Proactive Control of COD Discharges: Driving Compliance & Sustainability in Abattoir Wastewater Management

At a reputable UK abattoir, wastewater produced as part of the manufacturing process underwent treatment prior to discharge. The abattoir worked with a renowned wastewater consultancy to enhance its wastewater treatment and monitoring processes for safe disposal. With strict wastewater standards and discharge requirements to meet, the facility needed a reliable way to monitor the exceptionally high chemical oxygen demand (COD) levels in its wastewater and better understand effluent quality.

However, the facility faced challenges with online measurement in the demanding wastewater environment. Previous efforts to utilize methods of online measurement had all failed due to the high level of maintenance required to keep sensors clean enough for accurate measurement.

Managing COD in Abattoir Wastewater

With an increasing focus on discharge consents into sewers to safeguard the environment and public health, industrial manufacturers are turning to online chemical oxygen demand and biochemical oxygen demand instrumentation to enable the proactive management of effluent discharge.

For industrial manufacturers and processors, meeting strict wastewater standards, particularly for COD, presents an increasingly complex challenge.

In abattoirs, high COD levels in wastewater are due to the presence of blood, fat, manure, undigested food and cleaning agents. COD measures the amount of oxygen required to oxidize organic and inorganic matter in water, making it an important measurement when managing wastewater and discharge quality.

Regulatory standards for abattoir wastewater discharge vary globally, but generally they set limits on biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS) and nutrient concentrations. Compliance with these regulations is mandatory to avoid penalties and support sustainable operations.

While compliance tests are often carried out via the traditional dichromate laboratory test, there is an increased need to monitor COD in real time to demonstrate the process is under control. These regulations protect water bodies from pollution, which in turn safeguards human and animal health. Non-compliance can result in fines, operational restrictions and damage to the company’s reputation.

Monitoring COD in a High-Fouling Environment

The nature of the effluent’s content created a challenging environment to measure COD using optical sensors. In addition to the high levels of organic material, fats, oils and greases (FOG) created a high-fouling environment for the sensor’s optical area. Previous efforts to utilize methods of online measurement had all failed due to the high level of maintenance required to keep sensors clean enough for accurate measurement.

Given the levels of COD in the water, the spectro::lyser V3 ATEX online water quality spectrometer probe from Badger Meter was selected due to its proven success within similar applications and its short path length (1 mm) to handle the very high levels of UV absorption in the sample.

The spectro::lyser is a submersible dual-beam spectrophotometer that offers multiparameter measurement of water quality parameters, nutrients and organics such as COD and BOD, converting the raw absorption “fingerprint” of the waste stream into a COD value.

A unique cleaning mechanism was developed to remove the fats, oils and greases and minimize manual maintenance, as the more traditional compressed air cleaning of the sensor’s optical area was insufficient for the needs of abattoirs. The new cleaning mechanism utilized an air-powered blade with a purpose-designed material that could remove fats, oils and greases while not getting blocked.

In addition, a protective cage was fitted around the optical area to reduce the chances of fouling. This allowed the abattoir to reduce manual intervention for maintenance to less than once a week.

A specialized calibration procedure was also developed using non-standard wavelengths to handle the high levels of COD found in the effluent.

Data graphs from the spectro::lyser showed the original calibration values, where COD levels reached a maximum of 10,000 mg/L. However, the lab samples showed COD to be significantly higher. The new calibration procedure utilized different wavelengths to determine the COD, enabling the sensor to read up to 80,000 mg/L.

More Informed Discharge Decisions

The spectro::lyser offered a valuable solution to the complex pre-treatment requirements of the abattoir, providing operational stability and regulatory compliance peace of mind.

The data insights from this technology also allowed the manufacturer to decide whether it was safe to discharge the water or hold it on site and trickle the high COD effluent out over a period of time when the overall effluent COD was lower.

This provided the manufacturer with greater visibility into effluent conditions and supported more informed decisions about when wastewater could be discharged.

Supporting Proactive Trade Effluent Management

As trade effluent discharge costs rise, businesses in industries such as food and drink processing are increasingly relying on solutions that are more reliable, cost-effective and environmentally-friendly.

Online monitoring of organics is a proven, effective solution for managing industrial COD discharge consents, particularly for wastewater streams with high biodegradable organic content.

The spectro::lyser high-performance spectrometer from Badger Meter provides a proactive approach to managing trade effluent, minimizes environmental impact and remains competitive in a challenging market landscape.

Improving processes and effluent quality, or reducing the throughput of water, can significantly reduce trade effluent bills, making a clear business case for action.

By working with Badger Meter, this meat producer now has a reliable method of measuring COD online, without frequent and resource-intensive manual maintenance, providing environmental compliance, operational stability and the ability to better manage discharges to the local environment.