Dairy Sewage Research Articles

Structure and indicators of electric energy consumption in dairy wastewater treatment plant

The aim of the research was to determine the indicators of electricity consumption in every stage of the dairy sewage treatment process in relation to the sewage flow and the load of removed organics (BOD5, COD) and nutrients (TN, TP). The research was conducted in a dairy wastewater treatment plant (WWTP) consisting of mechanical treatment, averaging tank, dissolved air flotation (DAF) and biological treatment with sequence batch reactors (SBRs). Energy consumption was measured with the help of transducers. Indicators of unit electricity consumption were determined on the basis of 95 measurement series of energy consumption, sewage flow and removed load. The mean value of total unit energy consumption relating to the flow for the entire WWTP was 2.29 kWh·m−3, while for biological treatment 1.17 kWh·m−3 and 0.05 kWh·m−3 for DAF. The mean values of indicators relating to removed pollutants load for the entire WWTP were: 1.89 kWh·kgrem BOD5−1, 1.30 kWh·kgrem COD−1, 48.61 kWh·kgrem TN−1 and 160.01 kWh·kgrem TP−1. During biological treatment, energy consumption indicators were on average: 1.65 kWh·kgrem BOD5−1 and 1.19 kWh·kgrem COD−1, 52.90 kWh·kgrem TN−1 and 141.26 kWh·kgrem TP−1, while for DAF: 0.12 kWh·kgrem BOD5−1, 0.09 kWh·kgrem COD -1, 3.85 kWh·kgrem TN−1 and 16.17 kWh·kgrem TP−1. It was found that the biological treatment in SBRs was responsible for 54.1% of the total energy consumption of dairy WWTP. Aerobic sewage sludge treatment accounted for 17.0% of total consumption, mechanical treatment 17.1%, deodorization 2.6%, and other (social, lighting etc.) 6.9%, while DAF only 2.3%. The real-time electricity metering system enabled the optimisation of the electricity consumption in the WWTP, taking into account its consumption in unit processes and the removed pollutants load. The application of this system enabled to make corrections that reduced energy consumption while maintaining the required treatment efficiency.

Cow dung-derived biochars engineered as antibacterial agents for bacterial decontamination

Disposal of the pollutants arising from farming cattle and other livestock threatens the environment and public safety in diverse ways. Herein, we report on the synthesis of engineered biochars using cow dung as raw material, and investigating these biochars as antibacterial agents for water decontamination. By coating the biochars with N-halamine polymer and loading them with active chlorine (i.e., Cl+), we were able to regulate them on demand by tuning the polymer coating and bleaching conditions. The obtained N-halamine-modified biochars were found to be extremely potent against Escherichia coli and Staphylococcus aureus. We also investigated the possibility of using these N-halamine-modified biochars for bacterial decontamination in real-world applications. Our findings indicated that a homemade filter column packed with N-halamine-modified biochars removed pathogenic bacteria from mining sewage, dairy sewage, domestic sewage, and artificial seawater. This proposed strategy could indicate a new way for utilizing livestock pollutants to create on-demand decontaminants.

Effect of Low-Temperature Conditioning of Excess Dairy Sewage Sludge with the Use of Solidified Carbon Dioxide on the Efficiency of Methane Fermentation

This study aimed to determine the effect of the low-temperature conditioning of excess dairy sewage sludge using solidified carbon dioxide on the efficiency of methane fermentation. An increase in the solidified carbon dioxide to excess dairy sewage sludge volumetric ratio above 0.3 had no significant effect on chemical oxygen demand concentration in the dissolved phase. The highest chemical oxygen demand values, ranging from 490.6 ± 12.9 to 510.5 ± 28.5 mg·dm−3, were determined at solidified carbon dioxide to excess dairy sewage sludge ratio ranging from 0.3 to 0.5. The low-temperature conditioning caused ammonia nitrogen concentration to increase from 155.2 ± 10.2 to 185.9 ± 11.1 mg·dm−3 and orthophosphates concentration to increase from 198.5 ± 23.1 to 300.6 ± 35.9 mg·dm−3 in the dissolved phase. The highest unitary amount of biogas, reaching 630.2 ± 45.5 cm3·g o.d.m.−1, was produced in the variant with the solidified carbon dioxide to excess dairy sewage sludge volumetric ratio of 0.3. Methane content of the biogas produced was at 68.7 ± 1.5%. Increased solidified carbon dioxide dose did not lead to any significant changes in biogas and methane production. The efficiency of biogas production from unconditioned excess dairy sewage sludge was lower by 43.0 ± 3.2%. The analysis demonstrated that the low-temperature conditioning is an energetic viable technology aiding the methane fermentation process.

Potential application of Bacillus pseudofirmus SVB1 extract in effluent treatment

Abstract: The wastewater generated from food industries like dairy and meat processing industries are rich in organic compounds and nutrients having high concentrations of BOD, COD and suspended solids. However, most of the conventional techniques used for treatment are not so eco-friendly. The eco-friendly approaches mostly employ biological aid but are usually ineffective in treating high organic load under extreme conditions. This study uses alkaline protease isolated from Bacillus pseudofirmus SVB1 to treat effluents from dairy industry and domestic sludge. The results obtained from this study indicate that both crude and partially purified alkaline protease performed significantly well in the treatment of effluents from dairy and domestic sewage. They were also able to effectively lyse both Gram positive and Gram negative bacteria. Both crude and partially purified enzyme procured from SVB1 performed efficiently when compared to the already available commercial enzymes used in this study. The efficiency of the extract reduces the overall cost of treatment, hence can potentially be used for treating effluents, enhancing the economy of the entire process.

Community shift in structure and functions across soil profile in response to organic waste and mineral fertilization strategies

Significant differences in the microbial diversity, biochemical processes and enzyme activity in soil has been observed under various conditions of fertilization, but to date little research has been performed to explore these properties across soil profile after organic waste amendments, especially within deeper soil layers. Soil samples were collected from an experiment under winter wheat, and enzyme activity, microbial community structure were determined. All treatments amended with organic waste or mineral fertilizers and non-amended plots had different microbial communities, especially in various soil layers. Greater enzyme activity (9.82 mg PNP kg−1 h−1, 13.41 mg TPF kg−1 d−1), ammonification (44.31 mg NH4+ kg−1 d−1), and CO2 production (375.16 mg CO2 kg−1 d−1) were observed in the rhizosphere soil amended with dairy sewage sludge. Conversely, lower enzyme activity, ammonification, and CO2 production were detected in the deep soil layer (30–40 cm) compared to rhizosphere and non-rhizosphere soil. Overall, it was demonstrated that organic waste amendment supports soil microbial diversity and leads to enhanced functional potentials expressed as enzyme activity.

Enumeration of Polyhydroxyalkanoate (PHA) Producing Bacteria from Dairy Sewage Samples

Aims: The synthetic polymer plastics have become an integral part of contemporary life. Excess use of plastics and indiscriminate dumping of it in soil and water is polluting the environment. In order to overcome this problem, the production and applications of eco-friendly biodegradable products from microbes are becoming inevitable from the last decade and also are the good alternatives for synthetic polymers.
 Methods and Results: Polyhydroxyalkanoate producing bacterial strains were confirmed by serial dilution of sewage samples from dairies and pour plating using modified nutrient agar medium with 2% glucose and 0.3% sudan black. Commercial dairy sewage sample from III Dairy showed highest count of PHA producers (3.80 log10cfu/ml) followed by II Dairy (3.68 log10cfu/ml) and I Dairy (3.35 log10cfu/ml). On an average, 70 per cent were PHA producers among TBC of sewage samples.
 Conclusion: Dairy sewage sample from III Dairy showed highest count of PHA producers (3.80log10cfu/ml)
 Significance and Impact of the Study: This study provides importance of polyhydroxyalkanoates and their role against synthetic plastic by enumerating the polyhydroxyalkanoate (PHA) producing bacteria from Dairy sewage samples that can be effectively utilized for the synthesis of bioplastics.

Research of Effective Microorganisms on Dairy Sewage Sludge Stabilization

Research of Effective Microorganisms on Dairy Sewage Sludge Stabilization

Characterization of microbial functional and genetic diversity as a novel strategy of biowaste ecotoxicological evaluation

The goal was to elucidate the importance of the waste properties for effective exploitation in biogas production and for soil application, respectively, based on the physicochemical and microbial characterization of biowaste and the corresponding biogas residues. The following waste media were chosen: fruit waste, dairy sewage sludge, corn silage, grass silage, and grain brew to prepare three co-substrates for anaerobic bioconversion. The most satisfactory biogas yield was obtained from biowaste with the following composition: 25% fruit wastes, 25% dairy sewage sludge, 12% corn silage, and 38% grain brew. The study included functional and genetic diversity assessment through the characterization of the catabolic potential and structure of the microbial communities inhabiting the examined organic wastes and their relative biogas residues. The metabolome was based on the use of a Biolog® plate. The elucidation of the metagenome employed the genetic structure of prokaryotes and involved denaturing gradient gel electrophoresis and next-generation sequencing analyses. The usefulness of metagenomics was emphasized by ecotoxicological evaluation of biowaste and in determining the accurate start-up community composition for biogas production, highlighting the pivotal role of anammox and hydrolytic bacteria as marker groups. The high importance of the great diversity of fungi was also revealed based on a functional approach.

Trickling Filter for High Efficiency Treatment of Dairy Sewage

Trickling Filter for High Efficiency Treatment of Dairy Sewage

Evaluation of microbial community composition of dairy sewage sludge, corn silage, grass straw, and fruit waste biomass for potential use in biogas production or soil enrichment

The purpose of the study was to link microbial community composition and chemical properties of various biomass and their resulting digestate residues for their potential use in biogas production or soil enrichment. The order of biogas production, graded from high to low was as follows: corn silage, grass silage, fruit waste, and dairy sewage sludge. Different bacterial families were predominant in different biomass. Corn silage deteriorated as a result of long-term air exposition and may serve as an efficient feedstock substrate for anaerobic digestion. A positive role in plant biocontrol microorganisms found in grass straw residues, and reasonable biogas yield obtained from this substrate suggests the use of grass straw for biogas production and its residues to enrich the soil. Due to potential threat of introducing pathogens into the soil within fruit waste or dairy sewage sludge, or soil acidification by fruit waste repeated use in field application, this biomass should be sanitized prior to soil application. Simultaneously, low biogas yields from fruit waste and dairy sewage sludge substrates make it necessary to transform them in anaerobic digestion with more energetic co-substrates. Tested residues may deliver a robust and wide range of methanogens as inoculum for further anaerobic digestion process.

Variability of dairy wastewater characteristics in Piatnica – one of the largest and most advanced milk processing plants in Poland

The problem of industrial wastewater treatment from food processing, including dairy, is not completely solved. The aim of this study was to determine the variability of dairy sewage characteristics in one of the largest and most advanced milk processing plants in Piatnica, East-North Poland and review the opportunities for biological removal of nitrogen and phosphorus from wastewater. The study was conducted in the milk processing plant and WWTP in 2016 and 2017. The ratio of organic compounds for biogenic compounds in dairy wastewater were determined. During the two year study period there were no instances when the ratio of organic compounds for total phosphorus in Piatnica raw wastewater was lower than 25 gBOD5·gP-1. This indicates that in modern and innovative milk processing plants there are no instances when the amount of organic matter in dairy sewage is insufficient to remove phosphorus below 1.0 mgP·dm-3.

Characterization and Influence of a Multi-enzymatic Biopreparation for Biogas Yield Enhancement

A multi-enzymatic biopreparation of Trichoderma atroviride G79/11 origin was characterized. The fungus showed relatively high cellulase production in a soybean flour-cellulose-lactose medium. Subsequently, based on its post-culture liquid, the biopreparation of the enzyme mixture was developed and characterized. The liquid form of the enzyme mixture reached 22 U cm-3 of cellulolytic activity and its lyophilisate exhibited 1.09 U cm-3 at pH 5.1 and 50 °C. The enzyme mixture was characterized by the following activities: xylanase, β-glucosidase, carboxymethyl cellulase, polygalactouronase, pectinesterase, amylase, lactase, and protease. A method for an efficient conditioning process of organic waste (fruit processing waste, dairy sewage sludge, corn silage, and grain broth) for biogas yield enhancement using the enzyme mixture was proposed. The enzyme mixture increased the efficacy of biogas production by 30% when the lyophilizate (0.5 mg g-1 d.m.) was applied prior to fermentation. A method for conducting the enzymatic conditioning process of organic waste using the enzyme mixture as a pretreatment was proposed. This was part of the optimization of the methane fermentation process to increase the biogas yield. Consequently, after application of the biopreparation, the efficiency of anaerobic digestion of organic waste was improved.

Research on the influence of anaerobic stabilization of various dairy sewage sludge on biodegradation of polycyclic aromatic hydrocarbons PAHs with the use of effective microorganisms

Sewage sludge was taken from a dairy WWTP belonging to Mlekovita Cooperative in Wysokie Mazowieckie. There were excess sludge, flotation sludge and a mixture of excess and flotation sludge from pre-treatment of dairy sewage.The initial content of 16 PAHs in excess sludge before fermentation was approximately 689µg·kg−1 in dry mass, whereas in post-flotation sludge (which constituted around 30% of raw sludge) it was approximately 95µg·kg−1 in dry mass. A mixture of excess and flotation sludge had the content of 497,7µg·kg−1 in dry mass. Through comparison of particular hydrocarbons content in raw sewage sludge to the total PAHs content, it was shown that tricyclic compounds, which constituted 46,3% of the PAHs sum (excess sludge), and tetracyclic compounds, which constituted 60,0% of the PAHs sum (flotation sludge), were the dominating fractions.In the sludge subjected to fermentation in reactors with mixed sludge and surplus activated sludge, the general trend of the course of changes in concentrations of PAHs was similar. Both in the sludge inoculated with EM and in that not inoculated with EM, a significant increase in the total PAHs contents was observed in the first fermentation phase (acidic fermentation) after 7 days of the process. Addition of EM into the sludge did not prevent the PAHs release, and therefore higher concentrations of PAHs sum were recorded during the hydrolysis stage than in sludge before fermentation. A decrease in the sum of PAHs was observed after 2 weeks of fermentation in relation to the quantity observed after 1 week of fermentation (except from post-flotation sludge). In the following weeks, there was further decrease in the concentration of the 16 PAHs sum in all sludge types. However, in sludge without EM inoculation, it was lower than in sludge with EM inoculation. The loss of the majority of tested hydrocarbons was reported in the final phase of fermentation.

Rate of change in concentration of organic compounds and nutrients in municipal and dairy wastewater treated in full technical SBR scale

Municipal WWTP often receive the industrial wastewater, including dairy sewage. The problem of sewage treatment from this sector of economy is not completely solved, especially in plants of medium and small milk processing capacity. The aim of the study was to determine the rate of change in organic compounds and nutrients in municipal wastewater with the participation of dairy products during the processing phases of SBR-type reactor in a technical scale. The study was conducted in WWTP in Sokolka. Rate of changes in the concentrations of organic compounds, nitrogen and phosphorus in wastewater during the processing phases of SBR reactor was determined. Presence of dairy sewage (13% volume participation) affected the decrease in the rate of changes in organic compounds concentrations defined as BOD 5 during all processing phases of SBR reactor. Significant influence of dairy sewage on rates of change in nitrogen and phosphorus compounds concentrations during filling, aeration, stirring, sedimentation and decantation phases, was found.

Energy consumption modeling during dairy sewage pretreatment

The research was conducted in a dairy WWTP located in north-eastern Poland with the average flow of 546 m3 d-1 and PE 11500 in 2016. Energy consumption was measured with the help of Lumel 3-phase network parameter transducers installed within the plant. The modeling was conducted based on the quantity and quality of raw sewage, after its screening, averaging and dissolved air flotation. The following parameters were determined: BOD5 , COD. N-total and P-total. During the research period. 15 measurement series were carried out. Pollution loads removed in primary treatment varied from 167.0 to 803.5 kgO2 d-1 and 1205.9 to 10032 kgO2 d-1 for BOD5 and COD respectively. The energy consumption share during dairy pretreatment in relation to the total energy consumption was in the range from 13.8 to 28.5% with the mean value of 18.7% during the research period. Energy consumption indicators relating to removed pollution loads for primary treatment were established with the mean values of 0.74 and 0.83 kWhkg-1 d-1 for BOD5 and COD respectively. An attempt was made to determine the influence of raw sewage characteristics and pretreatment efficiency on energy consumption of the object. A model of energy consumption during pretreatment was estimated according to the experimental data obtained in the research period. It was modeled using the linear regression model and principal component analysis.

COD fractions changes in the SBR-type reactor treating municipal wastewater with controlled percentage of dairy sewage

The aim of study was to investigate the influence of percentage of dairy wastewater in the municipal wastewater on the changes of COD fractions during the cycle of SBR-type reactor. The scope of the research included physicochemical analyses of municipal wastewater without dairy wastewater, dairy wastewater, mixture of municipal and dairy wastewater as well as treated sewage. Both the concentrations and the proportions between COD fractions changed in the SBR cycle. In raw municipal and dairy wastewater - XS, insoluble hardly bio-degradable fraction of COD dominated (49.6 and 64.5% respectively). In treated wastewater SI, COD for dissolved compounds that are not biologically decomposed (inert) (from 62.1 to 74.6%) dominated, while XS fraction was from 19.1 to 24.4%. The consumption rate of organic compounds depended on the type of COD fraction, SBR cycle phase and the percentage of dairy wastewater. The highest rates of organic compounds consumption were noted in the phase of mixing. In the case of fraction SI, no differences in concentration in the SBR cycle time, were found. Concentration of COD in treated wastewater was from 34.8 to 58.9 mgO 2 ·L -1 (efficiency wastewater treatment from 96.0 to 98.6%).

Assessment of microbiological and biochemical properties of dairy sewage sludge

The rational utilisation of sludge as organic matter application into the soil permits enrichment in nutrients such as nitrogen and phosphorus. As dairy sewage sludge contains large amounts of organic matter and minerals, utilisation of such sludge in agriculture appears to be a noteworthy proposal. However, such waste can also be a source of toxic substances, heavy metals, inhibitors, xenobiotics and potentially pathogenic microorganisms. Therefore, it is so important to monitor its microbiological and biochemical properties in aspect of the safety for human health, natural environment preservation and a suitable level of agricultural production maintenance. The objective of study was the estimation of selected microbiological, biochemical and chemical properties of activated sludge (AS) and waste activated sludge (WAS) originating from the dairy sewage treatment plant. Nitrification and ammonification rates, respiratory, dehydrogenases, acid phosphatase, alkaline phosphatase, protease and urease activities were at significantly higher levels in the WAS than in the AS. The pH value of the AS and WAS oscillated within the range of neutral reaction.

Sistemas Alagados Construídos em Batelada: remoção de Demanda Bioquímica de Oxigênio e regulação de pH no tratamento de efluentes de laticínios

This work assessed the effectiveness of using constructed wetlands (CW's) to treat dairy effluent. The purpose of the research was to evaluate the influence of substrates and cultivated plants on the efficiency of Biochemical Oxygen Demand (BOD) removal and pH regulation in six experimental units operating at pilot scale. Six CW's for dairy sewage treatment were constructed in 100-liter High-Density Polyethylene Ethylene (HDPE) tanks. Three

Soil microbial functionality in response to dairy sewage sludge and mineral fertilisers application under winter rape

Microbial activity and the diversity of their catabolic potential would be stratified according to soil profile as a result of differing content of soil organic C and they would be altered by applying dairy sewage sludge (DSS) to the surface and subsequently ploughing. We applied 26 Mg ha−1 of DSS and the same nutrient dose of mineral fertilisers as an NPK reference to the soil before sowing winter rape (Brassica napus) in the field experiment. We evaluated the impact of the fertilisers on microbial activity, measured with dehydrogenase and respiratory activity, and diversity of the microbes’ catabolic potential from non-rhizosphere and rhizosphere soil at selected depths. In the surface rhizosphere soil, there were significant increases in microbial catabolic potential (>25 %) and respiratory activity (>20 %) due to DSS application. All of the microbial parameter values in non-rhizosphere soil were higher at 0–20 than at 25–30 cm. These results are important for improving the management approach of diary sewage sludge application to agricultural soils in the context of increasing microbial activity in the soil profile and reducing mineral fertiliser use.

The effect of dairy sewage sludge amendment on repellency and hydraulic conductivity of soil aggregates from two depths of Eutric Cambisol

AbstractAppropriate management of sewage sludge is an important worldwide issue due to the still growing amount of wastewaters. In the study we examined to what extent the addition of dairy sewage sludge compared with mineral fertilization affects porosity, repellency index, and hydraulic conductivity of variously sized aggregates from two soil depths of Eutric Cambisol derived from loess: 5–15 cm and 25–35 cm. The repellency index was calculated as a ratio of ethanol and water sorptivity. Data on water and ethanol sorptivities of initially air‐dry soil aggregate fractions were obtained from steady state flow measurements using an infiltration device. Hydraulic conductivity was determined by measuring water infiltration at five pressure heads: –8, –6, –4, –2, and 0 cm of water column with the same device as for sorptivity determination. Addition of sewage sludge to the soil decreased the soil repellency index by an average of 27% in topsoil and 32% in subsoil for both aggregate sizes, respectively, and increased hydraulic conductivity about four times in both layers. Smaller aggregates (15–20 mm diameter) from soil amended with sewage sludge, in comparison with larger ones (30–35 mm diameter), had a higher repellency index by 36 and 24% in topsoil and subsoil, respectively. As for aggregates from soil with mineral fertilization, those differences were smaller and equal to 15% in subsoil, in topsoil smaller aggregates even had slightly lower repellency index (by 5%). Aggregates taken from the upper soil layer were more water repellent and had smaller hydraulic conductivity than those taken from subsoil, regardless of soil treatment and aggregate size.