The activities of industrial enterprises, in particular malt plants, cardboard and
paper mills, include technological processes of washing and processing of raw
materials, which result in wastewater containing suspended solids, dissolved organic
compounds, heavy metal ions, in particular ferum, compounds of nitrogen and
phosphorus, et cetera, above concentrations and therefore need to be properly cleaned
before being discharged into the natural waterbodies.
Water macrophytes are considered the promising biological objects for the
treatment of wastewater from heavy metal ions, in particular ferum, nitrates and
phosphates, because of their high ability to remove these contaminants.
Scientific novelty.
1. For the first time, the efficiency of using L. minor duckweed for industrial
wastewater treatment from Fe3+ ions up to 90% as obtained with iron concentrations in
treated water less than 0.3 mg/dm3
, which meets the regulatory requirements for
wastewater discharge into natural reservoirs.
2. For the first time, the rational parameters for the removal of Fe3+ ions from
wastewater using L. minor were determined: duration 8±0.2 h; specific duckweed
biomass 25±1 g/dm3
; load on duckweed for iron ions 0.30 ± 0.05 mg/(g · day); specific
rate of extraction of iron ions by duckweed 0.25 ± 0.05 mg/(g · day); at a water
temperature of 18-20 ° C, artificial lighting for 12 hours a day with an intensity of 3000
lux and an initial iron concentration of 2.0 mg/dm3
.
3. For the first time rational parameters of malt plant wastewater treatment was
established using biocenosis of immobilized microorganisms and duckweed from iron
ions and nitrates at the initial concentration, respectively, up to 1.3 mg/dm3
and up to
53 mg/dm3
: duration – 8 ± 0.2 hour; the specific value of duckweed biomass - 25±1
mg/dm3
, biomass of immobilized microorganisms – 2.0 ± 0.1 mg/dm3
; the density of
the fibrous carrier in the bioreactor is 2.4 ± 0.1 g/dm3
; the degree of removal of iron
ions and nitrates was, respectively, up to 40% and up to 53% at a water temperature of
18-24 ° C.
4. For the first time for biological wastewater treatment a rational mode of
operation of a jet aerator of rotor type equipped with a ring nozzle with peripheral holes
with a diameter of 12 mm with an angular velocity of 38 s-1
, aeration intensity of 12-
14 m2
/(m3
· h) is established. Degree of wastewater treatment by COD up to 40%,
aggregative resistance of flakes and viability of activated sludge microorganisms,
sludge index up to 90 cm3
/g and reduction of energy costs.
Research methods and techniques. The study of the chemical composition
(concentration of ferric ions, nitrates, nitrites, ammonium nitrogen, phosphates, HCC,
dissolved oxygen) and physicochemical parameters (hydrogen index, temperature) of
wastewater was determined by spectroscopy, potentiometry, titration. The study of
11
duckweed growth was determined by gravimetric method, microscopy. Changes in the
parameters of activated sludge (activated sludge index, mixed liquor suspended solids,
qualitative evaluation) were investigated by gravimetric method and microscopy.
The practical value of a thesus is as follows:
The design of the bioreactor has been developed (patent of Ukraine for utility
model No. 136188), which ensures efficient sewage treatment of ferric ions.
The wastewater treatment plant biotechnology in the bioreactor with the
duckweed was developed and implemented, which ensures the removal of iron and
nitrate compounds as per the regulatory requirements. The technological and
instrumental schemes of sewage treatment of Slavuta Malt House in the bioreactor with
duckweed have been developed (the act of introduction). Cost of wastewater treatment
– 0,96 UAH/m3
.
The duckweed cultivation technology, its equipment and technological scheme
are developed. The technology is used for wastewater treatment. Cultivation
parameters were established: medium temperature 18-25 ° C, Steinberg medium,
dissolved oxygen concentration 1.5-2.0 mg/dm3
.
Testing showed that when the load on the duckweed in the bioreactor for ferric
ions 0.30 mg/(g·dm3
) the concentration of ferum in treated wastewater reached 0.8
mg/dm3
, which meets the regulatory requirements. The developed biotechnology is
implemented at the treatment plants of the Slavuta Malt House, which is confirmed by
the act of introduction.
Publications. 28 scientific papers have been published on the topic of the
dissertation, including 13 scientific articles, 11 of which have been published in
Ukrainian scientific publications of Ukraine on technical sciences, 1 article in scientific
journal registered in country-member of Organisation for Economic Co-operation and
Development (Hungary); 1 - in other publications; 1 patent of Ukraine for a utility
model; 14 abstracts of reports at national and international conferences
