Bulk pH and Carbon Source Are Key Factors for Calcium Phosphate Granulation.

Recovery of calcium phosphate granules (CaP granules) from high-strength wastewater is an opportunity to reduce the natural phosphorus (P) scarcity, geographic imbalances of P reserves, and eutrophication. Formation of CaP granules was previously observed in an upflow anaerobic sludge bed (UASB) reactor treating source separated black water and is enhanced by Ca2+ addition. However, the required operating conditions and influent composition for CaP granulation are still unknown. In this study, we have experimentally demonstrated that the carbon source and bulk pH are crucial parameters for the formation and growth of CaP granules in a UASB reactor, operating at relatively low upflow velocity (<1 cm h-1). Degradation of glucose yielded sufficient biomass (microbial cells and extracellular biopolymers) to cover crystal and amorphous calcium phosphate [Ca x(PO4) y], forming CaP granules. Influent only containing volatile fatty acids as the carbon source did not generate CaP granules. Moreover, bulk pH between 7.0 and 7.5 was crucial for the enrichment of Ca x(PO4) y in the granules over bulk precipitation. Bulk pH 8 reduced the Ca x(PO4) y enrichment in granules of >1.4 mm diameter from 9 to 5 wt % P. Moreover, for bulk pH 7.5, co-precipitation of CaCO3 with Ca x(PO4) y was reduced.

Recovery of calcium phosphate granules from black water using a hybrid upflow anaerobic sludge bed and gas-lift reactor.

Adding calcium during anaerobic digestion of vacuum collected black water (BW) in an up-flow anaerobic sludge bed (UASB) reactor increased the retention of total phosphorus (P) in the reactor from 51% to 87%. However, the insufficient mixing in the reactor caused cementation and relatively high content of organics in the recovered calcium phosphate (CaP) granules, limiting the P recovery. In this study, the UASB reactor was mixed with an internal gas-lift (UASB-GL) to prevent cementation and to enhance the P content in CaP granules. The novel UASB-GL reactor operated for 300 days, treating concentrated BW. At steady state, the removal of total COD and P was 92% and 90%, respectively. The gas injection created a sludge bed with an average total suspended solids concentration of 73 ±â€¯16 g/L at the bottom and 31 ±â€¯5 g/L at the top of the reactor. The concentration of solid P at the bottom of the reactor was 4.58 ±â€¯1.34 gP/L, while at the top a much lower concentration was obtained (0.75 ±â€¯0.32 gP/L). 89% of the CaP granules was found at the bottom of the reactor. The harvested CaP granules (>0.4 mm diameter) contained on average 7.8 ±â€¯0.6 wt% of P. A potential recovery of 57% of P in BW as CaP granules was calculated, considering actual application of the UASB-GL reactor in source separated sanitation.

The Effect of Bioinduced Increased pH on the Enrichment of Calcium Phosphate in Granules during Anaerobic Treatment of Black Water.

Simultaneous recovery of calcium phosphate granules (CaP granules) and methane in anaerobic treatment of source separated black water (BW) has been previously demonstrated. The exact mechanism behind the accumulation of calcium phosphate (Ca x(PO4) y) in CaP granules during black water treatment was investigated in this study by examination of the interface between the outer anaerobic biofilm and the core of CaP granules. A key factor in this process is the pH profile in CaP granules, which increases from the edge (7.4) to the center (7.9). The pH increase enhances supersaturation for Ca x(PO4) y phases, creating internal conditions preferable for Ca x(PO4) y precipitation. The pH profile can be explained by measured bioconversion of acetate and H2, HCO3- and H+ into CH4 in the outer biofilm and eventual stripping of CO2 and CH4 (biogas) from the granule. Phosphorus content and Ca x(PO4) y crystal mass quantity in the granules positively correlated with the granule size, in the reactor without Ca2+ addition, indicating that the phosphorus rich core matures with the granule growth. Adding Ca2+ increased the overall phosphorus content in granules >0.4 mm diameter, but not in fine particles (<0.4 mm). Additionally, H+ released from aqueous phosphate species during Ca x(PO4) y crystallization were buffered by internal hydrogenotrophic methanogenesis and stripping of biogas from the granule. These insights into the formation and growth of CaP granules are important for process optimization, enabling simultaneous Ca x(PO4) y and CH4 recovery in a single reactor. Moreover, the biological induction of Ca x(PO4) y crystallization resulting from biological increase of pH is relevant for stimulation and control of (bio)crystallization and (bio)mineralization in real environmental conditions.

Transumbilical videolaparoscopic (single site) liver biopsy with laparoscopy equipment.

INTRODUCTION: Liver diseases have a high incidence in the whole world. In order to diagnose, stage and follow these diseases it is often necessary the execution of liver biopsy. There are many possible ways to perform the procedure and the rise of transumbilical endoscopic surgery (TUES) brings to the medical practice an additional good option. MATERIALS AND METHODS: The study is prospective, nonrandomised and cohort type. It involves 42 patients who underwent liver biopsy through TUES using conventional video laparoscopic material. RESULTS: Among the patients 18 (42.86%) underwent isolated liver biopsy and 24 (57.14%) to liver biopsy associated with umbilical hernia repair. Within those, 27 (64.28%) were male and 15 (35.71%) female. The average body mass index (BMI) was of 27.26 kg/m(2), 10 were in the normal BMI range, 24 (57.14%) were in the overweight range, 6 (14.28%) had class I obesity and 2 (4.76%) had class II obesity. In none of the cases the procedure was converted to regular video laparoscopy, all the patients were discharged in the day after the procedure and reported a satisfactory aesthetic result. CONCLUSIONS: The study shows that liver biopsy using TUES has applicability and good results, including in obese patients that would have a contraindication to other methods.

Calcium addition to increase the production of phosphate granules in anaerobic treatment of black water.

Simultaneous recovery of calcium phosphate granules (CaP granules) and methane from vacuum collected black water (BW), using an upflow anaerobic sludge blanket (UASB) reactor was previously investigated. It was calculated that only 2% of the total phosphorus (P) fed was present as CaP granules whereas 51% of the P accumulated dispersed in the reactor, limiting the applicability of this process for recovery of phosphate. This study proposes adding calcium to increase the P accumulation in the reactor and the production of CaP granules. Calcium was added in a lab-scale UASB reactor fed with BW. An identical UASB reactor was used as reference, to which no calcium was added. The treatment performance was evaluated by weekly monitoring of influent, effluent and produced biogas. Sludge bed development and CaP granulation were assessed through particle size analysis. The composition and structure of CaP granules were chemically and optically assessed. Calcium addition increased accumulation of P in the reactor and formation and growth of granules with size > 0.4 mm diameter (CaP granules). Moreover, with calcium addition, CaP granules contained 5.6 ± 1.5 wt% of P, while without calcium a lower P content was observed (3.7 ± 0.3 wt%). By adding Ca, 89% of the incoming P from BW accumulated in the reactor and 31% was sampled as CaP granules (> 0.4 mm diameter). Addition of 250 mgCa L-1 of BW was the optimum loading found in this study. Furthermore, no significant reduction in CODTotal removal (> 80%) and CH4 production (0.47 ± 0.10 gCOD-CH4 g-1CODTotal-BW) was observed. Therefore, adding calcium can significantly increase the CaP granulation without inhibiting the simultaneous CH4 recovery. This further indicates the potential of this process for phosphate recovery.