<html>
<head>
</head>
<body>
<select class="filter" name="orderFilter">
<option value="" selected="selected">-</option>
<option value="14">Awaiting cod validation</option>
<option value="16">Failed</option>
...
</select>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script>
var a = 14;
$('select[name="orderFilter"] option[value='+a+']').prop('selected', true);
</script>
</body>
</html>
надеюсь правильно понял