Wastewater

A community generates 1 million litres/day (MLD) of wastewater. This wastewater is treated using activated sludge process (ASP). The working volume of the aeration tank of the ASP is $250 \mathrm{~m}^3$, and the biomass...

A facultative pond system is employed for wastewater treatment. Which of the following statements is/are true:

A compound has a general formula $\mathrm{C}_{\mathrm{a}} \mathrm{H}_{\mathrm{b}} \mathrm{O}_{\mathrm{c}} \mathrm{N}_{\mathrm{d}}$ and molecular weight 187. A $935 \mathrm{mg} / \mathrm{l}$ solution of the compound is pr...

The bacteria mainly responsible for crown corrosion in a sewer is $\qquad$

Which one of the following products is NOT obtained in anaerobic decomposition of glucose?

Activated carbon is used to remove a pollutant from wastewater in a mixed batch reactor, which follows first-order reaction kinetics. At a reaction rate of 0.38 /day, the time (in days) required to remove the pollutant b...

A circular settling tank is to be designed for primary treatment of sewage at a flow rate of 10 million liters/day. Assume a detention period of 2.0 hours and surface loading rate of 40000 liters/m 2 /day. The height (in...

The wastewater inflow to an activated sludge plant is 0.5 m 3 /s, and the plant is to be operated with a food to microorganism ratio of 0.2 mg/mg-d. The concentration of influent biodegradable organic matter of the waste...

The theoretical aerobic oxidation of biomass (C 5 H 7 O 2 N) is given below: C 5 H 7 O 2 N + 5O 2 → 5CO 2 + NH 3 + 2H 2 O The biochemical oxidation of biomass is assumed as a first-order reaction with a rate constant of...

For wastewater coming from a wood pulping industry, Chemical Oxygen Demand (COD) and 5-day Biochemical Oxygen Demand (BOD 5 ) were determined. For this wastewater, which of the following statement(s) is/are correct?

A 2% sewage sample (in distilled water) was incubated for 3 days at 27$$^\circ$$C temperature. After incubation, a dissolved oxygen depletion of 10 mg/L was recorded. The biochemical oxygen demand (BOD) rate constant at...

A wastewater sample contains two nitrogen species, namely ammonia and nitrate. Consider the atomic weight of N, H, and O as 14 g/mol, 1 g/mol, and 16 g/mol, respectively. In this wastewater, the concentration of ammonia...

A sewage treatment plant receives sewage at a flow rate of 5000 m 3 /day. The total suspended solids (TSS) concentration in the sewage at the inlet of primary clarifier is 200 mg/L. After the primary treatment, the TSS c...

Effluent from an industry 'A' has a pH of 4.2. The effluent from another industry 'B' has double the hydroxyl (OH - ) ion concentration than the effluent from industry 'A'. pH of effluent from the industry 'B' will be __...

A wastewater sample contains $$10^{-5.6}$$ mol/l of OH - ions at $$25^o$$ C. The pH of this sample is