DOI 10.1007/s10692-016-9780-8

Fibre Chemistry, Vol. 48, No. 3, September, 2016 (Russian Original No. 3, May-June, 2016)

ECOLOGICAL AND ECONOMIC TOOLS FOR ASSESSING EFFICIENCY OF PHYSICOCHEMICAL WASTEWATER TREATMENT METHODS I. I. Men’shova, M. V. Pyrkova, E. V. Churlyaeva, and D. O. Maslennikova

UDC [338:502.175]:628.349.08

Ecological and economic characteristics of wastewater treatment processes are studied by the example of assessment of effectiveness of synthetic and natural adsorbents and biocide flocculants. The norms for the maximum allowable discharge are calculated taking account of the achieved wastewater treatment quality indexes. Calculations of ecological hazard index that determines the adverse effect of highly concentrated wastewaters on the environment are presented. The effectiveness of nature protection measures for reducing the inflicted damage is shown.

In nature protection practice in Russia, as elsewhere in the world, normalization and standardization are used as one of the basic measures or instruments of environment protection. In his works, Z.A. Rogovin repeatedly referred to the subject of environmental safety of production [1]. Use of industrial safety standards is an objective step for protecting the environment from adverse effect and development and proliferation of degradative processes [2]. Standards of maximum allowable concentrations (MAC) are fixed for projected and existing enterprises on the ground that it is impermissible to exceed the MAC of noxious substances on the sites of the water facility with due regard for its appropriate use [3, 4]. The standard fixed for maximum allowable discharges (MAD) determines the degree to which the wastewaters need to be treated so that the condition Ccr ≤ MAC was not violated within the calculated control range and to what degree the wastewater needs to be diluted within the control range. An example of calculation of MAD of wastewater containing water-soluble organic matters into a river basin is given below. The allowable concentration of Bordeaux C chromium dye in wastewaters was calculated: Cw = (γ⋅Q/q)(MAC–Cb) + MAC,

(1)

where Cw is the maximum concentration of polluting matters in the wastewaters without exceeding the MAD of polluting matters, mg/liter, within the control range; γ is the mixing ratio; Q, q are respectively the rates of water flow in the water facility and wastewaters, m3/year; MAC is the maximally allowable concentration of a pollutant with due account of the category of water use by the facility, mg/liter; Cb is the background pollutant concentration in the water facility in the area of location of the wastewater discharge, mg/liter; Ccr is the concentration of one type of matters in the wastewaters before discharge of the wastewaters within the control range:

Cw =

qC cr + γQC b . q + γ +Q

(2)

If Ccr ≤ MAC, the prognosis is favorable and discharge is permissible, if Ccr > MAC, discharge should be reduced or treatment should be carried out. In the case where Ccr is much higher than MAC, discharge should be reduced significantly or be treated. Moscow State University of Design and Technology. Translated from Khimicheskie Volokna, No. 3, pp. 85-88, May-June, 2016

258

0015-0541/16/4803-0258© 2016 Springer Science+Business Media New York

Table 1. Standards of Wastewater Discharge Before and After Treatment with Various Adsorbents Sorbent Without treatmen t Zeopag Thermally treated zeopag Activated carbon OU Activated carbon BAU-A Sand PD-3 Shungite Hydroanth racite A Thermally treated hydroanthracite A

Ccr, mg/liter

M AC, mg/li ter

MAD, m 3/yr

6.4 0.1 1.9 3.8 0.1 6.4 0.1 4.5 4.8

0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

781 50000 2631 5262 50000 781 50000 1111 1041

Next was calculated the maximum allowable discharge of wastewater containing a pollutant. This value is taken as the base for planning measures for reducing pollutants. Also carried out was an assessment, based on the Ccr value [5], of the studied adsorbents: zeopag [5], thermally treated zeopag, activated carbon OU, activated carbon BAU-A [7], sand PD-3 [8], shungite [5], hydroanthracite A, and thermally treated hydroanthracite A [9] (Table 1). The calculation showed that the wastewater not cleaned from Bordeaux C chromium dye far exceeds the MAC value (by 6.3 mg/liter), and the dye content in the wastewater treated with such adsorbents as zeopag, activated carbon BAU-A, and shungite does not exceed MAC. A proximate assessment of impact risk should be made by reducing dimensional MAC and MAD indexes to dimensionless ones by formulating appropriate indexes and their subsequent grouping into criterial sets. Risk indexes can be used to assess the adverse effect on the environment not only of an individual manufactured product, but also of the enterprise as a whole, taking account of all the risk components of the production. Ecological hazard indexes are determined by direct statistical method and can be used to get an integral risk assessment without resort to detailed analysis of the production processes. Action of wastewaters does not have a negative effect if the the permissible level is not crossed in conformity with the Rules of Surface Water Protection from Pollution by Wastewaters. The content of suspended matters less than the wastewater discharge must not increase by more than 0.75 mg/liter. Thus, it can be assumed that any action whose risk index is less than 0.7 should be considered significant. For example, while dyeing aramid fibres, the residual dyeing bath after dyeing is treated with AUT-M carbon-reinforced fibre [10]. It is demonstrated experimentally that the effectiveness of treatment with this fibre is 97.1%. The risk index is calculated by the equation [11] р ⎛ к ⎞ I c = ⎜⎜ ∑ Cb j − ∑ C j ⎟⎟ Cb j , j =1 ⎝ j =1 ⎠

(3)

where Cbj is the quantity of actual discharges, 100 tons/yr; Cj is the concentration of dye in the discharges: taking account of MAD of 0.0475 ton/yr and after treatment with AUT-M carbon-reinforced fibre, 0.035 ton/yr [12]. The hazard index of wastewater discharges with due account of MAD Ic = (100 – 0.0475)/100 = 0.999 > 0.7. The hazard index of wastewater discharges after treatment with AUT-M carbon-reinforced fibre as sorbent Ic = (100 – 0.035)/100 = 0.999 > 0.7. Thus, the impact of wastewaters on the environment due to use of AUT-M carbon-reinforced fibre does not exceed the permissible level because the hazard index of discharges after treatment of the wastewaters is higher than 0.7 and corresponds to the MAD.

259

Table 2. Wastewater Treatment Coefficients for Various Sorbents WTC values Sorbent

d irect red 2C dye

direct red SV KU dye

acid red 4Zh dye

aci d blue K dye

0.98

0.93

0.92

0.95

0.98

0.96

0.97

0.96

0.83 0.86 0.58 0.58 0.58 0.56

0.94 0.83 0.44 0.6 0.6 0.52

0.05 0.03 0.14 0.02 0.02 0.02

0.91 0.82 0.54 0.02 0.22 0.02

Based on frothed urea poly mer [14] Based on urea and oil-acidifying cultures of microorganisms Based on polyurethane Based on cellulose Zeolite based on cl inoptilol ite, 0.5-1 mm fraction Zeolite based on cl inoptilol ite, 1-3 mm fraction Syntheti c zeolite NaX Syntheti c zeolite NaA

Table 3. Wastewater Treatment Coefficients fo r Various Flocculants WTC values Flocculent Polyacrylamide Biopag Guan idine derivatives

d irect black 3 dye

di rect brown KX dye

0.95 0.98 0.99

0.95 0.96 0.99

To determine the effectiveness of use of sorbents and flocculants, the integral index, i.e., the wastewater treatment coefficient (WTC) is used [13]. Wastewater treatment coefficient is a function of water quality parameters, such as content of suspended particles and dissolved substances, pH value, etc. When a dye is used as the test compound, the wastewater treatment coefficient in the absence of thermal pollution WTC = f (C) is evaluated by the following equation: WTC = (m1 – m2)/m1,

(4)

m1 and m2 are the mass of the dye in the waste water before and after treatment, respectively. In this work, a comparative analysis has been made of the integral treatment parameters for various types of sorbents and flocculants. The results are put in Tables 2 and 3. As can be seen from the data in Tables 2 and 3, the best sorbents and flocculants can ensure high parameters in adsorption method of wastewater treatment. The economic loss due to pollution calls for assessment of adverse impact on the environment. The effectiveness of nature protection measures at enterprises matches the reduced economic loss in terms of cost. To calculate the economic loss resulting from wastewater discharge into water bodies, the following equation was used: Yen = Pi MCel,

(5)

where Pi is the base payment norm for discharge of pollutants into surface and ground waters [14]; M is the reduced mass of annual discharge of wastewaters containing pollutants, nom. Ton/yr; Cel is the coefficient of ecological situation and economic importance of the region, which is 1.41 for Moscow [15]. The M value was calculated by the equation n

M = ∑ Ai mi = Σm / MAC i =1

(6)

where i is the type of discharged pollutant (i = 1, 2, 3…n); Ai is the relative hazard index of the i-th compound for water, nom. Ton; mi is the total mass of discharges, ton/yr. 260

The quantity A for any pollutant is determined by the equation A = 1/MAC

(7)

As shown in [16], such calculation of economic assessment of loss due to discharge of wastewaters containing direct red 2C dye shows that sorption treatment with a sorbent based on frothed urea polymer reduces economic loss by 90%. REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Z. A. Rogovin, Fundamentals of Chemistry and Technology of Chemical Fibres [in Russian], Vol. 2, Khimiya, Moscow (1974), p. 343. E. V. Girusov (editor), Ecology and Economics of Nature Management [in Russian], YuNITI-Dana, Moscow (2007), p. 591. I. I. Men’shova, V. V. Safonov, and I. I. Bululukova, Izv. Vuz. Tekhnol. Tekst. Prom., No. 2, 84-87 (2013). M. V. Pyrkova, I. I. Men’shova, et al., Butlerov. Soobshch. (Butlerov Communications), 37, No. 2, 52-56 (2014). I. I. Men’shova, M. V. Pyrkova, and Yu. S. Gorbunova, Collec. of Papers at Innovation-2014 [in Russian], MGUDT, Moscow (2014), pp. 204-206. P. A. Gembitskii and I. I Vointseva, Polymeric Biocide Preparation of Polyhexamethylene Guanidine [in Russian], Poligraph, Zaporozh’e (1998), p. 44. Yu. I. Shumyatskii, Adsorption Processes [in Russian], RKhTU im. D. I. Mendeleeva, Moscow (2005), p. 164. U. G. Distanov, A. S. Mikhailov, and T. P. Konyukhova, Natural Sorbents of the USSR [in Russian], Nedra (1990), p. 208. V. B. Artem’ev, Anthracites − A Special Class of Coals [in Russian], edited by L. A. Puchkov, Nedra Communications Ltd., Moscow (2001), p. 464. V. B. Fenelonov, Porous Carbon [in Russian], IK Sib. Otdel. RAN, Novosibirsk (1995), p. 513. I. I. Men’shova and E. I. Timakin, Collec. Sci. Papers on Fabric Processing [in Russian], MGUDT, Moscow (2014), pp. 22-27. S. F. Sadova, G. E. Krivtsova, and M. V. Konovalova, Ecological Problems of Finishing Industry [in Russian], edited by S. F. Sadova, MGTU im. A. N. Kosygina, Moscow (2002), p. 284. V. V. Glukhov and T. P. Nekrasova, Economic Foundations of Ecology [in Russian], Piter, St. Petersburg (2003), p. 384. Russian Federation Government Decision No. 7, dated 08.01.2009. Russian Federation Government Decision No. 410, dated 01.07.2005. V. M Gur’ev and I. I. Men’shova, Collec. of Papers at Search-2015 [in Russian], IGPU, Ivanovo (2015), page 84.

261