Elimination of total coliforms and Escherichia coli from water by means of filtration with natural clays and silica sand in developing countries.

This research presents the results of a pilot system used for water treatment to be supplied to single-family or small housing nucleus at rural sector. The pilot system is constituted by an up-flow aerated filter with ceramic carrier, followed by a second down-flow filter of silica sand. The pilot plant was installed in a rural sector of the province of Loja, Ecuador, with the main purpose of monitoring the reduction in bacteria in the water for human consumption.

Nitrogen removal capacity and bacterial community dynamics of a Canon biofilter system at different organic matter concentrations.

Three Canon bench-scale bioreactors with a volume of 2 L operating in parallel were configured as submerged biofilters. In the present study we investigated the effects of a high ammonium concentration (320 mgNH· L) and different concentrations of organic matter (0, 100 and 400 mgCOD·L) on the nitrogen removal capacity and the bacterial community structure. After 60 days, the Canon biofilters operated properly under concentrations of 0 and 100 mgCOD·L of organic matter, with nitrogen removal efficiencies up to 85%.

Archaeal and bacterial community dynamics and bioprocess performance of a bench-scale two-stage anaerobic digester.

Two-stage technologies have been developed for anaerobic digestion of waste-activated sludge. In this study, the archaeal and bacterial community structure dynamics and bioprocess performance of a bench-scale two-stage anaerobic digester treating urban sewage sludge have been studied by the means of high-throughput sequencing techniques and physicochemical parameters such as pH, dried sludge, volatile dried sludge, acid concentration, alkalinity, and biogas generation. The coupled analyses of archaeal and bacterial communities and physicochemical parameters showed a direct relationship between archaeal and bacterial populations and bioprocess performance during start-up and working operation of a two-stage anaerobic digester.

Impact of methionine on a partial-nitritation biofilter.

It has been demonstrated that an anaerobic digestion process cannot attain an efficient removal of several amino acids, with methionine being one of the most persistent of these. Thus, the effect that methionine amino acid has over the partial-nitritation process with fixed-biofilm configuration in terms of performance and bacterial community dynamics has been investigated. With respect to the performance with no addition, 100 mg/L methionine loading decreased ammonium oxidation efficiency in 60% and 100% at concentrations of 300 and 500 mg/L methionine, respectively.

[The role of thiazides in the prophylaxis of recurrent calcium lithiasis].

Objective: To show the prolonged efficacy of thiazides in the prophylaxis and treatment of recurrences in patients with calcium oxalate and phosphate lithiasis.

Methods: A randomised prospective study is conducted, with a three-year follow-up, in 150 patients diagnosed with recurrent calcium lithiasis. The patients are divided into three groups: A) 50 cases subject to observation with no treatment, B) 50 cases treated with 50 mg/day of hydrochlorothiazide, and C) 50 cases treated with 50 mg of hydrochlorothiazide and 20 mlEq of potassium citrate/day.