When designing surface runoff treatment facilities, it is crucial not only to determine the technical features of pollutant removal but also to correctly calculate the capacity of the treatment plants. In the case of designing a facility for the transshipment of a wide range of mineral fertilizers, this task is not as simple as it might seem at first glance. Let's explore the specific features and nuances together.
I. Methodology for Categorizing Enterprises
The main documents regulating the procedure for calculating the key parameters of engineering structures for surface runoff drainage systems, including the collector network and treatment facilities, are SP 32.13330.2018 "Sewerage. External Networks and Facilities. Updated version of SNiP 2.04.03-85" [1] and its mandatory appendix, the Methodological Manual "Recommendations for the calculation of systems for the collection, drainage, and treatment of surface runoff from residential areas, industrial sites, and the determination of conditions for its discharge into water bodies," NII VODGEO, Moscow, 2015 [2].
According to Clause 7.6.3 [1], when developing treatment technology and surface runoff drainage schemes at large enterprises, differences in the composition and quantity of pollutants across sites with different production purposes must be taken into account.
In accordance with the provisions of Clause 7.6.4 [1], depending on the composition of impurities accumulating on industrial sites and washed away by surface runoff, industrial enterprises and their individual territories are divided into two groups:
II. Surface Runoff Contamination and Its Impact on Category
In the case of transshipment of nitrogen, phosphate, potash, and complex mineral fertilizers, it is practically impossible to exclude dust emission and subsequent washout into surface runoff; therefore, the drained wastewater will contain ammonium ions and nitrate anions.
The handbook "Characteristics of Pollutants from Section II. For Water Bodies" of the "List of Pollutants Subject to State Regulation in the Field of Environmental Protection," approved by Order of the Government of the Russian Federation No. 1316-r dated July 8, 2015, UralNII "Ecology," 2016 [3], contains the following information on the toxic properties of substances:
Due to the presence of specific substances with toxic properties — Ammonium ion and Nitrate anion — in the surface runoff of mineral fertilizer transshipment facilities, they must be classified as Group 2 enterprises during design.
III. Specifics of Determining Treatment Plant Capacity
According to Clause 4.11 [1], the most contaminated part of the surface runoff, which is formed during periods of rainfall, snowmelt, and road washing, must be diverted to treatment facilities in an amount of at least 70% of the average annual runoff volume for residential areas of settlements, urban districts, and industrial sites similar to them in terms of pollution (Group 1) and the entire average annual volume of surface runoff for industrial sites (Group 2).
Summary: The territory of facilities for the transshipment of nitrogen and complex mineral fertilizers belongs to Group 2 enterprises according to SP 32.13330.2018, and 100% of the surface runoff volume must be diverted to treatment facilities. Therefore, the capacity of the treatment plants during design must be determined taking these features into account.
[1] SP 32.13330.2018 "Sewerage. External Networks and Facilities. Updated version of SNiP 2.04.03-85"
[2] Methodological Manual "Recommendations for the calculation of systems for the collection, drainage, and treatment of surface runoff from residential areas, industrial sites, and the determination of conditions for its discharge into water bodies," NII VODGEO, Moscow, 2015.
[3] Handbook "Characteristics of Pollutants from Section II. For Water Bodies" of the "List of Pollutants Subject to State Regulation in the Field of Environmental Protection," approved by Order of the Government of the Russian Federation No. 1316-r dated July 8, 2015, UralNII "Ecology," 2016