little dover decentralized

8/14/2019 Little Dover Decentralized

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THE MUNICIPALITY OF THE DISTRICT

OF GUYSBOROUGH

LITTLE DOVER DECENTRALIZED

SEWER SOLUTION


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Little Dover Decentralized Sewer Solution, Page 2

EXECUTIVE SUMMARY:

The Innovative Project which is being submitted by the Municipality of the District of

Guysborough for the Municipal InNOVAward is a decentralized wastewater collection and treatment

system specifically designed and implemented to meet the challenges faced in rural Nova Scotia,

particularly for small coastal communities. Little Dover, like most fishing villages in Nova Scotia, has

extremely poor soil conditions including a lot of rock; and, with the decline of the fishing industry the

income levels are very low. Therefore, this project provides a practical and efficient wastewater

collection system at an affordable cost using innovation in both the design and the funding/cost

sharing methods.

(RECIRCULATING SAND FILTER BELOW)


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REASON FOR INNOVATION:

The Municipality of the District of Guysborough was faced with a very serious environmental

concern in the community of Little Dover. Little Dover is a small fishing village at the eastern end of

Nova Scotia on the rocky shores of the Atlantic Ocean. This fishing village, like many others in Nova

Scotia, has approximately 150 homes nestled along the shoreline of a small fishing harbour. The

soil conditions in this village provide very poor conditions for on-site sewer systems which has

resulted in severe contamination problems within the community.

In 1974 a pollution control study was carried out in Little Dover which identified the need fora sewer system at that time. Again, in 1988 the Department of Health identified that only 22% of

sewer systems were functioning properly and that 80% of the wells were contaminated or threatened

by contamination. In 2000 the Municipality carried out a sanitary survey of the community which

indicated that 71% of the wells in the community were contaminated by fecal or total coliform

bacteria. Each home in the community releases approximately 200 gallons of contaminated water

and sewer per day. In total, there is approximately 30,000 gallons released in the community each

day with the majority of the contaminated water escaping into the ditches, shoreline and

surface/groundwater supplies. The 2000 survey confirmed that there was a serious environmental

hazard within this community which resulted in the Municipality proceeding with a design of a system

to collect and treat all contaminated water for treatment.

The decision was made by Guysborough Municipal Council that the sewer problem had to

be corrected in this village to prevent serious health problems from occurring directly related to

contaminated well water. One of the challenges faced by the Municipality in determining a solution

for this community was the high unemployment rate combined with both low and fixed incomes.

These economic conditions, created by the downturn in the fishing industry, required an affordable

solution that would achieve the goal of cleaning up this community.


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INNOVATIVE ELEMENTS OF THE PROJECT:

The Municipality had to implement many new policies, procedures and programs to allow

clean up of this community to proceed such as:

A. Innovative design for the wastewater collection & treatment system

B. Wastewater management district to allow access to all private properties

C. Low income exemptions and policies for capital charges and capital charge payment

plans (up to 10 years)

D. Partnerships with three levels of government and multiple government departments


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A. INNOVATIVE DESIGN FOR THE WASTEWATER COLLECTION &

TREATMENT SYSTEM:

The type of system to be installed in Little Dover is a Small Diameter Gravity Sewage

Collection System and a Recirculating Sand Filter Treatment System which consists of...........

A. A 1000 Gallon Waterproof Tank on each Property

i. A filter in tank to ensure no solids escape

ii. Tank will have watertight risers to surface for

monitoring and clean out

iii. Pumps in tanks below elevation of flow line

with electrical connection to home

iv. Tank system provides primary treatment

which is 75% of the necessary treatment

v. Scheduled for semi-annual monitoring for thickness of solids on top of

tank. Tank will only be pumped as required.

B. Small Diameter Sewage Collection Linesi. Main line along street approximately 5 feet deep for liquids. (6 inch & 4

inch diameter pipe is used)

ii. Whereas lines collect liquid only, clean outs are

used instead of expensive man holes

iii. Considered a closed system eliminating storm

water problems. Pumps are water pumps only.

Clean out protected by an outside manhole

eliminate storm water to enter the system

iv. 4 or 2 lateral extends to 1000 gallon tank on

property


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Design Advantages Versus Conventional System:

1. A small diameter gravity sewer system has a significantly reduced cost per foot to install

due to reduced pipe sizes and reduced depths for installation therefore allowing a much

greater area to be serviced within an acceptable cost per household making the small

diameter gravity sewer system the solution for decentralized communities with

contamination problems.

2. A small diameter gravity sewer system is a closed system which does not have manholes

or any opening collecting unwanted storm water in the system. Conventional systems

have manholes approximately every 100 metres which collect large amounts of storm

water, dirt, etc. in storm conditions substantially increasing flows to both pumps and

treatment facilities therefore significantly increasing operating costs for conventional

systems.

3. Mainline for a Small Diameter Gravity Sewer System is generally 4 in diameter and is

buried approximately 4 in depth following the contours of the land/street. A conventional

system normally ranges from 8 to 12 in depth. The advantage of shallower trenches is

less disturbance of streets and properties, reduced risk of impacting on the water table,

streams and dug wells. There is also a significant reduction in construction safety

concerns with shallow trenching versus deep trenches. Shallow trenches also reduce the

potential of having to blast ledge or rock which is a common problem encountered in

shoreline fishing communities. All of these considerations save capital costs.

4. The significant advantage for the homeowner is the fact that the Municipality installs the

complete system including the portion on the private property up to within 1 metre of the

dwelling. Each property receives a waterproof tank on the lot which provides 70% of the

necessary treatment of the solids generated at each property.


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5. A significant advantage on both capital and operating aspects of the system is that all

pumps in the collection system are water pumps only as all solids are contained within the

tank on the lot and the collection system is protected by a filter which allows water onlyto leave the tank.

6. In general the cost to install a small diameter gravity sewer system is 30% - 50% less

than the cost of a conventional system. While a complete conventional design was not

completed by the Municipality it is estimated that a capital savings of +- $1.2 million will

be realized. If greater savings can be realized in similar future projects due to design and

construction refinement then there would be tens of millions of tax dollars saved.

7. The operating costs should be substantially lower than a conventional system as it is a

closed system eliminating storm water and 70% of the treatment of solids occurs in a

water proof tank on each individual lot. (Tanks would be checked semi-annually and only

solids not processed by natural bacteria in the tank would be pumped.)


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B. LITTLE DOVER WASTEWATER MANAGEMENT DISTRICT:

The Wastewater Management District that was identified in the community of Little Dover as

having a serious sewage problem is 2 km long and contains approximately 4 km of road to be

serviced within the defined area. However, funding would not allow for a central sewage collection

and treatment system to be provided for the entire area therefore it was necessary to find another

approach. It was determined that in order for the wells, brooks and shoreline to be environmentally

reinstated there would have to be a community effort with all the designated area being addressed.

Two of the problems that were faced by the Municipality were access to private properties and cost

to residents. Therefore, in order to address many of the issues with servicing this large area Council

established a Wastewater Management District and adopted a Wastewater Management District

By-law.

The Wastewater Management District By-Law provides the necessary authority to proceed

with the installation of a sewer system on both public and private property. The By-law also

authorizes the Municipality to collect rates from residents toward capital charge for the project and

also rates for the operation and maintenance of the sewer system. The By-law established a

Wastewater Management District Area to be serviced and also regulates the type of pipe used and

the installation procedures and other matters concerning the installation and operation of the system.

The advantages of a wastewater management district is it identifies a specific target area with

environment problems resulting from wastewater discharge and provides Council with authority to

determine the most economical method of correcting all wastewater problems within the defined

area. It also provides access to both public and private property and allows either on-site or central

connections to be used. It allows a much larger area to be considered for clean up and also allows

capital and operation costs to be contributed to by larger groups of property owners. The Municipality

assumes responsibility for the management of wastewater for all existing and new developments and

it provides assurance to residents that all wastewater within the defined area is managed to ensure

protection of the environment.


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All registered property owners were given the opportunity to advise Council if they were in

favour or not in favour of a new sewer system and Wastewater Management District. An open house

information session was held to discuss the design, funding and costs for the project. (cost sheetspresented are attached). A public meeting was also held with a formal presentation by municipal

staff, council, engineering and environment representatives. In addition to informal meetings, flyers,

etc. a confirmation letter was sent to each property owner where they were asked to provide a

response for or against the project.


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C. PROJECT FUNDING & LOW INCOME EXEMPTION:

The project costs and sources of funding are broken down as follows:

The Municipality took several measures to ensure that the installation of a public sewer

system in Little Dover is affordable for the residents. First, the capital charge was established at$2,500 per equivalent unit. This amount reflects the investment some had already made in on-site

systems and the Councils desire to clean up the environment for the public good. The Council will

pay the balance of the local share from general rates. Second, the option of a 10 year payment

plan was adopted. This would allow residents without the ability to pay the $2,500 charge up front

the option of financing the capital charge over a period of up to d10 years. An interest rate of 9.25%

applies to these plans. The rate was intended to be competitive with bank borrowing rates so as to

not be either punitive to those who had to choose the payment plant or attractive to those who would

pay the lump sum up front. Third, a low income capital charge exemption was adopted. Thisexemption will provide for a $100 annual reduction for residents with incomes $12,000 or lower and

a $50 annual exemption for residents with incomes between $12,000 and $15,000. If residents

choose to take advantage of the 10 year payment plan this exemption could apply each year and

result in a savings of $500 to $1000.


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APPENDIX A

RELATIONSHIP OF PROJECT TO AWARD CRITERIA:

The Little Dover Sewer Project provides many benefits to the residents by, first of all, cleaning

up the environment in this community using a very cost effective method. This results in lower capital

installation costs for the residents as well as anticipated lower operating costs which is a direct cost

savings for residents on their annual operating charge.

An additional benefit to residents is due to the simplicity of the design of this system whichresulted in a large portion of the work under the contract being carried out by local residents.

The system installed in Little Dover allows the Municipality to provide public sewer service to

a large area in a rural community with medium density in a cost effective manner which could not be

serviced by a conventional sewer system within an acceptable cost.

The Little Dover Sewer Project is not only funded under the infrastructure program but has

also been supported by current programs and services available from many government departmentsas identified in the project description.

The Little Dover Sewer Project involves partnerships with all levels of government and multiple

departments as identified in the project description.


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