Study of Raw Wastewater BOD₅ and cBOD₅ Relationship Yields Surprising Results

Abstract

A study of the relationship of the raw wastewater BOD 5 :cBOD 5 ratio was conducted at three wastewater treatment plants across the United States. Gwinnett County, Georgia; King County, Washington; and Littleton-Englewood, Colorado conducted a 3-month study using side-by-side samplers. The purpose of the study was to determine if cleaning wetted sampler parts routinely affected the ratio. One of the samplers was cleaned twice a week and the other was not cleaned. The results of the study show that cleaning the wetted parts of the sampler has a small but statistically insignificant impact on the BOD 5 :cBOD 5 ratio. The study also showed a potential relationship of wastewater temperature to the BOD 5 :cBOD 5 ratio, and also the possible influence of sampler type on raw wastewater characterization.

Underestimation of Sector-Wide Methane Emissions from United States Wastewater Treatment

“…Monthly averages of influent BOD 5 concentration for the month during which each observational period took place were used, and uncertainty was calculated as the standard deviation of monthly values over the year prior to the observational period. The following assumption was made in converting reported ERs to EFs with respect to BOD 5 :1.2 g BOD 5 (g carbonaceous BOD; CBOD) −1 . Plants lacking publicly available monthly influent BOD 5 concentrations (14 of 63 plants) are not considered in Figure b and the associated EF analyses.…”

“…The following assumption was made in converting reported ERs to EFs with respect to BOD 5 :1.2 g BOD 5 (g carbonaceous BOD; CBOD) −1 . 40 Plants lacking publicly available monthly influent BOD 5 concentrations (14 of 63 plants) are not considered in Figure 2b and the associated EF analyses.…”

Modelagem da progressão da DBO obtida na incubação de esgoto doméstico sob diferentes temperaturas

“…Tal recomendação advém do fato de que não haveria tempo suficiente para o início do processo de nitrificação no meio e, com isso, se incorreria em erros de subestimativa no valor de DBO exercida, tendo em vista a possibilidade da ocorrência de ligações do TCMP aos substratos ou às próprias enzimas das bactérias presentes na amostra (ALBERSTON, 1995); ou superestimativa, em decorrência do consumo de OD para a oxidação da substância anti--nitrificante, aplicada em excesso ou sem necessidade (MUIRHEAD et al, 2006). Assim, o ideal é usar a inibição da nitrificação nos dias em que realmente ocorrer a demanda de segundo estágio, o que é, entretanto, de difícil previsão.…”