(WO9617949-A1)      Lactic acid is produced from municipal solid waste (I) by (a) obtaining (I); (b) removing tyres, bulk metals, plastic, glass and rubber to give a cellulosic component (II); (c) shredding (II); (d) treating shredded (II) with dilute sulphuric acid at 40-100 C to solubilise remaining heavy metals and give a soluble component (III) and an insoluble component (IV); (e) removing (IV) from (III); (f) drying (IV); (g) treating dried (IV) with an equal amt. of conc. sulphuric acid to give a partially hydrolysed mixture (V); (h) diluting (V) with water at 80-100 C; (i) agitating at 100 C to obtain a digested material (VI); (j) removing solids from (VI) to give a filtrate (VII); (k) separating (VII) into an acid-containing solution and a sugar-containing solution (VIII); (l) concentrating (VIII) to 1-20% sugar; (m) adjusting the pH to 4.5-7.5; (n) fermenting with lactic acid bacteria to give a solution (IX); and (o) processing (IX) to obtain commercially acceptable lactic acid. In a variant on the process, the cellulosic component of (I) is shredded and treated by steps (g)-(o); solids (VI) contain essentially all the heavy metals in (IV). Alternatively the shredded component is hydrolysed to give insoluble components (which are dried and burned as boiler fuel to obtain energy) and soluble components which are treated by steps (k)-(o).    USE -   Municipal solid waste and sewage sludge, esp. sewage sludge cake are treated efficiently without adverse environmental impact. Existing land fills may be treated.    (ZA9510368-A)      Lactic acid is produced from municipal solid waste (I) by (a) obtaining (I); (b) removing tyres, bulk metals, plastic, glass and rubber to give a cellulosic component (II); (c) shredding (II); (d) treating shredded (II) with dilute sulphuric acid at 40-100 C to solubilise remaining heavy metals and give a soluble component (III) and an insoluble component (IV); (e) removing (IV) from (III); (f) drying (IV); (g) treating dried (IV) with an equal amt. of conc. sulphuric acid to give a partially hydrolysed mixture (V); (h) diluting (V) with water at 80-100 C; (i) agitating at 100 C to obtain a digested material (VI); (j) removing solids from (VI) to give a filtrate (VII); (k) separating (VII) into an acid-containing solution and a sugar-containing solution (VIII); (l) concentrating (VIII) to 1-20% sugar; (m) adjusting the pH to 4.5-7.5; (n) fermenting with lactic acid bacteria to give a solution (IX); and (o) processing (IX) to obtain commercially acceptable lactic acid. In a variant on the process, the cellulosic component of (I) is shredded and treated by steps (g)-(o); solids (VI) contain essentially all the heavy metals in (IV). Alternatively the shredded component is hydrolysed to give insoluble components (which are dried and burned as boiler fuel to obtain energy) and soluble components which are treated by steps (k)-(o).    USE -   Municipal solid waste and sewage sludge, esp. sewage sludge cake are treated efficiently without adverse environmental impact. Existing land fills may be treated.    (JP10510154-W)      Lactic acid is produced from municipal solid waste (I) by (a) obtaining (I); (b) removing tyres, bulk metals, plastic, glass and rubber to give a cellulosic component (II); (c) shredding (II); (d) treating shredded (II) with dilute sulphuric acid at 40-100 C to solubilise remaining heavy metals and give a soluble component (III) and an insoluble component (IV); (e) removing (IV) from (III); (f) drying (IV); (g) treating dried (IV) with an equal amt. of conc. sulphuric acid to give a partially hydrolysed mixture (V); (h) diluting (V) with water at 80-100 C; (i) agitating at 100 C to obtain a digested material (VI); (j) removing solids from (VI) to give a filtrate (VII); (k) separating (VII) into an acid-containing solution and a sugar-containing solution (VIII); (l) concentrating (VIII) to 1-20% sugar; (m) adjusting the pH to 4.5-7.5; (n) fermenting with lactic acid bacteria to give a solution (IX); and (o) processing (IX) to obtain commercially acceptable lactic acid. In a variant on the process, the cellulosic component of (I) is shredded and treated by steps (g)-(o); solids (VI) contain essentially all the heavy metals in (IV). Alternatively the shredded component is hydrolysed to give insoluble components (which are dried and burned as boiler fuel to obtain energy) and soluble components which are treated by steps (k)-(o).    USE -   Municipal solid waste and sewage sludge, esp. sewage sludge cake are treated efficiently without adverse environmental impact. Existing land fills may be treated.    (EP795022-B1)      Lactic acid is produced from municipal solid waste (I) by (a) obtaining (I); (b) removing tyres, bulk metals, plastic, glass and rubber to give a cellulosic component (II); (c) shredding (II); (d) treating shredded (II) with dilute sulphuric acid at 40-100 C to solubilise remaining heavy metals and give a soluble component (III) and an insoluble component (IV); (e) removing (IV) from (III); (f) drying (IV); (g) treating dried (IV) with an equal amt. of conc. sulphuric acid to give a partially hydrolysed mixture (V); (h) diluting (V) with water at 80-100 C; (i) agitating at 100 C to obtain a digested material (VI); (j) removing solids from (VI) to give a filtrate (VII); (k) separating (VII) into an acid-containing solution and a sugar-containing solution (VIII); (l) concentrating (VIII) to 1-20% sugar; (m) adjusting the pH to 4.5-7.5; (n) fermenting with lactic acid bacteria to give a solution (IX); and (o) processing (IX) to obtain commercially acceptable lactic acid. In a variant on the process, the cellulosic component of (I) is shredded and treated by steps (g)-(o); solids (VI) contain essentially all the heavy metals in (IV). Alternatively the shredded component is hydrolysed to give insoluble components (which are dried and burned as boiler fuel to obtain energy) and soluble components which are treated by steps (k)-(o).    USE -   Municipal solid waste and sewage sludge, esp. sewage sludge cake are treated efficiently without adverse environmental impact. Existing land fills may be treated.