How can you monitor wastewater quality effectively?

Monitoring wastewater quality is imperative because the destination of the wastewater determines its potential impact on the environment and public health. If wastewater is discharged into receiving water bodies such as rivers, lakes, or oceans, it can introduce pollutants and contaminants, jeopardizing the health of aquatic ecosystems and, subsequently, human communities reliant on these water sources for drinking, recreation, and livelihoods. Similarly, if wastewater is repurposed for irrigation, ensuring its safety is crucial to prevent the contamination of agricultural crops and soil, as well as potential health risks to consumers.

Regular monitoring is crucial in identifying existing problems or any issues that could emerge in the future. Consistent monitoring of wastewater quality is therefore of high environmental importance. Proper monitoring provides information on whether oil separation from wastewater and surface water is within tolerable limits when discharged, as well as proving the downstream treatment stages are working properly. Proper treatment may also allow treated water to be reused in the production process or for other applications.

Both industry and daily life generate wastewater. Timely detection can detect whether chemicals and other substances in the water exceed the standard, ensuring environmental safety and avoiding the impact of wastewater on the environment and people. It can be recycled and reused,

The parameters to monitor in wastewater depend on its final destination and regulatory requirements. For discharge into water bodies, parameters such as biochemical oxygen demand (𝗕𝗢𝗗), chemical oxygen demand (𝗖𝗢𝗗), suspended solids (𝗧𝗦𝗦), 𝗽𝗛, and specific pollutants are typically monitored. If wastewater is intended for irrigation, parameters like pathogens (e.g., 𝗳𝗲𝗰𝗮𝗹 𝗰𝗼𝗹𝗶𝗳𝗼𝗿𝗺𝘀), nutrients (e.g., 𝗻𝗶𝘁𝗿𝗼𝗴𝗲𝗻 and 𝗽𝗵𝗼𝘀𝗽𝗵𝗼𝗿𝘂𝘀), 𝗵𝗲𝗮𝘃𝘆 𝗺𝗲𝘁𝗮𝗹𝘀, and 𝘀𝗮𝗹𝗶𝗻𝗶𝘁𝘆 may be of concern. Monitoring should align with regulatory standards and the specific environmental and health risks associated with the wastewater's use or disposal.

When it comes to parameters in wastewater we mostly drawn our attention to values like TSS, COD, BOD, dissolve oxygen, TDS, PH, turbidity, Nitrogen, Phosphorous and heavy metals. But the word 'effectively' can force us to neglect or ignore deeper thoughts. If the outgoing water of treatment is discharging in farm it might not be very effective to put so much effort to remove P or N from the water. On the other hand if we are facing a process water coming out from an ongoing industry it would be more effective to put much more effort on minimizing and monitoring the oil or heavy metal substances.

Biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), and total suspended solids (TSS) are the most commonly regulated wastewater effluent parameters. The measurement and prediction of these parameters are essential for assessing the performance and upgrade of wastewater treatment facilities.

Monitoring these parameters; flow rate, pH, temperature, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), nitrogen, phosphorus, metals, organic compounds, and pathogens over a short period of time is good bit also over a long period of time is also good depending on the discovered pollutants in the water, there are some parameter that will require constant monitoring and some long-term monitoring. The pollutants levels should be maintained in allowable limits otherwise there will be water pollution to a level that will raise concern.

1- In order to confirm to achieve the design objectives the main parameters in a conventional sanitary wastewater treatment include Total phosphorous, NH3, BOD5,TSS and DO 2- For environmental standard limits confirmation monitor parameter including DO, BOD, COD,PH, Temperature, phosphorous and ammonia, Toxic materials and heavy metals 3- If performing unit upgrade by doing design modification compare predicted (modeled) parameters with measured parameters including TP,NH3,BOD5,TSS and DO . 4- Selected parameters to be monitored also depend on type of wastewater and recipients environment. For example if releasing industrial waste to a river, parameters such as flow, PH, toxic materials, heavy metals, Do, temperature and COD are important

The grab sampling which is taken from a point using a bucket is proper for current situation of the treatment unit and does not represent overall treatment facility performance. Composite sampling can be conducted in two ways. One method is flow proportional in which the sampling is proportional to flow and the other way is volume equal in which equal volume of samples are taken at regular times. Samples containers must be sterilized and clean and must be traceable with identification labels and must be handled in a proper temperature. Using preservative for some volatile material testing is necessary. Sampler must wear proper PPE such as safety glass, mask, disposable gloves, safety boots and respirators if working with volatile compounds

During the sampling process, the discharged wastewater is periodically sampled according to standards, with fixed wastewater sampling and random sampling to ensure accuracy of sampling

When the required tests performed in refinery or in an environmental lab compare the results with established reference standards or plant performance benchmark. Any deviation of standards or treatment unit objectives may represent inefficiency of treatment unit and corrective action must be taken accordingly.

To analyze wastewater samples accurately, follow these steps: collect samples using proper techniques and containers, preserve them for transport, conduct analyses in the lab using suitable techniques like chemical analysis or microbiological testing, ensure quality control through instrument calibration and method validation, and interpret results by comparing them to regulatory standards. Maintain traceability by documenting each step and citing relevant protocols or standards to ensure the reliability and validity of the analysis.

It's essential to consider the potential valorization of waste generated from wastewater treatment processes. By-products such as sludge and biosolids can often be transformed into valuable resources through techniques like anaerobic digestion, composting, or nutrient recovery. These valorization opportunities not only reduce the environmental footprint of wastewater treatment but also offer economic benefits and contribute to sustainability efforts by turning waste into useful products like biogas, fertilizers, and soil amendments. Incorporating strategies for waste valorization maximizes the efficiency and sustainability of wastewater treatment processes.

In addition to the discussed parameters to be monitored in a wastewater treatment plant it is necessary to consider treatment process wastes. In conventional treatment (activated sludge ), primary and secondary sedimentation tanks dispose considerable amount of sludge. These treatment byproducts must be treated and disposed properly. Regularly sludge treatment includes: 1- sludge thickening, to be monitored by measuring sludge blanket thickness 2- sludge stabilization process including digestion, to be monitored by measuring dissolved oxygen amount. 3- sludge mechanical dewatering, to be monitored by measuring the percent solid.