Canadian Regulations for Waste Treatment

Gold Refining Forum

Help Support Gold Refining Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Noxx

Well-known member
Joined
Feb 24, 2007
Messages
3,365
Location
Quebec, Canada
According to Environment Canada:

4.3.4 Water Effluent Guidelines

Recommendation R 304

Wastewater treatment facilities should be designed, constructed, operated, and maintained to achieve the following effluent quality prior to release:

On a continuous basis:
pH
6.0-9.5

Maximum monthly mean concentration:
Total suspended solids
15.0 mg/L
Arsenic
0.5 mg/L
Copper
0.3 mg/L
Cyanide*
1.0 mg/L
Lead
0.2 mg/L
Nickel
0.5 mg/L
Zinc
0.5 mg/L

* If cyanide is used in the process.

Non-acutely lethal effluent:
No more than 50% mortality of Daphnia magna and rainbow trout test species in 100% effluent when tested in accordance with Environment Canada Reference Methods 1/RM/1355 and 1/RM/14.56

--------------------

Recommendation R 306

In addition to the source performance recommendations of R 304 and R 305, each facility should design and operate effluent discharge systems, taking into account local conditions and the following ambient water quality objectives:

Table 3: Ambient Water Quality GuidelinesSubstance Guideline (µg/L)*
Aluminum 5-100
Ammonia (total)** See table 4
Ammonia (un-ionized)*** 19
Arsenic (total) 5.0
Benzene 370
Cadmium 0.017
Chromium
- Trivalent chromium (Cr(III)) 8.9
- Hexavalent chromium (Cr(VI)) 1.0
Copper (total) 2-4
Cyanide (free) 5
Iron (total) 300
Lead (total) 1-7
Mercury
- Inorganic mercury 0.026
- Methylmercury 0.004
Molybdenum 73
Nickel (total) 25-150
pH 6.5-9.0****
Selenium (total) 1.0
Silver (total) 0.1
Thallium 0.8
Zinc 30


Notes:

* Canadian Council of Ministers of the Environment, Canadian Environmental Quality Guidelines for the Protection of Freshwater Aquatic Life (Summary Table update December 2003).
** Ammonia (total) is used to describe the sum of ammonia (NH3) and ammonium (NH4+).
*** Ionized ammonia refers to the ammonium ion (NH4+).
**** No units for pH.

Critical loads can be used to indicate whether deposition of sulphates, metals, and metal compounds to surface waters is above or below a level that would lead to environmental impacts.

Critical loads may be defined as the amount of deposition required for contaminant levels to reach threshold effect values in receiving media. For surface waters, the critical load is the rate of deposition to the water body or to areas draining to it that would lead (accounting for the fraction retained in the soil) to minimal effects on sensitive aquatic organisms.60

The estimated critical loads can be compared with actual deposition rates near a releasing facility and thereby act as one of the environmental quality objective indicators for evaluating the effectiveness of utilized pollution controls by the facility (see also Section 4.2.9 for more details on critical loads).

The total ammonia guideline is not a specific value, but rather a range of values over various pHs and temperatures. That is because ammonia toxicity is affected by various factors, among which are pH, the most important, and temperature.

Table 4 provides total ammonia guidelines over a range of pHs (6.0-9.5) and temperatures (0-30°C) based upon the un-ionized ammonia guideline of 0.019 mg/L and the following two equations:61

http://www.ec.gc.ca/lcpe-cepa/default.asp?lang=En&n=9233A7E7-1&offset=6&toc=show#s4_3
 
Back
Top