Energy potential and alternative usages of biogas and sludge from UASB reactors: case study of the Laboreaux wastewater treatment plant

This work assessed the energy potential and alternative usages of biogas and sludge generated in upflow anaerobic sludge blanket reactors at the Laboreaux sewage treatment plant (STP), Brazil. Two scenarios were considered: (i) priority use of biogas for the thermal drying of dehydrated sludge and the use of the excess biogas for electricity generation in an ICE (internal combustion engine); and (ii) priority use of biogas for electricity generation and the use of the heat of the engine exhaust gases for the thermal drying of the sludge. Scenario 1 showed that the electricity generated is able to supply 22.2% of the STP power demand, but the thermal drying process enables a greater reduction or even elimination of the final volume of sludge to be disposed. In Scenario 2, the electricity generated is able to supply 57.6% of the STP power demand; however, the heat in the exhaust gases is not enough to dry the total amount of dehydrated sludge.

Experience with the design and start up of two full-scale UASB plants in Brazil: enhancements and drawbacks

This paper discusses the main drawbacks and enhancements experienced with the design and start up of two full-scale UASB plants in Brazil. The topics addressed are related to blockage of inlet pipes, scum accumulation, seed sludge for the start-up, corrosion and gas leakage, odour generation and sludge management. The paper describes the main improvements achieved.

Progression of the renal graft: treatment of acute rejection based on a biopsy against a presumptive diagnosis

The aim of this study was to compare the progression of renal grafts following treatment of an acute rejection event based on the histological diagnosis of a graft biopsy compared to a presumptive (clinical and laboratory) diagnosis. A historical cohort was used to study 44 patients undergoing a living haploidentical related donor renal transplant, using a similar immunosuppressive treatment: cyclosporine, azathioprine, and prednisone. Acute rejection events were treated with methylprednisolone (250 mg for 3 to 5 days) based on a histological diagnosis (biopsy group = 14) or on a clinical and laboratory diagnosis (presumptive group = 30), which consisted of an elevation over 20% in plasma creatinine in 24 hours and renal ultrasound or scintigraphy findings. The study demonstrated no significant difference in renal function (plasma creatinine) and other outcomes 2 years following transplantation in both groups. The results show that treatment of acute rejection based on a presumptive diagnosis is not a risk factor for unfavorable outcomes following 2 years of renal transplantation monitoring.

Treatment of dairy effluents in an aerobic granular sludge sequencing batch reactor

Aerobic granular sludge can successfully be cultivated in a sequencing batch reactor (SBR) treating dairy wastewater. Attention has to be paid to the fact that suspended solids are always present in the effluent of aerobic granular sludge reactors, making a post-treatment step necessary. Sufficient post-treatment can be achieved through a sedimentation process with a hydraulic retention time of 15-30 min. After complete granulation and the separation of biomass from the effluent, removal efficiencies of 90% CODtotal, 80% Ntotal and 67% Ptotal can be achieved at a volumetric exchange ratio of 50% and a cycle duration of 8 h. Effluent values stabilize at around 125 mg l-1 CODdissolved. The maximum applicable loading rate is nevertheless limited, as the stability of aerobic granules very much depends on the presence of distinct feast and famine conditions and the degradation of real wastewaters shows slower kinetics compared with synthetic wastewaters. As loading rate and volumetric exchange ratio are coupled in an SBR system, the potential of granular sludge for improving process efficiency is also limited.

Heterotopic ciliary epithelial differentiation in a patient with trisomy 13

A premature infant was born with congenital anomalies suggestive of trisomy 13, confirmed by karyotype analysis. Pathologic examination of the eyes revealed typical features of trisomy 13, including microphthalmos, extensive colobomata, and retinal dysplasia. A heterotopic ciliary body had also developed in the posterior segment of the left eye in the region of the posterior coloboma. The development of a well-formed ciliary body in the posterior segment of the eye questions the hypothesis that physical contact between the lens primordium and neuroepithelium is required for ciliary body development.

A comparative study of photic injury in four inbred strains of albino rats

The effects of light damage were studied in four inbred strains of albino rats, Fischer (F344), Lewis (L), Wistar (W), and Buffalo (BUF). Thirty-five-day-old rats (3 from each strain) were kept in cyclic light for two weeks, after which they were exposed to constant fluorescent light (180-190 foot-candles, 490-580 nm) for 24 hours. The rats were sacrificed 6 days after exposure. Photic injury to the exposed eyes was evaluated morphometrically by measuring the mean outer nuclear layer (ONL) thickness and qualitatively by light microscopy. Statistical analysis of the quantitative data revealed that the Lewis and Buffalo strains were more severely affected than the Wistar and Fischer strains. The effects of injury were more severe in the superior and temporal quadrants. Taking both quantitative and qualitative assessment into consideration, it appeared that, among the strains studied, the rats from the Lewis strain were most sensitive to photic damage. These findings support previous findings of differential light sensitivity and further suggest that similar variability occurs among inbred strains with type 1 light damage.

Unusual subarachnoid metastasis of an intracranial chordoma in infancy

The authors report a case of large clivus chordoma in a 61/2-year-old child with multiple subarachnoid metastatic dissemination over the cerebellar hemispheres and spinal cord.