Pick DSI Improves Thermophilic Digestion Process

Although production of Class A bio solids can be achieved through several different methods of pathogen treatment, thermophilic aerobic digestion of sludge is becoming the method of choice in large municipal treatment plants. Preheating primary sludge upstream of the digestor speeds the process. A secondary advantage is reduced steam input to the digestor, minimizing foaming. Conventional indirect heat exchangers, however, are expensive, bulky, and costly to maintain. Direct Steam Injection is an excellent alternative.

A direct steam injection (DSI) heater offers several advantages over an indirect heat exchanger. It is compact and easily retrofitted into existing sludge piping. It imposes negligible pressure drop, even at high sludge flows. Plus, it is easy to maintain. DSI is rapidly gaining acceptance in two areas of the thermophilic digestion process. First, an inline heater is used to elevate sludge temperature upstream of the digestor. A second heater serves to maintain sludge at 132°F in holding tanks downstream of the digestor.

Pick can fabricate heaters with ports to match your sludge piping - either straight flow through or 90 degree elbow design.

Features and Benefits:

• Simple
• Economical
• Compact
• Thermal Efficient
• Low Pressure Drop