| Parameter | Purpose of Test | Method |
|---|---|---|
| BOD5 | Provides a relative measure of "food" available, the degree of stabilization of the wastewater and to estimate the effect of the effluent on the receiving water body. Used for plant loading/design, discharge rate for industrial facilities, and EPA NPDES reporting. 5 day test is too long for process control — many plants use COD or TOC as early estimate. Used to calculate % removal. | 8043 8215 8229 |
| Nitrite, LR |
Indicative of the stage of conversion of ammonia and organic nitrogen forms to nitrate by the aerobic biological treatment steps (nitrification). Nitrite is the intermediate nitrogen form between ammonia and nitrate. Nitrite is highly toxic, and small amounts can upset the delicate biology of a wastewater plant. | 8507 10019 10207 |
| Ammonia |
Monitor conversion of ammonia and organic nitrogen forms to nitrite and nitrate during the WW treatment process. Provices information on process conditions in biological treatment stages. At high concentrations an pH, ammonia can be toxic to sludge digestion microbes. | 8038 10031 10205 |
| Phosphate, Reactive LR |
Phosphorus effluent concentrations are often controlled by discharge permits, to limit addition of nutrients to the receiving body. Phosphate is removed via biological nutrient removal prcesses and/or chemical precipitation. Reactive (ortho) phosphate is the phosphorus form that is most available to biological species. Total Phosphate includes orth-, poly-, and organic forms. | 8048 8178 10209 |
| Nitrate, HR |
Indicative of the stage of conversion of ammonia and organic nitrogen forms to nitrate by the aerobic biological treatment steps (nitrification). | 8039 10020 10206 |
| pH |
Maintain proper (narrow) pH range for optimal biological processes — especially nitrification. Can indicate plant upsets by industrial discharges or development of anaerobic conditions within the plant. Important condition for methane formation and avoiding ammonia toxicity in sludge digesters. | pH meter & electrode - see instrument manual |
| Alkalinity |
Maintain buffering to mediate effects of acidic industrial discharges. Control nitrification conditions in secondary treatment processes. Maintain proper bacterial conditions in sludge digester. | 8203 8221 |
| Phosphate, Total LR |
Phosphorus effluent concentrations are often controlled by discharge permits, to limit addition of nutrients to the receiving body. Phosphate is removed via biological nutrient removal prcesses and/or chemical precipitation. Reactive (ortho) phosphate is the phosphorus form that is most available to biological species. Total Phosphate includes orth-, poly-, and organic forms. | 8190 10209 10210 |
| Oxygen, Dissolved | Measured to control aeration and save money. Also measures the amount of available oxygen for aquatic life in the effluent. DO is also commonly measured reportable parameter on NPDES permits. | 8166 8215 8229 8316 8332 8333 |
Application - Wastewater Chemistries - Nutrient Removal
Most Frequently Asked Questions
Also Consider
| Parameter | Purpose of Test | Method |
|---|---|---|
| Nitrogen, Total | Total of ammonia, nitrate, nitrite, and organic nitrogen forms. | 10071 10072 10208 |
| Nitrate, LR | Indicative of the stage of conversion of ammonia and organic nitrogen forms to nitrate by the aerobic biological treatment steps (nitrification). | 8192 |
| Nitrite, HR | Indicative of the stage of conversion of ammonia and organic nitrogen forms to nitrate by the aerobic biological treatment steps (nitrification). Nitrite is the intermediate nitrogen form between ammonia and nitrate. Nitrite is highly toxic, and small amounts can upset the delicate biology of a wastewater plant. | 8153 10237 |
| TKN Total Kjeldahl Nitrogen |
Total of organic and ammonia forms of nitrogen. | 8075 |
| Flow | Measure standard in-pipe flow rate for NPDES permit requirements and to establish concentrations/total presence of key analytes. | |
| Solids | Most commonly measured and regulated parameter on NPDES permits. Used to measure mixed liquor suspended solids concentration, return activated sludge/waste activated sludge concentration, influent suspended solids concentration, effluent suspended solids concentration, and % removal. | 8006 |


