TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The step (A) of the process (M1) involves skimming the olive oil from the surface of a body of aqueous waste; centrifugation; and removing a fraction of the olive oil contained in the aqueous waste. The step (B) is preceded by agitating the remaining aqueous waste, to cause suspension of solids. The agitation is carried out on the aqueous waste in a storage lagoon, by a circulating pump, nozzles and eductors. The process further involves the introduction of anti-caking agents to the process during step (B) to reduce caking of the dried product. The exhaust gases generated by at least one internal combustion engine or gas turbine or furnace are utilized in step (B) to provide generation of hot combustion gases as usable heat. The internal combustion engines or gas turbines are used for co-generation of electricity and heat. The dried product contains moisture in an amount of 0-40 (preferably 5-10) wt.%. The step (C) is followed by the step of compressing the dried product to form pellets or briquettes for use as a fuel, or used for animal feed. The aqueous waste is katsigaros, liozoumi, mourka, alpechin, or jamila. Preferred Composition: The solid fuel contains moisture in an amount of 0-40 (preferably 5-10) wt.%, and has a significant energy content. CHEMICAL ENGNEERING - Preferred System: The storage container includes: (i) a drain for removal of at least a portion of the aqueous waste to retain at least a portion of oil within the storage container; and (ii) at least one skimmer operable to skim at least a portion of the olive oil from the top of the aqueous waste for removal from the storage container. The system further comprises: a centrifugal separator to separate the aqueous waste from at least a portion of the olive oil contained in it; and a filtration system to filter the hot gases for the removal at least a portion of any waste contained in it. The system further comprises a storage area including agitators, the storage area is linked to the storage container and the drying vessel and operable to store the aqueous waste and agitate the aqueous waste to ensure a even distribution of waste within the aqueous waste prior to the waste being sent to the drying vessel. The drying vessel includes an arrangement to add an anticaking agent to the aqueous waste. The drying vessel is operable to cause the dried product deposited from the aqueous waste. The drying vessel comprises a spray drying chamber. The heating arrangement comprises a hot gas system to perform the heating. The hot gas system allows a gas to heat the aqueous waste by direct or indirect contact. EXAMPLE - No suitable example is given.