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Water Well Rehabilitation
Published in Neil Mansuy, Water Well Rehabilitation, 2017
The better choice as far as the disinfectant goes is sodium hypochlorite (otherwise known as liquid bleach). In addition to that, this is also very important when looking at effective well disinfection. If you are concerned about an unsafe bacterial sample, chlorination is often not just the only thing that needs to be done. We often have to take exactly the same approach with this unsafe bacterial sample as we would for the well if it had lost specific capacity. Both of these needs involve removing the same material! Although the goals for disinfecting the well would appear different from bringing back a lost capacity, rehabilitation of the well in removing the buildup of biofilms, scales and deposits achieves both of these goals. Disinfection will not dissolve the deposits harboring bacteria and will not bring back capacity, but a full rehabilitation has the potential to remove those bacteria along with the other deposits and essentially “disinfect” that well. In other words, an unsafe bacterial sample may not be tackled simply by the application of a disinfectant alone because many of the bacteria may be protected by the various biofilms and deposits in the well system. We therefore have to become more aggressive in dealing with water well problems to ensure that all of the deposits, scaling, nutrients, biofilms and tubercles are dissolved, disrupted and removed. Only then is it probable that the well would not be experiencing an unsafe bacterial problem. Better chemistries are clearly a major factor in the rehabilitation and disinfection of these plugged wells.
Water Treatment
Published in Frank R. Spellman, The Science of Water, 2020
Combining chlorine with calcium or sodium produces hypochlorites. Calcium hypochlorites are sold in powder or tablet forms and can contain chlorine concentrations up to 67%. Sodium hypochlorite is a liquid (bleach, for example) and is found in concentrations up to 16%. Chlorine concentrations of household bleach range from 4.75% to 5.25%. Most small system operators find using these liquid or dry chlorine compounds more convenient and safer than chlorine gas.
Water Treatment Operations
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
Combining chlorine with calcium or sodium produces hypochlorites. Calcium hypochlorites are sold in powder or tablet forms and can contain chlorine concentrations up to 67%. Sodium hypochlorite is a liquid (bleach, for example) and is found in concentrations up to 16%. Chlorine concentrations of household bleach range from 4.75% to 5.25%. Most small system operators find using these liquid or dry chlorine compounds more convenient and safer than chlorine gas.
The contribution of the Clinica del Lavoro of Milan to the development of industrial hygiene and toxicology in the twentieth century
Published in Archives of Environmental & Occupational Health, 2018
Michele A. Riva, Michael Belingheri, Silvia Fustinoni
In that period, Gianmarco Cavagna, one of the most important Italian industrial toxicologists of that period, conducted several studies on byssinosis.37–40 At the same time, in the Clinica del Lavoro, Vito Foà and Carla Antonini, demonstrated the presence of endotoxins in the atmosphere of a cotton carder,41 supporting that the pathogenesis of byssinosis was based on endotoxin and anticipating studies of Rylander.42 Furthermore, Cavagna developed pioneering researches on health effects of insecticides and carbon disulfide.43–50 Zurlo, Cavagna and their team also wrote several contributions on lead intoxications, pneumoconiosis and toxics in atmosphere and at the workplace.51–62 In this context, Zurlo invented a valuable mercury clepsydra vacuum pump to measure concentrations of atmospheric dusts by counting particles, internationally known as ‘Zurlo’s pump’.63 The Clinica del Lavoro conducted several studies on industrial and environmental toxicology on nitroglycol and nitroglycerin (and its correlation with ‘Monday disease’), trichloroethylene, polytetrafluoroethylene, indene, penicillin, sodium hypochlorite (liquid bleach) and on zinc-fume fever.64–80 General papers on the development of industrial hygiene, its role and its problems were also published.81–85 Works by Grisler on diagnosis and treatment of lead intoxication and on the development of other biomarkers related to occupational exposures are also noteworth.53,86–94