Wastewater Recycling Is a Pathway to Lower Risk Exposure and Water Costs in Pharmaceutical Manufacturing

by Mike Hook, Jai McIntosh

19 July 2023

13:25

Mike Hook is the Sales & Marketing Director for PRAB and has more than 15 years of mechanical design and application experience. PRAB is a leading supplier of wastewater treatment solutions as well as engineered conveyors, and equipment for processing stamping scrap, turnings, chips, and spent metalworking fluids.

With water costs on the rise and the gap between global water supply and demand projected to reach 40% by 2030 if current practices continue, water usage in pharmaceutical product development not only contributes to a global water supply shortage, it also elevates risk at the corporate level.

According to a report from the U.S. Department of Energy, the average annual price escalation rate for water is 4.1% based on reported rates from 2008 through 2016. In addition to the cost of raw materials, wastewater compliance costs are mounting. Several factors contribute to higher water expenses – such as sewer fees for discharge to a wastewater treatment plant (WWTP), sewer permits for effluent, biological oxygen demand (BOD), chemical oxygen demand (COD), and fines for overages.

Both reputation and operational sustainability are at stake. Fortunately, as pharmaceutical companies hone environmental, social, and corporate governance strategies, sustainability improvements are helping these entities demonstrate responsible operating practices that benefit both the global community and the bottom line.

Not only is water a fundamental excipient in pharmaceutical development, it is also essential for numerous processes used to support production. Generators of wastewater in pharmaceutical manufacturing include:

Chemical reactors: Wastewater is produced with each chemical modification as reactors are emptied, cleaned, and refilled. The wastewater may include reaction residues, unreacted reactants, product, and by-products including acids, bases, metals, halides, nitrates, cyanides, sulfates, and active pharmaceutical ingredient (API) traces.

Fermentation and purification processes: The wastewater may include biologically active substances (such as enzymes), nutrients (starches, sugars, polyols), trace elements, vitamins, amino acids, inorganic and organic salts, surface active agents, or complex (undefined) ingredients.

Extraction processes: More than 30 solvents are regularly used in pharmaceutical manufacturing including ethanol, methanol, acetone, isopropanol, and acetic acid. Although some solvents are recovered prior to discharge, a portion remains in the plants’ wastewater.

Mixing and granulation processes: Wastewater is produced after equipment used to mix APIs and excipients is rinsed. The wastewater may contain residues from detergents, excipients, and APIs, such as waste starches and sugars.

Equipment and floor cleaning: Wastewater contains detergents and pollutants resulting from equipment utilisation.

Scrubber blowdown: Wastewater produced from scrubber blowdowns contain soluble and insoluble organic compounds and absorbed chemicals (acids/bases).

Laboratory facilities: Wastewater from laboratory facilities may include toxic compounds and traces of APIs.

Production of compendial and utility waters: Examples of this include reverse osmosis concentrates and cooling tower/boiler blowdown wastewaters, which contain dissolved salts, alkalinity, Clean-In-Place (CIP) chemicals, and Total Suspended Solids (TSS).

Sanitary wastewater: This wastewater may contain organic pollutants, suspended solids, fat, oil, and grease (FOG), and microorganisms. If wastewater is to be treated and re-used, sanitary wastewater should not be combined with other wastewaters intended for re-use.

To combat rising costs and meet compliance directives, many pharmaceutical companies are adopting Zero Liquid Discharge (ZLD) programs that minimise or eliminate discharge of effluent by treating and recycling wastewater. Capable of reducing water volumes up to 98%, wastewater treatment systems allow pharmaceutical manufacturers to decrease their water expenses, meet ZLD goals, and comply with state and local regulations. Disposal costs can drop as low as 15 times the original amount. With capabilities that are proven to not only reduce water consumption but also lower CO2 emissions, wastewater recycling equipment is progressively becoming a part of pharma sustainability action plans as a result.

For instance, a research laboratory center developing therapeutic products to help with respiratory, musculoskeletal, and cardiovascular diseases was consuming high quantities of water in its processes. During a typical day, the lab discharged about 4 tons of effluent. This resulted in a high volume of wastewater and disposal costs. If the pharma lab treated the wastewater and re-used the treated water in its processes, water consumption and disposal costs would decrease substantially. The pharmaceutical laboratory added vacuum evaporation to treat its wastewater, which enabled the facility to recover more than 90% of the water for re-use.

While pharmaceutical manufacturers have much to gain from wastewater treatment, adding these capabilities on-site is not without challenges. Pharmaceutical wastewater treatment is a particularly specialised process because wastewaters from pharmaceutical manufacturing are highly inconsistent. Whether producing APIs or finished products via chemical synthesis or bioprocessing, each wastewater is derivative of the unique processes used to develop the product. In fact, plants producing the same product can have variations in the wastewater. As a result, wastewater treatment systems are equally diverse.

A laboratory analysis of the wastewater, a careful review of the production process, and a goal assessment provide a starting point for specifying a treatment solution. During the review, water volumes, water temperature, and flow rates all need to be defined. Additionally, operational goals need to be discussed. For a treatment plan that includes re-use, parameters of the recycled water are dependent on the re-use application. In most cases, re-use applications are for low-grade water requirements such as makeup water for cooling towers, boilers, cleaning, or irrigation.

Parameters that are analysed during laboratory testing include:

The results of the lab analysis will help wastewater treatment experts define a system that will perform the processes needed to meet compliance and business objectives. There are several key processes used to treat pharmaceutical wastewaters. They include:

Segregating or deactivating wastewater streams: This may be necessary to treat highly concentrated or toxic streams, or it may be more cost-effective in cases where the bulk of wastewater does not contain APIs and, therefore, treating the full volume of the wastewater for API reduction/removal is inefficient. Streams containing biologically active ingredients may need to deactivate those substances prior to being combined with other wastewater streams.

Equalisation: Placing wastewater in an equalisation tank equalises the flow rate, balances the contaminants, and eliminates temperature fluctuation.

pH adjustment: Adjusting the alkalinity or acidity of wastewater may be needed to achieve efficient processing in downstream treatment stages.

Removing suspended solids: This may be achieved through a combination of coagulation, which clumps particles together, flocculation, which removes the clumps, flotation, sedimentation, or filtration.

Aerobic or anaerobic biological treatment: This converts biodegradable organic matter into biomass that may then be separated from the treated water.

Evaporation: Also known as evapoconcentration or distillation, this process is used to reduce the volume of wastewater prior to disposal. It produces high-quality condensate that in many cases may be recycled and re-used.

Because treatment of pharmaceutical wastewaters is unique to the specific production process, modular wastewater treatment solutions complete specific treatment processes. Here are four common solutions that pharma manufacturers are using to lower costs and meet sustainability goals:

Oil water separators: These systems can reduce haul-away costs up to 90%, decrease water consumption, and increase the lifespan of soluble oils, wash water, rinse water, and pressure wash-down water (or process water). A down-flow gravity coalescing method separates oil from water to less than 15 ppm. The oil/water mixture is pumped via a floating skimmer or is gravity fed into a separator, where free and mechanically dispersed oil is removed from the influent. The separated oil is automatically gravity discharged to a waste container. The clean water is discharged by gravity or through an optional discharge pump to the sewer, or back into the process.

Ultrafiltration (UF): These systems clarify solutions containing suspended solids, bacteria, and high concentrations of macromolecules, including oil and water. Ultrafiltration utilises crossflow filtration to remove emulsified oils, suspended solids, metal hydroxides, emulsions, dispersed material, suspended solids, and other large molecular weight materials.

During UF, fluid flows parallel to a semi-permeable membrane, which retains the emulsified oils and the suspended solids, while the water and dissolved solids pass through the membrane. Different membrane configurations help pharma companies accommodate unique operational considerations such as floor space and energy consumption.

Additionally, the quality of the effluent that UF produces is typically very consistent. This dependability reduces the amount of testing required to validate the quality of the water for re-use.

Vacuum evaporation: Evaporation differentiates itself from other separation processes by removing water from contaminants, as opposed to filtering contaminants from the water. Vacuum evaporators achieve the highest rates of water recovery and concentration. Capable of treating and distilling pharmaceutical wastewater volumes from 1 to 120 tons per day and producing residual total solids concentrations of more than 85%, vacuum evaporators can reduce water costs up to 99%. Three types of vacuum evaporators include:

Heat pumps: Flexible and versatile with low electrical energy consumption and superior reliability.

Hot water/cold water: Utilises existing excess hot water/steam and cooling water to lower operating costs.

Mechanical Vapor Recompression (MVR): Uses low boiling temperatures to treat wastewater volumes with high flow rates.

Reverse osmosis (RO): This filtration technology removes dissolved solids and impurities from water using a semi-permeable membrane. The membrane allows the passage of water but retains the majority of dissolved solids and other contaminants. An RO system that is properly designed and operated can remove up to 99.5% of incoming dissolved salts and impurities. However, RO membranes require high water pressure (greater than osmotic pressure) to work effectively.

Although pharma companies should first look at water usage in their own operations, supply chain sources also merit scrutiny. An estimated 80% of the world’s APIs come from China, India, and a few other foreign countries. Because water insecurity is a global concern, risk management must extend beyond the walls of a company’s manufacturing plant—especially as drug developers intensify production efforts to meet the growing demand for pharmaceuticals.

According to a report from Barclays, the cost for biotech, healthcare, and pharma industries to address water usage is $4 billion, compared to the $52 billion potential maximum financial impact the industries could face if they fail to address water insecurity. Drug producers that utilise on-site wastewater treatment and recycling will simultaneously advance their sustainability practices, safeguard the pharmaceutical supply, and develop a competitive advantage.

Editorial Content Producer at EPM, looking after all the editorial content for the magazine and website.

19 July 2023

13:25