Proper and complete laboratory analysis of wastewater and sludge is essential in the proficient operation of a wastewater treatment plant. Collected samples must be handled with care, and laboratory work must be carried out with a high degree of accuracy. Laboratory analyses are the sole guide available to an operator, providing information as to the success of maintaining process control. Thorough laboratory analysis also aids in maintaining operating costs and allows the treatment facility to develop and record historical operational data. Laboratory analysis is necessary to meet the effluent discharge requirements designated by the state and federal monitoring agencies. These regulatory agencies have established specific concentrations for several parameters that must be met when water is discharged from the plant. Severe penalties will be leveled against plants that do not meet discharge requirements outlined for their particular plant.
Laboratory analysis can be used for the following:
- To maintain proper process control and overall plant efficiency. For example, an analysis of the wastewater flowing through the aeration tanks for Total Kjeldahl Nitrogen (TKN), would allow the operator to know if any degree of nitrification is occurring in the aeration tanks. Biochemical Oxygen Demand (BOD) would be analyzed on the plant effluent to give the operator an indication of the removal rates through the system.
- To minimize chemical usage. For example, the chlorine residual test is used to control the disinfection of wastewater and dosage applied per unit flow. This has a direct effect on the cost of hypochlorination.
- To provide data necessary to operate and troubleshoot individual unit processes. By documenting day-to-day operation of the plant in terms of field log data and laboratory results; personnel can evaluate the operation of the plant over any given time frame (weeks, months, or years). When problems occur in process control, treatment plant personnel can study the laboratory results prior to the disturbance. By conducting this type of study, including noting variations in operational trends and sudden changes in process loading, the operator can us the results to aid in regaining control of the process. This information can assist in the design of plant expansions and can satisfy public or private inquiries about the plant operation.
- To provide data for interstate, federal, and state permit requirements. Influent and effluent samples are collected by operators and analyzed by laboratory personnel according to the frequency and methodology specified under the SPDES permit. These analyses include conventional parameters such as flow, pH, settleable arid suspended solids, BOD, and fecal coliform. This data is then provided in the form of reports to the various agencies.
- To monitor the pollutant load into the receiving water. This includes any and all tests necessary to indicate compliance with the SPDES permit, and to ensure the wastewater will not have an adverse effect on the receiving water. The community near the point of discharge will almost surely notice any adverse effects on the waterway, all of which can be public relations nightmares. Such effects can include fish kills, algal blooms, pathogenic organism contamination of the water forcing beach closures, or simply water with a foul odor.
- To monitor the various industrial waste discharges into the sewer system and insure that these industries pay a fair and equitable share of the cost of treatment. This includes characterizing industrial discharges; determining the pollutant strength, toxicity, and its impact on the treatment processes and receiving waters; and providing a database of evidence to legally prevent an industry from dumping harmful waste without a viable pretreatment process.
|
