The first discharge standard: COD ≤ 100mg / L, ammonia ≤ mg / L, phosphorus ≤ 0.5mg / L, residual chlorine ≤ 0.5mg / L. These are more common. Specific or depends on the local environmental protection department to the standard. Individual enterprises will be more lenient. Detection of less on the local testing department can be sent to test. More can buy their own test strips or instruments more cost-effective.