$string = '(1234) S*m@#ith S)&+*t `E}{xam)ple?>land - - 1!_2)#3)(*4""5';

// remove all non alphanumeric characters except spaces
$clean = preg_replace('/[^a-zA-Z0-9\s]/', '', strtolower($string));

// replace one or multiple spaces into single dash (-)
$clean = preg_replace('!\s+!', '-', $clean);

echo $clean; // 1234-smith-st-exampleland-12345