Purification of wastewater from industrial pig farms in the USSR

J. agric. Engng Res. (1991) 49, 21-31

REVIEW

PAPER

Purification of Wastewater from Industrial Pig Farms in the USSR K. R. GRAY;*

A. V. UvARKIN;t

A. J. BIDDLESTONE*

* School of Chemical Engineering, University of Birmingham, Birmingham B15 2’IT, UK t Kursk Polytechnic Institute, Kursk, USSR (Received

11 July

1989; accepted

in revised

form

16 October

1990)

In the USSR the very large industrial pig farms have outputs between 12 and 216 thousand pigs per year. For historical reasons almost all these farms employ water for flushing the manure away from the livestock housing. The resulting manurial wastewater contains up to 40.2 g/l suspended solids (SS), 33-O g/l biochemical oxygen demand (BOD,), 44.Og/l chemical oxygen demand (COD), 1.4 g/l ammoniacal nitrogen (N) and 4.4 g/l total nitrogen WI. The wastewater is initially processed using screen separators and sedimentation to remove suspended solids. Up to 80% of the SS, 70% of the COD and 30% of the total nitrogen is removed in this way. On some of the large farms the manurial wastewater can then be utilized on agricultural fields; however, with others there may be insufficient local agriculture due to climatic and hydrogeological conditions. The wastewater then needs extensive purification to enable it to be discharged to rivers, or to permit its further use for manure flushing operations. Some treatment techniques enable the SS to be reduced to 5 mg/l, BOD, to 12 mg/l, COD to 40 mg/l and ammoniacal N to 2 mg/l. This paper reviews the mechanical, biological and physicochemical methods used for this purification.

1. Introduction The intensification of agricultural production, especially that involving livestock on an industrial basis, was the major objective adopted by the Foodstuff Programme of 1982 in the USSR. In accordance with Government policy a major building programme of industrial pig farms is being undertaken. Depending on the regional conditions and the resources available, the building of farms with outputs of 12,24,54, 108 and 216 thousand pigs per year is being achieved in the USSR. The total number of farms by 1985 was 500; these fattened 19.5 M pigs per year.’ This intensification of pig raising on an industrial basis on comparatively small areas of land has led to the generation of considerable volumes of manurial wastewater, because the pig wastes are flushed from the housing using water. This has created the threat of spreading infectious diseases and pollution to the surrounding areas. After much research the main approaches to solving the problems of utilizing these pig wastes have now been determined. The main difficulty remaining is the development of suitable process schemes for purification of the wastewater which will guarantee the quality of the treated effluent flowing to local rivers, or else permit the repeated use of the water for flushing away the manure from the pig houses. These technological schemes are vitally important in the 21 0021-8634/91/050021

+ 11 $03.00/O

0

1991 The British

Society

for Research

in Agricultural

Engineering

22

PURIFICATION

OF

WASTEWATER

FROM

PIG

FARMS

IN

USSR

Soviet North, Siberia and the Far East of the country; in these areas there is virtually agriculture on which the manurial wastewater can be used. 2. The characteristics

The principles of industrial following features.

of wastewater

from industrial

livestock production

no

pig farms

on these farms are characterized

by the

(1) Specialization of the livestock enterprise into either the complete production cycle (70-80% of the farms), specialist weaner production or specialist fattening units. (2) Uniform production of output over the course of a year. (3) Narrow specialization of the work force. (4) Feeding the pigs with a complete feedstuff of full nutritional value, together with protein, vitamin and mineral additions. (5) No exercise for the pigs. (6) Intensive employment of cross-bred and hybrid breeds. (7) Complex mechanization and automation of the industrial processes. On industrial pig farms the removal of manure from the pig housing is done by a stream of water. This is an historical approach stemming from the erection of the first industrial pig farms under licence in the period 1972-80. In retrospect, flushing by water may bring more problems than it cures but virtually all the farms are now geared to this technique. Usually, human sewage is carried away from the farms by a separate piping system and rain water by a third. The quantities of manurial wastewater naturally depend on the number of pigs. For farms with productions of 24, 54, 108 and 216 thousand pigs per year, the wastewater generated’ is 700, 1500, 3000 and 6000 m3/d. There are fluctuations of up to 20% depending on the water system employed. An investigation on several farms showed that the wastewater output flow is rather irregular during the day with the maximum flow being about twice the average value.3 The composition of the wastewater at an individual farm is also subject to sharp fluctuations. For example, at the “Ilinogorski” farm which produces 216 000 pigs/year the concentrations fluctuate as follows:3 suspended solids (SS) between 0.8 and 40.2 g/l; chemical oxygen demand (COD) between 5.0 and 33.0 g/l; biochemical oxygen demand (BODS) between 1.2 and 31.0 g/l. Practically all industrial pig farms employ similar regimes for feeding the stock and for the compositions of the resulting removal of the manure by water. Consequently wastewaters” fall within the wide ranges shown in Table 1. The wastewater from a farm is normally monitored every day for the items listed in the table. 3. Mechanical

treatment

The removal of suspended solids from pig farm wastewater is a necessary stage of treatment prior to disposal of the liquor on agricultural fields or to further purification by biological or physicochemical methods. The costs of transporting and spreading the slurry are reduced, while the effects of further purifications are increased. In the USSR such separation is carried out using screen separators or centrifugal machines. Table 2 shows results from some of the devices when working on industrial pig farms. At present, screen separators are employed on the majority of farms. To achieve additional removal of suspended solids from the effluent leaving these separators, gravity sedimentation is widely used. Both vertical and radial sedimentation tanks are employed. 3*s*‘o Residence times of 2-3 h are normal. Using sedimentation, the following

K. R. GRAY

ET

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AL

The composition

Table 1 of wastewaters on industrial

Analysis

Range

“C cm*

12-20 0.7-1.0

Temperature, Transparency,

Suspended solids, g/l BOD,, g/l COD, g/l Ammoniacal N, g/l Nitrate & nitrite N, g/l Total N, g/l Urea, g/l Soluble P, g/l (PO:-) Total P, g/l (PO:-) Chlorides, g/l Sulphates, g/l Bicarbonates, g/l Sodium, g/l Potassium, g/l Calcium, g/l Magnesium, g/l PH Total microbe numbers,

ml-’

pig farms

(after ten-fold with water)

0.8-40-2 1.2-33.0 5.0-44.0 0.1-1.4 absent 17-4.4 1.5-7.2 0.4-0.9 O-5- 1.6 0.1-0.6 0.1-0.2 2.0-5.1 0.1-0.2 0.1-0.7 0.1-0.4 O-1-0.3 6.8-8.1 105-10’

*Transparency to printing is a standard test in the USSR for drinking height of a column of the water through which standard book type placed read. For drinking water the transparency must be >30 cm Table Characteristics

Machine Vibroscreen, GIL-52 Rotary screen Inclined screen SD-F-50 Filtering centrifuge YON-700 Sedimenting >97 centrifuge OGSH-502-K-4 Hydrocyclonest

m.c. * of wastewaler entering, %

dilution

water. It is the below can just be

2

of some separation

machines

ouiput, m ‘/h

Reducrion of SS by separation, 70

m.c.* of solids removed. 5%

>98

loo-120

25-35

85-86

Vostochni (Leningrad)

4.5

>96

35-80

35-40

84-86

4

>96

50-60

18-37

83-88

Ilinogorski (Gorky) Povolgski (Kubishev)

>91

25-30

24-50

78-81

Kuzneceovski (Moskow)

5.7

>97

25

65-75

65-70

Luzinski (Omsk)

578

>91

-

60-67

W-92

IlinogorskiP (Gorky)

7

* m.c. is moisture content, t Hydrocyclone diameters: screen separators 8 Trials

the % by weight of pure water in the total 250 mm 1st stage, 75 mm 2nd stage. Input

Name of farm (District)

stream wastewater

was the output

Reference

67

from

rotary

24

PURIFICATION

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FARMS

IN

USSR

removals are achieved: SS 75-80%; COD <70%, total N ~30%; soluble phosphorus (PO:-) ~44%. The sludges have a moisture content of 93-96% and amount to 2-6% of the quantity of wastewater. An investigation was carried out at the Ilinogorski farm to assess the effect of biocoagulation of wastewater, after mechanical separation and prior to sedimentation, using waste activated sludge.” The results showed that removals of suspended solids and COD were increased by about 10% and 8% respectively using doses of activated sludge in the range 400-700 mg/l. The organic solids removed by mechanical separation and sedimentation, plus any sludges recovered during subsequent operations, are used in agriculture or amenity horticulture, normally after some degree of cornposting. 4. Biological

treatment

Depending on the total output of wastewater from the farm, the availability of agricultural fields and the climatic and hydrogeological conditions of the locality, purification of the wastewater is carried out either by field irrigation, aeration tanks or shallow aerobic lagoons. At more than 50 industrial pig farms in the USSR there is the possibility of purifying the wastewater by irrigation on to agricultural fields; this follows mechanical treatment and either nil, one or two stages of biological treatment in aeration tanks. Following irrigation on to the fields at appropriate flowrates, the drainage water”*‘* had the following range of composition: BOD 9-30 mg/l, COD 80-90 mg/l, SS 63-100 mg/l, ammoniacal N 1-17 mg/l, nitrate N O-5 mg/l and phosphate O-2 mg/l. Although such fields allow the possibility of effective purification of the wastewater, their use is governed by both hydrogeological constraints and climatic conditions. The main use of biological treatment is in one or two stages of aeration tanks. Approximately 70% of farms employ the processing sequence of mechanical separation, then sedimentation tanks, followed by one or two stages of aeration tanks, Fig. la. The first aeration stage uses aeration for 45-50 h, the second uses lo-12 h aeration; activated sludge is present at a concentration of 2-5 g/l on a dry basis. Table 3 shows typical wastewater analyses’*” from some farms employing this purification sequence. The results obtained by the treatment stations which use this scheme of mechanical separation plus sedimentation, then two stages of biological treatment, were generally worse than the quality standards13 laid down for purified wastewater. These standards, shown in Table 4, indicate the maximum degree of purification which can be expected from this processing sequence; they were derived from the results of model investigations. At some farms, shallow aerobic lagoons are used as the final stage of treatment after aeration tanks. With these lagoons the wastewater passes successively through an algal lagoon, a shrimp lagoon, and finally a fish-rearing lagoon. Three separate lagoons are necessary, each with its distinct population of flora/fauna, not a single lagoon containing a mixed population. Neither shrimps nor fish can live in the wastewater leaving the aeration tanks due to toxic components arising from the metabolism of the activated sludge; algae are needed to remove these impurities. Shrimps are very good purifiers but are rapidly devoured by the fish if put together. In the lagoons the average residence time13 is 20-30d while the year-round average air temperature must be more than +lO”C. The depths of the algal and shrimp lagoons are 0.6-0.8 m; that of the fish-rearing one is 1.2-1.5 m. After passing through the lagoon sequence the average analysis of the wastewater” is BOD 30-80 mg/l, COD 150-200 mg/l, ammoniacal N 30-40 mg/l and phosphate (PO:-) 40-50 mg/l. In some cases there may be upsets in the water composition leaving the lagoons due to mineralization of the algae. At the Povolgski farm, in 1982, the concentration of N + P + K in the water roughly doubled due to this cause.’

K.

R.

GRAY

ET

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AL. (a)

Wastewater

,To mter course

Biological

treatment (b)

Wastewater

c To biological treatment solids i ; Electrocoagulation

(cl

Wastewater

To biological treatment

Sepkated solids

Heat

treatment

Wastewater

Cd)

-To water course

Lime

treatment

Fig. 1. Wastewater treatment processes in the USSR. 1, separator; 2, sedimentation tank; 3, aeration tank; 4, chiorination tank; 5, electrocoagulation; 6, heat exchanger; 7, steam heater; g, mixer; 9, , wastewater; - - - - - -, sludges sludge tank.

26

PURIFICATION

Farm (District) Kalitynski (Kiev) Kuzneceovski (Moskow) Ilinogorski’ (Gorky) Gubkinski (Belgorod) *This farm being recycled

OF

analyses

WASTEWATER

Table 3 after two stages

FROM

Farm

wastewater

oulpul, thousands

SS,

BOD,

COD,

Total

of pigs/a

w/l

w/l

w/l

108

75-780

100-920

108

70-120

216

35-105

108

200-275

operated a recycle system for manure flushing

of aeration

PIG

FARMS

IN

USSR

tanks

Phosphnre PO:-,

K,

w/l

w/l

mgP

300-1000

190-400

60-180

110-190

55-70

300-420

120-280

60-110

loo-150

105-170

400-600

230-500

80-200

140-200

60-80

350-500

100-300

35-90

110-160

with

1000 m’/d

of wastewater

after

N,

two

steps of biological

treatment

In order to improve the results from the second stage of the aeration tanks, the joint use of activated sludge and certain strains of protococcal algae was investigated. 4 A significant reduction in organic compounds resulted, with BODS reduced to ~36 mg/l; however, no success was obtained in reducing the concentrations of either N or P. An algae-bacteria complex” consisting of activated sludge (4.8-5.5 g/l) and the green algae chlorella (l-3-3.6 M/ml) was tried out in the second stage of the aeration tanks with an aeration time of 12-16 h. It gave the following quality of wastewater: COD 460 mg/l; ammoniacal N 103 mg/l and phosphate 183 mg/l. 5. Physicochemical

treatment

The degree of purification of the wastewater achieved by the combination of mechanical separation and biological treatment appeared to be inadequate. Trials were therefore conducted in the USSR using physicochemical methods at different stages in the purification sequence. These included electrocoagulation, heat treatment, chemical reagents and ozonation. Leningrad Civil Engineering Institute suggested and tested the method of electrocoagulation’5 on the wastewater. In this technique anodes and cathodes of either aluminium or iron are suspended in the flowing stream of wastewater and direct current passed between them. The coagulants A1(OH)S and Fe(OH), are generated according to the relationship Fe3’ + 30HTable Quality

standards

for

Suspended

solids, mg/l COD, mg/l Total N, mg/l Phosphate, mg/l Potassium, mg/l

4

puritied wastewater pig farms”

Analysis

BOD,,

= Fe(OH)3

from

industrial

Concentration mg/l

Cl20 <75 <300
K.

R.

GRAY

ET

AL.

27

and cause deposition of fine suspended solids from the polluted water. Because of the influence of the electrical field electrocoagulation is sometimes more effective than is chemical coagulation by direct addition of FeCI, or A&(SO&. In this instance, electrocoagulation was employed after mechanical separation, and was followed by further treatment using aeration tanks and aerobic lagoons, Fig. lb. The input of energy required was 9-10 kWh/m3 of wastewater. Immediately following the electrocoagulation and its subsequent sedimentation step, the average analysis of the wastewater was: SS 1500 mg/l; total N 1100 mg/l and phosphate 100 mg/l. In spite of the subsequent successful biological purification stage the use of electrocoagulation is problematical because of the following drawbacks which were uncovered. 1. After 36-40 h the effect of electrocoagulation fell off sharply because of passivation of the electrodes.‘6 2. The limitation of quotas for use of the resulting sludges as fertilizers” because of abnormally high levels of A13+ and Fe3+ (O-7-1.0%). 3. The considerable reduction in effectiveness of the technique’* if the wastewater has a concentration of SS >6.2 g/l. Trials on the use of heat treatment of wastewater” prior to the sedimentation tank, using steam heating, were conducted at the Vladimirski farm, Fig. Ic. The objective was to reduce the organic loading on the subsequent biological treatment stage. Unfortunately, during the period of the trials the work of the whole purification train broke down due to the abnormally high temperature of the wastewater (40-5O”C), even after cooling. The application of heat treatment was obviously not pertinent because of the low reduction of N and P compounds during the subsequent biological treatment stage, the considerable energy expenditure required, and the need for expensive corrosion-resistant materials of construction. For the first time in the USSR, trials were conducted at the Vladimirski farm on the use of chemical treatment.” Wastewater, after mechanical separation, was treated with A12(S04)3 mixed with Ca(OH), and the polyelectrolyte polyacrylamide in doses of 700, 1000 and 10 mg/l respectively. After sedimentation the wastewater passed to two stages of aeration tanks. Because of upsets in the process arising from faults in reagent addition and overload of the biological treatment stage, the purified wastewater had an unsatisfactory analysis of COD 600 mg/l, ammoniacal N 120 mg/l and phosphate 30 mg/l. The Kiev Civil Engineering Institute, together with the Ukrniigiproselhoz (The Ukranian Scientific Research Institute), proposed the use of A12(S0J3, or FeCl,, or a waste roduct from titanium-magnesium production prior to the biological treatment The waste included chlorides of aluminium, iron and other metals. This stage. &’ modification enabled the time needed for bio-purification from organic compounds to be reduced to one-third of that required without the reagents; phosphate was also reduced to 15 mg/l. Unfortunately, effective removal of N compounds was not obtained. Gorky Civil Engineering Institute, in common with the UN11 VODGEO (All-Union Scientific Research Institute of Water Supply, Sewerage, Hydrotechnical Constructions and Hydrogeological Engineering), investigated another processing scheme employin chemical treatment for removal of organic, N and P compounds from wastewater.lo2 $ Their scheme involved two stages of treatment with lime, before and after the biological treatment stage. Lime treatment prior to biological treatment is aimed at: (a) Maximizing activated sludge ammoniacal N;

the removal of organic compounds in order to increase the age of the in the aeration tank, thereby achieving effective nitrification of

28

PURIFICATION

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(b) Maximizing the removal of organic N, which is mainly present as urea and is the source of ammoniacal N, during the period of biological ammonification; and (c) Increasing the alkalinity of the wastewater for effective nitrification. The lime treatment after the biological treatment stage is for more complete removal of phosphate. Pilot plant trials using this lime treatment resulted in the following analyses: COD 220 mg/l, ammoniacal N 2-7 mg/l and phosphate l-10 mg/l. Experiments were carried out to try to reduce the lime dose needed prior to biological treatment. This required an addition of 3-3.5 g/l and was proving expensive because of the large quantities needed by the large flows of water. Several variations of gravity biocoagulation by waste activated pre-purification were investigated: sedimentation, sludge, treatment by lime-sludges obtained by sedimentation after the stages of lime treatment, and treatment by lime-sludges plus activated sludge.“” These trials employed the following sequential processing schemes: lime treatment, sedimentation, biotreat(a) Mechanical separation, sedimentation, ment, sedimentation, lime treatment, sedimentation; (b) Mechanical separation, sedimentation with waste activated sludge, then as scheme (4; (c) Mechanical separation, sedimentation with lime-sludges, then as scheme (a); (d) Mechanical separation, sedimentation with waste activated sludge plus limesludges, then as scheme (a). Economic evaluation of the four processing schemes took into account the treatment of all the final sludges by gravity concentration, vacuum filtration and disinfection by the “bio-heat” (cornposting) method. Scheme (d), shown in Fig. Id, proved to be the most effective approach. As a result of recycling the various sludges, the requirement of lime in the first stage of lime treatment was reduced by about 40%, representing a significant reduction in operating costs. Lime dosages in the first and second stages are now 1.5-2.0 and 0.20-0.22 g/l respectively. Residence time in the aeration tank is 35-40 h. The cost of purification of the wastewater is now 0.72 roubles per m3; this includes treatment costs for the sludges and an allowance for use of part of the purified water in the recycle water system for manure flushing.” Processing scheme (d) is being used in the reconstruction of the treatment station at the Ilinogorski farm. Gorky Civil Engineering Institute, together with UN11 VODGEO tested a processing scheme for the removal of organic compounds from wastewater leaving the aeration tanks ‘a This scheme included treatment by catalytic ozonation, followed by high-rate sand filtration. In the ozonation step the wastewater passed through a packed bed of activated carbon countercurrent to a stream of ozone; the activated carbon accelerated the oxidation of organic material, reducing the BOD and COD. The wastewater analysis after this final purification was SS 5-7 mg/l, BODS 12-15 mg/l and COD 40-60 mg/l. The scheme was used for the final purification of wastewater at the Konosha farm in Arkhangelsk district. 6. Wider

operations

Winter conditions in the Soviet Union can be very severe, with temperatures falling to the range -10 to -30°C. With careful design and construction, however, the low temperatures do not have a disastrous effect on the operation of the treatment processes such as that shown in Fig. la. Wastewater entering from the pig housing is warm, with an average temperature in the range 12-20°C; by the time it has passed through the first sedimentation tank, which has a residence time of 2-3 h, it has not cooled to freezing

K. R. GRAY

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point. Where the following aeration tanks employ mechanical agitation, the vessels have walls and roofs built of brick or concrete. Where aeration is by compressed air and diffusers, then the tanks are open topped; in this case the heat of compression, giving a compressed air temperature >4O”C, is enough to balance the heat losses from the open tank and freezing is avoided. The treatment operations which succumb to harsh conditions are the shallow aerobic lagoons with algae, shrimps and fish; these can only be used in mild climates. However, much deeper lagoons can be brought into operation for the winter period in regions with moderately low temperatures. The various sludges arising from mechanical separation and the sedimentation tanks are put out onto bare fields in spring and summer; the fields are then cropped. 7. Process

improvements

At the present time in the USSR much research and development is being conducted to improve the operations of these large wastewater treatment units. Some major topics under study are as follows. (a) Optimization of process parameters to improve the degree of purification of the wastewater which can be achieved. (b) Improvement of the design and operation of the aeration tanks to increase nitrification-denitrification. (c) Selection of better strains of algae for more effective purification in the shallow lagoons. (d) Production of biogas from the various sludges. 8. Conclusions

(1) Wastewaters from industrial pig farms are highly polluting both with regard to organic materials (BODS 1.2-33.0 g/l and COD 5-44 g/l), nitrogen (total N 1.7-4.4 g/l) and phosphorus (total P 0.5-1.6 g/l). (2) Output flows of wastewater display considerable fluctuations, with the maximum values being about twice the mean values. (3) Irrigation of wastewater onto agricultural fields is possible on some farms after at least mechanical treatment. At appropriate application rates this permits effective purification. (4) After mechanical treatment and two stages of biological treatment in aeration tanks the wastewater has analyses in the range SS 35-780 mg/l, BODs 55-920 mg/l, COD 3001000 mg/l, total N 100-500 mg/l, phosphate 35-200 mg/l and potassium 100-200 mg/l. (5) Purification of wastewater by mechanical treatment, aeration tanks and aerobic lagoons gives analyses in the range BODS 30-80 mg/l, COD 150-200 mg/l, ammoniacal N 30-40 mg/l and phosphate 40-50 mg/l. (6) Processing schemes employing chemical treatment with metal salt coagulants prior to biological treatment enable aeration times to be reduced to one-third and improve the removal of phosphate. (7) Processing schemes employing two stages of lime treatment, before and after biological treatment, enable much better removal of ammoniacal N compounds (down to 2-7 mg/l) and phosphate (reduced to l-10 mg/l). To reduce the lime dosage required in the first stage the wastewater can be pre-treated with a combination of waste activated and lime sludges. (8) A final purification of the wastewater, after the aeration tanks, can be carried out by catalytic ozonation and high-rate sand filtration. This yields water with SS 5-7 mg/l, BODS 12-15 mg/l and COD 40-60 mg/l.

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References S. V.; Naidenko, V. V.; Shvetsov, V. N. Problema ochistki i ispolzovania stochnih vod. [The problem of purifying and using wastewater.] Vodosnabjenie i sanitarnia technika 1984,s: 7-9 * Ukazania po proektirovaniu sistem navozoudalenia. [Instructions for the design of manure removal systems.]Moskva, Rosselhozizdat1982 M. M. Stochnie vodi svinokompleksov. ’ Demidov, 0. V.; Naidenko, V. V.; Kolihan, [Wastewatersfrom industrial pig farms.] Trudi VNII VODGEO 1977,64: 176-179 * Kovalev, N. G.; Glazkov, I. K.; Matiash, I. N. Uborka i utilizacya navoza na svinovodcheskih fermah. [Tidying-up and utilizing the manure on pig farms.] Moskva, Rosselhozizdat, 1981 ’ Pererabotka navoza jivotnovodcheskih ferm i kompleksov. [Processing the manure from stock-breeding farms and industrial farms.] Leningrad-Pushkin, Leningrad Agricultural Institute 1980 ’ Glazkov, I. K.; Raziapov, R. A.; Denisov, V. I. Resultati ispitani pervoi ocheredi ochistnih soorujeni kompleksa“Povolgski”. [Results of trials on the first installationsat the purification station of the industrial pig farm “Povolgski”.] Tez. dokl. na Vsesouznoi nauch.-proizv. sovech. po biologicheskimmetodam pererabotki navoza. Kiev 1983:78-80 ’ Batsanov, I. N.; Lukaninko, I. I. Uborka i utilizacya navoza na svinovodcheskih kompleksah. [Tidying-up and utilizing the manureon industrial pig farms.] Moskva, Rosselhozizdat1977 * Melnikov, S. V.; Kaluga, V. V.; Afanasev, V. N. Tehnologicheskoeoborudovanie svinovodcheskih kompleksov. [The technical equipment of industrial pig farms.] Moskva, Rosselhozizdat 1979 ’ Kovalenko, V. P. Mehanizatsia obrabotki bespodstilochnogonavoza. [Mechanizing the treatment of litterless manure.] Moskva, Kolos 1984 lo Uvarkin, A. V. Ochistka stochnih vod svinovodcheskih predpriati. [Purification of wastewater from industrial pig farms.] Dissertation for the degree of candidate in technical sciences. Gorki , 1984 ” Mojaev, E. A.; Talapa, A. I. Gigienicheskaotsenka metoda ochistki stochnih vod svinovodcheskogo kompleksa na zemledelcheskihpolah oroshenia. [Hygienic evaluation of a method of purifying wastewater from an industrial pig farm on agricultural fields.] Gigiena i sanitaria 1982,6: 13-16 ” Novikov, V. M.; Dmitrieva, V. I.; Polenina, V. A. Sposobi predotvrachenia zagraznenia vodoemov stochnimivodami jivotnovodcheskih kompleksov. [Methods of preventing pollution of the water environment by wastewater from industrial stock-breeding farms.] Sbornic nauchnihtrudov VNIIGIM 1975,2: 6-13 l3 Obshesouznie normi tehnologicheskogo proektirovania sistem udalenia, obrabotki, obbezarajivania, hranenia, podgotovki i ispoizovania navoza i pometa (ONTP 17-81). [The All-Union standardsof technical designof systemsfor the removal, processing,disinfection, storage, preparation and use of animal manure and poultry litter.] Moskva, Giproniselhoz 1982 ” Kovalenko, V. A.; Smimov, 0. P.; Thigankov, S. P. Biologicheska ochistka stochnih vod na svinovodcheskihkompleksah. [Biological purification of wastewater on industrial pig farms.] Jivotnovodstvo i sanitaria 1982, 1: 52-54 l5 Melnlkov, S. V.; Kaluga, V. V.; Safonov, U. K. Gidravlicheski transport v jivotnovodstve. [Hydraulic transport in stock-breeding.] Moskva, Rosselhozizdat1976 lo Balandin, E. M.; Kihno, V. S.; Vlasuk, N. V. Issledovanie kinetiki elektroflokylachionnoi ochistki stokov jivotnovodcheskih kompleksov. [Investigation of electroflocculant purification of wastewater from industrial stock-breeding farms.] Himia i technologia vodi 1982, 4(2): 129-131 ” Drohent, 2. Elektrokoagulacja sciekow z fermy bydla. [Electrocoagulation of wastewater from farms.] JospodazkaWo-dna 1983,43(7): 211-220 ‘* Sergeev, A. L. K obosnovaniu diapazonov effectivnogo ispolzovania elektroflotocoagulatsii dla ochistki stokov svinoferm. [The scopefor effective use of electroflotocoagulation in purification of wastewaterfrom pig farms.] Electronna obrabotka materialov 1982, 1: 87-88 ’ Iakovlev,

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” Iakubov, K. A. Effectivnost biologicheskogo okislenia zagrazneni stokov svinovodcheskih kompleksov. [The effect of biological oxidation of pollution in wastewater from industrial pig farms.] Tez. doklada na Vsesousnomnauchno-prouzv. sovesh.po biol. metodam pererabotki navoza. Kiev 1983:53-55 *’ Kulski, L. A.; Smiruov, 0. P.; lakubov, K. A. Opredelenie optimalnoi dozi koagulanta s uchetom fazovo-dispersnogo sostoaniaprimesei. [Defining the optimal dose of coagulant, taking into considerationthe phasedispersionconditions of the pollutants.] Himia i tehnologia vodi 1983,5(3): 258-261 ” Naideuko, V. V.; Demidov, 0. V.; Uvarkin, A. V. Gluboka ochistka stochnih vod svinovodcheskih predpriati ot soedineni azota i fosfora. [The high purification of wastewater from industrial pig farms from nitrogen and phosphoruscompounds.] Trudi VNII VODGEO 1985: 51-58 n Metodicheski recomendatsi po proektirovaniu sistem udalenia, obrabotki, obbezarajivania, hranatsii navoza i pometa. [Recommendationsfor the design of systemsfor the removal, processing,disinfection, storage and utilization of animal manure and poultry litter.] Moskva, Kolos 1983