Disinfection kinetics of pathogens in physicochemical sludge treated with ammonia.

Ammonia is a disinfectant which can diffuse through the membrane of highly resistant structures like helminth ova. Thus, it can be considered an alternative disinfectant of wastewater sludge with high pathogenic content. In this study, the kinetic parameters of the Hom model were used to describe the inactivation with ammonia of faecal coliforms, Salmonella spp. and viable helminth ova. These were obtained in processes considering the addition of ammonia alone as well as for ammonia combined with an increase in temperature. The sludge was sampled from a municipal wastewater treatment plant using an APT (Advanced Primary Treatment) or CEP (Chemical Enhanced Primary) process. With 20% w/w of ammonia, 7 logs of faecal coliforms, 6 logs of Salmonella spp., and 83% of viable helminth ova were reduced in 2 hours contact time. To eliminate 100% of the helminth ova from samples having 88-132 ova/g TS it was needed to combine 20% of ammonia with 50 degrees C. The analysis of parameters k, n and m indicate higher resistance to inactivation of helminth ova compared to bacteria and a better performance of the ammonia process than lime stabilization to inactivate microorganisms. In addition, ammonia increased the agricultural value of the biosolids produced.

[1]  R Briancesco,et al.  Pilot-plant comparative study of peracetic acid and sodium hypochlorite wastewater disinfection. , 2003, Water research.

[2]  B. Jiménez,et al.  Comparison of the quantity and quality of the microbiological content of sludge in countries with low and high content of pathogens. , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.

[3]  L. Schwartzbrod,et al.  Evaluation of bacteriophages during the treatment of sludge. , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.

[4]  B. Jiménez,et al.  Improved alkaline stabilization of municipal wastewater sludge. , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.

[5]  B. Jiménez,et al.  Class B biosolids production from wastewater sludge with high pathogenic content generated in an advanced primary treatment , 2000 .

[6]  I. Booth,et al.  The regulation of intracellular pH in bacteria. , 2007, Novartis Foundation symposium.

[7]  C. Genchi,et al.  Survival of Ascaris suum eggs in ammonia-treated wastewater sludges , 1997 .

[8]  P. Rossi,et al.  Viability of Ascaris suum, Ascaris lumbricoides and Trichuris muris eggs to alkaline pH and different temperatures. , 1995, Parassitologia.

[9]  D. Pernitsky,et al.  Disinfection kinetics of heterotrophic plate count bacteria in biologically treated potable water , 1995 .

[10]  A. Ferrari,et al.  Inactivation of fecal bacteria in sewage sludge by alkaline treatment , 1994 .

[11]  Cecil Lue-Hing,et al.  Municipal sewage sludge management : processing, utilization and disposal , 1992 .

[12]  Daniel A. Okun,et al.  Guidelines for water reuse. , 1992 .

[13]  A. Bruce Sewage sludge stabilisation and disinfection , 1984 .