Abstract: The invention provides a sampling process and apparatus therefor for the control of the addition of expensive conditioning material, referred to as polymers, to suspensions, sludges and the like, particularly sewage sludge, to facilitate its dewatering. The process employs a viscometer able to measure rapidly the shear stress of the sludge and obtain a typical peak value characteristic of optimum conditioning of the sludge. The process and apparatus also operate in a new mode involving charging a sample vessel with unconditioned sludge, taking a measurement to obtain an "unconditioned" signal, and then filling with conditioned sludge and obtaining a "conditioned" signal, the unconditioned signal indicating the solids content of the sludge and being used to modify the signal controlling the polymer flow and therefore the dosage to compensate for this charge. The viscometer rotor and the vessel interior are rinsed to remove the conditioned sludge before a fresh batch of unconditioned sludge is introduced.

Abstract: An apparatus for the conversion of sludge including a heated continuous tubular member having a continuous conveyor extending therethrough and defining along its length in succession a heating zone, a connecting zone and a reaction zone. The connecting zone conveys solid products from the heating zone to the reaction zone without substantial passage of gaseous material therethrough, and a duct means separate from the tubular member connects the heating zone and the reaction zone for the passage of gaseous products from the heating zone to the reaction zone.

Abstract: There is disclosed a new process for the conversion of the organic components of sludge, particularly sewage sludge, to produce useful, storable, energy-containing oil products, apparatus for carrying out the process and a control process for optimization of the process temperature. The sludge preferably is mechanically dewatered to about 20-25% solids by weight and thermally dried to about 90% solids by weight. The resultant material is comminuted and heated in the apparatus of the invention to at least 250.degree. C. in a heating zone in the absence of oxygen to generate a gaseous atmophere containing volatiles; this atmosphere is then removed, scrubbed of H.sub.2 S and NH.sub.3 if required, and passed preferably in countercurrent flow in a heated reaction zone in intimate contact with the "devolatilized" sludge solids from the heating zone, again in the absence of oxygen, at a temperature of at least 280.degree. C., resulting in catalyzed vapor phase oil-producing reactions.

Abstract: The invention provides processes and apparatus for the controlled addition of conditioning (polymer) material to sewage sludge to improve its dewaterability. These materials are expensive and overdosage is to be avoided, while underdosage causes difficulty in sludge handling. The principal problem has been the absence of a system capable of continuous determination of proper dosage. It has been found that shear stress tests with a viscometer result in characteristics that exhibit a unique peak when dosage is adequate or above. A control system controlling the rate of pumping of the polymer to mix with the sludge is operative by measuring the shear stress and increasing the dosage in the absence of a peak. Upon detection of a peak the rate of decrease after the peak is also measured and used to resolve the potential ambiguity of whether dosage should be increased, decreased or remain steady.