Fermentative Pharmaceutical Wastewater Treatment: Segregated Pretreatment, Anaerobic Inhibition Boundaries and Residue Control under HJ 2044-2014

1. Status of the standard and the prohibited-streams list

HJ 2044-2014, Technical specifications of wastewater treatment for the fermentative pharmaceutical industry, was approved on 2014-10-24 and took effect on 2015-01-01 as a first issuance. It is expressly a guidance standard: its clauses are technical guidance rather than mandatory limits, and in engineering practice it must be used together with GB 21903, the discharge standard of water pollutants for the fermentative pharmaceutical industry. It applies to treatment projects for wastewater dominated by fermentation-based pharmaceutical production, and serves as a technical basis for environmental impact assessment, design and construction of environmental protection facilities, completion acceptance and subsequent operation and management. It was drafted by the Chinese Society for Environmental Sciences, Jiangsu Nanda Environmental Technology Co., Ltd., the Hebei Provincial Academy of Environmental Sciences, the Zhejiang Provincial Academy of Environmental Science and Design, and Shandong Shengli Bioengineering Co., Ltd.

Clause 4.1.3 draws a red line that must appear in design documents. High-strength still residues, waste solvents, spent mycelium and bacterial residues, and mother liquors from genetic-engineering pharmaceutical processes, which are separately regulated in the technical policy on pollution prevention and control in the pharmaceutical industry and the national hazardous waste catalogue, shall not enter the wastewater treatment system. Clause 4.1.2 also divides the wastewater into four classes: process wastewater, mainly spent mother liquor and wastewater from extraction or refining, such as extraction spent liquor, refining spent liquor and resin regeneration wastewater; production rinse water; utility system drainage; and domestic sewage. Process wastewater carries the highest concentration.

2. Segregated pretreatment: five routing criteria

Clause 5.1.3 establishes the general principle of separating clean and dirty streams and treating by wastewater class, and clause 6.2.2 gives five executable routing criteria:

• Wastewater containing antibiotic active pharmaceutical ingredients, biological toxicity or ecological risk shall be pretreated separately in accordance with the provisions of the relevant authorities.
• High ammonia nitrogen wastewater, defined as ammonia nitrogen above 500 mg/L, may be pretreated by one or a combination of steam stripping, evaporation and air stripping, with the ammonia-bearing off-gas collected and treated.
• Refractory organic wastewater should be pretreated by chemical oxidation, iron-carbon micro-electrolysis or rectification.
• High-strength organic wastewater should be treated by rectification, physical phase separation or incineration.
• High-salinity wastewater should be desalinated by evaporation or similar means.

Clause 6.4.3 adds an economic criterion: organic wastewater with a solvent content above 5 percent, or where the recovery revenue exceeds the disposal cost, should first be recovered by rectification, physical phase separation or comparable methods. This turns the question of whether recovery is worthwhile from a process-selection issue into a mass-balance exercise, and it is the step most often skipped during scheme comparison. Clause 6.4.5 further refines the chemical oxidation options for refractory organics, naming ozone oxidation, chlorine dioxide oxidation and Fenton oxidation.

3. Sulphate: the first inhibition factor in the anaerobic stage

Clause 6.4.2 gives three graded limits, the numbers most worth remembering in this specification. Where the sulphate concentration exceeds 5000 mg/L, multi-effect evaporation or similar pretreatment may be applied. The sulphate concentration in wastewater entering a completely mixed anaerobic system should be below 1500 mg/L. The sulphate concentration in wastewater entering UASB and EGSB reactors shall be below 1000 mg/L. Note that the wording differs across the three tiers, moving from "may be applied" through "should be below" to "shall be below", so the binding force increases step by step, and the UASB and EGSB tier is an explicit "shall".

Clause 6.5.5 folds the clause 6.4.2 limits into the overall anaerobic influent conditions. The CODCr concentration entering the anaerobic reactor should be held below 10000 mg/L, the sulphate concentration should be within the limits required by clause 6.4.2, and the influent suspended solids concentration should be held below 1000 mg/L. Where the influent CODCr or suspended solids concentration cannot meet these conditions, pre-acidification or other pretreatment may be provided, and the hydraulic retention time and pH range for pre-acidification design shall be determined from bench-scale or pilot-scale test results. The standard therefore explicitly requires testing rather than supplying an empirical figure.

Table 2 of the annex shows why this matters so much. Sulphate in beta-lactam process wastewater reaches 500 to 8000 mg/L, whereas aminoglycoside wastewater carries only 500 to 800 mg/L, macrolide 200 to 800 mg/L and the miscellaneous class 150 to 300 mg/L. Although all are antibiotic wastewaters, the upper bound of sulphate differs by more than an order of magnitude, so the answers to whether anaerobic treatment is appropriate and which reactor type to use differ completely.

4. Pollution load: how to use the three tables

Clause 4.3 requires sampling and analysis of the wastewater from each production step in accordance with HJ/T 91. Where measured data are absent, analogy with an existing plant of the same capacity, raw materials, products and process may be used; if that is also unavailable, Annex Tables 2 and 3 apply. Annex Table 1 gives the unit product drainage in cubic metres per tonne for representative products: penicillin 400 to 800, cephalosporin 1400 to 2000 and other beta-lactams 960 to 1320; streptomycin and dihydrostreptomycin 1160 to 1600, gentamicin 5200 to 7150, spectinomycin 1200 to 1650 and other aminoglycosides 2400 to 3300; erythromycin 680 to 900, meleumycin 600 to 800 and other macrolides 680 to 900; the miscellaneous class, including lincomycin and rifamycin, 4800 to 6600; vitamin C 240 to 330, with vitamin B12 at 92 to 126 cubic metres per kilogram and other vitamins 24 to 33 cubic metres per kilogram; glutamic acid 60 to 90, lysine 40 to 60 and other amino acids 160 to 220; and other categories 1200 to 1650. The unit product drainage of gentamicin and penicillin differs by about an order of magnitude, which sets the magnitude of the hydraulic shock when switching products on the same line.

Annex Table 2 gives the quality of antibiotic process wastewater in mg/L. Beta-lactams: pH 3 to 7, CODCr 15 000 to 28 000, BOD5 3000 to 7000, SS 1100 to 3400, sulphate 500 to 8000, ammonia nitrogen 100 to 360. Aminoglycosides: pH 4 to 7, CODCr 5000 to 13 000, BOD5 3000 to 5100, SS 1000 to 4000, sulphate 500 to 800, ammonia nitrogen 30 to 160. Macrolides: pH 3 to 7, CODCr 5000 to 13 000, BOD5 2500 to 5600, SS 1000 to 3000, sulphate 200 to 800, ammonia nitrogen 40 to 150. Miscellaneous: pH 4 to 9, CODCr 4000 to 15 000, BOD5 1000 to 4000, SS 500 to 3000, sulphate 150 to 300, ammonia nitrogen 50 to 100.

Annex Table 3 covers vitamin and amino acid production. Vitamins: pH 3 to 9, CODCr 1000 to 14 000, BOD5 260 to 3500, SS 100 to 3150, sulphate 100 to 1000, ammonia nitrogen 80 to 420. Amino acids: pH 5.5 to 7, CODCr 2500 to 5600, BOD5 1600 to 2900, SS 400 to 2500, sulphate 100 to 2000, ammonia nitrogen 120 to 350. Equipment and floor wash water: pH 5.5 to 9, CODCr 500 to 2000, BOD5 200 to 900, SS 50 to 300, sulphate 40 to 100, ammonia nitrogen 50 to 350.

One further constraint is often overlooked. Clause 4.2.3 states that where the treated wastewater is reused in production, the cumulative effect of pollutants in the reuse water shall be considered. A reuse scheme therefore cannot rely on a single compliance check; it requires a mass balance over the number of cycles.

5. Selection thresholds and operating requirements for the biological stage

Clause 6.5.3 is the most direct criterion for the biological stage: where the CODCr concentration after pretreatment is below 3000 mg/L, a hydrolysis-acidification process is preferred; where it is above 3000 mg/L, anaerobic treatment is preferred. Clause 6.5.2 recommends multi-stage biological units, and where an anaerobic-anoxic-aerobic activated sludge process is used, HJ 576 applies. For the aerobic system (clause 6.5.7), conventional activated sludge, SBR, biological contact oxidation and MBR may be selected, with design parameters determined from test results; the oxygen demand shall be derived from the BOD5 and ammonia nitrogen to be removed, following the method in GB 50014; aeration equipment shall be able to adjust the oxygen supply to water quantity and quality, and automatic regulation is preferred for projects above 20000 m3/d; where a completely mixed aeration tank with a selector is used, the selector hydraulic retention time is 30 to 50 min, mechanical mixing power should exceed 25 W per cubic metre, and with aerated mixing the air rate should exceed 3 m3 per square metre per hour; a secondary clarifier shall follow the aerobic biological tank, other than for SBR and MBR, with a surface loading of 0.5 to 0.7 m3/(m2 h) and a solids loading of 60 to 150 kg per square metre per day.

6. Construction scale, secondary pollution and three operating red lines

Clause 5.2.1 gives the scale-up factor: the treatment scale may be scaled up from the calculated water and pollutant quantities, with a scale-up factor generally of 1.2 to 1.5; clause 5.2.2 requires the collection and equalisation units to match the construction scale of the associated production units and to be calculated at the peak hourly flow. On secondary pollution, clause 6.7.2 requires odour collection and centralised deodorisation at collection tanks, equalisation tanks, hydrolysis-acidification tanks, sludge storage tanks and sludge dewatering rooms; the deodorisation process should combine physical, chemical and biological methods, including adsorption, absorption, chemical oxidation, low-temperature plasma oxidation, biological scrubbing and biological filtration; and the gas discharge concentration of the odour treatment facility shall comply with GB 14554. Clause 6.7.4.5 requires sludge and spent adsorbents listed in the national hazardous waste catalogue or identified as hazardous waste to be stored and disposed of in accordance with GB 18597, GB 18598 and HJ 2025. Clause 6.7.1.2 requires dedicated storage areas for materials, chemicals, sludge and residues, which shall not be stacked in the open, with storage sites treated for seepage, rain and overflow control.

Where data are lacking, clause 6.7.4.2 permits sludge quantities to be estimated as follows: with an activated sludge process, the sludge production may be designed at 0.5 to 0.7 kg DS per kg BOD5, checked against a sludge quantity of 1.5 to 2.0 percent of the treated wastewater volume at a moisture content of 99.3 to 99.4 percent; with biological contact oxidation, the sludge production may be designed at 0.4 to 0.5 kg DS per kg BOD5, checked against the same 1.5 to 2.0 percent; and coagulation sedimentation may be designed at 3 to 5 percent of the treated wastewater volume where placed after biological treatment, and 4 to 6 percent where placed before it, with a sludge moisture content of 99.6 to 99.7 percent.

On monitoring and control, chapter 8 gives two directly applicable thresholds. Clause 8.1.2 recommends on-line monitoring of dissolved oxygen, pH, temperature, water level and oxidation-reduction potential, with sampling frequency and items set according to process control needs. Clause 8.2.2 requires that a central control room be provided for comprehensive wastewater treatment projects with a capacity above 5000 m3/d, using a computer control system with centralised management and monitoring and distributed control, together with complete central control and on-line automatic monitoring facilities.

Chapter 12 adds one requirement with a distinctly sector-specific character. Clause 12.3.3 states that testing for antibiotic residues and acute toxicity in the wastewater shall be carried out periodically. This brings ecological risk beyond the routine water quality indicators into day-to-day monitoring, and it is the core management action that distinguishes fermentative pharmaceutical wastewater from other industrial wastewaters.

Two items remain for the designer to settle. The specification does not give volumetric loading, surface loading or retention times for individual units; per clause 6.5.6 these shall be taken from the dedicated specifications HJ 2013 for UASB, HJ 2023 for EGSB, HJ 2024 for completely mixed anaerobic reactors, HJ 576 for anaerobic-anoxic-aerobic, HJ 577 for SBR, HJ 578 for oxidation ditches, HJ 2009 for biological contact oxidation and HJ 2010 for MBR, and confirmed by testing. For biogas, clauses 6.7.3.1 and 6.7.3.2 only require that the purification and utilisation technology comply with NY/T 1220; the detailed heat balance and hydrogen sulphide removal parameters must be obtained from the dedicated standards. This article is based on the issued draft; the formally published standard text prevails.