Is a paper that takes existing techniques to solve a practical and more specific problem valuable enough to get published? Let's consider a paper that uses many different techniques to solve a practical problem. The techniques that the paper uses have all already been published by others. This paper only modifies or customizes these techniques a bit to fit the particular question that the paper is solving.

The techniques used are from different disciplines. So the paper is more or less similar to an integration of these techniques. These different techniques were proposed or published for a general purpose with no specified applications before. Now this paper integrates them together and solves a rather specific and practical problem.

I understand that this kind of very-specific-problem-solver application paper will get cited less often than those algorithm papers that may be applicable to many applications. However, let us leave the impact factor issue aside first.

Is this integration and application valued by the peers? Is this paper valuable enough to get published? (not considering its impact first)
In my opinion, yes.

You paper will prove that those techniques are useful and usable by using them to solve a practical problem. I consider it a contribution to human kind, thus valuable to get published.

Whether or not it will be accepted by journal/conference is another issue. You should try. Please send it to be peer-reviewed.