Pathogens are usually removed by

A circular sedimentation tank is designed to handle 6 million liters per day (MLD) of water. If the detention period of the tank is 5 hours and the depth of the tank is 4.5 m, then the diameter of the tank required is

The following are the sewage treatment processes:

1. Screening

2. Grit removal

3. Primary sedimentation

4. Secondary sedimentation

When only preliminary treatment is to be given for sewage, select the required treatment processes including their correct sequence from the options below:

A sample of domestic sewage is digested with silver sulphate, sulphuric acid, potassium dichromate and mercuric sulphate in chemical oxygen demand (COD) test. The digested sample is then titrated with standard ferrous ammonium sulphate (FAS) to determine the un-reacted amount of

Consider the following statements about the necessity of ventilation in sewer lines:

1. To avoid the buildup of sewer gases
2. To ensure atmospheric pressure in the wastewater surface
3. To ensure the safety of sewer maintenance personnel
4. To provide oxidation facility to sewage

Which of these statements are correct?

Which of the following statements about the design period for engineering projects are true?

A portion of waste water sample was subjected to standard BOD test (5 days, 20°C), yielding a value of 180 mg/L. The reaction rate constant (to the base 'e') at 20°C was taken as 0.18 per day. The reaction rate constant at other temperature may be estimated by k_T = k₂₀(1.047)^T-20. The temperature at which the other portion of the sample should be tested, to exert the same BOD in 2.5 days, is

The wastewater from a city, containing a high concentration of biodegradable organics, is being steadily discharged into a flowing river at a location S. If the rate of aeration of the river water is lower than the rate of degradation of the organics, then the dissolved oxygen of the river water

A milk factory processing 172,000 kg of milk daily produces an average of 280 cubic meters per day of waste water with a BOD (Biochemical Oxygen Demand) of 1.3 mg/L. Calculate the BOD equivalent population and the hydraulic equivalent population. Assume 70 g of BOD per person per day and the waste water production at 350 L/person/day.