Water quality regulations developed by governmental agencies usually have effluent standards and rules for issuing and enforcing permits for individual effluent outfalls (Goldsteen, 1999).
Water quality standards are designed to prevent effluents from causing negative impacts on receiving waters (Gallagher and Miller, 1996; Boyd, 2000).
Standards normally specify limits for selected water quality variables and may contain other restrictions. A water quality standard might contain the following water quality restrictions: pH, 6 to 9; dissolved oxygen, 5 mg/l or more; 5-day biochemical oxygen demand (BOD5), 30 mg/l or less; total suspended solids, 50 mg/l or less.
Sometimes, the standard also may place a restriction on discharge volume or restrict discharge volume indirectly by specifying a maximum daily load for a variable.
To illustrate, the maximum daily volume might be 10,000 m3 /day, or the maximum BOD5load cannot exceed 100 kg/day. The load limit would restrict volume to 3333 m3 /day at a BOD5concentration limit of 30 mg/l, or restrict BOD5 concentration to a maximum of only 10 mg/l at a maximum daily discharge.
There may be qualitative criteria in standards, such as no discernable odour, no foam, or no visible plume at the outfall. Effluent permits often are issued on a case-by-case basis, and the numerical and qualitative criteria of the standard will depend upon the nature of the effluent and the
characteristics of the receiving water. Sometimes, industry-wide general permits are issued for a particular activity. In this situation, permits for all operations will be similar. An effluent permit for a particular discharge point also will contain a list of numerical and qualitative criteria, and it also will give instructions on sampling, analysis, and reporting.
Sometimes, discharge permits only require the application of specific practices called best management practices (BMPs, to be discussed below), while others may contain both water quality standards and BMPs. Where BMPs are mandated, there will be an inspection procedure for verification and continuation of discharge permit validity (United States Environmental Protection Agency, 1995).
Effluent permits have been required by the government for some aquaculture operations in the United States and other developed nations. Some developing nations have already developed effluent standards for aquaculture, and possibly, a few permits have been issued.
The aquaculture effluent rule now being developed in the United States is expected to contain some numerical standards but to be based primarily on BMPs (Boyd and Tucker, 2000; Boyd and Hulcher, 2001). Many developing nations often adopt regulations similar to those used in the United States.
Thus, the final form of the aquaculture effluent rule now being developed by USEPA may have far reaching effects on governmental regulations for aquaculture in other nations. The development of aquaculture regulations does not assure that the regulations will be applied at the farm level.
The effort to enforce compliance with effluent permits would be a difficult and expensive activity in many nations. Ideally, a producer would be issued either an individual or general permit, and the effluent would have to be monitored according to a specific schedule. Usually, the farmer would be responsible for monitoring and would either make the analyses on farm or send the samples to a qualified laboratory.
The farmer also would be responsible for reporting results to the permitting agency. The agency would evaluate the report and decide if the farm is in compliance. The agency also would be responsible for enforcing cases of non-compliance.
Moreover, the permitting agency would have to check a sample of farms periodically to assure that analyses are being done in the proper manner and that reports are accurate.
In a developed country such as the United States where aquaculture farms are not extremely numerous, the financial resources and personnel needed to issue permits, review and verify monitoring and reporting efforts, and provide enforcement usually would be available.
Most of the aquaculture in the world is conducted in developing countries and especially in Asia. In the major aquaculture nations of Asia, there are tens of thousands of small farms operated by individuals with relatively little technical knowledge. The large personnel and financial requirements would make it virtually impossible for these nations to effectively regulate aquaculture effluents by application of traditional effluent standards.
At least two non-governmental organizations have made effluent standards for aquaculture. The Global Aquaculture Alliance (GAA) is an international aquaculture organization promoting environmentally responsible production. It suggests that members use environmentally responsible culture methods to comply with effluent standards (Table 1).
The GAA standards consist of initial, rather lenient limits, and stricter target limits with which the member should comply within 5 years (Boyd and Gautier, 2000). The International Finance Corporation (IFC) sometimes provides low interest loans to aquaculture projects in developing countries. The IFC requires compliance with water quality standards (International Finance Corporation, 1998).
The standards that have been required for farm effluents apparently are the same ones required for fish processing operations (Table 2). Of course, the GAA program is just being initiated, and only a few aquaculture facilities are funded by IFC.
It is important to note that when governmental or other organizations require compliance with effluent permits and standards, these organizations do not usually mandate what procedures must be used to achieve compliance. If the effluent does not comply with the permit or standards, it must be treated by some procedure that will improve its quality or management changes must be made that will result in higher quality effluent.
Author:
Claude E. Boyd
