The belt filter press is operated in batch process. The operation and maintenance cost for se equipments is very high. It also requires high labour cost.

Waste solids production in primary and secondary processing can be estimated using calculation above. Ws stand for total dry solids. W_sp stands for raw primary solids. Wss stands for secondary biological solids.

Hydrolysis of chlorine in water is a first order reaction. Any first order reactions with rate constant > 1s^-1 is considered as a fast reaction. Hence above reaction is a fast reaction.

If aeration is not provided, baffles or mechanical mixers must be provided to avoid stratification and short circuiting in equalization basins. The size and shape of an equalization facility will vary with quantity of waste and patterns of waste discharge.

The size of openings for a fine screen is 0.2-0.6mm. These are used as a substitute for a primary clarifier. These are used to remove suspended particles.

Thickening is often first step in a sludge treatment process. Sludge from primary or secondary clarifiers may be stirred (often after addition of clarifying agents) to form larger, more rapidly settling aggregates.

Coarse screens are classified as preliminary treatment. This is mainly to remove grit, sand particles. This prevents clogging of pipe and pump.

The physical operations to remove impurities present in water and waste water are called unit operations where as unit processes are chemical and biological conversion on status of impurities that y will be converted to a form that can be easily separated.

The temperature at which sludge has to be frozen in order to carry out conditioning is -10 to -20 degree. This should be frozen for at least 30 mins. This technology works on even difficult-to-dewater sludge.

Fluidized bed bioreactor is comparable to bubble column bioreactor except top position is expanded to reduce velocity of fluid. The design of fluidized bioreactors is such that solids are retained in reactor while liquid flows out.