Ph.D Semenova E. I.
Ph.D Bublienko N. N.
Master's
degree Reshetitska V. P.
Master's
degree Firsova J. S.
National University of Food Technologies, Kiev,
Ukreine
Improved technology of wastewater treatment from dairy plant
For wastewater treatment of food industry is used the technology that ensures the complete
removal of contaminants. This technology combines mechanical, physico-chemical
and biological treatment of wastewater pollutants. The wastewater of the
enterprise, which produces different types of drinking milk, some dairy
products are not concentrated (Chemical Oxygen Demand (COD) is up to 2000 mgO2/dm3), while the enterprise,
the main products of which are butter, cheese, include concentrated wastewater
(COD is up to 5000 mgO2/dm3).
In the first case you can use aerobic fermentation, and in the second case - an integrated anaerobic-aerobic technology, the
main stage of which is the methanogenic fermentation [1].
Anaerobic wastewater treatment technology has a number of
significant benefits compared to generally
accepted "conventional" aerobic.
Methane fermentation is carried out with less use of
biogenic substances, so the ratio Biochemical Oxygen Demand (BOD))
: N: P = (300 - 500) 7: 1.
The difficulty of aerobic fermentation of wastewater
dairies is that they contain slowly metabolizing lactose and proteins that are
difficult to decompose by aerobic microorganisms.
Methane fermentation allows to get economically
valuable biogas which contains 50 - 80% methane and gaseous fuels [2,3].
In recent years there has
been a phase change of the disperse composition of the dairies wastewater,
which is associated with an increase in demand for dairy products and a
decrease in the types of milk production. This could be the remains of dairy
products, which fall into drains from cleansing solutions.
The low efficiency of primary sedimentation in dairy
enterprise wastewater treatment and increased concentration of suspended solids
is the cause of finding new solutions for disposal of sewage dairy industry.
On the basis of modern theoretical data there is a
technological sequence proposed for wastewater treatment facilities, which
realize the benefits of spatial succession of organisms and a branched trophic
chain.
7
Pic.1 Flowchart of dairy enterprise wastewater treatment.
1 – mechanical treatment unit
2 – averager
3 – trickling filter
4 – sump
5 –bio rates
6 – sludge treatment unit
7 – decontamination unit
8 – compressor
In the averager originates the decrease of BOD, COD, ammonia nitrogen
during the process control by chemical oxidation, venting and bio flocculation.
The lack in technology treatment of primary sump
wastewater of dairy enterprise and the ability to mineralize undissolved
organic particles by artificially created biocoenosis of the biofilter.
In laboratory conditions was investigated influence on
the biological treatment of wastewater by prior aeration. the aeration of
wastewater was conducted by bubbling method in the averager in a specified
period of time and then was delivered on the biofilter. Aeration period changed
from 1 to 24 hours at intensity 3 m3/m2 h.
As a result of experimental studies there were identified optimal values
for the proposed technology for wastewater treatment: hydraulic
load on the biofilter 1.5 - 2.5 m3 / (m2 h), the load on
the organic matter - up to 3.6 kg / (m3 day), growth of of the
biofilm on treatment facilities will be 0.02 - 0.08 g / g BOD5.
Literature
1. Kuc A.M., Shiyan P.L., Domareckiy V.A. Innovative anaerobic-aerobic technology of wastewater treatment and waste products from facilities of food industry.// NUFT scientific works,
№ 33., 2010.
– p. 42 – 44.
2.
Bayader V, Dene E.,
Brenndofer M. Biogas - theory and practice. – М. : 1982. – 148
p.
3.
Nikitin G.A. Methanogenesis in the
biotechnology. M.: Stroizdat, 1990. – 207 p.