Alcohol and yeast production is the most important part of the biotechnological production in Yugoslavia, with annual production of 13 667 867 liters of absolute alcohol and of 20 947 490 kg of yeast in the year 1998. Large environmental load is produced by wastewaters from alcohol and yeast factories (512 000 P.E.), especially by alcohol stillage (BOD 40 000 - 50 000 mg/L). Anaerobic treatment is suitable process for treatment of alcohol stillage, and of yeast factory wastewater. In this paper, effects of treatment process (organic load reduction, energy of produced biogas) are discussed; and potential of anaerobic treatment os wastewaters from Yugoslavia's alcohol and yeast factories is reviewed.

To better promote environment friendly development of the coal chemical industry, this study investigated effects of methanol, sodium citrate, and chlorella powder (a type of microalgae) as co-metabolic substances on enhanced anaerobic treatment of coal pyrolysis wastewater with anaerobic sludge. The anaerobic sludge was loaded into four 2 L anaerobic reactors for co-metabolism enhanced anaerobic experiments. Anaerobic reactor 1 (R1) as control group did not add a co-metabolic substance; anaerobic reactor 2 (R2) added methanol; anaerobic reactor 3 (R3) added sodium citrate; and anaerobic reactor 4 (R4) added chlorella powder. In the blank control group, the removal ratios of total phenol (TPh), quinoline, and indole were only 12.07%, 42.15%, and 50.47%, respectively, indicating that 50 mg/L quinoline, 50 mg/L indole, and 600 mg/L TPh produced strong toxicity inhibition function on the anaerobic microorganism in reactor. When the concentration of methanol, sodium citrate, and chlorella was 400 μg/L, the reactors with co-metabolic substances had better treatment effect on TPh. Among them, the strengthening effects of sodium citrate (TPh removal ratio: 44.87%) and chlorella (47.85%) were better than that of methanol (38.72%) and the control group (10.62%). Additionally, the reactors with co-metabolic substances had higher degradation ratios on quinoline, indole, and chemical oxygen demand (COD). The data of extracellular polymeric substances showed that with the co-metabolic substances, anaerobic microorganisms produced more humic acids by degrading phenols and nitrogen-containing heterocyclic compounds (NHCs). Compared with the control group, the reactors added with sodium citrate and chlorella had larger average particle size of sludge. Thus, sodium citrate and chlorella could improve sludge sedimentation performance by increasing the sludge particle size. The bacterial community structures of reactors were explored and the results showed that Aminicenantes genera incertae sedis, Levinea, Geobacter, Smithella, Brachymonas, and Longilinea were the main functional bacteria in reactor added with chlorella.

This article presents a review of anaerobic treatment technologies to treat slaughterhouse wastewater including its advantages and disadvantages. Physico-chemical characteristics and biochemical methane potential (BMP) of slaughterhouse wastewater are addressed. Various anaerobic treatment technologies are presented with the related operating parameters, viz., hydraulic retention time (HRT), organic loading rate (OLR), upflow velocity (Vᵤₚ), and biogas yield vis-a-vis treatment efficiency in terms of chemical oxygen demand (COD). In addition, various factors that affect the anaerobic treatment of slaughterhouse wastewater such as high oil & grease (O & G) concentration in influent, inhibitors, volatile fatty acids (VFAs), and the loading rate are also addressed. The literature review indicated that the slaughterhouse wastewater can be treated effectively by employing any anaerobic treatment technologies at OLRs up to 5 kg COD/m³.d with more than 80% COD removal efficiency without experiencing operational problems. Anaerobic hybrid reactors (AHRs) were found the most effective among various reviewed technologies because of their ability to operate at higher OLRs (8 to 20 kg COD/m³.d) and lower HRTs (8 to 12 hrs).

Parametric data from anaerobic digestion processes are normally collected once every couple of days and not daily. As a result, only a small amount of data could be collected and this is not sufficient for the neural network analysis. In this research, interpolations were used during the modelling process to increase the sample data used for Elman neural network (Elman NN) modelling. Laboratory digestion of silage cornstalk was conducted for 54 days, and a portion of the biogas data was used for training the Elman neural network (Elman NN) model, while the remaining biogas data were used to verify the prediction capability of the model. Compared to the Elman NN model without interpolations, using an interpolation coefficient of 0.2 increased the number of experimental data from 54 to 266 and the correlation coefficient of prediction data and sampling data from 0.7966 (for no-interpolation) to 0.9962 (for cubic spline interpolation) and 0.9942 (for piecewise linear interpolation). In addition, the mean square error decreased from 0.1190 (for no interpolation) to 0.001 (for cubic spline interpolation) and 0.001 (for piecewise linear interpolation), while the average relative error decreased from 63.04% (for no interpolation) to 3.93% (for cubic spline interpolation) and 4.01% (for piecewise linear interpolation). The Elman NN simulation results thus showed that the interpolation algorithm can greatly improve the prediction accuracy of biogas production from an anaerobic digestion process.

Leachate recirculation is a leachate management technique and an option for faster stabilization of MSW. The objective of this research is to highlight the effects of leachate recirculation on waste stabilization in simulated bioreactor. The study was conducted in a laboratory in a cylindrical shaped bioreactor loaded with MSW waste maintained under controlled anaerobic condition. The leachate quality was regularly measured and operating parameters like pH, VFA, alkalinity, etc. were found in the optimum range of anaerobic degradation. The leachate recirculated bioreactor is an effective option for MSW management, as COD removal observed was 96% during the study period. These observations indicate that the leachate recirculation technique is a viable approach to treat landfill leachate and stabilize the MSW.

Petrochemical industrial effluent contains industrial wastewater from various manufacturing processes. The mixed treatment of these different petrochemical wastewater effluents may influence the organic removal performance of the anaerobic processes. In this study, three typical petrochemical effluents, including polyester (PE), polyethylene terephthalate, and purified terephthalic acid wastewater, were collected. The effect of the mixed petrochemical wastewater on the organic removal and microbial community structure was investigated in the anaerobic batch assays via spectroscopy and high-throughput sequencing. The organic removal efficiencies were similar (71–85%) in all the batch assays for 90 h acclimation. The mixture of wastewater, especially the addition of PE wastewater, significantly prolonged organic removal process. It was related to the aromatic removal performance and microbial community structure during the mixed wastewater treatment. The microbial community structure in the mixed wastewater batch assay showed high similarity with that in the PE wastewater batch assay. Ignavibacterium, Syntrophus, and Pelotomaculum were crucial to the degradation of aromatic compounds together with Methanosaeta. The mixture of wastewater, especially the addition of PE wastewater, caused the decay of these functional microbes and resulted in the inefficient removal of the aromatic compounds.

Dairy industry contributes to the pollution of the environment, both in quality and quantity. It generates about 0.2 to 10 L of effluent per liter of milk processed. Up-flow anaerobic sludge blanket is most suitable for biodegradable wastes, hence the present study evaluated the performance of UASBR through a laboratory model (25 liters of volume) for treating the dairy effluent with maintained psychrophilic temperature (15-20ºC) at phase I and mesophilic temperature (30-40ºC) at phase II. This model was studied for its treatment efficiency in terms of COD reduction. In the phase I, the average varying influent COD applied over the model are 1684, 2693, 3160, 3637, and 4059 mg/L with flow rates for each average influent COD as 4.80, 9.60, 14.40, 19.20 and 24.00 L/d. It was found that, successful COD removal of 91.42% was for the operating conditions of OLR at 0.039 kg COD/kg VSS day, VLR at 0.70 kg COD/m3 day and HRT at 5.21 days. In the phase II the average varying influent COD of 2316, 2827, 3329, 3908 and 4522 mg/L were applied with same flow rates. The experimental work on UASBR model was found successful with 94.70% COD removal under the operating conditions of OLR at 0.037 kg COD/kg VSS day, VLR at 0.630 kg COD/m3day and HRT at 5.21 days. The reactor achieved BOD, TSS, TDS, N and P removal efficiency, observed in phase I and II, as 91%, 82%, 89%, 42% and 46% and 96.4%, 86%, 91%, 41% and 50% respectively.

The disposal of food waste has attracted worldwide attention. Each year, the amount of wasted food accounts for an estimated one third of annual food production globally. This large amount of food waste has caused serious land, water, and air pollution. In the past, most research on food waste was focused solely on food waste disposal processing. Only a few studies analysed the flow of materials in food waste treatment processes. Therefore, this paper focused on the process of food waste anaerobic treatment in Beijing and investigated the treatment. According to a life cycle theory, the food waste treatment process is divided into three processes: “collection and transportation, disposal, and resource utilization.” This paper analysed the input and output of food waste treatment in different processes and evaluated the economic and environmental costs and benefits of food waste treatment. The study found that 200 t of food waste anaerobic treatment can obtain benefits 66,888 Chinese yuan, generate electricity energy 43,350 kW⋅h, and reduce carbon dioxide emissions 16,087 kg. Generally, the economic and environmental benefits of the food waste anaerobic treatment project are considerable. However, the economic benefits are mainly from government subsidies. There are many impurities in food waste, which indicates some problems in food waste treatment. Thus, the proposals to strengthen waste classification, optimize the layout of garbage collection and transportation, and accelerate the development of waste treatment plants have been put forward.

Veterinary antibiotics could enter the environment after the application of manure or farm wastewater on soil as fertilizer. In this study, a UPLC-MS/MS analytical method was developed and validated for the simultaneous determination of enrofloxacin (ENR) and ciprofloxacin (CIP) at environmental relevant concentrations in piggery wastewater, piggery wastewater solids, agricultural soil and ground water with good performance characteristics. The method recovery for ENR and CIP was 94.2 and 89.9% in the filtered piggery wastewater, 81.3 and 82% in the wastewater solid material, 78.1 and 76.8% in the soil and 95.6 and 97.3% in the ground water. The Limit of Detection (LOD) and Limit of Quantification (LOQ) for ENR were 21 and 64 ng L⁻¹ and for CIP was 18 and 54 ng L⁻¹, respectively. The method was implemented to monitor ENR and CIP in the wastewater of a piggery facility in Cyprus which applied anaerobic treatment before the final disposal of the reclaimed water. The highest antibiotic concentrations were measured in the wastewater samples collected from the nursery, where ENR is continuously used, with average concentration 31.4 μg L⁻¹ for ENR and 16.0 μg L⁻¹ for CIP. After the anaerobic digester, the two antibiotics were found only on the solid matter of the treated wastewater with an average concentration of 1.7 μg kg⁻¹ for ENR and 1.0 μg kg⁻¹ for CIP. The antibiotics adsorption at pH = 7 on clay soil, quartz sand and on solid matter isolated from the piggery wastewater was found to be higher than 95% for all solid materials. The concentration of the antibiotics in soil samples taken from a field where reclaimed piggery wastewater was applied for 10 years and in samples of groundwater from a nearby well was found for all samples below the LOD.

Lipase, a versatile hydrolytic enzyme, is gaining more importance in environmental applications such as treatment of oil and grease containing wastewater, pretreatment of solid waste/industrial wastewater for anaerobic treatment. In the present study, the attempts have been made to improve the production of lipase from Staphylococcus hominis MTCC 8980 by optimization of pH, temperature, and agitation speed in lab scale shake flasks culture. The experiments were designed using the full factorial central composite design of experiment. A total of 20 experiments were conducted, and the optimized pH, temperature, and agitation speed were found to be 7.9, 33.1 °C, and 178.4 rpm, respectively. The results of the analysis of variance (ANOVA) test revealed that the linear terms for temperature and agitation were significant (p value < 0.05). Interaction for pH and agitation speed was found to have a significant effect on lipase production from S. hominis MTCC 8980. A 150% increase in enzyme activity was observed under the optimized conditions with the maximum lipase activity of 1.82 U/ml. Further enhancement of enzyme activity can be expected from the optimization of medium components.