Zero Liquid Discharge Evaluation of Pharmaceutical Wastewaters in India

Introduction
In late 2018, Geosyntec Consultants, Inc. (Geosyntec) was retained by a confidential pharmaceutical client to perform an independent review of zero liquid discharge (ZLD) systems at two pharmaceutical manufacturing facilities in in India. Geosyntec worked with a local firm who provided on-site observation and evaluated process data from each facility to document the wastewater flow balance and confirm controls were in place. Geosyntec provided project management, technical support and peer review of the final report. The Central Pollution Control Board (CPCB) of India defines ZLD as the installation of facilities and systems which will enable industrial effluent for absolute recycling of permeate and converting solute (dissolved organic and inorganic compounds/salts) into residue in the solid form by adopting a method of concentration and thermal evaporation. ZLD is a rising technology in India because of regulatory pressure to select ZLD. Analysis carried out by Global Water Intelligence showed that over 30 environmental clearance reports granted to industrial projects by the Ministry of Environment, Forests and Climate Change (MoEF&CC) since February 2020 showed that all projects have ZLD conditions attached as part of the project development. Other industries in India, such as food and beverage, steel and textile have incorporated ZLD, even with the high energy consumption, operational costs for equipment cleaning and the need for skilled manpower. In pharma, ZLD was getting attention due to the global concern of antibiotics in the environment and antimicrobial resistance (AMR). The discharge of antibiotics and Active Pharmaceutical Ingredients (APIs) in water bodies have been critically investigated in India for over the last 10 years. As of now, the AMR Industry Alliance has called on pharma facilities to reduce the quantity of API released into the environment and evaluate risk by comparing the predicted environmental concentration (PEC) to the predicted no-effect concentration (PNEC). Academia and researchers, working to mitigate antibiotic resistance, believe the PEC should be extremely stringent at the fence line, some suggesting that the effluent limit should equal the PNEC. In January 2020, a full year after our evaluation, MoEF&CC announced very strict standards on concentrations for 121 antibiotics found in the waste discharged by pharmaceutical factories into rivers and the surrounding environment. Pharma facilities and common effluent treatment plants (CETP) with membership of bulk drug and formulation units were subject to the rule. The rule also incorporated ZLD as the technology standard. India became the first country in the world to introduce such standards, meant to reduce chances of creating drug-resistant bacteria, and were ahead of the US and EU in developing numerical permit standards. However, the numerical values were eliminated in a revision in the rule published in August 2021, and the rule is silence to the presence of antibiotics in the effluents and the requirements of ZLD. Treatment Alternatives to Address the Discharge of Antibiotics Many advanced treatment technologies are available to reduce the concentration of antibiotics and other APIs in the final effluent. ZLD is an approach to water treatment where all water is recovered and contaminants are reduced to solid waste. While many water treatment processes attempt to maximize recovery of freshwater and minimize waste, ZLD is the most demanding target since the cost and challenges of recovery increase as the wastewater gets more concentrated. Salinity, scaling compounds, and organics all increase in concentration, which adds energy costs associated with managing these increases. ZLD is achieved by stringing together water treatment technologies that can treat wastewater as the contaminants are concentrated.
Goals and Objectives
The overall goal was to document that each facility maintained in-plant source control and wastewater treatment systems in place to minimize or eliminate the release of treated wastewater and any antibiotics to the environment. Objectives consisted of confirmation that the two plants are: designed and operated as ZLD with no treated wastewater discharge to the environment; well maintained and operated with trained and qualified personnel; and adequate redundancy is provided for standby equipment and storage volumes.
Project Methods/Approach
The Client and Geosyntec conducted the work in a collaborative fashion with the local India team and US team. Our Client's manufacturing platform at the time includes a number of facilities which are in India. Plant A and Plant B, which was the subject of the evaluation, are considered bulk API facilities and designed for antibiotic production. Our approach to perform the work consisted of reviewing: - Sources of wastewater generation; - Wastewater flow generation; - Treatment system review; - Process flow diagram and hydraulic balance; - Permit limits and conditions; - Residual waste handling and disposal; and - Unit operations evaluation , including evaporator, crystallizer and reverse osmosis units. Based on our review, our findings were developed and compared to legal and permit requirements and to determine if the facilities were designed and operated as zero liquid discharge with no treated discharge to the environment. Evaluation of Plant A and Plant B Pant A and Plant B are similar in design. Figure 1 and Figure 2 present the hydraulic balance and ZLD flow diagram for Plant A, respectively. Figure 3 presents the hydraulic balance for Plant B. Table 1 and Table 2 present the flow evaluation of Plant A and Plant B, respectively. All flows are presented as 1000 liters per day (KLD). The treatment technologies evaluated for the high total dissolved solids (TDS) wastewater included solids removal, steam stripping, multiple effect evaporator (MEE), agitated thin film dryer (ATFD) and salt collection and disposal. Condensate from the MEE and ATFD are combined with the low TDS streams generated from equipment washing, utility blowdown, etc. Subsequential process units consist of primary and biological treatment, membrane bioreactor polishing and reverse osmosis in series for utility reuse. The paper and presentation will also include other design and operational issues, water chemistry objectives for reuse in utilities and cooling tower makeup, membrane fouling challenges, RO recovery, brine management and disposal alternatives and energy consumption and operational cost. Conclusions The ZLD facility at both Plant A and Plant B are designed and operated as ZLD with no treated wastewater discharge to the environment. Both plants are well maintained and operated with trained and qualified staff and adequate redundancy is provided for standby equipment and storage volumes. In addition, periodic reviews are completed and ensure proper operation and consistent performance.