Abstract
While yeast manufacturing consumes a large amount of water per unit of product, water use efficiency varies widely within the industry due to disparity in water-saving technologies. By stipulating water intake per unit of product, the Norm of Water Intake––Part 41: Yeast Production (GB/T 18916.41-2019) will standardize production water use and improve the water-saving level of the yeast manufacturing industry. This paper estimates the industry’s production capacity from 2020 to 2024 through regression analysis. It examines the distribution of water use efficiency under different policy scenarios based on the standard for water intake, including the business-as-usual scenario, the bottom-line scenario, the ideal scenario, and the expected scenario. Then, the water use of the yeast manufacturing industry under different scenarios is calculated, and the water-saving potential is analyzed by comparing it with the business-as-usual scenario. The results indicate that depending on the intensity of policy implementation, the average annual water savings will range from to . The cumulative water savings will add up to to in the next five years, which is very large.
1. Introduction
Common challenges regarding water resources in the world include rising demands for water resources due to population growth, difficulty in balancing agriculture and urban development, and various consequences of changing climate. The water-saving potential is an essential indicator to measure and guide water resource allocation and planning. As a part of the fermentation industry, the yeast manufacturing industry mainly produces yeast and yeast derivatives. While yeast manufacturing consumes a large amount of water per product, water use efficiency varies widely due to disparity in water-saving technologies. At present, water intake per product unit stands at about 70~100 m3/t for yeast and 95~120 m3/t for yeast derivatives. There is considerable room for water saving in the industry as a whole. The Norm of Water Intake––Part 41: Yeast Production (GB/T 18916.41–2019) [1], one of China’s national standards for water use, specifies water intake per unit of yeast and yeast derivatives. Under this norm, water authorities carry out planned water management and water licensing, and yeast manufacturers control water saving. The standard reflects the current level of water use in the yeast manufacturing industry and will steer the drive towards a higher level of water saving.
Many studies on potential energy savings and emission reductions regarding energy and resource conservation can be found. Typical models include the Market Allocation of Technologies Model (MARKAL) [2, 3], the Asian-Pacific Integrated Model (AIM) [4], the Long-range Energy Alternatives Planning System (LEAP) [5, 6], the Computational General Equilibrium Model (CGE) [7], and cluster analysis [8]. Regarding water-saving areas, research mainly focuses on agricultural irrigation [9], residential water use, and total water consumption in regions or cities. The Alliance for Water Efficiency [10] evaluated water-saving potential for single-family households in Detroit via inefficient toilet replacement and estimated a saving value of 9,721 gallons per year. The average potential for potable water savings by using rainwater and greywater ranges from 39.2% to 42.7% among the sample blocks in southern Brazil [11]. Analysis for the water-saving potential in California shows that water savings would be 0.74 million to 1.6 million acre-feet per year in the commercial, institutional, and industrial sectors, and 2.2 million to 3.6 million acre-feet water per year would be reduced at home due to the considerable progress in improving water use efficiency [12]. Qin et al. [13] calculated the water-saving potential of the Beijing-Tianjin-Hebei area in the dimensions of water saving and resource saving by analyzing the process and influencing factors of water use in various industries in the region. Zhu [14] compared the industrial water use efficiency of different areas in China and estimated the water-saving potential of other provinces with the water use efficiency of Shandong Province as a reference. Song and Gao [15] identified the advanced level of urban water use based on the normal distribution and comprehensively proposed a coefficient to assess urban water-saving potential. Zhao et al. [16] examined the water consumption of thermal power generation and evaluated its water-saving potential by comparing it with the indicators in the relevant national standards. Zhao Z et al. [17] evaluated the water resource utilization efficiency and water-saving potential development landscape and path of different scenarios in 2035 in comparison to Shenzhen. Recently, study on the coal-to-synthetic natural gas process showed that by taking water-saving gasification technology, zero liquid discharge, integrating the water networks, and improving other units, water consumption can be lower than 3.50 t/kNm3 water saved [18].
The existing studies on water-saving potential are mainly conducted about water appliances and unconventional water use at a regional scale, with few studies specific to industries. Water quota is also rarely considered. Without adequate decision-making support for quotas and policy targets, the norm fails to produce the desired effect. The scenario analysis is commonly used in forecasting and assessing the water availability and consumption [19, 20], simulation and impact of technological introduction, and governance regimes about water [21–24].
In this work, we used a combination of regression analysis and scenario analysis to explore the changes in the corresponding industry scale and water intake after the implementation of the water intake quota standard, establish a water-saving forecast model, and explore its water-saving potential.
2. Method
Based on stipulated water use level, combined with survey data, industry size in five years (2019–2024) after the Norm of Water Intake––Part 41: Yeast Production (GB/T 18916.41–2019) enters into force is identified through regression analysis. Taking into account the distribution of water use levels in the industry when the standard was released (2019), three policy scenarios of water use are designed, in contrast to the business-as-usual (BAU) scenario where the norm is absent, to analyze the possible impact of the standard on water use efficiency. Water savings under these scenarios are estimated, that is, the water-saving potential brought by the standard under different scenarios.
3. Production Capacity Forecast
Yeast and yeast derivatives are the main products of the yeast manufacturing industry, approximately representing 70% and 30% of the industrial production capacity, respectively. Yeast, characterized by complete yeast cells, includes highly active dry yeast, fresh yeast, nutritional yeast, and inactive yeast. Yeast derivatives encompass yeast extract, autolysed yeast, yeast protein, polypeptide, yeast cell wall, and yeast zymosan. According to the China Yeast Industry Analysis Report, 2020–2026: Development Model and Planning, China’s yeast production grew year by year from 2012 to 2018 as the specific numbers are 280,000 tons, 294,000 tons, 308,000 tons, 318,000 tons, 330,000 tons, 350,000 tons, 373,000 tons, and 394,000 tons (Figure 1).
Based on the 2012–2018 data of yeast production, the linear regression equation for annual yeast production is created in Excel, as shown below:
The results show that the correlation coefficient () of variables in the linear regression equation is 0.9798. In other words, yeast production is positively and increasingly correlated with the year.
According to the equation, it is inferred that, after implementing the norm mentioned above, the annual yeast production will be 402,000 tons, 420,000 tons, 438,000 tons, 457,000 tons, and 474,000 tons from 2020 to 2024, respectively. Since yeast and yeast derivatives account for 70% and 30% of the total production capacity according to industry research, it is estimated that the annual output of yeast derivatives during this period will reach 172,000 tons, 180,000 tons, 188,000 tons, 196,000 tons, and 203,000 tons, respectively.
4. Scenario Analysis of Water Use in the Yeast Manufacturing Industry
The structure of production capacity with different water use efficiency before the Norm of Water Intake––Part 41: Yeast Production (GB/T 18916.41–2019) takes effect (2019) is regarded as the BAU scenario (scenario 0). Based on the standard for water intake specified in the norm (Table 1), three states of water use efficiency distribution after the entry into force of the norm are drawn, i.e., the bottom-line scenario (scenario 1), the ideal scenario (scenario 2), and the expected scenario (scenario 3), to represent different water-saving management levels and policy implementation intensity. Table 2 shows the specific scenario setting method and the policy implication.
According to the survey of yeast factories, yeast output totals 202,000 tons. Among them, about 32,000 tons, that is, 16% of the surveyed production capacity, used 85 m3/t of water per unit of product in 2016. In addition, 60% met the standard (70 m3/t) for water use efficiency of newly built (renovated and expanded) enterprises, while 24% reached the advanced level (65 m3/t).
Enterprises covered by the survey are generally large and technologically advanced in China. Those not included in the study may be small and relatively backward, with a weak capacity to promote cleaner production and advanced technology. Hence, their water use efficiency is very likely to exceed 85 m3/t. Taking into account the water use efficiency and production capacity of such enterprises, more than 30% of the yeast production capacity in China has water use efficiency higher than 85 m3/t; about 55% has water use efficiency up to the minimum standard, but still below the standard for newly built (renovated and expanded) enterprises (70~85 m3/t); about 10% reaches the standard for newly built (renovated and expanded) enterprises, but not the advanced level (65~70 m3/t); and around 5% achieved the advanced level (65 m3/t).
Suppose the norm of water intake is not adopted. In that case, under the BAU scenario, the water efficiency is slowly improving from 30%, 55%, 10%, and 5% of 2019 to 10%, 60%, 20%, and 10% of 2024 for the production capacity of more than 85 m3/t, in the range of 70~85 m3/t, in the field of 65~70 m3/t, and less than 65 m3/t, respectively, as in Figure 2.
In the bottom-line scenario, with the norm’s implementation, the backward production capacity meets the standard, and five years after the norm takes effect, the main production capacity (60%) reaches the bars for newly built enterprises, and the production capacity that only passes the bars for existing enterprises and reaches the advanced ones, respectively, accounts for 20%. More specifically, the production capacity of water use efficiency in the range of 70~85 m3/t, in the field of 65~70 m3/t, and less than 65 m3/t slowly changed from 70%, 20%, and 10% to 20%, 60%, and 20%, respectively, as shown in Figure 3. The production capacity below the minimum standard is eliminated in the ideal scenario. All the production capacity reaches the advanced level five years after the norm enters into force (2024), as shown in Figure 4. The production capacity below the minimum standard is eliminated in the expected scenario. 70% of the production capacity in the industry gradually reaches the standard for newly built (renovated and expanded) enterprises, and 30% reaches the advanced level five years after the norm enters into force (2024), as shown in Figure 5.
5. Analysis of Water-Saving Potential
Water savings from yeast and yeast derivative production are estimated by calculating water use under different scenarios and comparing it with the BAU scenario.
5.1. Calculation of Water Use under the BAU Scenario
The BAU scenario (scenario 0) assumes that the industry water efficiency is slowly increasing, including the backward capacity that does not meet existing enterprises’ standards. In the BAU scenario, water efficiency remains the same after 2019 as in 2018. In other words, 30%, 55%, 10%, and 5% of the production capacity have water use per unit of product larger than 85 m3/t, in the range of 70~85 m3/t, in the field of 65~70 m3/t, and less than 65 m3/t, respectively. With the advancement of technology, the water efficiency of the industry is slowly improving. By 2024, the excellent production capacities that achieve the above water efficiency will be 10%, 60%, 20%, and 0%. From 2019 to 2024, the water used for yeast production is calculated to be , , , , , and , respectively. The water used to produce yeast derivatives is estimated to be , , , , , and , respectively. Thus, the water consumption of the yeast manufacturing industry as a whole in the next five years will reach , , , , , and , respectively. Table 3 shows the output and water use of different products and the total water use under the BAU scenario in the next five years.
5.2. Water-Saving Potential in the Bottom-Line Scenario
The bottom-line scenario (scenario 1) assumes that the backward production capacity meets the standard, and five years after the norm takes effect, the main production capacity (60%) reaches the bars for newly built enterprises, and the production capacity that only passes the bars for existing enterprises and reaches the advanced ones, respectively, accounts for 20%. That is to say, in the bottom-line scenario, the production capacity of water use efficiency in the range of 70~85 m3/t, in the field of 65~70 m3/t, and less than 65 m3/t slowly changed from 70%, 20%, and 10% to 20%, 60%, and 20%, respectively. From 2019 to 2024, the water used for yeast production is calculated to be , , , , , and , respectively. The water used for the production of yeast derivatives is estimated to be , , , , , and , respectively. Therefore, the water consumption of the yeast manufacturing industry as a whole in the next five years will be , , , , , and , respectively. Compared with the BAU scenario, water savings in the bottom-line scenario are expected to reach per year and in total by 2024, the water efficiency increased by 8.9%. Table 4 shows the output and water use of different products and the total water use in the next five years in the bottom-line scenario and water savings compared with the BAU scenario.
5.3. Water-Saving Potential in the Ideal Scenario
The ideal scenario (scenario 2) assumes that the backward production capacity meets the standard, and five years after the norm takes effect, all the production capacity is advanced. In other words, under the ideal scenario, 100% of the production capacity uses less than 65 m3/t of water per unit of product. In the early implementation of the norm, the water use of the whole industry will shrink due to water use efficiency improvement of inefficient production capacity. Still, later, it will tend to rise, driven by a substantial increase in production. From 2019 to 2024, the water used for yeast production is calculated to be , , , , , and , respectively. The water used for the production of yeast derivatives is estimated to be , , , , and , respectively. Hence, the water consumption of the yeast manufacturing industry as a whole in the next five years will stand at , , , , , and , respectively. Compared with the BAU scenario, annual water savings under the ideal scenario are expected to reach, making a total ofby 20 shows the output and water use of different products and the total water use in the next five years under the bottom-line scenario and water savings are shown in Table 5.
5.4. Water-Saving Potential in Expected Scenarios
The expected scenario (scenario 3) assumes that the backward production capacity meets the standard, and five years after the norm takes effect, 70% of the production capacity reaches the bars for newly built enterprises, and 30% reaches the advanced level. In other words, in the expected scenario, 70% and 30% of the production capacity reduce water use to 65~70 m3/t and less than 65 m3/t, respectively. In the early implementation of the norm, the water use of the whole industry will decline due to water use efficiency improvement of inefficient production capacity. Still, it will increase later as production expands significantly. From 2019 to 2024, the water used for yeast production is calculated to be , , , , , and , respectively. The water used to produce yeast derivatives is estimated to be , , , , , and , respectively. Hence, the water consumption of the yeast manufacturing industry as a whole in the next five years will amount to , , , , , and , respectively. Compared with the BAU scenario, of water can be saved annually under the expected scenario, making . By 2024, the water efficiency will increase by 12.5%. Table 6 shows the output and water use of different products and the total water use in the next five years under the expected scenario and water savings compared with the BAU scenario.
6. Conclusion
This study uses a combination of regression analysis and scenario analysis to explore the changes in the corresponding industry scale and water intake after the implementation of the water intake quota standard, establish a water-saving forecast model, and explore its water-saving potential. The results show that under the guidance of different implementation efforts and policies, the predicted average annual water saving within five years after implementing the standard is . The accumulated water saving will be about 24~46 million m3, and the water efficiency will be increased by 8.9~19.4%. Due to the high concentration of yeast manufacturing industry, the likely expected scenario is that all production capacity will meet the new (reconstruction and expansion) index requirements stipulated in the water intake quota standard, and 30% of them will reach the advanced value after five years. Compared with the BAU scenario, the annual water saving after implementing the standard will get more than . The total water savings will exceed by 2024 in total. The water efficiency will increase by about 12.5% in the typical situation. Therefore, the water intake norm will help create huge water-saving potential in the yeast manufacturing industry.
Data Availability
All data can be obtained through the manuscript or by contacting the authors.
Conflicts of Interest
The authors declare that they have no conflicts of interest.