Pilot project – recycling sludge from wastewater treatment plants in concrete products used in water managment

S obzirom na pozitivne rezultate laboratorijskih ispitivanja mogućnosti korištenja pepela dobivenog spaljivanjem mulja s uređaja za pročišćavanje otpadnih voda (UPOV) kao zamjene za cement, javila se potreba za daljnjim ispitivanjima u proizvodnji betonskih proizvoda u stvarnoj veličini. Pilot projekt rezultat je suradnje Građevinskog fakulteta Sveučiliša u Zagrebu i tvrtke Beton Lučko d.o.o. Pepeo dobiven spaljivanjem mulja u kontroliranim laboratorijskim uvjetima korišten je kao zamjena za 10 % cementa u šesterokutnim prizmama s direktnom primjenom u području vodnog gospodarstva. Na ovaj se način direktno zatvara krug u ostvarenju temeljnih postavki cirkularne ekonomije, budući da se pepeo koji nastaje kao nusproizvod spaljivanjem mulja generiranog pročišćavanjem otpadnih voda primjenjuje u betonskim prozvodima korištenim, između ostalog, i u izgradnji objekata vodnog gospodarstva. U radu su dani kemijski sastavi dobivenih pepela, potencijalni utjecaji na okoliš ispitivani kroz izluživanje, iz pepela i iz betona s ugrađenim pepelom te rezultati ispitivanja tehničkih zahtjeva za gotove betonske proizvode prema normama definiranim zahtjevima i ustaljenoj praksi u partnerskoj tvrtki.Considering the positive results of a laboratory testing of potential uses of ash obtained by sludge incineration from wastewater treatment plants (WWTPs) as cement replacement, the need arose for further testing of the production of concrete products in actual size. The pilot project was a result of the cooperation between the Faculty of Civil Engineering of the Zagreb University and the company Beton Lučko d.o.o. The ash obtained by sludge incineration in controlled laboratory conditions was used as a replacement for 10 % of cement in hexagonal prisms that are directly used in water management. In this manner, the closed circle meant the achievement of the basic principles of circular economy, since the ash generated as a byproduct of sludge incineration from wastewater treatment is used in concrete products utilized, among others, in the construction of water management facilities. The paper contains the chemical compositions of the obtained ashes, potential environmental imapcts tested through leaching from ash and concrete containing ash as well as the test results of technical requirements for finished concrete products according to the standards and established practice in the partner company