Dairy Wastewater Research Articles

Comparison of Biohydrogen Production by Tetraselmis subcordiformis During Cultivation Using Soil-Less Agricultural Wastewater and Effluent from Microbial Fuel Cells

The development and implementation of innovative production technologies have a direct influence on the creation of new sources of pollution and types of waste. An example of this is the wastewater from soil-less agriculture and the effluent from microbial fuel cells. An important topic is the development and application of methods for their neutralisation that take into account the assumptions of global environmental policy. The aim of the present study was to determine the possibilities of utilising this type of pollution in the process of autotrophic cultivation of the biohydrogen-producing microalgae Tetraselmis subcordiformis. The highest biomass concentration of 3030 ± 183 mgVS/L and 67.9 ± 3.5 mg chl-a/L was observed when the culture medium was wastewater from soil-less agriculture. The growth rate in the logarithmic growth phase was 270 ± 16 mgVS/L-day and 5.95 ± 0.24 mg chl-a/L-day. In the same scenario, the highest total H2 production of 161 ± 8 mL was also achieved, with an observed H2 production rate of 4.67 ± 0.23 mL/h. Significantly lower effects in terms of biomass production of T. subcordiformis and H2 yield were observed when fermented dairy wastewater from the anode chamber of the microbial fuel cell was added to the culture medium.

Studies on Kinetics, Isothermal Modelling and Optimization of Cow Dung Adsorbent for Synthetic Dairy Wastewater Treatment

<p style="line-height:200%;text-align:justify;"><span style="line-height:200%;">The dairy industry is a major food industry that processes raw milk into a variety of products. The milk processing factory produces DWE with soluble organic components, suspended particles, and trace elements. These components degrade, causing cloudiness and odour. Adsorbing total solids (TS) and controlling odour levels in dairy wastewater help to minimize odour. This study investigates the process of producing activated carbon from cow dung (ACDC) and its use in cleaning synthetic dairy wastewater (SDW) by batch adsorption and column adsorption studies. Cow dung powder is chemically activated by soaking it in 1N ZnCl<sub>2</sub> and 1N KOH solutions in a 2:1 ratio. The optimal adsorbent concentration for both ACDC was 2.5 g/50 ml. The effectiveness of ACDC treatment was evaluated by its ability to reduce turbidity, TDS, and COD. The study found that activated carbon with ZnCl<sub>2</sub> was slightly more effective than activated carbon with KOH. While the KOH ACDC was more effective at a pH of 8, achieving a removal rate of 92.88%, the ZnCl<sub>2</sub> ACDC achieved a turbidity removal of 93.3% at a pH of 4. The present work highlights the potential for activated carbon derived from cow dung to effectively and sustainably treat dairy effluent.</span></p>

Preliminary Study on The Characteristics of Effluent From A Cachoeiro de Itapemirim – ES and Analysis of Possible Biotechnological Treatments

Purpose: The objective of this research was to organize and evaluate physical-chemical parameters of the industrial dairy effluent and to propose viable alternative treatments using biotechnological methods, aiming not only to prepare the effluent for disposal but also to generate value-added products Theoretical framework: With the growth of the population, the food industry sector expands exponentially. Brazil ranks among the top five milk producers globally, with the dairy industry being a significant producer of effluent, generating between 1.1 m³ and 6.8 m³ of effluent per cubic meter of processed milk. Dairy wastewater carries a high pollutant load and requires treatment prior to discharge into water bodies. There is an increasing demand for converting waste into raw materials, prompting research into biotechnological treatments that not only prepare effluent for disposal but also yield products from such waste. Method/design/approach: The data on wastewater characteristics were provided by the dairy itself, and the physicochemical aspects of the effluents over 19 months were interpreted, establishing relationships among key parameters, as well as the ratios BOD/COD, BOD: N and COD: N. The survey of biotechnological treatments was conducted through bibliographic research on Google Scholar, Scielo, Web of Science, and Scopus databases. Results and conclusion: Through the analysis and correlations of the physicochemical characteristics of effluents from the Cachoeiro dairy, it is evident that this type of effluent is rich in low biodegradability organic matter, as the BOD5/COD ratio was less than 0.15 in over 79% of the samples, indicating that physical-chemical treatment is the most appropriate approach for this effluent. The linear correlation coefficient between BOD5 and COD was 0.6, suggesting a weak correlation that does not allow one parameter to be accurately predicted from the other. According to the literature, it is possible to derive biofuels, bioplastics, single cell protein, organic acids, polysaccharides, biosurfactants, and other products from dairy effluent, while also meeting environmental requirements Research implications: Evaluation of optimal treatments based on effluent characteristics and suggestion of alternative treatments aiming to utilize wastewater as a raw material for obtaining secondary products complementary to the industry's focus, in addition to compliance with current disposal regulations. Originality/value: Development of relationships to assist in evaluating effluent treatments and identification of treatments that can reuse this substantial volume of generated waste.

Electrocoagulation-Electro-Fenton hybrid system for dairy wastewater treatment: A comprehensive test and analysis, in aqueous solution

This study aimed to assess the efficacy of a treatment system combining electrocoagulation (EC) and Electro-Fenton (EF) for the remediation of the wastewater dairy industry. Synthetic samples simulating dairy effluent were prepared and subjected to characterization for turbidity, chemistry oxygen demand (COD), and pH. The Box-Behnken design, comprising operating parameters such as electric current (0.5 to 1.5 A), electrolysis time (5 to 17.5 min), initial pH (4.0 to 9.0), and hydrogen peroxide concentration (0 to 9.0 g/L), with three replications at the central point. The combined treatment was conducted in a batch reactor using iron electrodes and subsequently filtered using a qualitative filter paper. Analysis revealed the significance of electric current, electrolysis time, and peroxide concentration at a 5 % probability level for COD reduction. A reduction of 80 % in chemical oxygen demand (COD) and a 99 % reduction in turbidity were achieved by maintaining the original pH of the wastewater and using a combination of an electric current greater than 1 A and an electrolysis time of 11.5 min, without the addition of hydrogen peroxide. The results showed that the treatment followed the standards of the Brazilian legislation.

Maximizing resource efficiency with dairy and municipal wastewater as nutrient media for Chlorella vulgaris with simultaneous CO2 sequestration

Addressing critical environmental challenges such as greenhouse gas emissions, global warming, and eutrophication demands urgent and innovative solutions. In recent years, microalgae have emerged as a promising avenue for addressing these pressing issues. In this study, the combination of dairy and municipal wastewater is proposed as a culture medium for cultivating microalgae strains capable of sequestering atmospheric CO2. Specifically, the growth of Chlorella vulgaris was investigated using Bold's basal medium, along with varying concentrations of municipal and dairy wastewater, both with and without CO2 supplementation, to assess their CO2 capture potential. Concurrently, the efficiency of chemical oxygen demand (COD), total nitrogen, potassium, and phosphate removal from the wastewater was evaluated. Additionally, the combination of wastewater media with CO2 supplementation yielded the highest CO2 uptake rates, indicating the feasibility of simultaneous CO2 capture during microalgae cultivation. Media composition with 25% municipal wastewater: 75% dairy wastewater supplemented with CO2 demonstrated superior COD elimination with a higher percentage of nutrient removal from wastewater compared to other wastewater proportions. The nutrient removal capacity of aforementioned media also comes in line with high CO2 sequestration rate (13.57 mg L−1 h−1). These findings underscore the potential of utilizing wastewater from diverse sources as a viable culture medium for microalgae cultivation, facilitating concurrent CO2 capture and wastewater treatment.

Multienzyme Immobilization on PVDF Membrane via One-Step Mussel-Inspired Method: Enhancing Fouling Resistance and Self-Cleaning Efficiency.

Immobilizing different enzymes on membranes can result in biocatalytic active membranes with a self-cleaning capacity toward a complex mixture of foulants. The membrane modification can reduce fouling and enhance filtration performance. Protease, lipase, and amylase were immobilized on poly(vinylidene fluoride) (PVDF) microfiltration membranes using a polydopamine coating in a one-step method. The concentrations of polydopamine precursor and enzymes were optimized during the immobilization. The higher hydrolytic activities were obtained using 0.2 mg/mL of dopamine hydrochloride and 4 mg/mL of enzymes: 0.90 mgstarch/min·cm2 for amylase, 10.16 nmoltyrosine/min·cm2 for protease, and 20.48 µmolp-nitrophenol/min·cm2 for lipase. Filtration tests using a protein, lipid, and carbohydrate mixture showed that the modified membrane retained 41%, 29%, and 28% of its initial water permeance (1808 ± 39 L/m2·h·bar) after three consecutive filtration cycles, respectively. In contrast, the pristine membrane (initial water permeance of 2016 ± 40 L/m2·h·bar) retained only 23%, 12%, and 8%. Filtrations of milk powder solution were also performed to simulate dairy industry wastewater: the modified membrane maintained 28%, 26%, and 26% of its initial water permeance after three consecutive filtration cycles, respectively, and the pristine membrane retained 34%, 21%, and 7%. The modified membrane showed increased fouling resistance against a mixture of foulants and presented a similar water permeance after three cycles of simulated dairy wastewater filtration. Membrane fouling is reduced by the immobilized enzymes through two mechanisms: increased membrane hydrophilicity (evidenced by the reduced water contact angle after modification) and the enzymatic hydrolysis of foulants as they accumulate on the membrane surface.

Optimization of two-stage thermophilic anaerobic digestion of dairy wastewater: Effect of carrier material on process performance and microbial community

Although two-stage anaerobic digestion (TSAD) is not a novel process, information of the process stability, microbial community and effective operating conditions is limited and often contradictory. In this work, the influence of different carrier materials (polyurethane foam, carbon felt, Raschig rings and a combination of carbon felt and Raschig rings) on the performance of the thermophilic TSAD of dairy wastewater was studied. The organic loading rate (OLR) in the acidogenic reactor (RH) was gradually increased from 13.74 to 32.56 g COD/(L d), and from 0.64 to 11.46 g COD/(L d) in the methanogenic reactors by correspondingly reducing the hydraulic retention time (HRT). The highest hydrogen production rate of 1280.3 mL/(L·d) and hydrogen yield of 93.2 mL/g COD were achieved at OLR of 13.74 g COD/(L·d), but hydrogen production stopped at higher OLR. The main soluble metabolites in RH were butyrate and lactate, and the microbial community was dominated by Streptococcus, Thermoanaerobacterium, Veillonellales-Selenomonadales and Pseudomonas. The highest methane production rate (2674 mL/(L·d) at HRT of 0.5 days) was observed in the reactor with polyurethane foam, while the highest methane yield (305.5 mL/g COD at HRT of 1.5 days) was obtained in a reactor containing carbon felt. Spirochaetaceae, Desulfomicrobium, Anaerolineaceae, Candidatus Caldatribacterium and Cloacimonadaceae W5 were linked to these materials and explained the highest methanogenic performance.

Enhancement of biomass production and some biochemical compound of Dunaliella salina cultivated in dairy wastewater by plant growth regulators

Enhancement of biomass production and some biochemical compound of Dunaliella salina cultivated in dairy wastewater by plant growth regulators

Coupling Biogas Upgradation and Dairy Wastewater Treatment for Simultaneous Carbon Capture and Bioelectricity Generation Using an Algae-Assisted Microbial Fuel Cell

Coupling Biogas Upgradation and Dairy Wastewater Treatment for Simultaneous Carbon Capture and Bioelectricity Generation Using an Algae-Assisted Microbial Fuel Cell

Enhancing methane yield and shifting microbial communities in anaerobic reactors treating lipid-rich dairy wastewater through exogenous lipase addition

This study explores a novel enzymatic pretreatment approach in anaerobic reactors for dairy wastewater, using lipase AY Amano to enhance methane production and modify microbial and archaeal community composition. Batch and semi-batch reactors with a total volume of 2000 mL were used to treat dairy wastewater with initial COD of 2000 and 15,000 mg L−1, respectively. In a new novel approach, the semi-batch reactors underwent a three-phase operation: 30 days of acclimation, 30 days of rest, and 30 days of active operation. Adding lipase (0.05% wv−1) as a pretreatment significantly increased methane yield over the 90 days by 135–138% compared with the control (without enzyme addition). The organic loading rate reached 0.22 g COD day−1 L−1. Furthermore, 30 days after the end of the semi-batch reactor approach (120 days from the start), reusing sludge in batch reactors increased methane yield by 114–122% compared to the control. This increase was linked to the emergence and shift of new methanogenic communities within the sludge. Integrating hydrolytic enzymes into the anaerobic treatment enhances performance and sustainability by fostering methanogen-enriched microbial communities. This is crucial for maximizing methane production but may increase costs, requiring further economic feasibility research.

Influence of earthworm population density on the performance of vermifiltration for treating liquid dairy manure.

The dairy industry has seen notable changes in the last couple of decades, including increased size of farms and regional concentrations of dairies. This has resulted in substantial manure production in small geographical areas, raising environmental concerns. Vermifiltration, an emerging low cost and eco-friendly technology for treating wastewater, was evaluated to assess the influence of earthworm population density on the performance of a laboratory-scale vermifilter treating liquid dairy manure. We monitored the reduction efficiencies of various components, including total nitrogen (TN), ammonium-nitrogen (NH4 +-N), nitrate-nitrogen (NO3 --N), total phosphorus (TP), orthophosphate (ortho-P), chemical oxygen demand (COD), total solids (TS), and total suspended solids (TSS), in treated dairy wastewater. This evaluation was conducted at 0; 5000; 10,000; and 15,000 earthworm densities per cubic meter (m-3) of bedding. Reduction efficiencies of 41%-89% (TN), 46%-86% (NH4 +-N), 34%-74% (NO3 --N), 3%-17% (TP), 18%-38% (ortho-P), 35%-66% (COD), 24%-54% (TS), and 50%-87% (TSS) were observed with higher earthworm densities exhibiting greater reduction efficiencies. Notably, the densities of Eisenia fetida at 10,000 and 15,000 earthworms m-3 showed no significant difference in vermifilter performance. This suggests that increasing the Eisenia fetida density beyond 10,000 earthworms m-3 may not further improve the vermifilter's performance in treating dairy wastewater. This study's findings indicate that using vermifiltration with an earthworm population density of 10,000 earthworms m-3 could effectively mitigate the negative environmental impact of liquid dairy wastewater at a low cost and sustainably.

Selection and characterization of a Parachlorella kessleri microalgal strain able to assimilate lactose, and grow on dairy waste

One of the main limitations of commercial production of algae is the cost of cultivation, largely attributed to the cost of the nutrients; hence, finding cheap alternative substrates has been a significant line of research in this field. The dairy industry produces large amounts of wastewater that might be used as a cost-effective nutrient alternative, containing lactose as a main carbon source, as well as other essential nutrients like nitrogen and phosphate. Nevertheless, just a few algal species of commercial value can grow on any organic carbon sources, and even less are able to utilize lactose. In this work we have identified a Parachlorella kessleri strain capable of utilizing lactose for growth, and have characterized its ability to accumulate metabolites of commercial interest under heterotrophic growth conditions. P. kessleri was capable to utilize lactose from dairy wastewater, and to accumulate several amino acids, dicarboxylic acids, such as tartaric acid and succinic acid, and triacylglycerols in heterotrophic conditions. These metabolites have applications in the food, feed, and pharmaceutical industries, and in the green chemical industry for the production of bio-based green polymers and biofuels. The significance of these findings for future product development is discussed.

Dairy wastewater treatment with direct-contact membrane distillation in Oman

Direct contact membrane distillation (DCMD) process was implemented for treating dairy wastewater (DWW) from an Omani dairy industry. Commercial polytetrafluoroethylene (PTFE) and polypropylene (PP) membranes were tested under different temperatures. The aim of this study in to investigate the potential of pure water production rejecting salts, volatile and non-volatile organic compounds present in DWW. Using laboratory techniques such as gas chromatography, we inspected permeate composition, identifying both volatile and non-volatile organic matter. Comprehensive characterization of membrane surface properties via Fourier-transform Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Thermal Gravimetric analysis (TGA) provided critical insights. Findings revealed the denaturation of proteins at 60 °C, leading to significant pore blockage and a consequential 50.3 % reduction in flux. Impressively, the membranes achieved rejection rates of 89–99 % for non-volatile organic matter, while completely rejecting D-limonene. However, traces of volatile fatty acids were detected in the permeate. Elemental analysis exposed the presence of various dairy-derived elements at the membrane surface. FTIR peaks highlighted distinct functional groups of dairy components, while TGA affirmed the accumulation of dairy aggregates with rising temperature. These findings underscore membrane distillation's competence in dairy wastewater treatment, presenting a compelling case for its widespread application in environmental remediation endeavors.

Comprehensive assessment of microalgal-based treatment processes for dairy wastewater.

The dairy industry is becoming one of the biggest sectors within the global food industry, and these industries use almost 34% of the water. The amount of water used is governed by the production process and the technologies employed in the plants. Consequently, the dairy industries generate almost 0.2-10L of wastewater per liter of processed milk, which must be treated before being discharged into water bodies. The cultivation of microalgae in a mixotrophic regime using dairy wastewater enhances biomass growth, productivity, and the accumulation of value-added product. The generated biomass can be converted into biofuels, thus limiting the dependence on petroleum-based crude oil. To fulfill the algal biorefinery model, it is important to utilize every waste stream in a cascade loop. Additionally, the harvested water generated from algal biomass production can be recycled for further microalgal growth. Economic and sustainable wastewater management, along with proper reclamation of nutrients from dairy wastewater, is a promising approach to mitigate the problem of water scarcity. A bibliometric study revealing limited work on dairy wastewater treatment using microalgae for biofuel production. And, limited work is reported on the pretreatment of dairy wastewater via physicochemical methods before microalgal-based treatment. There are still significant gaps remains in large-scale cultivation processes. It is also crucial to discover robust strains that are highly compatible with the specific concentration of contaminants, as this will lead to increased yields and productivity for the targeted bio-product. Finally, research on reutilization of culture media in photobioreactor is necessary to augument the productivity of the entire process. Therefore, the incorporation of the microalgal biorefinery with the wastewater treatment concept has great potential for promoting ecological sustainability.

Utilizing Mixed Cultures of Microalgae to Up-Cycle and Remove Nutrients from Dairy Wastewater.

This study explores the novel use of mixed cultures of microalgae-Spirulina platensis, Micractinium, and Chlorella-for nutrient removal from dairy wastewater (DW). Microalgae were isolated from a local wastewater treatment plant and cultivated under various light conditions. The results showed significant biomass production, with mixed cultures achieving the highest biomass (2.51 g/L), followed by Spirulina (1.98 g/L) and Chlorella (1.92 g/L). Supplementing DW (75%) with BG medium (25%) significantly enhanced biomass and pH levels, improving pathogenic bacteria removal. Spirulina and mixed cultures exhibited high nitrogen removal efficiencies of 92.56% and 93.34%, respectively, while Chlorella achieved 86.85% nitrogen and 83.45% phosphorus removal. Although growth rates were lower under phosphorus-limited conditions, the microalgae adapted well to real DW, which is essential for effective algal harvesting. Phosphorus removal efficiencies ranged from 69.56% to 86.67%, with mixed cultures achieving the highest removal. Microbial and coliform removal efficiencies reached 97.81%, with elevated pH levels contributing to significant reductions in fecal E. coli and coliform levels. These findings suggest that integrating microalgae cultivation into DW treatment systems can significantly enhance nutrient and pathogen removal, providing a sustainable solution for wastewater management.

Full-scale study on high-rate low-temperature anaerobic digestion of agro-food wastewater: process performances and microbial community.

The fast-growing global population has led to a substantial increase in food production, which generates large volumes of wastewater during the process. Despite most industrial wastewater being discharged at lower ambient temperatures (<20 °C), majority of the high-rate anaerobic reactors are operated at mesophilic temperatures (>30 °C). High-rate low-temperature anaerobic digestion (LtAD) has proven successful in treating industrial wastewater both at laboratory and pilot scales, boasting efficient organic removal and biogas production. In this study, we demonstrated the feasibility of two full-scale high-rate LtAD bioreactors treating meat processing and dairy wastewater, and the microbial communities in both reactors were examined. Both reactors exhibited rapid start-up, achieving considerable chemical oxygen demand (COD) removal efficiencies (total COD removal >80%) and generating high-quality biogas (CH4% in biogas >75%). Long-term operations (6-12 months) underscored the robustness of LtAD bioreactors even during winter periods (average temperature <12 °C), as evidenced by sustained high COD removal rates (total COD removal >80%). The stable performance was underpinned by a resilient microbial community comprising active acetoclastic methanogens, hydrolytic, and fermentative bacteria. These findings underscore the feasibility of high-rate low-temperature anaerobic wastewater treatment, offering promising solutions to the zero-emission wastewater treatment challenge.

Preparation of low‐cost peridotite ceramic microfiltration membrane for treating industrial wastewater

AbstractThe aim of this work is to fabricate a low‐cost ceramic microfiltration (MF) membrane made from a new geomaterial named peridotite. The membrane was prepared by uniaxial pressing and followed by sintering. The effect of sintering temperature, in the range of 1100–1225°C, on the permeability, porosity, mechanical strength, and pore size was investigated. The optimized MF membrane sintered at 1200°C exhibits 1198.9 L h−1 m−2 bar−1 of permeability, 36.41% of porosity, 12.9 MPa of mechanical strength, and 1.56 µm of pore size. The prepared membrane was used for the MF treatment of dairy wastewater. It was found that the membrane is able to remove 88.56% and 69.54% of turbidity and chemical oxygen demand, respectively. Furthermore, the cost of the peridotite membrane was estimated to be $10.3 m−2.

The impact of alternative recycled and synthetic phosphorus sources on plant growth and responses, soil interactions and sustainable agriculture - lettuce (Lactuca sativa) as a case model

This research assesses the efficacy of two phosphorus (P) adsorbents as alternative fertilizers in promoting lettuce growth. A synthetic Mg/Al-layered double hydroxide (LDH) and an iron-based recycled water treatment residual (Fe-WTR), both enriched with P from dairy wastewater and added at three dosage levels. We hypothesized that the adsorbents' physicochemical nature will overshadow the biological efforts in the plant ecosystem to increase P solubility, impacting plant growth, nutritional composition, and metabolite profiles.Fe-WTR significantly enhanced lettuce biomass compared to LDH. Yet, elemental analysis revealed higher or equal P concentrations in the low-biomass LDH plants relative to other treatments. Phosphorus uptake appears to influence the assimilation of other nutrients that divided into two groups: calcium, magnesium, zinc, and copper with notable correlations to P and nitrogen, iron, aluminum, vanadium and manganese with low correlations to P. Conversely, P retained poor correlation with most metabolites whereas iron showed a higher correlation with numerous metabolites. Analysis of metabolites, encompassing carbohydrates, the Krebs cycle, amino acids, nucleic acids, and stress and regulatory pathways, revealed diminished levels in the LDH treatments. Overall, carbon assimilation (plant growth) was more effectively predicted by soil P availability (adsorbent type and dose) rather than by cellular P concentration, suggesting root signaling was at play, influencing carbohydrate translocation to the roots. Diminished levels of cellular sugars further affect metabolic pathways and iron uptake, thus restricting photosynthesis. The results illustrate the substantial influence of the P source on the plant's metabolic processes and soil biogeochemistry. The synthetic LDH adsorbent with high sorption capacity, tightly binds its substantial P pool, rendering it inaccessible and potentially disrupting rhizosphere biogeochemical interactions. In contrast, the chemical nature of Fe-WTR enabled efficient nutrients acquisition bioactivity. The study highlights Fe-WTR as a promising sustainable alternative to conventional fertilizers, emphasizing its potential scalability and adaptability in agricultural contexts.

Microbial quality and macronutrient of vermicompost produced by Eisenia fetida in dairy wastewater solids

Abstract. Marlina ET, Hidayati YA, Harlia E, Badruzzaman DZ, Meynadhea N, Rahayu NA. 2024. Microbial quality and macronutrient of vermicompost produced by Eisenia fetida in dairy wastewater solids. Biodiversitas 25: 2729-2737. Dairy Wastewater Solids (DWS) contain enough nutrients for the growth of earthworms and utilize the nutritional requirements of livestock waste for growth. The growth of earthworms affects the quality of vermicompost or castings that are useful as organic fertilizers. This research aimed to determine the growth of Eisenia fertida using DWS as a growth medium, and its effect on the quality of vermicompost produced. The organic material decomposed in DWS by indigenous microorganisms and earthworms can convert DWS into organic fertilizer through composting. Rice straw was added as a carbon source to obtain the ideal C/N ratio for the growth of decomposing microorganisms. Good growth of decomposer microorganisms can increase the availability of nutrients in DWS as a source of plant nutrition. E. fetida was used in vermicomposting for 14 days after the initial decomposition phase had passed. This research used the experimental method of Completely Randomized Design (CRD) with three stocking density treatments (T1: 6.6 g/L; T2: 13.3 g/L; T3: 20.0 g/L ) and six replications. The results showed that higher stocking density promoted an increase in the biomass weight of earthworms. Various indigenous microorganisms act as decomposers and work with earthworms to convert organic matter into inorganic matter as a plant nutrient. The stocking density treatment had no significant effect on vermicompost production, total nitrogen content, and P2O5 vermicompost but had a significant effect on K2O, Ca, Mg, population of Nitrogen-Fixing Bacteria (NFB) and Phosphate-Solubilizing Bacteria (PSB). Vermicomposting, DWS, and rice straw mixture produced vermicompost with high functional microbial and macronutrient concentrations.

Remediation and management techniques for industrial dairy wastewater and sludge: a review

Remediation and management techniques for industrial dairy wastewater and sludge: a review