scholarly journals Influence of pH and Temperature on Struvite Purity and Recovery from Anaerobic Digestate

2021 ◽  
Vol 13 (19) ◽  
pp. 10730
Author(s):  
Carolina González-Morales ◽  
Belén Fernández ◽  
Francisco Molina ◽  
Darío Naranjo-Fernández ◽  
Adriana Matamoros-Veloza ◽  
...  
Keyword(s):  
Saturation Index ◽  
Anaerobic Sludge ◽  
Batch Reactors ◽  
Sludge Dewatering ◽  
Optimum Ph ◽  
Struvite Precipitation ◽  
Co Precipitation ◽  
Influence Of Ph ◽  
P Removal

The precipitation of struvite (MgNH4PO4.6H2O) from wastewater streams simultaneosuly recovers nitrogen (N) and phosphorus (P) for reuse as fertilisers. Struvite crystallisation is controlled by pH, saturation index, temperature and other ions in the solution (e.g., Ca2+, Mg2+ and CO32−). This work studies the effect of pH and temperature on phosphorus and nitrogen removal via struvite precipitation and the quality of the resulting precipitate product (i.e., crystal size, morphology and purity). Struvite was precipitated in batch reactors from the supernatant produced during anaerobic sludge dewatering at a wastewater treatment works, under controlled pH (8, 9 and 10) and temperature (25, 33 and 40 °C) conditions. The optimal P removal as struvite, reduction of the co-precipitation with Ca and the increase in particle size of the struvite precipitates were determined. The results showed that temperatures of 33 °C and 40 °C are not recommended for struvite precipitation—i.e., at 33 °C the purity is lower, and at 40 °C the ammonia losses are induced by volatilisation. At all pH-tests, the P removal efficiency was >93%, but the highest phosphate content and purity as struvite were obtained at a pH of 9.0. The optimum pH and temperature for the formation of large crystals (84 µm) and a high purity (>70%) of the struvite precipitates were 9 and 25 °C, respectively.

Struvite precipitation in raw and co-digested swine slurries for nutrients recovery in batch reactors

2015 ◽  
Vol 71 (6) ◽  
pp. 892-897 ◽  
Author(s):  
Raffaele Taddeo ◽  
Raghida Lepistö
Keyword(s):  
Environmental Concern ◽  
Calcium Phosphates ◽  
Industrial Effluents ◽  
Organic Content ◽  
Batch Reactors ◽  
Ph Values ◽  
Batch Tests ◽  
Struvite Precipitation ◽  
Excessive Nutrients ◽  
Co Precipitation

The release of nitrogen (N) and phosphorus (P) from agro-industrial sources is a major environmental concern. Furthermore, the scarcity of mineable P and the growing demand for food worldwide necessitate that we find an alternative P source. This study applied struvite precipitation for N-P recovery to slurries with high levels of organics and ammonia to achieve environmental protection from excessive nutrients diffusion and to generate a sustainable P source. Batch tests were carried out on raw and co-digested swine slurries to study the feasibility of struvite precipitation and the effect of several parameters, including pH, reaction time, competing ions (Ca2+, K+), total solids (TS), and alkalinity. The batch assays with raw swine slurries showed high N-P removals (up to 80%), while the anaerobic liquor returned lower recovery efficiency due to the high solids and alkali content. Struvite crystallization was detected at pH values as low as 6, and the characteristics of the recovered struvite matched those of the theoretical. Slight co-precipitation of calcium–phosphates occurred and was dependent on the Ca2+/Mg2+ ratio rather than on varying pH values. Struvite precipitation was shown to be feasible in complex matrices as agro-industrial effluents, characterized by high NH4+, alkalinity, solids and organic content, and interfering ions such as Ca2+ and K+.

The joint acute effect of tetracycline, erythromycin and sulfamethoxazole on acetoclastic methanogens

2015 ◽  
Vol 71 (8) ◽  
pp. 1128-1135 ◽  
Author(s):  
Sevcan Aydın ◽  
Bahar Ince ◽  
Orhan Ince
Keyword(s):  
Mrna Level ◽  
Acute Effect ◽  
Anaerobic Treatment ◽  
Anaerobic Sludge ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Acetyl Coa ◽  
Acetate Accumulation ◽  
Acetate Degradation ◽  
Industry Wastewater

In this study, we aimed to develop an understanding of the triple effects of sulfamethoxazole–erythromycin–tetracycline (ETS) and the dual effects of sulfamethoxazole–tetracycline (ST), erythromycin–sulfamethoxazole (ES) and erythromycin–tetracycline (ET) on the anaerobic treatment of pharmaceutical industry wastewater throughout a year of operation. Concentrations of the antibiotics in the influent were gradually increased until the metabolic collapse of the anaerobic sequencing batch reactors (SBRs), which corresponded to ETS (40 + 3 + 3 mg/L) and ST (25 + 2.5 mg/L), ET (4 + 4 mg/L) and ES (3 + 40 mg/L). Acetate accumulation in the anaerobic SBRs, acetoclastic activity of the anaerobic sludge taken from different antibiotic feeding stages and also expression of acetyl-coA synthetase from the acetoclastic methanogenic pathway on the mRNA level were assessed. The results indicated that, while acetate accumulation and decrease of acetoclastic activity were observed after stage 3 in the ST and ES reactors, and stage 7 in the ETS and ET reactors, the expression of acetyl-coA synthetase was mostly decreased in the last stages in all SBRs, in which antibiotic mixture feeding was terminated. It might be speculated that acetoclastic methanogens have an important role in acetate degradation by expressing acetyl-coA synthetase.

scholarly journals Bioenergy recovery from cattle wastewater in an UASB-AF hybrid reactor

2017 ◽  
Vol 76 (9) ◽  
pp. 2268-2279 ◽  
Author(s):  
Henrique Vieira de Mendonça ◽  
Jean Pierre Henry Balbaud Ometto ◽  
Marcelo Henrique Otenio ◽  
Alberto José Delgado dos Reis ◽  
Isabel Paula Ramos Marques
Keyword(s):  
Biogas Production ◽  
Upflow Anaerobic Sludge Blanket ◽  
Hybrid Reactor ◽  
Anaerobic Sludge ◽  
The Novel ◽  
Organic Loading ◽  
Loading Rates ◽  
Volatile Solids ◽  
Anaerobic Sludge Blanket

Abstract New data on biogas production and treatment of cattle wastewater were registered using an upflow anaerobic sludge blanket-anaerobic filter (UASB-AF) hybrid reactor under mesophilic temperature conditions (37 °C). The reactor was operated in semi-continuous mode with hydraulic retention times of 6, 5, 3 and 2 days and organic loading rates of 3.8, 4.6, 7.0 and 10.8 kg CODt m−3 d−1. Biogas volumes of 0.6–0.8 m3 m−3 d−1 (3.8–4.6 kg CODt m−3 d−1) and 1.2–1.4 m3 m−3 d−1 (7.0–10.8 kg CODt m−3 d−1), with methane concentrations between 69 and 75%, were attained. The removal of organic matter with values of 60–81% (CODt) and 51–75% (CODs) allowed methane yields of 0.155–0.183 m3 CH4 kg−1 CODt and 0.401–0.513 m3 CH4 kg−1 CODs to be obtained. Volatile solids were removed in 34 to 69%, with corresponding methane yields of 0.27 to 0.42 m3 CH4 kg−1 VSremoved. The good performance of the novel hybrid reactor was demonstrated by biogas outputs higher than reported previously in the literature, along with the quality of the gas obtained in the various experimental phases. The hybrid reactor investigated in this study presents comparative advantages, particularly in relation to conventional complete mixture units, considering economic factors such as energy consumption, reactor volume and installation area.

scholarly journals Treatment of industrial used water by UASB+CMBR process to produce industrial grade water for reuse

2018 ◽  
Vol 13 (2) ◽  
pp. 424-430 ◽  
Author(s):  
H. Noguchi ◽  
T. Niwa ◽  
Y. Nakamura ◽  
J. K. Agrawal ◽  
W. S. Ang ◽  
...  
Keyword(s):  
Ceramic Membrane ◽  
Operating Conditions ◽  
Anaerobic Sludge ◽  
Stable Operation ◽  
High Quality ◽  
Joint Project ◽  
Industrial Grade ◽  
One Year ◽  
Anaerobic Sludge Blanket

Abstract Joint project has been conducted in a demonstration plant with 1-MGD capacity at Jurong Water Reclamation Plant to produce high quality effluent through a combined process of up-flow anaerobic sludge blanket reactor and ceramic membrane bioreactor (UASB-CMBR). Water quality of the product and energy consumption met target which were evaluated after one-year operation. The joint project has further been conducted to optimize operating conditions including cleaning procedure. Recovery cleaning (RC) of the ceramic membrane was carried out after 18 months operation and permeability was recovered to be initial value. Stable filtration at 25 LMH was achieved after the RC. RO filtration test was also carried out to treat effluent from the UASB-CMBR. Stable operation in the RO system was achieved with flux of 15 LMH and recovery of 60%. Quality of RO permeates met criteria for industrial water. It is concluded that UASB-CMBR process with RO system can produce high quality water for reuse from industrial used water.

ÉTUDE DE LA RÉACTION DE L'ADRÉNALINE AVEC L'ÉTHYLÈNEDIAMINE

1959 ◽  
Vol 37 (1) ◽  
pp. 231-244
Author(s):  
Guy Nadeau ◽  
Louis-Philippe Joly
Keyword(s):  
Hydrochloric Acid ◽  
Complex Formation ◽  
Beneficial Effect ◽  
Ultraviolet Light ◽  
Room Temperature ◽  
Aliphatic Alcohols ◽  
Fluorescent Material ◽  
Optimum Ph ◽  
Formation Efficiency ◽  
Influence Of Ph

The influence of pH, reagent composition, time, temperature, light, and various ions, on the reaction of fluorescence between adrenaline and ethylenediamine, has been investigated. The necessity of a preliminary oxidation to adrenochrome is confirmed. Optimum pH of reaction is situated at 10.4 ± 0.1, while extraction with isobutanol is best performed at pH 10.1 ± 0.1. A satisfactory reagent is one that contains 114.5 millimoles of ethylenediamine base per 100 ml of reacting mixture and sufficient hydrochloric acid to bring the pH to 10.3 ± 0.1. Temperature and length of reaction may be conveniently set at 50 °C and 20 to 30 minutes. Increasing the temperature significantly lowers the yield of fluorescent material; performing the reaction at room temperature increases the yield, but lengthens the procedure. Exposure to diffuse and ultraviolet light also affects the yield of fluorescence. All these factors (temperature, light, as well as excess of oxygen) appear to exert their influence in the first stages of the reaction, since the fluorescent material, once formed, is relatively stable. The beneficial effect of various ions, including Cu++, Al+++, and MoO4−−, is discussed in relation to complex formation. Efficiency of extraction with aliphatic alcohols has also been investigated; true yield from C14-adrenaline is estimated. In the light of recent findings on the structure of adrenochrome, new pathways for the reaction are suggested.

The performance of batch stabilization reservoirs for wastewater treatment, storage and reuse in Israel

1996 ◽  
Vol 33 (10-11) ◽  
pp. 149-159 ◽  
Author(s):  
Marcelo Juanico
Keyword(s):  
Wastewater Treatment ◽  
Controlled Release ◽  
Treated Wastewater ◽  
Batch Reactors ◽  
Batch Mode ◽  
Removal Of Heavy Metals ◽  
In Series ◽  
Order Of Magnitude ◽  
Real Scale

Stabilization reservoirs receive partially treated wastewater effluents for storage and controlled release. They are used in Israel for two purposes: a) to upgrade the quality of the effluents during the long residence time within the reservoirs and, b) to store the effluents during the rainy winter in order to perform agricultural irrigation during the dry summer. The improvement obtained in the quality of the effluents (i.e., the treatment capacity of the reservoirs) depends on the operational regime of the reservoirs as reactors: continuous flow, in series, batch, etc. The performance of the reservoirs as batch reactors for wastewater treatment is herein analyzed based on outdoor experiments carried out in real scale reservoirs with different hydraulic and organic loadings. The results of the experiments are compared with forecasts obtained through statistical and kinetic models. Stabilization reservoirs working in batch mode, when properly designed and operated, are able to remove COD, BOD, TSS and detergents by up to one order of magnitude, and Faecal coliforms by up to five orders of magnitude (before chlorination). A significant removal of heavy metals, bacteriophages and other pollutants is also obtained. The quality of the effluents released from the reservoirs, added to the capability for controlled release, permits both wide crop rotation and easy management of irrigation.

EFFECT OF PROCESSING AND STORAGE ON THE QUALITY OF GELOSE FROM IRISH MOSS (CHONDRUS CRISPUS)

1948 ◽  
Vol 26f (3) ◽  
pp. 160-167
Author(s):  
D. MacDougall
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
East Coast ◽  
Storage Temperature ◽  
Chondrus Crispus ◽  
Irish Moss ◽  
Optimum Ph ◽  
Processing And Storage ◽  
And Storage

Irish moss (Chondrus crispus) from Canada's east coast was used to study possible improvements in the production and storage of gelose. The optimum pH for the extraction of gelose from Irish moss was between 6 and 7. Fine leaf particles, which prevent rapid filtration, were readily removed by supercentrifuging. Comparison of drum drying and drying from the frozen state showed that the former caused a marked lowering of viscosity but had little effect on suspending power or jelly strength. The logarithm of the viscosity determined by means of a MacMichael viscosimeter was related directly to the concentration; therefore, viscosity measurements can be corrected for the moisture content of the samples. The effect of storage temperature on deterioration was greater than the effect of relative humidity. Samples stored at 0° and 40° F. for 12 weeks showed no significant changes in viscosity or suspending power, whereas those stored at 80° and 120° F. deteriorated very rapidly. Material was vacuum ice-dried to 2% moisture without damage but the quality decreased when the extracts were stored at high temperatures.

Model-based evaluation of struvite recovery from an in-line stripper in a BNR process (BCFS)

2006 ◽  
Vol 53 (3) ◽  
pp. 191-198 ◽  
Author(s):  
X.-D. Hao ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Nutrient Removal ◽  
Phosphate Concentration ◽  
Phosphate Removal ◽  
Carbon Oxidation ◽  
P Efficiency ◽  
Effluent Quality ◽  
P Recovery ◽  
Struvite Precipitation ◽  
Removal And Recovery ◽  
P Removal

Phosphate removal and recovery can be combined in BNR processes. This may be realised by struvite precipitation from the supernatant of the sludge in anaerobic compartments. This can be beneficial for either improving bio-P removal effluent quality or lowering the influent COD/P ratio required for bio-P removal. For this reason, a patented BNR process, BCFS®, was developed and applied in The Netherlands. Several questions relating to P-recovery and behaviour of the system remain unclear and need to be ascertained. For this purpose, a modelling technique was employed in this study. With the help of a previous developed model describing carbon oxidation and nutrient removal, three cases were fully simulated. The simulations demonstrated that there was an optimal stripping flow rate and P-recovery would increase in costs and bio-P activity might be negatively affected due to decreased bio-P efficiency if this value was exceeded. The simulations indicated that the minimal CODbiod/P ratio required for the effluent standard (1 g P/m3) could be lowered from 20 to 10 with 36% of P-recovery. A simulation with dynamic inflow revealed that the dynamic influent loads affected slightly the anaerobic supernatant phosphate concentration but the effluent phosphate concentration would not be affected with regular P-recovery.

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