Single view application으로 프로젝트를 생성하고 아래 코드와 같이 ViewController를 구성하니 #이 잘 동작합니다.

urlWithSharp에 들어있는 url의 #뒤를 one, two,three등으로 변경하면서 실행해 봤어요.

import UIKit
import WebKit

class ViewController: UIViewController,WKNavigationDelegate {

    var webView : WKWebView!
    override func viewDidLoad() {
        super.viewDidLoad()
        let urlWithSharp = "http://www.owlcarousel.owlgraphic.com/demos/urlhashnav.html#three"
        let url = NSURL(string: urlWithSharp)
        let request = NSURLRequest(URL: url!)

        // init and load request in webview.
        webView = WKWebView(frame: self.view.frame)
        webView.navigationDelegate = self
        webView.loadRequest(request)
        self.view.addSubview(webView)
        self.view.sendSubviewToBack(webView)

    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}