As the population of Orangeville - and all Dufferin County for that matter - rises, there is no shortage of developers willing to build the homes to accommodate the influx.

Unfortunately, adequate sewage treatment for these proposed developments is in short supply in Orangeville and Shelburne, and the towns are having to take a cautious approach to allocating what treatment capacity it has available.

"We are trying to be fair to the developers and protect the community at the same time," said James Stiver, Orangeville's director of planning. "It's not an easy thing to do."

Needless to say, potential developers have their concerns over the allocation process. Currently, the Orangeville sewage treatment plant can process 14,400 cubic metres (m3) of sewage a day at full capacity.

Just 12,993 m3 per day is being processed right now, and a further 846 m3 has been committed to development projects that are currently under way.

That leaves just 560 m3 of "uncommitted reserve capacity," or enough for only 400 new residential units.

The town has altered its traditional "first-comefirst serve" policy of capacity allocation. There is now a criteria of conditions, and whatever allocations are handed out will be phased in over a period of three years.

While there may be enough capacity for 400 homes, the town is limiting allocation to a maximum of 100 homes per year. The developers will have to reapply for allocations each year.

The purpose of this, town officials maintain, is to monitor how effectively the treatment plant can handle the extra load.

It's an added condition that has some potential developers ill at ease.

In a letter to council, Christopher Matson of the Matson, McConnell Ltd. land management group, points out: "If there is a yearly restriction, some development projects may prove not to be financially viable in situations where major infrastructure projects are required, and a minimum threshold of units to pay for that infrastructure may not be achievable."

As well, Mr. Matson suggests that builders actively working on a project should be allowed to reapply every six months, instead of every year. His letter also suggests the 12- month policy should apply to projects that have been previously allocated but have sat idle for years and have not proceeded to develop.

There is one criterion that stipulates council will look favourably on proposals that provide for such public infrastructure as parks, trails or recreational facilities.

There are fears that such a criterion could allow council to play one developer off against another.

Mr. Stiver says this will not be the case, since the process is a one-shot deal where developers present their plans and council will make a decision based on those plans, alone. There will be no provision for renegotiating after the fact.

Meanwhile, Orangeville is looking toward expanding its sewage treatment capacity to 17,500 m3 per day, a figure Doug Jones, managing director of environmental development services, feels can accommodate close to all the undeveloped areas within the Orangeville boundaries.

"In a perfect world, my sense of it is that we should have an approved environmental assessment by 2009," says Mr. Jones. "After that, we would proceed with detailed design and construction which, in an ideal world, can move ahead in 2010."

Yet there are several factors that could delay such an expansion, and perhaps put the kibosh on it.

For one thing, the treated effluent from Orangeville is emptied into the Credit River below Island Lake, where the stream flows are well below those farther south. Since the buzz phrase in sewage treatment circles is "dilution is the solution to pollution," effluent discharged into smaller area with less water is prone to cause more damage to the area.

"When you're drawing water from Lake Ontario and discharging effluent into it, you are really only constrained by the size of your pumps and your pipes," says Mr. Jones. "The issue in Orangeville is that we're headwaters country."

Thus, Orangeville's sewage treatment is severely scrutinized by environmental agencies, notably the Credit River Conservation authority (CVC).

When the town expanded its treatment plant in 1985, it incorporated a system of "denitrification," which Mr. Jones says is still relatively state-of-the-art.

Denitrification is the process of reducing nitrate to nitrous oxide, which results in a reduction of nitrogen and inhibits excessive plant growth that can damage a wetlands ecosystem.

Studies conducted on the local Orangeville Marsh have concluded that the effects of the discharge have been "indistinguishable from natural climatic fluctuation." That means, essentially, that the effects of the effluent on the marsh are no more drastic than if nature had been left to its own devices.

The CVC is not yet convinced, however, and is requiring more studies and marsh monitoring before it decides when, and if, to lend its blessing to a sewage treatment plant expansion.

Although it would be technologically simple to deliver the sewage effluent down to the major sanitary sewer system in Peel Region, which sends the effluent directly into Lake Ontario, this has been ruled out by current provincial government policy.