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G Salgado

Publications and source records attributed to G Salgado.

16 recordsLinked to original sources
PubMed2004

Characterization and evaluation of potential reuse options for wastewater sludge and combined sewer system sediments in Mexico.

Combined sewer systems generate sediments that have characteristics similar to those of primary sludge. Mexico City has such a system composed of a network of pipes, regulation structures (dams, basins) and open channels. The annual generation of sediments is estimated at 2.8 Mm3, which includes 0.41 Mm3 of sludge. As a result, the total capacity for transporting water is reduced considerably, making it necessary to extract yearly an approximate 0.85 Mm3 of those materials and to send them to a final disposal site with a capacity that is being exhausted. As part of the local Governmental effort, this project evaluates the quality of sediments from 6 dams, 4 regulation basins, 2 open channels, and 3 transfer stations. Also, sludge from 20 wastewater treatment plants was sampled. The results showed an important presence of lead and hydrocarbons in some sediments, and some sludge samples contained arsenic and nickel above the limits. Moreover, microbial levels exceeded the limits in all the sediments and sludge samples. Erosion was linked to the generation of an important amount of sediments based on lead concentration. A classification was established to determine the degree of contamination of the sediments as well as the required treatment to allow their potential reuse.

Bacteria↗
PubMed2001

Growth of faecal coliforms and Salmonella spp. in physicochemical sludge treated with acetic acid.

The use of advanced primary treatment (APT) to remove helminth ova from wastewater has raised the issue of treating the generated sludge to allow its reuse or disposal. Several studies have been performed in Mexico in order to treat the sludge with the main goal of destroying helminth ova and bacteria, one of them analysing the acid treatment. Previous research has demonstrated the feasibility of applying such a process using acetic acid to disinfect the sludge, but the potential for bacterial growth was still to be proved. The results of a growth study of faecal coliforms and Salmonella spp. in sludge treated with acetic acid are presented in this paper. Physicochemical sludge generated in a semi-rural area of Mexico City was treated using acetic acid in 6 different doses ranging from 3,700 to 22,000 ppm (w/w) and the concentrations of faecal coliforms, Salmonella spp., and total and volatile solids, were monitored after 30 minutes, and 8, 21 and 35 days. Average initial concentrations in sludge were 1.1 x 10(8) MPN/g TS and 1.5 x 10(5) MPN/g TS for faecal coliforms and Salmonella spp., while pH, total and volatile solids were 5.4, 5.0% and 73% respectively. Apparently, some acidified samples presented anaerobic activity, observed as a change in sludge coloration, as well as bacterial growth. pH of the treated samples with less than 18,400 ppm raised from the initial value of approximately 4.0 up to 5.9 units, while samples with 18,400 and 22,000 ppm maintained the pH close to 4. Total and volatile solids did not present important changes except in the untreated sample where they were reduced by 0.3 and 3.4% respectively. Samples treated with more than 14,700 ppm of acetic acid did not present any increase in bacterial density. Additionally, concentrations of faecal coliforms and Salmonella spp. in untreated sludge were reduced throughout the time, in contrast to samples treated with doses lower than 14,700 ppm that showed some growth, which suggests that the use of acetic acid in doses lower than 15,000 ppm stimulates in some way the growth of these bacteria.

Acetic Acid↗
PubMed1999

[Bone scintigraphy in prostatic cancer. Correlation with clinical and laboratory features and with survival].

BACKGROUND: The yield of bone scintigraphy is specially good in some types of neoplasia such as mammary and prostate carcinoma, whose metastases cause a marked osteoblastic reaction in bone. AIM: To assess the usefulness of bone scintigraphy in patients with prostate carcinoma. PATIENTS AND METHODS: A retrospective analysis of bone scintigrams performed to 79 patients with prostate carcinoma aged 56 to 83 years old, describing their relationship with prostate specific antigen and bone pain. The predictive value of bone scan, prostate specific antigen and clinical variables was analyzed using Kaplan Meier survival tables. RESULTS: Scintigraphy disclosed bone metastases in 22 patients (28%). The most frequently involved zones were pelvis (86%), rib cage (67%) and spine (57%). The association with pain was low specially for limbs, rib cage and skull. The better efficacy of prostate specific antigen for the prediction of bone metastases was obtained with a cutoff value of 50 ng/ml (sensitivity 72%, specificity 86%). With a cutoff value of 10 ng/ml, the negative predictive value was 100%. The only significant predictor of a lower patient survival was the presence of bone metastases on bone scintigraphy. CONCLUSIONS: In this series of patients, bone scintigraphy was an excellent diagnostic tool for bone metastases and had a survival prognostic value.

Aged↗
PubMed1999

[Obstructive jaundice in prostate neoplasm. Case report].

We report a 58 years old male, presenting with malaise, weight loss and jaundice. An abdominal ultrasound showed multiple lymphadenopathies in the hepatic bilus and around the pancreas. Fine needle aspiration of these nodes demonstrated an undifferentiated carcinoma. Prostate specific antigen was over 100 ng/ml and a prostate biopsy demonstrated a high grade carcinoma. The patient was subjected to an orchiectomy and hormone therapy (flutamide). Jaundice subsided and he is well after 3 years of follow up and maintained hormone therapy.

Adenocarcinoma↗
PubMed1980

[Acute mixed portal hypertension. Experimental study (author's transl)].

Experimental studies were conducted in dogs to establish a new model for portal hypertension. The model chosen depends on partial obstruction of the portal vein to obtain a portal pressure of 11 +/- 4 ml. and the injection of 600 U. of secretin over a period of 35 min. The validity of the model was demonstrated by hemodynamic studies which resulted in a portal pressure, mesenteric blood flow, and mesenteric vascular resistances similar to those observed in clinical practice (hepatic cirrhosis).

Acute Disease↗