An adjustment device for the steering assembly of an electric scooter is provided. The press is controlled to vary the flow rate of the sludge in response to at least one sensed operational parameter of the press, such as the momentary power for operating the press, pressure in the sludge in the press, sludge concentration in the press, sludge feed flow to the press or separated water flow from the press. The layered system includes a core infrastructure and a configurable, domain-specific implementation. In the preferred embodiment, the mating surface includes a male portion on one of the bodies and a corresponding female portion on the other of the bodies. The screen reader voices the first web data displayed on the displaying unit and fails to voice the second web data displayed on the displaying unit. The washer has a round or oval cross-section and sets apart a shoulder of the valve housing from a shoulder of the cylinder head.