance of a full-scale anaerobic biochemical system for treating DIP wastewater. The model was based on Anaerobic Digestion Model No. 1 (ADM1), which was modified according to the specific anaerobic digestion process for DIP wastewater treatment. The hydrodynamic behavior of a full-scale anaerobic biochemical system was considered in this model. The characteristics of the influent DIP wastewater were assessed, and then, the substrate COD proportion was divided successfully for the necessity of ADM1 applying. The Monte Carlo technique was implemented to distinguish the most sensitive parameters that influenced the model output indicators comprising effluent COD and biogas production. The sensitive parameters were estimated and optimized. The optimized value of k_m_pro is 12.02, K_S_pro is 0.35, k_m_ac is 4.26, K_S_ac is 0.26, k_m_h2 is 16.62, and K_S_h2 is 3.21 × 10–5. The model was calibrated with 150 days operation values measured in the field. The subsequent 100 days on-site values were used to validate the model, and the results obtained by the simulations were in good agreement. This study provides a meaningful and theoretical model guidance for full-scale wastewater anaerobic biochemical treatment simulation.

Wastewater from the Edible Oil Industry as a Potential Source of Lipase- and Surfactant-Producing Actinobacteria

Wastewaters generated from various stages of edible oil production in a canola processing facility were collected with the aim of determining the presence of lipase-producing actinobacteria of potential industrial significance. The high chemical oxygen demand (COD) readings (up to 86,700 mg L−1 in some samples) indicated that the wastewater exhibited the nutritional potential to support bacterial growth. A novel approach was developed for the isolation of metagenomic DNA from the oil-rich wastewater samples. Microbiota analysis of the buffer tank and refinery condensate tank wastewater samples showed a dominance of Cutibacterium acnes subsp. defendens, followed by a limited number of other actinobacterial genera, indicating the presence of a highly specialized actinobacterial population. Cultured isolates with typical actinobacterial morphology were analyzed for their ability to produce lipases and biosurfactants. Two strains, designated as BT3 and BT4, exhibited the highest lipase production levels when grown in the presence of tributyrin and olive oil (1.39 U mg−1 crude protein and 0.8 U mg−1 crude protein, respectively) and were subsequently definitively identified by genome sequencing to be related to Streptomyces albidoflavus. Cultivation of the strains in media containing different types of oils did not markedly increase the level of enzyme production, with the exception of strain BT4 (1.0 U mg−1 crude protein in the presence of peanut oil). Genome sequencing of the two strains, BT3 and BT4, revealed the presence of a range of lipase and esterase genes that may be involved in the production of the enzymes detected in this study. The presence of gene clusters involved in the production of biosurfactants were also detected, notably moreso in strain BT3 than BT4.

Comparative study between synthetic and dairy wastewaters in single chamber microbial fuel cell for power generation

To investigate the performance of microbial fuel cell (MFC) with a single-chamber membrane, Pseudomonas aeruginosa is used as a bio catalyst for various synthetic wastewaters rich in carbohydrate and is compared with real dairy wastewater in this experiment. Therefore, the choice of appropriate carbon, nitrogen, NaCl, inoculum content, temperature, and pH process parameters are used for preparing synthetic wastewater was agreed upon by one-variable-at-a time approach. Maximum levels of voltage generation attained from the synthetic wastewater was 485 mV when supple­mented with 1.5 % of lactose as a source of carbon, 0.3 % of ammonium chloride as a decent nitrogen source, 0.03 % of NaCl, inoculum concentration of 3 %, the temperature at 37 oC and pH 7. On the other hand, the maximum voltage attained with real dairy wastewater was 561 mV with high chemical oxygen demand (COD) value of 801 mg l-1. The maximum power density obtained from dairy wastewater was 73.54 mW m-2. Thus, High voltage achieved for MFC operating with real dairy wastewater suggests that it can be used not only for the industrial application to generate more renewable power, but also for the wastewater treatment carried out at the same time.

Membrane-based conceptual design of reuse water production from candy factory wastewater

Intense pressure on water resources has led to efforts to reuse reclaimed processing wastewater in the food industry. There are tight rules for water quality, but efficient separation technologies such as reverse osmosis possess good possibilities for water reuse. This study developed a membrane-based reuse water concept for wastewater from the candy industry emphasizing the pre-treatment stage in the concept to reduce fouling. The wastewater contained suspended solids, sugar compounds and the ingredients for candy gelation, which had a tendency to foul membranes, making pre-treatment essential for successful concept. Cross-rotational ultrafiltration, which featured enhanced fouling prevention for membranes, functioned well for the removal of challenging substances. Conventional filtration technologies were impractical due to a low flux, even when the viscosity of the wastewater was reduced using surfactants. The wastewater had a high chemical oxygen demand, meaning that there were a strong fouling potential for reverse osmosis membranes, but also high osmotic pressure. A spiral wound reverse osmosis functioned well when the wastewater was pre-treated, and it produced good quality water with respect to all the other studied parameters except the chemical oxygen demand. However, chemical oxygen demand rejection was 99% since the concentration in the wastewater was originally very high.

Coffee Processing Wastewater Management: An Overview

Globally, one amongst the major agro-based industry contributing significantly is Coffee. Coffee growing estates use water for pulping and the wastewater generated from coffee pulping activity is generally discharged to the water bodies. The objective of this study was to evaluate the impact of effluents from traditional wet coffee processing plants on the water quality. Coffee fruits are processed by two methods, wet and dry process. The wet processing produces a drink of higher quality and has the advantage of reducing the drying space area and time required. However, this preparation step generates high volume of coffee wastewater as it involves utilizing large volumes of water with concurrent generation of wastewater. Throughout wet processing, coffee fruits generate enormous quantities of high strength wastewater. The so generated wastewater is characterized by high concentrations of organic matter, low pH, nutrients, suspended matter associated with odor and dark color with high chemical oxygen demand and biochemical oxygen demand requiring systematic treatment before disposal. The inadequate disposal of the coffee wastewater into environment directly without proper management and handling will pose aa pollution risk to receiving water body. Efforts have made by various researchers to evolve an alternative method for the treatment of coffee pulping waste and the same is discussed in this paper.

TREATMENT OF TRADITIONAL ETHANOL FERMENTATION WASTE WITH ELECTROLYSIS METHOD FOR DECREASING COD AND SULFIDE

Ethanol is produced from molasses by a fermentation process. In Bekonang, ethanol manufacturingby a home-scale industry so the waste just thrown away in free water then pollution occurs both in rivers and in paddy fields. Ethanol waste has very high chemical oxygen demand (COD) and contain high sulfide. Electrolysis that use for reduce leves COD dan Sulfide with electricity as main source for direct current flowing electricity (dc) to the anode and cathode. Electrolysis time 10, 15, 20, 25 and 30 minutes and voltage variation 5, 10 and 15 volt. Based on data obtained in the test COD obtained optimum levels of 284.5 mg/L from the initial content of 586 mg/L , at a time variation of 30 minutes and voltage 15 volt. The sulfide test obtained optimum levels of 0.0661 mg/L from the initial content of 0.305 mg/L, at time variation of 25 minutes and a voltage of 15 volt.