Q1: The rate of accumulation of sludge in septic tanks is recommended as

ANS:A - 30 litres/person/year

The rate of accumulation of sludge in septic tanks is commonly recommended in terms of liters per person per year. The recommended rate of accumulation of sludge in septic tanks is typically around 30 liters per person per year. This recommendation is based on various factors such as the size of the septic tank, the number of occupants in the household, and the characteristics of the sewage being generated. It's important to periodically monitor and pump out the accumulated sludge from the septic tank to prevent it from reaching excessive levels, which can lead to clogging, reduced treatment efficiency, and potential overflow issues. Therefore, the commonly recommended rate of accumulation of sludge in septic tanks is approximately 30 liters per person per year.