300 mL of wastewater was collected, aerated and seeded with bacteria. The dissolved oxygen content was 7.4 mg/L initially. After 5 days, the dissolved oxygen content had dropped to 2.3 mg/L. Estimate the BOD, and the ultimate BOD? Assume that k (base e) = 0.20 day %3D

Wastewater Engineering civil engineering (10)

An anaerobic digester (AD) is designed with the following data. Organic loading rate 1.0 kg VSS/m³.day VSS load 120 kg/day (i). (ii). Estimate the volume of the AD. If the VSS is 12 kg/m³, estimate the retention time.

The following data on the substrate removal rate and the substrate concentration is available for wastewater treatment (S) mol Rate, r (mol/min) 0.04 0.57 0.06 1.05 0.8 2.32 0.10 3.00 0.12 4.68 0.14 5.42 2.0 5.78 Estimate the value of substrate removal constant Km and the value of Vmax

1. The following information is provided for an activated sludge system design: Parameter Symbol Value Units Flow rate Q 10000 m³/d Influent BOD So 150 mg/L Effluent BOD S 2 mg/L Hydraulic residence time Ꮎ 4 hr Mean cell residence time Oc 6 d Maximum specific growth rate μm 3 1/d Half saturation constant Ks 40 mg/L Yield coefficient Y 0.5 Endogenous decay coefficient b 0.08 1/d Death rate coefficient γ 0.04 1/d Determine: a) The aeration tank biomass concentration (X) in mg/L b) The aeration tank oxygen requirement in kg/d c) The rate of biomass wasting in kg/d

In the lead content analysis of a wastewater sample, 25.00 mL of the original sample was taken and diluted with 175.00 mL deionized water. The diluted sample was found to have a lead content of 12.7 ppb. What is the lead content (in ppb) of the original wastewater sample?

Q- If the BOD3 of a wastewater sample is 75 mg/L and reaction rate constant k (base e) is 0.345 per day, find the amount of BOD remaining in the given sample after 10 days.

In a BOD test, the amount of organic matter remaining in the wastewater was measured at certain time intervals, instead of measuring the dissolved oxygen content. The amount of organic matterremaining after 4 and 9 d was measured as 52.86 mg/L and 8.11mg/L, respectively. Calculate the ultimate BOD and BOD rate constant k for the wastewater.

From water sample, 25 mg/L HCO3" as CacO3, 10 mg/L C032 as Caco3 and 50 mg/L Ca* as CaCO3 were measured. pH was near neutral. What is alkalinity? () mg/L as Cac03 (*Answer in whole number only)