Sludge Thickening and Dewatering Bob Dabkowski Katy Craig Hach company Sludge Thickening and Dewatering Bob Dabkowski Katy Craig

Hach History Over 75 years of innovation, customer support and expertise 1947: Hach founded in Ames, Iowa by Clifford and Kitty Hach For more than 60 years, we've been finding solutions that help you best manage your water and wastewater. Water analysis has to be right. You deserve complete solutions you can be fully confident in. Hach is your resource for expert answers, outstanding support, and reliable, easy-to-use products.

Who we are Brand Promise Manufacturer and distributor of process and laboratory instruments, chemistries, service and software for water analysis Solution provider for diverse markets in the industrial and municipal sectors Innovation leader 527 patents covering 130 patent families Strong investment in R&D and acquired technologies to drive industry firsts Driver of the highest quality, delivery and customer value Leader in customer service, technical support and training Water analysis has to be right. You deserve complete solutions you can be fully confident in. Hach is your resource for expert answers, outstanding support, and reliable, easy to use products. Brand Promise

Sludge thickening (ST) vs. sludge dewatering (sd) Produce consistent thickened sludge Prevent clogging of sludge pump Reduce polymer consumption Improve biogas production in anaerobic digester Primary benefits: Operational Improvements Dewatering Create cost savings in Polymer consumption Sludge disposal Primary benefit: Cost Savings Digester Static thickener Static thickener Filtrate Centrate e.g. Drum thickener Centrifuge Poly Poly

Real time control systems – theory of operation Specific polymer dose Set-point: g polymer / kg TSS RTC will calculate the optimal polymer dose for every combination of sludge consistency and technology: 2 ways to optimize Adjust TSS load Adjust polymer dose SPECIFIC POLYMER DOSE

Sludge thickening with RTC-ST Variant 1: Load based feed Digester Static thickener Q TSS Q TSS thick + Filtrate TSS = constant e.g. Drum thickener Poly Polymer

Sludge thickening with RTC-ST Variant 2: Load based polymer dosing Digester Static thickener Q Poly. TSS thick + constant Filtrate Q TSS e.g. Drum thickener TSS Q Poly. Poly Polymer

Sludge dewatering with rtc-sd Variant 1: Load based feed Digester Static thickener Q TSS Q TSS Centrate + Centrate TSS = constant Centrifuge Dewatered sludge Poly Polymer

Sludge dewatering with rtc-sd Variant 2: Load based polymer dosing Digester Static thickener Q Poly. TSS Centrate + constant Centrate Q TSS Centrifuge TSS Q Poly. Dewatered sludge Poly Polymer

Real time control sludge thickening Case Study – Thames Water

The following data is from an installation of the Hach RTC-ST System designed to control polymer dose into a sludge thickening application The wastewater treatment plant co-thickens primary and secondary sludge with rotary drum thickeners and polymer

Thames water sludge thickening From a gravity thickener the sludge is mixed with polymer and added to the rotary drum thickener The thickened sludge is then sent to anaerobic digestion Digester Static thickener Filtrate e.g. Drum thickener Poly Polymer

Before the RTC-ST: Static polymer dose Thickened Sludge Concentration Influent Sludge Flow Influent Sludge Concentration

Thames water RTC-ST installation Feed sludge flow and concentration are used by the RTC-ST to set an initial polymer dose (lb/ton) Thickened sludge concentration is used by the RTC-ST to adjust the dose to maintain a desired thickened sludge setpoint Digester Static thickener Q Poly. TSS thick + TSS Filtrate Q TSS e.g. Drum thickener TSS Q Poly. Poly Polymer

After the RTC-st: variable polymer dose Targeting 4% Thickened Sludge Thickened Sludge Concentration Influent Sludge Concentration

In conclusion Experimented with different Thickened Sludge concentrations 6.1% Average TWAS concentration over study period About 1% increase compared to original operation 35% Reduction in polymer 5.9% Increase in biogas production (and electricity) From 45,700 m3/d to 48,400 m3/d

Next steps for technology development Sludge Dewatering – RTC-SD Seeking US installation site for evaluation and case study – currently only 5 sites in EU Need data demonstrating cost savings and successful deployment To improve technology, we would like a partner to assist in testing and refining ability to monitor in centrate (currently experiencing application challenges with air in sample) Sludge Thickening – RTC-ST Currently have 1 recently completed installation in US Seeking US evaluation site and case study Seeking range of partners with diverse sludge thickening technology for evaluation sites, including DAF (not common in EU) Ideal Partner Willing to share investment in site evaluation Willing to participate in technical presentations/papers