Choosing chemicals for wastewater sludge dewatering at small-scale wastewater treatment facilities

Summary

The results of studying the effect of introducing cationic Ultraflok K370 and Ultraflok K390 flocculants with different doses and concentrations of the chemical solution on the efficiency of dewatering aerobically stabilized excess activated sludge in a dehydrator at the wastewater treatment facilities of a cottage village in the Novosibirsk Region are presented. It has been established that Ultraflok K390 flocculant with a 0.1% solution concentration and a flocculant dose of 3.8–4.4 kg/t of dry matter is the optimal chemical for sludge dewatering in a screw dehydrator providing for reducing the sludge moisture content to 81.4–81.7%. Increasing or decreasing the dose and concentration of flocculant solutions results in an increase in moisture content up to 82.1–92.8%. The use of Ultrafloc K370 flocculant provides for achieving 83–84% sludge moisture content at 0.2% solution concentration and chemical dose of 3–3.4 kg/t of dry matter.

Key words

domestic wastewater , flocculant , filter cake , sludge dewatering , dehydrator , sludge treatment

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UDC 628.292.65.011.4

KINEBAS A. K., PANKOVA G. A., LOMBAS S. V., JUDIN M. Iu., Il'in Iu. A., IGNATCHIK V. S., Ignatchik S. Iu.

Methods of Monitoring of Sewerage Pumping Stations (on the example of SPS № 10 of the St. Petersburg’s water disposal system)

Summary

Methods of the monitoring of sewerage pumping stations tested at the SPS № 10 of St. Petersburg are presented. These methods allow to determine (taking into account the changes in the receiving tank – pumps – network system during the operation) technological characteristics of reliability of the pumping station operation necessary for selection of pumps and substantiation of power saving decision at reconstruction.

Key words:

monitoring , designed model , domestic wastewater , sewerage pumping station , technological characteristics of reliability , power saving

UDC 628.3
DOI 10.35776/VST.2023.06.03

Koulakov A. A.

Features of wastewater composition at small-scale treatment facilities

Summary

The composition of wastewater at small-scale treatment facilities differs significantly from the composition of municipal wastewater both in terms of pollution concentrations and their proportions. Information is presented on the collection and analysis of data from long-term observations of the composition and temperature of wastewater from small settlements at 31 treatment facilities. It has been revealed that an increased concentration of nitrogen at medium concentrations of organic substances is typical for these facilities. Such a disproportion results in a shortage of substrate for biological treatment – denitrification; consequently, dosing an external source of organic matter is required. Wastewater supplied to the treatment facilities has a very low N–NH₄/N_total ratio, which indicates incomplete ammonification and the need to take into account total nitrogen during laboratory control. At some facilities, the temperature of incoming wastewater is below 10–12°C during most of the year, which significantly reduces the efficiency of biochemical treatment processes.

Key words

domestic wastewater , sewerage treatment facilities , temperature , wastewater composition , denitrifying potential

DOI 10.35776/VST.2022.03.06
UDC 628.3

Koulakov A. A.

Estimation of the achievability of the environmental and technological regulations at small wastewater treatment facilities

Summary

The transition of water and wastewater services to technological regulations imposes new environmental requirements for wastewater treatment facilities. The probability of meeting environmental and technological regulations at 117 sites was estimated. For two groups of treatment facilities (midget, small and minor), the achievability of the regulations for suspended solids, BODtotal, nitrogen (ammonium, nitrite, nitrate) and phosphate-phosphorus was determined. The smallest proportion of the facilities could provide for meeting the maximum permissible concentrations of suspended solids (12.2 and 8.8%), phosphate-phosphorus (24.5 and 8.3%) and ammonium nitrogen (12.2 and 9%) in the effluents discharged into water bodies of commercial fishing importance. Meeting the technological regulations for water bodies of category B looks more likely and is 30.6% for ammonium nitrogen, for other indicators – more than 70%.

Key words

domestic wastewater , sewerage treatment facilities , technological indicators , environmental regulations , achievability

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UDC 621.61.003.13

Berezin S. E.