Denmark has taken a very positive view of recovering energy from organic wastes by anaerobic digestion (AD) and then using the digestate (digested material) on land. Substituting CHP (combined heat and power) from AD for fossil energy is part of the national energy plan. Co-digestion of manure, putrescible waste and biosolids is becoming increasingly common. Part of the reason for digesting manure is so that it can be transferred from areas of intensive animal production to arable farming areas. The WwTW of Fredericia in Denmark had conventional mesophilic anaerobic digestion. It treats wastewater from, dairies, breweries, other food industries, refineries, and a fertilizer factory. The total population is approximately 50,000 and the total combined load is 350,000 population equivalent. Cambi thermal hydrolysis has been retrofitted and was commissioned in 2001. This paper will be an independent review of the effect this has had on digestibility, biosolids quality, energy recovery, pathogen reduction, dewaterability and the market for beneficial use. It will also report the operating experience and operational availability of the facility and a financial appraisal. A smaller WwTW, at which thermal hydrolysis has been operating for longer, was studied to confirm the information from Fredericia.