Determination of critical operational conditions favoring sulfide production from domestic wastewater treated by a sulfur-utilizing denitrification process.

The aim of this study was to determine the critical operational conditions leading to the generation of sulfide in a domestic wastewater treated by a sulfur-utilizing denitrification process. The influence of various important parameters on the reduction of the sulfates present in denitrified domestic wastewaters to sulfide was studied. Experiments were carried out in batch mode with denitrified domestic wastewaters containing various amounts of both organic matter and sulfates. Preliminary results showed that aqueous sulfide was generated for DOC and sulfate contents higher than 56 mg/L and 371 mg/L, respectively, while DOC and sulfate contents of 77 mg/L and 412 mg/L, respectively, were required to allow the release of gaseous H2S. Good correlations were also observed between gaseous sulfide production and the values of ORP and DOC, while the amounts of dissolved sulfide produced seemed to be correlated with the ORP values and the concentration of sulfates. Additional experiments were conducted using a Box-Behnken methodology to determine if the production of aqueous or gaseous sulfide can be predicted depending on the DOC (from 50 to 90 mg/L) and sulfate contents (from 160 to 380 mg/L) at various temperatures ranging from 5 to 25 °C. The highest sulfide generation (H2S(g) = 84.8 ppm and H2S(aq) = 2.42 mg/L) occurred at 25 °C with DOC and sulfate concentrations starting from 90 mg/L and 270 mg/L, respectively, indicating that the production of sulfides from denitrified domestic wastewaters required conditions not likely to occur at the effluent of a sulfur-based denitrification unit following secondary treatment.

[The value of radiotherapy in the treatment of aggressive and localised gastric lymphomas]. / Intérêt de la radiothérapie dans le traitement des lymphomes gastriques agressifs localisés.

PURPOSE: To evaluate the treatment results of localised aggressive gastric lymphomas with favourable prognosis using chemotherapy and radiotherapy. PATIENTS AND METHODS: Between February 1993 and December 2004, nine patients with primary gastric high-grade lymphoma have been treated by the Lymphoma Committee of Sfax (Tunisia). The sex ratio was 1.5. The mean age was 44.9 years. Histological type was the large cell B lymphoma in 100% of the cases. Disease was stage I in eight cases and stage II in one case (Ann Arbor Classification). The treatment consisted in primary chemotherapy followed by radiotherapy of the stomach with or without regional nodes (40 Gy). RESULTS: After treatment, all patients had complete remission. With a mean follow-up of 55.7 months, one patient was lost to follow-up; the other patients were alive with complete remission. No major acute toxicities or late effects were found. Overall survival was 100% at five years. CONCLUSION: Chemotherapy associated with radiotherapy can be proposed to patients having localised and aggressive primary gastric lymphoma with favourable prognosis, since this treatment is well tolerated and provides satisfactory control of the disease.

Assessment of sulfide production risk in soil during the infiltration of domestic wastewater treated by a sulfur-utilizing denitrification process.

This study aimed to determine the potential of sulfide generation during infiltration through soil of domestic wastewater treated by a sulfur-utilizing denitrification process. Three types of soil with different permeability rates (K s = 0.028, 0.0013, and 0.00015 cm/s) were investigated to evaluate the potential risk of sulfur generation during the infiltration of domestic wastewater treated by a sulfur-utilizing denitrification system. These soils were thoroughly characterized and tested to assess their capacity to be used as drainages for wastewaters. Experiments were conducted under two operating modes (saturated and unsaturated). Sulfate, sulfide, and chemical oxygen demand (COD) levels were determined over a period of 100 days. Despite the high concentration of sulfates (200 mg/L) under anaerobic conditions (ORP = -297 mV), no significant amount of sulfide was generated in the aqueous (<0.2 mg/L) or gaseous (<0.15 ppm) phases. Furthermore, the soil permeability did not have a noticeable effect on the infiltration of domestic wastewater treated by a sulfur-utilizing denitrification system due to low contents of organic matter (i.e., dissolved organic carbon, DOC). The autotrophic denitrification process used to treat the domestic wastewater allowed the reduction of the concentration of biochemical oxygen demand (BOD5) below 5 mg/L, of DOC below 7 mg/L, and of COD below 100 mg/L.

Value-added performance of processed cardboard and farm breeding compost by pyrolysis.

This study aims to underline the huge potential in Canada of adding value to cardboard and compost as a renewable fuel with a low ecological footprint. The slow pyrolysis process of lined cardboard and compost blend was investigated. Thermal behavior was investigated by thermogravimetric analysis coupled with mass spectrometry (TGA-MS). The thermal profiles are presented in the form of TGA/DTG curves. With a constant heating rate of 10 °C/min, two parameters, temperature and time were varied. Cardboard decomposition occurred mostly between 203 °C and 436 °C, where 77% of the sample weight was decomposed. Compost blend decomposition occurred mostly between 209 °C and 373 °C, with 23% of weight. The principal gaseous products that evolved during the pyrolysis were H2O, CO and CO2. As a result, slow pyrolysis led to the formation of biochar. High yield of biochar from cardboard was found at 250 °C for a duration of 60 min (87.5%) while the biochar yield from the compost blend was maintained constant at about 31%. Finally, kinetic parameters and a statistical analysis for the pyrolysis process of the cardboard and compost samples have been investigated. Both materials showed a favorable thermochemical behavior. However, unlike cardboard, compost pyrolysis does not seem a promising process because of the low superior calorific and biochar values.

[Non-Hodgkin lymphoma of maxillofacial soft tissue: a report of two cases and review of the literature]. / Lymphomes non-hodgkiniens des tissus mous maxillofaciaux : à propos de deux cas et revue de la littérature.

The extranodal non-Hodgkin lymphomas of maxillofacial soft tissues are rare. We report two cases of maxillofacial soft tissue non-Hodgkin lymphoma treated with chemotherapy followed by localized radiotherapy with complete remission after 3 and 6 months. We study the clinical, radiological and histopathological features as well as the treatment and the prognosis of extranodal non-Hodgkin lymphomas maxillofacial muscles.

[Clinical aspects of brain metastases from nasopharyngeal carcinoma]. / Aspects anatomocliniques des métastases cérébrales des carcinomes nasopharyngés.

Metastasis to the central nervous system, either through a hematogenous route or through the cerebrospinal fluid, is extremely rare in nasopharynx cancer. We aim to expose clinical aspects, therapeutic features and prognosis of nasopharyngeal carcinoma with brain metastases. We retrospectively reviewed the medical history of about 420 patients with nasopharyngeal carcinoma treated during 17 years at the university hospital of Sfax (Tunisia). Among them, three patients had brain metastasis. We excluded patients with direct extension to the brain. Tumours of the nasopharynx were locally advanced. The first patient had brain metastases at the initial diagnosis. The two other patients had brain metastases at 10 and 16 months during the follow-up. Ocular signs were the symptoms. Lesions were unique in two patients. Synchronous bone metastases were recorded in the three cases. All patients had whole brain radiation therapy and palliative chemotherapy. All patients had a progression of the disease and died. Brain metastases in nasopharynx cancer represent a rare event. Prognosis is poor, depending on age, surgical excision and synchronous metastases. Survival does not exceed 6 months.

[Pediatric nasopharyngeal carcinoma: Anatomoclinic aspects, therapeutic results and evolutive particularities]. / Le cancer du cavum de l'enfant et l'adulte jeune : aspects anatomocliniques, thérapeutiques et particularités évolutives.

PURPOSE: We retrospectively analyzed anatomoclinic, therapeutic and evolutive particularities of 74 young patients (< or =20 years) with nasopharyngeal carcinoma treated between 1993 and 2005. PATIENTS AND METHODS: Initial work-up included a fiberoptic nasofibroscopy with biopsy, tomodensitometry and/or MRI of nasopharynx and neck, chest X-ray, abdominal ultrasonography and bone scan. Patients were treated with either primary chemotherapy (epirubicin and cisplatin) followed by radiotherapy or concomitant radiochemotherapy (five fluorouracil and cisplatin). Radiotherapy was delivered to a total dose of 70 to 75 Gy to nasopharynx and involved cervical lymph nodes and 50 Gy to the remainder cervical areas. RESULTS: The median age was 16 years. Sixty-three percent of patients had undifferentiated tumors. Sixty-six percent had locally advanced tumor. With a median follow-up of 107 months, one patient presented a local relapse, 24 patients developed distant metastases with a median delay of 7 months. The 5 years overall survival and disease-free survival were 66 and 65 %. Late complications were dominated by dry mouth and endocrine disorders. COMMENTS: Pediatric nasopharyngeal carcinoma is characterized by an early metastatic diffusion. Local control is excellent but with severe late toxicities. New techniques of radiotherapy and new molecules of chemotherapy could improve these results.