The good news from the city is that Oahu seems to have more time than previously expected to solve its ongoing challenge over locating a new landfill.

There is no bad news — assuming city officials can make a persuasive case to planning authorities. But there is this reality check: Postponing a final decision might be the prudent, but it requires that the city commit to vigorous policies that continue to reduce the municipal waste stream.

And that means consumers should support initiatives to reduce the waste that they add. Turning away from throwaway shopping bags and foam boxes looks more and more sensible.

On Monday the city released a study that took another look at 11 landfill sites first identified five years ago. But the bottom line in the city’s announcement was that officials resolve to continue using the Waimanalo Gulch Sanitary Landfill for the near term.

That’s a decision that won’t set well with West Oahu residents who have beat the drum for a closure of the landfill, sooner rather than later.

It’s the city Planning Commission that needs to be convinced first, as the landfill operates under a permit that requires a backup landfill for waste that is not eliminated by the HPOWER garbage-to-energy incinerator.

That hearing has not been scheduled; the regulatory stop after that will be the state Land Use Commission.

The hope, said Mayor Kirk Caldwell on Monday, is that a large landfill won’t be needed for daily use, given technological solutions that have been developing. Everyone has to hope that he is correct.

But in order to pursue this vision to completion, the city has to show progress in its pursuit of that technology. City Environmental Services Director Lori Kahikina said there should be evidence of that by the end of the year.

That’s when requests for proposals are due to go out on projects that should reinforce the city’s waste-reduction efforts, Kahikina said. One is a process in which two companies have demonstrated the ability to eliminate the problem of “fly-ash” in automotive shredded residue, a component of the landfill, she added.

This can be processed into a product that, lacking the high-metal contaminant of the fly-ash, can be used in paving and backfilling trenches, Kahikina said.

There is another initiative that would get underway — again, with an RFP issued at year’s end — to use discarded glass locally, she said.

All of this sounds encouraging, but the search for innovative strategies can’t end there. There are other “recyclables” — plastics, in particular — that should be recycled. Finding a local use would be ideal, although the economies of scale in the small Hawaii marketplace are difficult to establish.

Also unfortunately, the cost of shipping the materials to willing markets elsewhere has been rising. It may be necessary to convert some of this material to energy, and the city may need more flexible laws to enable that, if alternatives can’t be found.

If the city can show an aggressive posture on these initiatives, the planning agencies ought to support a delay in a final landfill selection.

The current assessment (download at opala.org) ranks the possible sites with a slightly different emphasis, which tended to demote some alternatives that were far off the beaten track. Trucking trash farther inland might end up too costly and impractical, Kahikina said.

That meant the leading sites were Upland Nanakuli, the Ameron Quarry, Kapaa Quarry Road, Keaau and a Kaneohe site by the H-3 freeway. But in the 20-year remaining capacity at Waimanalo Gulch, she said, options should expand and smaller sites might be workable.

The prospects do look hopeful. But it will take more than hoping to hit Oahu’s waste-reduction marks. The city must pick up the pace toward that end.