.reciclagem{
    background-image: url(../img/fundo-reciclagem.jpg);
    background-repeat: no-repeat;
    background-size: cover;
    text-align: center;
}
.ferro{
    background-image: url(../img/fundo-ferro.jpg);
    text-align: center;
    background-repeat: no-repeat;
    background-size: cover;
}
html, body, .container-fluid, .row, .col-md-6 {
    height: 100%;
  }