스위스 호수 근처 주택들은 어떻게 하수 처리 할까?
<iframe width="1280" height="720" src="https://www.youtube.com/embed/B9VRvOKKwfs" title="SWITZERLAND • 4K Relaxation Film: Winter to Spring • Relaxing Music - Nature 4k Video UltraHD" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>