Energy and Nutrient Recovery from Sewage Sludge and Manure via Anaerobic Digestion with Hydrothermal Pretreatment.

Global expectation for sustainability has prompted the transition of practices in wastewater treatment plants toward not only waste management but also energy and nutrient recovery. It has been shown that low-temperature hydrotherm (HT) treatment can enhance downstream biogas production via anaerobic digestion (AD). Yet, because the application of combined HT and AD is still at an early stage, a systematic understanding of the dynamic speciation evolution of important elements is still lacking. This study investigates energy and nutrient recovery from sewage sludge and swine manure via combined HT-AD treatment. Bench-scale investigation was conducted to evaluate biogas production and understand the dynamic evolution of organic carbon (C) and phosphorus (P) speciation. C and P speciations were characterized using complementary chemical and spectroscopic techniques, including 13C nuclear magnetic resonance (NMR) spectroscopy, P X-ray absorption near edge structure (XANES) spectroscopy, and sequential chemical extraction. Results from this study suggest that low-temperature HT pretreatment can achieve enhanced biogas production for sludge compared to the minimal effect on the biogas production from manure. It also provides guidance for P recovery from liquid digestate and solid residue after the AD process.

Transformations of Phosphorus Speciation during (Hydro)thermal Treatments of Animal Manures.

Phosphorus (P) in animal manures is an important P pool for P recycling and reclamation. In recent years, thermochemical techniques have gained much interests for effective waste treatment and P recycling. This study comparatively characterized the transformation of P during two representative thermochemical treatments (pyrolysis and hydrothermal carbonization, HTC) of four animal manures (swine, chicken, beef, and dairy manures) by combining nuclear magnetic resonance spectroscopy, X-ray absorption spectroscopy, and sequential extraction. For both pyrolysis and HTC treatments, degradation of organic phosphate and crystallization of Ca phosphate minerals were observed and were highly dependent on treatment temperature. Extensive crystallization of Ca phosphate minerals occurred at temperatures above 450 °C during pyrolysis, compared to the lower temperature (175 and 225 °C) requirements during HTC. As a result, P was immobilized in the hydrochars and high temperature pyrochars, and was extracted primarily by HCl. Because Ca is the dominating P-complexing cation in all four manures, all manures showed similar P speciation and transformation behaviors during the treatments. Results from this work provided deeper insights into the thermochemical processes occurred during the pyrolysis and HTC treatments of biological wastes, as well as guidance for P reclamation and recycling from these wastes.

Transformation of Phosphorus during (Hydro)thermal Treatments of Solid Biowastes: Reaction Mechanisms and Implications for P Reclamation and Recycling.

Phosphorus (P) is an essential nutrient for all organisms, thus playing unique and critical roles at the food-energy-water nexus. Most P utilized by human activities eventually converges into various solid biowastes, such as crop biomass, animal manures, and sewage sludges. Therefore, integration of efficient P recovery practices into solid biowaste management will not only significantly reduce the dependence on limited geological P resources but also reduce P runoff and related water contamination issues associated with traditional waste management strategies. This study reviews the applications of (hydro)thermal techniques for the treatment of solid biowastes, which can greatly facilitate P recovery in addition to waste volume reduction, decontamination, and energy recovery. Research showed that P speciation (including molecular moiety, complexation state, and mineralogy) can experience significant changes during (hydro)thermal treatments, and are impacted by treatment techniques and conditions. Changes in P speciation and overall properties of the products can alter the mobility and bioavailability of P, and subsequent P reclamation and recycling efficiency of the treatment products. This review summarizes recent progresses in this direction, identifies the challenges and knowledge gaps, and provides a foundation for future research efforts targeting at sustainable management of nutrient-rich biowastes.

Phosphorus recovery from biogas fermentation liquid by Ca-Mg loaded biochar.

Shortage in phosphorus (P) resources and P wastewater pollution is considered as a serious problem worldwide. The application of modified biochar for P recovery from wastewater and reuse of recovered P as agricultural fertilizer is a preferred process. This work aims to develop a calcium and magnesium loaded biochar (Ca-Mg/biochar) application for P recovery from biogas fermentation liquid. The physico-chemical characterization, adsorption efficiency, adsorption selectivity, and postsorption availability of Ca-Mg/biochar were investigated. The synthesized Ca-Mg/biochar was rich in organic functional groups and in CaO and MgO nanoparticles. With the increase in synthesis temperature, the yield decreased, C content increased, H content decreased, N content remained the same basically, and BET surface area increased. The P adsorption of Ca-Mg/biochar could be accelerated by nano-CaO and nano-MgO particles and reached equilibrium after 360min. The process was endothermic, spontaneous, and showed an increase in the disorder of the solid-liquid interface. Moreover, it could be fitted by the Freundlich model. The maximum P adsorption amounts were 294.22, 315.33, and 326.63mg/g. The P adsorption selectivity of Ca-Mg/biochar could not be significantly influenced by the typical pH level of biogas fermentation liquid. The nano-CaO and nano-MgO particles of Ca-Mg/biochar could reduce the negative interaction effects of coexisting ions. The P releasing amounts of postsorption Ca-Mg/biochar were in the order of Ca-Mg/B600>Ca-Mg/B450>Ca-Mg/B300. Results revealed that postsorption Ca-Mg/biochar can continually release P and is more suitable for an acid environment.

An amperometric method for the determination of cystine in urine samples and pharmaceutical tablets using screen-printed silver electrodes.

Elevated urinary cystine levels are closely associated with the development of cystine stone. Therefore, the ability to rapidly and efficiently determine urinary cystine levels is crucial for physicians to manage patients with cystinuria or those undergoing cystine medication. In this study, an amperometric method employing a commercial screen-printed silver electrode was successfully established. The resulting calibration curve indicated a detection limit of 0.65 mg/dL. Satisfactory recoveries ranging from 89% to 109% were obtained for urine samples. The method was also effective for the quality control analysis of cystine in pharmaceutical tablets. The recovery of cystine from pharmaceutical tablets ranged from 98% to 101% using the developed method. This method enables the rapid and accurate determination of cystine in both urine samples and pharmaceutical tablets and provides valuable information for clinical diagnosis and pharmaceutical quality control.

A new dabco-templated metal sulfate: 1,4-diazo-niabicyclo-[2.2.2]octane hexa-aqua-cadmium bis-(sulfate).

The title double mol-ecular salt, (C(6)H(14)N(2))[Cd(H(2)O)(6)](SO(4))(2), is an isostructure of its Mn and Co analogues. The Cd(II) atom adopts a near-regular CdO(6) octa-hedral coordination geometry. The crystal structure can be described as an alternation of cationic and anionic layers along [010], and numerous O-H⋯O and N-H⋯O hydrogen bonds are observed. No thermal anomalies corresponding to possible phase transitions were observed in DSC (differential scanning calorimetry) measurements and the 93 K structure is almost the same as the room-temperature structure.

Allicin affects the pharmacokinetics of sulfadiazine and florfenicol by downregulating the expression of jejunum P-gp and BCRP in broilers.

Allicin, one of the main bioactive compounds in garlic, is an excellent feed additive. It is unknown whether allicin affects the expression of P-gp and BCRP, 2 important ABC efflux transporters related to the pharmacokinetics of antimicrobials in chickens. In this study, by bidirectional transport test and broiler jejunum in situ perfusion, we found that allicin inhibited the efflux transport of P-gp and BCRP for their substrates sulfadiazine and florfenicol, 2 commonly used antimicrobials in broilers. Furthermore, we observed that allicin decreased the mRNA expression of chicken jejunum P-gp and BCRP. Pretreatment with allicin changed the pharmacokinetic behavior of orally administered sulfadiazine, by increasing AUC (41.85 vs. 31.24, P < 0.01) and Cmax values (9.82 vs. 8.40, P < 0.05) and decreasing CLZ (0.45 vs. 0.62, P < 0.01). Similarly, pretreatment with allicin also altered pharmacokinetics of orally administered florfenicol, by increasing AUC (18.38 vs. 13.52, P < 0.01) and decreasing CLZ. The results indicate that allicin could inhibit jejunum P-gp and BCRP expression and efflux function, thereby increasing the plasma concentrations of their substrates in broilers.

Identification of Functional Transcriptional Binding Sites within Chicken Abcg2 Gene Promoter and Screening Its Regulators.

Breast cancer resistance protein (BCRP), an ATP-binding cassette (ABC) half transporter encoded by the Abcg2 gene, is reported to influence the pharmacokinetics of substrate drugs during clinical therapy. The aim of this study was to clarify the mechanisms that regulate the transcription of the chicken Abcg2 gene through cloning and characterization of its promoter region. Results showed that the Abcg2 gene is transcribed by a TATA-less promoter with several putative Sp1 sites upstream from two putative CpG islands. A luciferase reporter assay conducted both in chicken leghorn male hepatoma (LMH) cells and chicken primary hepatocytes mapped a basal promoter to nucleotides -110 to +30, which is responsible for the constitutive expression of Abcg2. The 5'-region upstream of the basal promoter was characterized by both positive and negative regulatory domains. Further, using the cell-based reporter gene assay combined with RT-PCR and drug accumulation analysis, we found that four xenobiotics, daidzein, clotrimazole, ivermectin, and lipopolysaccharide (LPS), influence the expression and function of BCRP through significant regulation of the Abcg2 gene promoter. Interaction sites with the Abcg2 gene promoter of these four selected regulators were clarified by progressive deletions and mutation assays. This study shed some light on the regulatory mechanisms involved in chicken Abcg2 gene expression and the results may have far-reaching significance regarding the usage and development of veterinary drugs.

Phosphate enhance recovery from wastewater by mechanism analysis and optimization of struvite settleability in fluidized bed reactor.

Since phosphorus, a non-renewable and non-substitutable resource, has become the principal contributor and limiting factor to water eutrophication, achieving phosphorus removal and recovery from wastewater is pretty essential. Even though struvite crystallization process has been widely used for phosphate (P) recovery in wastewater treatment, its application is hampered by difficulties controlling small particle size and crystal growth. This study was conducted to control the settleability of struvite by calculating and predicting the struvite-settling percentage (Ps), which is always affected by the initial concentration of P (CP), solution pH (pH), reaction time (t), reaction temperature (T), agitation rate (Ar), and inlet flow velocity (vf) of the fluidized bed reactor. The results showed that the settleability of struvite could be enhanced by increasing T and decreasing pH, Ar, or vf, and would perform worse with overlong t or excessive CP. The dynamic variation process of the solution supersaturated index (SI) combined with the phase equilibrium theory and Ostwald ripening mechanism explained the above results sufficiently. The logistic model was chosen to predict the Ps under multi-factors, but the accuracy needs to be improved.

Application of magnesium modified corn biochar for phosphorus removal and recovery from swine wastewater.

The recycling of lost phosphorus (P) is important in sustainable development. In line with this objective, biochar adsorption is a promising method of P recovery. Therefore, our study investigates the efficiency and selectivity of magnesium modified corn biochar (Mg/biochar) in relation to P adsorption. It also examines the available P derived from postsorption Mg/biochar. Mg/biochar is rich in magnesium nanoparticles and organic functional groups, and it can adsorb 90% of the equilibrium amount of P within 30 min. The Mg/biochar P adsorption process is mainly controlled by chemical action. The maximum P adsorption amount of Mg/biochar is 239 mg/g. The Langmuir-Freundlich model fits the P adsorption isotherm best. Thermodynamics calculation shows ∆H > 0, ∆G < 0, ∆S > 0, and it demonstrates the P adsorption process is an endothermic, spontaneous, and increasingly disordered. The optimal pH is 9. The amounts of P adsorbed by Mg/B300, Mg/B450, and Mg/B600 from swine wastewater are lower than that adsorbed from synthetic P wastewater by 6.6%, 4.8%, and 4.2%, respectively. Mg/biochar is more resistant to pH and to the influence of coexisting ions than biochar. Finally, postsorption Mg/biochar can release P persistently. The P release equilibrium concentrations are ordered as follows: Mg/B600 > Mg/B450 > Mg/B300. The postsorption Mg/B300, Mg/B450, and Mg/B600 can release 3.3%, 3.9%, and 4.4% of the total adsorbed P, respectively, per interval time.