scholarly journals Struvite Precipitation for Sustainable Recovery of Nitrogen and Phosphorus from Anaerobic Digestion Effluents of Swine Manure

2020 ◽  
Vol 12 (20) ◽  
pp. 8574 ◽  
Author(s):  
Hong-Duck Ryu ◽  
Do Young Lim ◽  
Sun-Jung Kim ◽  
Un-Il Baek ◽  
Eu Gene Chung ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Biological Treatment ◽  
Swine Manure ◽  
Molar Ratio ◽  
Optimal Conditions ◽  
Nitrogen And Phosphorus ◽  
Treatment Facilities ◽  
Struvite Precipitation ◽  
Major Factors ◽  
Sustainable Recovery

In this study, we propose the application of struvite precipitation for the sustainable recovery of nitrogen (N) and phosphorus (P) from anaerobic digestion (AD) effluents derived from swine manure. The optimal conditions for four major factors that affect the recovery of N and P were derived by conducting batch experiments on AD effluents obtained from four AD facilities. The optimal conditions were a pH of 10.0, NH4-N:Mg:PO4-P molar ratio of 1:1.4:1, mixing intensity of 240 s−1, and mixing duration of 2 min. Under these optimal conditions, the removal efficiencies of NH4-N and PO4-P were approximately 74% and 83%, respectively, whereas those of Cu and Zn were approximately 74% and 79%, respectively. Herein, a model for swine manure treatment that incorporates AD, struvite precipitation, and biological treatment processes is proposed. We applied this model to 85 public biological treatment facilities in South Korea and recovered 4722 and 51 tons/yr of NH4-N and PO4-P, respectively. The economic analysis of the proposed model’s performance predicts a lack of profitability due to the high cost of chemicals; however, this analysis does not consider the resulting protection of the hydrological environment. Field-scale studies should be conducted in future to prove the effectiveness of the model.

The Effect of Organic Compounds on the Recovery of Ammonium by Struvite Precipitation from Swine Anaerobic Digester Effluent

2012 ◽  
Vol 610-613 ◽  
pp. 2350-2355 ◽  
Author(s):  
Ji Dan Liu ◽  
Zu Xin Xu ◽  
Wei Gang Wang ◽  
Wei Jin
Keyword(s):  
Organic Compounds ◽  
Swine Manure ◽  
Swine Wastewater ◽  
Molar Ratio ◽  
Nitrogen And Phosphorus ◽  
Anaerobic Digester Effluent ◽  
Potassium Hydrogen ◽  
External Sources ◽  
Struvite Precipitation ◽  
Co Precipitation

Recovering nitrogen and phosphorus through struvite crystallization from swine wastewater has gained increasing interest. However, effluents of anaerobic digested swine wastewater contains other constituents including complex and hardly definited organic compounds, which may hinder the formation of struvite crystal and affect the purity of the precipitates by forming other insoluble minerals. Struvite precipitation was carried out at laboratory scale by adding magnesium chloride and potassium hydrogen as external sources of magnesium and phosphorus to equal Mg: N: P molar ratio, respectively, and regulating the pH at 9.5 in the absence and presence of organic compounds. Exceeded 70% phosphate and ammonium reduction were obtained. The recovered products were detected and analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and chemical methods, which were proved to be struvite crystals. The soluble organic compounds had less than 6% changes in amount during struvite precipitation and it was proved that the removal of TCOD during the precipitation of struvite may be attributed to the co-precipitation of struvite. The results indicate that struvite precipitation could be a viable method of ammonium removal in the presence of organic compounds from anaerobically digested swine manure.

Improving nutrient fixation and dry matter content of an ammonium-rich anaerobic digestion effluent by struvite formation and clay adsorption

2014 ◽  
Vol 70 (2) ◽  
pp. 337-344 ◽  
Author(s):  
Maria M. Estevez ◽  
Roar Linjordet ◽  
Svein J. Horn ◽  
John Morken
Keyword(s):  
Anaerobic Digestion ◽  
Dry Matter ◽  
Liquid Fraction ◽  
Oxygen Demand ◽  
Matter Content ◽  
Molar Ratio ◽  
Dry Matter Content ◽  
Soluble Chemical Oxygen Demand ◽  
Struvite Precipitation ◽  
Clay Materials

The anaerobic digestion (AD) of organic wastes that contain nitrogen leads to its mineralization, yielding a digestate rich in ammonium (NH4+), an important fertilizing nutrient. The applicability of AD digestate as fertilizer can be improved by fixating the nutrients and increasing its dry matter content. Methods for the fixation and recovery of the digestate's NH4+ and possible also PO43− include struvite precipitation and adsorption in clay materials such as bentonite. These techniques were tested in batch experiments employing the liquid fraction of a digestate originating from the AD of a substrate mix containing lignocellulose, cattle manure and fish industrial waste. The concentration of NH4+-N in this digestate was 2,300 mg L−1. Struvite precipitation conditions at a molar ratio of 1.2:1:1 (Mg2+:NH4+:PO43−) and pH 9.5 were best in terms of simultaneous removal of NH4+-N (88%), PO43− (60%) and soluble chemical oxygen demand (44%). Bentonite adsorption gave comparably high removal levels for NH4+-N (82%) and PO43− (52%). Analysis of the precipitates' morphology and elemental composition confirmed their struvite and bentonite nature. Dry matter content was increased from 5.8% in the AD digestate to 27% and 22% in the struvite and bentonite sludges, respectively.

Effect of Dissolved Ca2+ and Mg2+ in Excess Sludge on Phosphorus and Nitrogen Recovery under Acidic-Base Condition

2013 ◽  
Vol 726-731 ◽  
pp. 2670-2676
Author(s):  
Hong Ying Yuan ◽  
Ting Wang ◽  
Yi Chen ◽  
Li Qi ◽  
Si Fang Niu
Keyword(s):  
Phosphorus Recovery ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Excess Sludge ◽  
Acid Base ◽  
Nitrogen And Phosphorus ◽  
Percent Recovery ◽  
Rich Solution ◽  
Struvite Precipitation ◽  
The Impact

Calcium(Ca2+) and magnesium(Mg2+) ions dissolve out in the process of getting phosphorus-rich solution by hydrolysis and acidification of sludge. To study the effect of dissolved Ca2+ and Mg2+ on nitrogen and phosphorus recovery, this paper investigated the dissolution of NH4+, PO43-, Ca2+ and Mg2+ in the process of hydrolysis and acidification of excess sludge under the condition of different pH and discussed the impact of Ca2+ and Mg2+ ions on the recovery of nitrogen and phosphorus by struvite precipitation method. The result indicates that the adjusting of acid-base environment can contribute to the release of NH4+-N and PO43--P in the process of hydrolysis and acidification and pH=3 is the best and the best reaction time is 5 days. The fact that the molar ratio Ca2+: Mg2+ is greater than 1 has influence on nitrogen and phosphorus recovery but whether additional magnesium existed or not has little effect on the percent recovery of nitrogen and phosphorus when pH=3.

Aerobic biological treatment of thermophilically digested sludge

2011 ◽  
Vol 63 (10) ◽  
pp. 2340-2345 ◽  
Author(s):  
M. V. Kevbrina ◽  
Y. A. Nikolaev ◽  
D. A. Danilovich ◽  
A. Ya. Vanyushina
Keyword(s):  
Retention Time ◽  
Biological Treatment ◽  
Hydraulic Retention Time ◽  
Treatment Plant ◽  
Ammonium Nitrogen ◽  
Wastewater Sludge ◽  
Optimal Conditions ◽  
Nitrogen And Phosphorus ◽  
Digested Sludge ◽  
Sludge Treatment

Aerobic biological treatment of digested sludge was studied in a continuously operated laboratory set-up. An aerated reactor was filled with thermophilically digested sludge from the Moscow wastewater treatment plant and inoculated with special activated sludge. It was then operated at the chemostat mode at different flow rates. Processes of nitrification and denitrification, as well as dephosphatation, occurred simultaneously during biological aerobic treatment of thermophilically digested sludge. Under optimal conditions, organic matter degradation was 9.6%, the concentrations of ammonium nitrogen and phosphate decreased by 89 and 83%, respectively, while COD decreased by 12%. Dewaterability of digested sludge improved significantly. The processes were found to depend on hydraulic retention time, oxygen regime, and temperature. The optimal conditions were as follows: hydraulic retention time 3–4 days, temperature 30–35 °C, dissolved oxygen levels 0.2–0.5 mg/L at continuous aeration or 0.7–1 mg/L at intermittent aeration. Based on these findings, we propose a new combined technology of wastewater sludge treatment. The technology combines two stages: anaerobic digestion followed by aerobic biological treatment of digested sludge. The proposed technology makes it possible to degrade the sludge with conversion of ∼45% volatile suspended solids to biogas, to improve nitrogen and phosphorus removal in reject water from sludge treatment units, and to achieve removal of malodorous substances after 8–9 days of anaerobic–aerobic sludge treatment.

scholarly journals Effectiveness of struvite precipitation and ammonia stripping for recovery of phosphorus and nitrogen from anaerobic digestate: a systematic review

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Dag Lorick ◽  
Biljana Macura ◽  
Marcus Ahlström ◽  
Anders Grimvall ◽  
Robin Harder
Keyword(s):  
Anaerobic Digestion ◽  
Grey Literature ◽  
Evidence Base ◽  
Bibliographic Databases ◽  
Nutrient Recovery ◽  
Nitrogen And Phosphorus ◽  
Ammonia Stripping ◽  
Anaerobic Digestate ◽  
Struvite Precipitation ◽  
The Impact

Abstract Background A regular supply of nutrients such as nitrogen and phosphorus to agriculture is needed for global food security, and increased recycling of nutrients back to agriculture from organic waste streams is necessary for increased rural–urban sustainability. Anaerobic digestion of sewage sludge and agricultural wastes is widely applied to stabilize the substrate and capture some of its energetic value via biogas production. Anaerobic digestate is a concentrated source of nutrients to which nutrient recovery technologies can be applied. By combining anaerobic digestion and nutrient recovery technologies on the digestate, both energy and nutrient recovery can be achieved. Two promising technologies that could increase nutrient recycling from different types of wastewater are struvite precipitation and ammonia stripping. This review examined the effectiveness of these ecotechnologies for the recovery of nitrogen and phosphorus from anaerobic digestate with the aim of reducing the impact of waste on the environment. Methods We searched for academic and grey literature published after 2013. Searches were performed in 5 bibliographic databases in English, in the search engine Google Scholar in English, Swedish, Finnish and Polish, and across a range of organisational websites in English, Swedish, Finnish and Polish. Eligibility screening was conducted at two levels: ‘title and abstract’ and ‘full text’. Included eligible studies were subject to a critical appraisal that assessed external and internal study validity. We extracted information on study characteristics, intervention, comparators, effect modifiers, and measured outcomes. Data synthesis included narrative synthesis of each study of sufficient validity. We performed quantitative synthesis on a subset of studies. Review findings The review included 30 studies on struvite precipitation and 8 studies on ammonia stripping. Both pH and Mg:PO4 ratio were found to have a clear influence on the effectiveness of struvite precipitation process (and thus nutrient removal rates). The response to pH was found to be non-linear, resembling a bell curve with a maximum around pH 9.5. Mg:PO4 ratio was found to have a positive effect on removal up to a ratio as high as 4:1. However, it should be noted that high removal efficiencies were sometimes achieved at a ratio as low as 1:1 as well. Although the effects of pH and Mg:PO4 ratio were clear, the model developed could not accurately predict removal based on these two parameters alone. Studies on ammonia stripping were relatively heterogeneous. Due to the small size of the evidence base, and the heterogeneity between studies, no conclusions are presented regarding the influence of different process parameters on the outcome of ammonia stripping. Conclusions In conclusion, when performed under the right conditions (i.e. pH around 9.5 and Mg:PO4 ratio of at least 1:1), available evidence suggests that struvite precipitation is an effective technology for the recovery of nutrients from the liquid phase of anaerobic digestate. The evidence base is limited for ammonia stripping. We provided suggestions of which data to report in future studies.

Solid state anaerobic digestion as a possible solution for managing existing mechanical biological treatment plants in a more efficient way: a real case analysis

2012 ◽  
pp. 37-50
Author(s):  
Francesco Di Maria
Keyword(s):  
Anaerobic Digestion ◽  
Solid State ◽  
Biological Treatment ◽  
Treatment Plant ◽  
Electric Energy ◽  
Real Case ◽  
Organic Load ◽  
Organic Fraction ◽  
Load Rate ◽  
Treatment Facilities

The exploitation of Mechanical Biological Treatment is quite diffused for treating fractions of Non-Differentiated Waste. A large part of the Italian Mechanical Biological Treatment facilities operate mainly by reducing and stabilizing the Non-Differentiated Waste mass before landfilling. This way of managing Mechanical Biological Treatment can be improved by the adopting a new treatment section, based on the Solid State Anaerobic Digestion process. In this way, the Waste Organic Fraction arising from the mechanical sorting of the Non-Differentiated Waste can be treated before the aerobic stabilization section of the existing Mechanical Biological Treatment. In Italy more than 40% of the working Mechanical Biological Treatment facilities have features suitable for being upgraded with a new Solid State Anaerobic Digestion section. In these plants the amount of the rapidly biodegradable fraction is about 1,100,000 tonnes per year, leading to the production of about 300 GWh of renewable energy. The results concerning a real case study show that, with the adoption of a new Solid State Anaerobic Digestion section, about 150 kWh of electric energy would be able to be produced per each tonne of Waste Organic Fraction. Furthermore, there would be a significant reduction in the Organic Load Rate [kgVS/m3*day] for the existing aerobic section of the plant, leading to additional savings of 160-320 kWh per day, depending on the amount of Waste Organic Fraction diverted from the Solid State Anaerobic Digestion. Results from the economic analysis show that the Solid State Anaerobic Digestion treatment cost ranges from about 6 up to 23 € per each tonne of Non-Differentiated Waste entering the existing Mechanical Biological Treatment plant.

scholarly journals Improving the Anaerobic Digestion of Swine Manure through an Optimized Ammonia Treatment: Process Performance, Digestate and Techno-Economic Aspects

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 787
Author(s):  
Anna Lymperatou ◽  
Niels B. Rasmussen ◽  
Hariklia N. Gavala ◽  
Ioannis V. Skiadas
Keyword(s):  
Anaerobic Digestion ◽  
Large Scale ◽  
Treatment Process ◽  
Aqueous Ammonia ◽  
Swine Manure ◽  
Batch Experiments ◽  
Ammonia Treatment ◽  
Aqueous Ammonia Soaking ◽  
High Ammonia ◽  
Reduction Efficiency

Swine manure mono-digestion results in relatively low methane productivity due to the low degradation rate of its solid fraction (manure fibers), and due to the high ammonia and water content. The aqueous ammonia soaking (AAS) pretreatment of manure fibers has been proposed for overcoming these limitations. In this study, continuous anaerobic digestion (AD) of manure mixed with optimally AAS-treated manure fibers was compared to the AD of manure mixed with untreated manure fibers. Due to lab-scale pumping restrictions, the ratio of AAS-optimally treated manure fibers to manure was only 1/3 on a total solids (TS) basis. However, the biogas productivity and methane yield were improved by 17% and 38%, respectively, also confirming the predictions from a simplified 1st order hydrolysis model based on batch experiments. Furthermore, an improved reduction efficiency of major organic components was observed for the digester processing AAS-treated manure fibers compared to the non-treated one (e.g., 42% increased reduction for cellulose fraction). A preliminary techno-economic analysis of the proposed process showed that mixing raw manure with AAS manure fibers in large-scale digesters could result in a 72% increase of revenue compared to the AD of manure mixed with untreated fibers and 135% increase compared to that of solely manure.

scholarly journals Two-Stage Biodiesel Synthesis from Used Cooking Oil with a High Acid Value via an Ultrasound-Assisted Method

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3703
Author(s):  
Ming-Chien Hsiao ◽  
Wei-Ting Lin ◽  
Wei-Cheng Chiu ◽  
Shuhn-Shyurng Hou
Keyword(s):  
Acid Value ◽  
Molar Ratio ◽  
Optimal Conditions ◽  
Two Stage ◽  
Cooking Oil ◽  
High Acid ◽  
Used Cooking Oil ◽  
Biodiesel Synthesis ◽  
Stage Process ◽  
Ultrasound Assisted

In this study, ultrasound was used to accelerate two-stage (esterification–transesterification) catalytic synthesis of biodiesel from used cooking oil, which originally had a high acid value (4.35 mg KOH/g). In the first stage, acid-catalyzed esterification reaction conditions were developed with a 9:1 methanol/oil molar ratio, sulfuric acid dosage at 2 wt %, and a reaction temperature of 60 °C. Under ultrasound irradiation for 40 min, the acid value was effectively decreased from 4.35 to 1.67 mg KOH/g, which was decreased to a sufficient level (<2 mg KOH/g) to avoid the saponification problem for the subsequent transesterification reaction. In the following stage, base-catalyzed transesterification reactions were carried out with a 12:1 methanol/oil molar ratio, a sodium hydroxide dosage of 1 wt %, and a reaction temperature of 65 °C. Under ultrasound-assisted transesterification for 40 min, the conversion rate of biodiesel reached 97.05%, which met the requirement of EN 14214 standard, i.e., 96.5% minimum. In order to evaluate and explore the improvement of the ultrasound-assisted two-stage (esterification–transesterification) process in shortening the reaction time, additional two-stage biodiesel synthesis experiments using the traditional mechanical stirring method under the optimal conditions were further carried out in this study. It was found that, under the same optimal conditions, using the ultrasound-assisted two-stage process, the total reaction time was significantly reduced to only 80 min, which was much shorter than the total time required by the conventional method of 140 min. It is worth noting that compared with the traditional method without ultrasound, the intensification of the ultrasound-assisted two-stage process significantly shortened the total time from 140 min to 80 min, which is a reduction of 42.9%. It was concluded that the ultrasound-assisted two-stage (esterification–transesterification) catalytic process is an effective and time-saving method for synthesizing biodiesel from used cooking oil with a high acid value.

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