Treatment of sulphate containing yeast wastewater in an anaerobic sequence batch reactor/Parmitoostuse sulfaate sisaldavate reovete tootlemine anaeroobse annuspuhasti reaktoris

Anaerobic mesophilic fermentation of sulphate containing yeast industry wastewaters at laboratory scale with anaerobic sequence batch reactors (ASBR) was studied. Three different treatment schemes were investigated--ASBR with and without a polymeric filler and coupled micro-aerophilic/ anaerobic SBR (CSBR). The optimal concentration of sludge (total solids 17.3 g [L.sup.-1]) in the reactor and the optimal reaction time (22 h) were determined. It was shown that in the case of ASBR efficient treatment characterized by chemical oxygen demand (COD) removal of 75-82% took place at volume loading rates up to 7.7-8.0 kg COD [m.sup.-3] [d.sup.-1] and at COD/[(S[O.sub.4]).sup.2-] ratio 8.0. In optimal conditions the methane content of the biogas was 60%. The best results for sulphate removal (99%) were achieved in the CSBR with the concentration of sulphide in the reactor effluent being about 10 mg [L.sup.-1]. Decreasing treatment efficiency after a long-time exploitation of these reactors occurred as a result of the formation of insoluble sediment (presumably CaC[O.sub.3] and [Ca.sub.3][(P[O.sub.4]).sub.2]). Key words: anaerobic sequence batch reactor (ASBR), calcium precipitates, high strength wastewater, sulphate reduction, yeast industry. Laboratoorse annuspuhastina tootava anaeroobse reaktori (ASBR) vahendusel on uuritud parmitoostuse mesofiilsel temperatuurireziimil sulfaate sisaldavate reovete puhastusprotsessi. On kasutatud kolme erinevat reziimi: puhastusprotsessi labiviimist vabalt elunevate anaeroobsete bakterite suspensiooniga, polumeerse taidise pinnale kinnitunud anaeroobsete bakteritega ja mikroaerofiilset/ anaeroobset tootlust annuspuhastis (CSBR). Anaeroobsete bakterite suspensiooni optimaalseks kontsentratsiooniks on leitud 17,3 g [L.sup.-1] kuivaine jargi ja reaktsiooniajaks 22 tundi. ASBR-i reziimis tootavas seadmes alaneb KHT 75-82% mahukoormuse 7,7-8,0 kgKHT [m.sup.-3] [d.sup.-1] ja KHT/[(S[O.sub.4]).sup.2-] suhte 8,0 korral. Eralduvas biogaasis on metaanisisaldus optimaalsete tingimuste korral 60%. Parim tulemus (99%) sulfaatioonide sisalduse alandamisel saavutatakse CSBR-i reziimil, kusjuures reaktorist valjunud reovees on sulfiidioonide sisaldus 10 mg [L.sup.-1] piires. Annuspuhastina tootava anaeroobse reaktori pikaajalisel toos hoidmisel vaheneb puhastusprotsessi efektiivsus, mis on autorite hinnangul tingitud lahustumatu mineraalse sette moodustumisest, mis voib koosneda kaltsiumkarbonaadist (CaC[O.sub.3]) ja kaltsiumfosfaadist ([Ca.sub.