BIOSOLIDS/SLUDGE

A Water Treatment Plant By-Product

Biosolids Disposal

Governed under the Environmental Protection Act - Ministry of Environment. Also administered by the Ministry of Agriculture, Food and Rural Afairs. Approved by the Environmenal Assessment - Approvals Branch of the MOE. Medical Officer of Health - if public health issue identified. The biosolids can be disposed of in three different ways:

• Landfill, with applicable approval

• Organic Soil Conditioner

• Incineration

Utilization vs Disposal

Landfilling biosolids provides no economic / environmental benefit. As well, landfilling concentrates disposed material in a centralized area. And incineration is not cost effective. Utilization promotess the three R's - Reduce, reuse and recycle.

How Biosolids Can Be Utilized?

Organic Soil Conditioning vs. Fertilization. Spreading or injection of biosolids to agricultural land. Active farming / crop planting and rotation to make use of available nutrients. Require input from an agronomist for best field application rates as per requirements of specific crops.

Waste Management System

Required for all Organic Soil Conditiong Sites and Systems

• Approved by Approvals Branch - Toronto

• Includes vehicles used for transportation and spreading

• All disposal sites are governed by Certificates of Approval - issued by regional Office of the Ministry of Environment

Allows for the use of biosolids for the purpose of soil conditioning, for agricultural purposes. It becomes a living document, changes to equipment or soil conditioning sites can be reflected with amendments.

Organic Soil Conditioning Sites

Plots of land for which a Certificate of Approval has been issued. C. of A.'s are issued by the Regional Office of the ministry of Environment.

• Reflects regional characteristics - in tune with local needs

• Subject to an assessment of the site(s)

Desired - Not Desired Constituents

Waste material must provide nutrient benefit to operation. Nutrient benefit must be compared to fertilizer application rate. Undesired constituents - garbage, trash, heavy metals, chemicals - requires analysis of the waste source (batch samples) prior to approval.

Site Assessment

• Require map, topographical, soil, drainage

• Terrain description, site physiology

• Soil description and depth

• Presence of groundewater table, nearby surface water bodies

• Nearby drinking water supplies

• Clearance distance

Soils
The ability of the environmnet to absorb the effects of biosoild utilization is reflected in the ability of the soil to treat/absorb the contaminants ñ nutrients available in the biosolid.

Crop Utilization
Specific crops utilize certain nutrients in varying levels. Available nutrients with specfic biosolid sources can be tailored to required crop needs

Groundwater Table
In order to provide a minimum level of protection of existing groundwater supplies, no utilization program involving biosolids can occur if the disposal area is within 900 mm of the groundwater table.

Clearance to Surface Water

Any disposal plot must be located a minimum of:
50 meters for rapid, moderate, slow soils, 0-3% Slope
100 meters for rapid, moderate, slow soils, 3-6% Slope
200 meters for rapid, moderate, slow soils, 6-9% Slope
Not permitted for moderate to slow soils, >9% Slope

Drinking Water Supplies

Any disposal plot must be located a minimum of:
15 meters for drilled wells >15 meters in depth
90 meters for all other types of wells, including dug well

Residences
Any disposal plot must be located a minimum of:
90 meters for any private residence
450 meters for residential areas

Groundwater Protection
In order to protect the existing ground water supplies, a minimum clearance distance (vertical) of 900 mm is required, to provide an optimum treatment horizon (physical, chemical, biological treatment)

Public Acceptance
Public concern over biosolid use is commonly related to matters related to odours, air bourne drift or surface run-off. To minimize these concerns, the Guidelines incorporate minimum clearance distances. Clearance distances are affected by the type of spreading

Soil Criteria

Dense clays, poor draining or excessive soils are not acceptable for the utilization of biosolids for organic soil conditioning. Waste materials can be applied to mineral soils, but not organic soils.Organic soils are soils which contain 17% or more organic carbon by weight, and which have a depth of 0.4 meters or more unconsolidated organic material.

Soil Tests

In order to utilize specific soil plots for organic soil conditioning, tests for soil pH, phosphorous and heavy metal content are required. Reflects geographical difference in area across the province, to ensure that the practice of biosolid utilization does not pose a detriment to the environment

Biosolid Spreading

To minimize the risk of runoff, spreading is discouraged during frozen or ice covered conditions. Slope of the disposal plot must be less than 3%. Where surface run off is expected, waste materials should not be applied, or clearance distances should be increased

Spreading Restrictions ­ Public Health and Pathogens

Dependent upon the type of crop, spreading practices should not occur:

Hay and Haylage ­ 3 weeks before grazing

Pasture (horses, cattle)- 2 months before grazing

Commercial Sod ­ 12 months before harvest

Vegetables ­ 12 months before harvest.

Waste Handling

In order to minimize the public health concerns for handlers of biosolids, care must be taken to handle such materials in a safe manner. Persons dealing with biosolids must operate/use equipment in such a manner so as to not endanger themselves. Follow requirements for entry into confined spaces as required under the Occupational Health and Safety Act

Responsibilities

It is the responsibility of all parties involved to adequately safeguard against any action, which may result in degradation of the natural environment, groundwater or surface water supplies of Ontario.

Complaints

Where the utilization of biosolids on agricultural lands results in condition or conditions, which are not in compliance with the Guidelines, MOE regulations, or established practices for biosolid disposal, such complaints are to be forwarded to:

• The District Office of the Ministry of Environment

• The local staff of the Ontario Ministry of Agriculture Food and Rural Affairs

• The local Medical Officer of Health

So what's at Risk?

Overall, the practice of biosolid utilization has to be viewed as risk assessment of the pro's and con's of the practice.

• Are the wastes buried in the landfill less or more detrimental to the environment?

• Are the sampling and testing protocols established by the MOE and OMAFRA stringent enough to protect and safeguard public health and drinking water supplies?

What's the Choice?

As part of the evolution of municipal services and protection of discharges to the surface water of the environment, improved treatment measures has resulted in greater biosolid production. To discharge this material and bury underground does not fully utilize the nutrient benefit of the compound.

Risk Assessment

Overall , the practice of biosolid utilization does not work in all parts of Ontario, and not all biosolids are suitable for this program. Sources which do not meet the criteria for disposal in this manner are not eligible. Sites which do not meet the limited parameters are not suitable.

Taken into Context...

Thousands of private on-site sewage systems discharge partially treated effluent, with no secondary or tertiary level of treatment to the groundwater table. Most on-site sewage systems have no maintenance or monitoring program to ensure proper operation of effluent characteristics.

Time for Change

If the analysis, stringent control measures, approval process, sampling, testing, evaluation and on-going monitoring of biosolid utilization reduces the amount of material that is buried, instead of being utilized for some practical purpose, then this practice should be fostered and explored.