The present disclosure relates to methods of treating highly contaminated wastewater using waste activated sludge as an adsorbent. This method senses the failure of a relay’s contacts to open once it has been commanded to trip. In this way, the cast trailing arm is positively and rigidly secured to the steel torsion beam. In a second embodiment, a shingle has a solar collector strip mounted to its surface extending along a forward edge of the shingle, and in another, the solar collector surrounds the tabs of their shingles. Expansion in the z-direction is also possible.