Subsurface wastewater option rejected

Erin Town Councillors still want to explore alternative technologies for Erin’s future wastewater system, but discharging treated effluent into the ground instead of the river will not be one of them.

They received a detailed technical report last week by engineer Gary Scott of Ainley Associates that says a subsurface disposal system would be impractical, risky and more costly than surface disposal. The analysis is backed up by Credit Valley Conservation and the Ministry of the Environment and Climate Change.

“It’s not competitive with surface water disposal and doesn’t give any cost advantage,” said Scott. Council authorized the investigation last year.

“The Master Plan had mentioned it, but subsurface disposal hadn’t been looked at in detail, so we have plugged that hole.”

This will avoid the possibility that the overall study could be challenged and delayed for failing to have studied sufficient options.

The projections are based on the possibility of “full build-out”, meaning that homes could be built over a 20-30 year period on all of the lands within the urban areas of Hillsburgh and Erin village that are already designated for that use in the Official Plan.

Current homes in Erin village would generate wastewater of 2,244 cubic metres per day (m³/d), but that could more than double to 4,767 m³/d. The Hillsburgh flow could quadruple, from 600 to 2,400 m³/d.

For a subsurface discharge bed, Erin village would need 40 hectares (98 acres), set back at least 300 metres from any creek or wetland. Such lands do not exist near Erin village, even if they could be purchased.

“The MOECC would likely require a spare bed,” said Scott. “There is a history of failure for subsurface systems in North America and Europe. The ministry is cautious in approving them.”

Hillsburgh would require a 19.5 hectare (48 acre) lot, which Scott say may be possible. But he said the costs of building and maintaining subsurface disposal in Hillsburgh, plus traditional river disposal in Erin village, are 10-20 per cent higher than pumping Hillsburgh sewage to a single treatment plant in Erin village.

Preliminary estimates (at full build-out) show the cost of treating waste at two separate areas at $71 million, compared to $61.7 million at a single Erin village site. That does not include the huge separate cost of building the collection pipe system throughout the villages.

Previously, new growth was expected to be limited to 6,000 residents. But a strategy suggested last year (but not yet approved by council) could see well over 10,000 new residents. Some existing neighbourhoods could be exempt from having sewers, and intensive treatment of sewage could allow for more effluent being allowed in the river.

Full details of the strategy are to be presented at a Public Information Centre (PIC). This has been delayed, and is expected this spring. The current phase of the Environmental Assessment is intended to research various practical options for collection and treatment of wastewater. 

With fewer children, Erin is stuck in the middle ages

The number of children living in the Town of Erin is at its lowest point in more than 20 years, according to 2016 census data released last week by Statistics Canada.

Although the town’s population rose 6.2 per cent to 11,439 from 2011 to 2016, the proportion of children aged 0-14 continued a long-term decline.

Back in 1996, Erin had 2,558 children, making up 24 per cent of the population. Now, we’re down to 1,750 children, making up only 15.3 per cent of the population.

By comparison, the national average for the proportion of children 0-14 is 16.6 per cent, while in nearby Georgetown, the proportion is 19.4 per cent.

The total number of children in Erin is down 6 per cent in the last five years, but it’s not as drastic as in the previous 5 years (2006-2011) when the decline was 15 per cent.

Within the 0-14 age group, Statistics Canada reports 450 Erin kids aged 0-4, 595 aged 5 to 9 years and 705 aged 10-14. If these numbers were to stay consistent, it would mean a substantially lower number of elementary school age children, since fewer young children would be entering the school system.

Among adults, Erin’s lowest population groups are ages 25-29 (490 people) and ages 30-34 (450 people). In contrast, the age 50-54 group has 1,275 people and the 55-59 group has 1,105 people.

The population is heavily weighted in the middle groups, with the number aged 35-64 totalling 5,475, almost half the total population.

The number of people in Erin aged 65 and older is 1,725, or 15.1 per cent of the population, which is also lower than the national average of 19.9 per cent.

Population growth in the urban areas of Erin village and Hillburgh is lower than the Town average of 6.2 per cent, meaning that most growth has been in the rural areas.

Erin village up is up 4.9 per cent to 2,647 people, in 1,011 private dwellings (845 being single detached homes). Hillsburgh is up 5.5 per cent to 1,124 people, in 430 private dwellings (365 being single detached homes).

Overall the Town of Erin including rural areas has some 4,100 dwellings, with 3,770 as single-detached homes, 80 attached homes, 150 apartments and 100 moveable homes.

The average household size is 2.8 persons. The breakdown is 635 dwellings with one person, 1,525 with two people, 725 with three people, 795 with four people, and 415 with five or more.

While the census has Erin’s 2016 population at 11,439, the actual number of people living in the Town is probably higher. Some people are normally missed in the census. For the 2011 census, Statistics Canada estimated the “undercount” at 4.1 per cent.